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Important Note: The following information
is provided for your education. It should not be relied upon for
personal diagnosis or treatment. If you believe that a
particular therapy applies to you or someone you care about, be
sure to consult a doctor before trying it.
Dyslexia
Research: 2002-2006
Dyslexia. 2006 Aug;12(3):155-76.
Treatment integrity in a home-based pre-reading intervention
programme.
van Otterloo SG, van der Leij A, Veldkamp E.
Department of Education, University of Amsterdam, The Netherlands.
S.G.vanOtterloo@uva.nl
Treatment integrity is an underexposed issue in the phonological awareness
intervention research. The current study assessed the integrity of treatment of
the families (N = 32) participating in the experimental condition of a
home-based pre-reading intervention study. The participating kindergartners were
all genetically at risk for developing dyslexia. Two aspects of treatment
integrity, the number of lessons completed (quantity) and the quality of the
administration of the programme (observed in a videotaped session), were
investigated. The level of treatment integrity turned out to be 66% when
completion of all lessons was taken as quantitative criterion, and about 74%
when quality of the parent-child interaction was assessed. The two measures
could predict the pre-reading skills at the end of kindergarten. Together they
accounted for 43% of the variance in this dependent variable. Together with
pre-reading scores at the pre-test the total predicted variance was 87%. The
number of lessons completed still contributed 12% to the prediction after
controlling for pre-test scores. The results indicated that treatment integrity
indeed appears to be an important aspect of treatment outcome and should
therefore be included in intervention studies.
-----
Arch Pediatr. 2006 Jul;13(7):1071-5. Epub 2006 Jun 9.
[What should be done when a child cannot learn to read?]
[Article in French]
Billard C.
Centre de reference sur les troubles du langage de l'enfant, CHU de Bicetre, 78,
rue du General-Leclerc, 94275 Le Kremlin-Bicetre, France. catherine.billard@bct.ap-hop-paris.fr
When a child faces difficulties in learning to read, clinicians should, first of
all, examine cognitive functions. The actual reading level is checked using a
test calibrated on normal reading development. They are thus able to
differentiate between global learning disorders (related to mental deficiency or
pervasive disorders) and specific reading impairment. Specific reading
impairment might be a simple delay or developmental dyslexia. We described the
first at-school training, as well as the criteria of speech therapy.
-----
Dyslexia. 2006 May;12(2):115-33.
Resistant readers 8 months later: energizing the student's
learning milieu by targeted counselling.
Andreassen AB, Knivsberg AM, Niemi P.
National Centre for Reading Education and Research, University of Stavanger,
Norway. anne-brit.andreassen@uis.no
Several studies have reported that an alarming large subgroup of poor readers
seems to be treatment resistant. This group obviously needs attention beyond
standard special education instructions. In Norway, the National Centre for
Reading Education and Research has been assigned the task of assisting the
school psychological services nationwide in severe cases of reading
disabilities. The aim of the present study of a clinical sample of students with
severe dyslexia, due to phonological deficits, was to evaluate effects of
counselling 8 months after a 2-day assessment at the centre. Sixty-five
students, with a mean age of 12.3 years, participated. A thorough assessment of
each student's strengths and problems was conducted at the centre. Additional
information was obtained from the school psychological services, the teachers,
and the parents. Diagnostic reports and proposals for remediation were forwarded
to the school psychological services. Students', parents', and teachers'
evaluation of the students' reading abilities 8 months after the assessment was
retrieved for 75% of cases. Of these, 80% reported clear progress in the
students' reading abilities. The progress could not be related to age, cognitive
level, place of residence, or previous special education received, but instead
to improved motivation.
-----
Dyslexia. 2006 May;12(2):81-95.
Stability of IQ measures in teenagers and young adults with
developmental dyslexia.
Ingesson SG.
Department of Psychology, Lund University, Box 213, SE-221 00 Lund, Sweden.
gunnel.ingesson@psychology.lu.se
A follow-up study was performed to investigate the stability of IQ measures in a
group of dyslexic teenagers and young adults. Earlier research had shown
contradictory results. The 65 subjects, 12 years old on the average at first
test, were retested after a mean interval of six and a half years. There was a
significant relative decrease in verbal IQ (VIQ), which was interpreted as
either an effect of low reliability of tests used, or an effect of the dyslexic
individuals' less experience with reading and writing, and as a consequence, a
lag in verbal ability, the second interpretation being in line with earlier
findings in groups of children with learning disabilities. Performance IQ
improved significantly and the tentative interpretation was that of a
compensatory process, in the sense that the dyslexic children might develop a
more visual, intuitive and creative way to process information and solve
problems. The conclusion was that caution should be taken, before making
important decisions on the basis of a single intelligence test, and that
dyslexic children might be at risk to lag behind their peers in terms of VIQ,
especially if they are not provided with suitable special education.
-----
NeuroRehabilitation. 2006;21(1):9-21.
Oculomotor rehabilitation for reading in acquired brain injury.
Ciuffreda KJ, Han Y, Kapoor N, Ficarra AP.
SUNY/State College of Optometry, and Department of Clinical Sciences, Raymond J.
Greenwald Rehabilitation Center, New York, NY 10036, USA. kciuffreda@sunyopt.edu
The purpose of this study was to assess reading-related oculomotor
rehabilitation in individuals with acquired brain injury. Adults with either
stroke (n=5) or traumatic brain injury (n=9) participated. Training paradigms
included single-line and multiple-line simulated reading, as well as basic
versional tracking (fixation, saccade, and pursuit), twice per week over an 8
week period. Training modes included normal internal oculomotor visual feedback
either in isolation (4 weeks) or concurrent with external oculomotor auditory
feedback (4 weeks). Training effects were assessed objectively using infrared
eye movement recording technology for simulated and actual reading, with the
assessments occurring before, midway, and after training. In addition, the
individuals were assessed subjectively using a reading rating-scale
questionnaire. All reported considerably improved reading ability, and this was
confirmed by several of the objective oculomotor measures. There was a trend for
improvement to be better with the combined visual and auditory oculomotor
feedback. Reading-related oculomotor rehabilitation produced significant gains
in both the subjective and objective domains. It is believed that rapid saccadic
oculomotor adaptation, as well as the training of rhythmicity and automaticity,
were involved in modifying eye movement behavior to produce a more systematic
approach and resultant improved reading profile.
-----
Mem Cognit. 2006 Apr;34(3):703-14.
Use of morphology in spelling by children with dyslexia and
typically developing children.
Bourassa DC, Treiman R, Kessler B.
Department of Psychology, University of Winnipeg, 515 Portage Ave., Winnipeg, MB
R3B 2E9, Canada. d.bourassa@uwinnipeg.ca
In English and some other languages, spelling problems that arise at a
phonological level can sometimes be solved through consideration of morphology.
For example, children could infer that tuned should contain an n and that
fighting should contain a t because their stems include these letters. Children
could thus avoid misspellings that might otherwise occur, such as "tud" and "fiding."
We used a spelling-level match design to examine the extent to which children
with dyslexia and younger typical children use morphology in this way. Both
groups of children benefited from morphology to some extent, but not as much as
they could have given their knowledge of the stems. Our results suggest that the
spellings produced by older children with dyslexia are similar to those of
younger normal children in their morphological characteristics, as well as in
other ways.
-----
Dev Neuropsychol. 2006;30(1):547-89.
Converging evidence for triple word form theory in children with
dyslexia.
Richards TL, Aylward EH, Field KM, Grimme AC, Raskind W, Richards AL, Nagy W,
Eckert M, Leonard C, Abbott RD, Berninger VW.
Department of Radiology, University of Washington, Seattle, WA 98195, USA. toddr@u.washington.edu
This article has 3 parts. The 1st part provides an overview of the family
genetics, brain imaging, and treatment research in the University of Washington
Multidisciplinary Learning Disabilities Center (UWLDC) over the past decade that
points to a probable genetic basis for the unusual difficulty that individuals
with dyslexia encounter in learning to read and spell. Phenotyping studies have
found evidence that phonological, orthographic, and morphological word forms and
their parts may contribute uniquely to this difficulty. At the same time,
reviews of treatment studies in the UWLDC (which focused on children in Grades 4
to 6) and other research centers provide evidence for the plasticity of the
brain in individuals with dyslexia. The 2nd part reports 4 sets of results that
extend previously published findings based on group analyses to those based on
analyses of individual brains and that support triple word form awareness and
mapping theory: (a) distinct brain signatures for the phonological,
morphological, and orthographic word forms; (b) crossover effects between
phonological and morphological treatments and functional magentic resonance
imaging (fMRI) tasks in response to instruction, suggestive of cross-word form
computational and mapping processes; (c) crossover effects between behavioral
measures of phonology or morphology and changes in fMRI activation following
treatment; and (d) change in the relationship between structural MRI and
functional magnetic resonance spectroscopy (fMRS) lactate activation in right
and left inferior frontal gyri following treatment emphasizing the phonological,
morphological, and orthographic word forms. In the 3rd part we discuss the next
steps in this programmatic research to move beyond word form alone.
-----
J Learn Disabil. 2006 Mar-Apr;39(2):157-69.
Response to intervention as a vehicle for distinguishing between
children with and without reading disabilities: Evidence for the role of
kindergarten and first-grade interventions.
Vellutino FR, Scanlon DM, Small S, Fanuele DP.
Department of Psychology, University of Albany, State University of New York,
Albany, USA.
Children at risk for early reading difficulties were identified on entry into
kindergarten, and half of these children received small-group intervention two
to three times a week during their kindergarten year. The other half received
whatever remedial assistance was offered by their home schools. These children
were again assessed at the beginning of first grade, and those who continued to
have difficulties in reading received either one-to-one daily tutoring offered
by project teachers from the beginning to the end of first grade or whatever
remedial assistance was offered by their home schools over the same time period.
All target children were periodically assessed through the end of third grade.
Results suggest that either kindergarten intervention alone or kindergarten
intervention combined with first-grade intervention are both useful vehicles for
preventing early and long-term reading difficulties in most at-risk children.
-----
Neuropsychol Rehabil. 2006 Apr;16(2):194-212.
Effects of visual hemisphere-specific stimulation versus
reading-focused training in dyslexic children.
Lorusso ML, Facoetti A, Paganoni P, Pezzani M, Molteni M.
Scientific Institute, E. Medea, Unit of Cognitive Psychology and Neuropsychology
of Developmental Disorders, Bosisio Parini, Lecco, Italy. mluisa@bp.lnf.it
Two groups of children with developmental dyslexia were treated over a period of
four months. Fourteen children received visual hemisphere-specific stimulation (VHSS)
and 11 children were treated with a customary, reading-focused training
programme (RT). Reading performance was investigated before and after treatment,
as were spelling abilities, phonemic awareness and verbal memory. Improvement in
reading accuracy was significantly greater in the VHSS group than in the RT
group. Significant improvements were also observed for memory and phonemic
skills. The results were compared to existing data on spontaneous reading
development. The better results after single-hemisphere stimulation (VHSS) are
discussed in terms of the specific characteristics of the treatment, and of the
possible contributions of visual-spatial attention, memory functions and
phonemic awareness.
-----
Pro Fono. 2006 Jan-Apr;18(1):69-78.
[Alphabetization and rehabilitation of reading/writing disorders
through a phonetic-visual-articulatory method]
[Article in Portuguese]
Jardini RS, de Souza PT.
Pesquisadora do Centro de Pesquisas e Tratamento das Deformidades Buco-Faciais
de Araraquara. rsjardini@aol.com
BACKGROUND: Alphabetization and rehabilitation of reading/writing disorders
through a phonetic-visual-articulatory method (Metodo das Boquinhas - Jardini,
1997). This methodology combines neuropsychological inputs, such as
sounds/phonemes, letters/graphemes to the visual representation of mouth
position/articulemes. AIM: To alphabetize and/or rehabilitate children who
presented reading/writing disorders, of varied etiologies, with consistent
short-term results, in a combined intervention with a speech-language
pathologists and a psycho-pedagogue. METHOD: Participants of this study were 30
children, with the diagnoses of dyslexia, ADHA, mild cognitive retardation,
infant psychoses and borderline behavior, some of which presented comorbidities.
Children ranged between 7 and 10 years of age, all presenting at least a
six-month delay in regular schooling. The children along with their parents and
teachers took part in the research. Parents and teachers assessed the children
through a multiple choice questionnaire at the beginning of treatment (T0),
three (T1) and six months after intervention (T2), according to parameters of
reading, reading comprehension, spelling, blackboard copying, attention,
concentration and confidence for learning. The questionnaire qualified children
as incapable, intermediate and capable for learning in each of the assessed
parameter. The adopted therapeutic approach was the application of a
phonetic-visual-articulatory method, with two weekly sessions with a
speech-language pathologist and a psycho-pedagogue. Besides the therapeutic
interventions, children continued to attend regular school. RESULTS: An
expressive development was observed for all of the assessed parameters,
according to parents and teachers. After the first 3 months of intervention, the
performance of the children was classified at an intermediate level of learning
and after 6 months they were considered as being capable for learning in each of
the assessed parameters. These results not only favored a better performance at
school, but also raised the children's self-esteem in terms of learning.
CONCLUSION: After 6 months of intervention with the phonetic-visual-articulatory
methodology children were able to continue with their learning process in a
regular school, following the performance of the other members of class.
-----
Eur Child Adolesc Psychiatry. 2006 Feb;15(1):19-29.
Does successful training of temporal processing of sound and
phoneme stimuli improve reading and spelling?
Strehlow U, Haffner J, Bischof J, Gratzka V, Parzer P, Resch F.
Dept. of Child & Adolescent Psychiatry, Klinik an der Lindenhohe, Bertha-von-Suttner-Str.
1, 77654, Offenburg, Germany. ulrich.strehlow@t-online.de
OBJECTIVE: The aim of this study was to measure and train auditory temporal
processing in children with dyslexia and to examine whether there was a transfer
of improved auditory temporal processing to reading and spelling skills.
METHODS: Computer-based procedures to measure and train temporal processing of
sound and phoneme stimuli were developed. Test-scores for a normal control group
consisting of 8-year-olds were established. Second graders with dyslexia were
included in the training condition and divided into three groups: a control
group, a group specifically trained in sound processing, and a third group
specifically trained in phoneme processing. After an initial diagnostic
procedure, both training groups received specific training every day for 4
weeks. All children, regardless of the group, received the same standard reading
training programme designed for children with dyslexia at school. Outcome
measures were assessed immediately after training as well as 6 and 12 months
later. RESULTS: Tests for temporal processing of sound and phoneme stimuli
proved to be highly reliable. Children with dyslexia (N = 44) showed impaired
auditory processing of sound and phoneme stimuli compared to normal controls (N
= 51). There was a specific significant improvement in sound, respectively
phoneme, processing for the training groups immediately after the end of
training. The improvement of phoneme processing remained stable after 6 months
and as a trend after 12 months. After 6 and 12 months of training, children of
all three groups improved significantly in reading no matter what group. In
spelling, the sound training group had a slight advantage after 6 months, which
was not stable after 12 months. CONCLUSIONS: Auditory temporal processing could
be trained effectively at the sound and phoneme levels. However, no significant
stable transfer of these improved abilities on reading and spelling exceeding
the effect of the school-based standard training was demonstrated.
-----
J Learn Disabil. 2006 Jan-Feb;39(1):56-73.
Effectiveness of Spanish intervention for first-grade English
language learners at risk for reading difficulties.
Vaughn S, Linan-Thompson S, Mathes PG, Cirino PT, Carlson CD, Pollard-Durodola
SD, Cardenas-Hagan E, Francis DJ.
University of Texas at Austin, Center for Reading and Language Arts, College of
Education, Austin, TX 78712-0365, USA.
The effectiveness of an explicit, systematic reading intervention for
first-grade students whose home language was Spanish and who were at risk for
reading difficulties was examined. Participants were 69 students in 20
classrooms in 7 schools from 3 districts who initially did not pass the
screening in Spanish and were randomly assigned within schools to a treatment or
comparison group; after 7 months, 64 students remained in the study. The
intervention matched the language of instruction of their core reading program
(Spanish). Treatment groups of 3 to 5 students met daily for 50 min and were
provided systematic and explicit instruction in oral language and reading by
trained bilingual intervention teachers. Comparison students received the
school's standard intervention for struggling readers. Observations during core
reading instruction provided information about the reading instruction and
language use of the teachers. There were no differences between the treatment
and comparison groups in either Spanish or English on any measures at pretest,
but there were significant posttest differences in favor of the treatment group
for the following outcomes in Spanish: Letter-Sound Identification (d = 0.72),
Phonological Awareness composite (d = 0.73), Woodcock Language Proficiency
Battery-Revised Oral Language composite (d = 0.35), Word Attack (d = 0.85),
Passage Comprehension (d = 0.55), and two measures of reading fluency (d =
0.58-0.75).
-----
Dev Neuropsychol. 2006;29(1):243-60.
Effects of prior attention training on child dyslexics' response
to composition instruction.
Chenault B, Thomson J, Abbott RD, Berninger VW.
Department of Educational Psychology, University of Washington, Seattle, 98195,
USA.
Twenty children (Grades 4 to 6) who met research criteria for dyslexia were
randomly assigned to a treatment (attention training) or contact control
(reading fluency training) group during their regular language arts block at a
school that had emphasized multisensory, structured language treatment for
reading disability. A university team provided either individual attention
training (sustained, selective, alternating, and divided attention) or reading
fluency training during the first 10 sessions and group composition instruction
during the next 10 sessions. Analysis of variance evaluated the significance of
Treatment x Session interactions from pretest to midtest (before composition
instruction began) and midtest to posttest (when compositon instruction ends).
Treatment x Time interactions were not significant between pretest and midtest,
but the Treatment x Time interactions were significant from midtest to posttest
for Wechsler Individual Achievement Test, Second Edition Written Composition and
Delis-Kaplan Executive Function System Verbal Fluency (attention treatment group
improved more over time). Individual children showed the same pattern as group
results. For child dyslexics in upper elementary school, attention training did
not transfer directly to improved composition but prior attention training led
to faster improvement in composing and oral verbal fluency once composition
instruction was introduced. Effective instruction for dyslexia may depend on the
sequencing as well as the nature of instructional components and require
specialized instruction for writing as well as reading.
-----
Dev Neuropsychol. 2006;29(1):243-60.
Effects of prior attention training on child dyslexics' response
to composition instruction.
Chenault B, Thomson J, Abbott RD, Berninger VW.
Department of Educational Psychology, University of Washington, Seattle, 98195,
USA.
Twenty children (Grades 4 to 6) who met research criteria for dyslexia were
randomly assigned to a treatment (attention training) or contact control
(reading fluency training) group during their regular language arts block at a
school that had emphasized multisensory, structured language treatment for
reading disability. A university team provided either individual attention
training (sustained, selective, alternating, and divided attention) or reading
fluency training during the first 10 sessions and group composition instruction
during the next 10 sessions. Analysis of variance evaluated the significance of
Treatment x Session interactions from pretest to midtest (before composition
instruction began) and midtest to posttest (when compositon instruction ends).
Treatment x Time interactions were not significant between pretest and midtest,
but the Treatment x Time interactions were significant from midtest to posttest
for Wechsler Individual Achievement Test, Second Edition Written Composition and
Delis-Kaplan Executive Function System Verbal Fluency (attention treatment group
improved more over time). Individual children showed the same pattern as group
results. For child dyslexics in upper elementary school, attention training did
not transfer directly to improved composition but prior attention training led
to faster improvement in composing and oral verbal fluency once composition
instruction was introduced. Effective instruction for dyslexia may depend on the
sequencing as well as the nature of instructional components and require
specialized instruction for writing as well as reading.
-----
J Clin Exp Neuropsychol. 2005 Oct;27(7):886-96.
Lateral and central presentation of words with limited exposure
duration as remedial training for reading disabled children.
Berends IE, Reitsma P.
PI Research, Vrije Universiteit Amsterdam, The Netherlands.
In two studies it is examined whether lateral presentation of words in remedial
practice for reading disabled children has additional effects to central
presentation. The effect of limited exposure duration (LED) is also studied as a
possible factor in inducing higher level decoding processes or increased
processing speed of words. Two groups of Dutch reading disabled children (n1 =
25, mean age = 9;8 years and n2 = 36, mean age = 7;1 years) repeatedly practiced
reading words presented in the left, right or the central visual field. The
results show that all children improved substantially both in reading speed and
accuracy, which demonstrates the importance of repetitive practice in reading to
attain fluency in reading disabled children. Further analysis demonstrated that
neither site of presentation nor limited exposure duration added significantly
to the training results. These findings do not corroborate neuropsychological
theories suggesting a special role for lateral presentations.
-----
J Learn Disabil. 2005 Sep-Oct;38(5):456-72.
The effects of varying group size on the reading recovery
approach to preventive early intervention.
Iversen S, Tunmer WE, Chapman JW.
Macmillan Education Australia.
The purpose of this study was to determine whether an early intervention program
based on the Reading Recovery (RR) format could be developed for pairs of
struggling readers that would allow them to make accelerated progress similar to
that experienced in the 1-to-1 RR tutorial. A preliminary pilot study showed
that the RR lesson format could be adapted for teaching pairs of struggling
readers without compromising the integrity of the lesson content, provided that
the average length of the lesson was increased to 41 min. An experimental study
comparing the effectiveness of 1-to-1 RR instruction with RR instruction in
pairs showed that although RR instruction in pairs required somewhat longer
lessons (42 min vs. 33 min), there were no major differences between the two
groups on any measures at discontinuation and at the end of the year, nor was
there a significant difference between the groups in mean number of lessons to
discontinuation. The results further indicated that by discontinuation, the
children in the treatment groups were performing within the average range on all
measures, and that these positive effects were maintained on end-of-year
measures. Thus, by increasing instructional time by about a quarter, RR teachers
can double the number of students served without making any sacrifices in
outcomes.
-----
J Learn Disabil. 2005 Sep-Oct;38(5):424-33.
Effects of a peer-mediated phonological skill and reading
comprehension program on reading skill acquisition for middle school students
with reading disabilities.
Calhoon MB.
Educational Psychology and Special Education Department, Georgia State
University, Atlanta 30303, USA. mbcalhoon@gsu.edu
The purpose of this study was to examine the effect of a peer-mediated
instructional approach on the teaching of phonological skills and reading
comprehension for middle school (sixth- to eighth-grade) students with reading
disabilities. All students (n = 38) were identified as having learning
disabilities and reading at the third-grade level or below. One group was taught
using a peer-mediated phonological skill program, Linguistics Skills Training (LST),
and a peer-mediated reading comprehension program, Peer Assisted Learning
Strategies (PALS). The contrast group was taught in the more traditional
whole-class format using a widely implemented remedial reading program. The
results showed significant differences between conditions, with students
receiving the LST/PALS instruction outperforming the contrast group on
Letter-Word Identification, Word Attack, and Passage Comprehension using the
Woodcock-Johnson Test of Achievement-III. Furthermore, large effect sizes for
growth were found on Letter-Word Identification, Word Attack, and Passage
Comprehension for the LST/PALS treatment group. No differences were found
between conditions for reading fluency. Findings are discussed in regard to
instruction delivery format (peer tutoring vs. whole class) with respect to best
practices for middle school students with reading disabilities.
-----
J Learn Disabil. 2005 Sep-Oct;38(5):411-23.
The strategies adopted by Dutch children with dyslexia to
maintain their self-esteem when teased at school.
Singer E.
Department of Developmental Psychology, University of Utrecht, The Netherlands.
e.singer@fss.uu.nl
This article reports on a study of children's narratives about the relationships
between dyslexia and being teased at school and explores the dynamics between
dyslexia, being bullied, self-esteem, and psychosocial problems. We
reconstructed four profiles of inner logic in the children's reactions to being
teased or humiliated as a consequence of their dyslexia. Most children with
dyslexia protect themselves against teasing and feeling worthless by concealing
both their emotions and their academic failures. Others, however, concentrate on
their academic progress, and their self-esteem seems to be strengthened by
fighting against dyslexia.
-----
J Neurol Neurosurg Psychiatry. 2005 Oct;76(10):1392-7
Do children with developmental dyslexia have an implicit learning
deficit?
Vicari S, Finzi A, Menghini D, Marotta L, Baldi S, Petrosini L.
Servizio di Neurologia e Riabilitazione, IRCCS, Children's Hospital Bambino Gesu,
Santa Marinella, Rome, Italy. vicari@opbg.net
OBJECTIVE: The purpose of this study was to investigate the effects of specific
types of tasks on the efficiency of implicit procedural learning in the presence
of developmental dyslexia (DD). METHODS: Sixteen children with DD (mean (SD) age
11.6 (1.4) years) and 16 matched normal reader controls (mean age 11.4 (1.9)
years) were administered two tests (the Serial Reaction Time test and the Mirror
Drawing test) in which implicit knowledge was gradually acquired across multiple
trials. Although both tests analyse implicit learning abilities, they tap
different competencies. The Serial Reaction Time test requires the development
of sequential learning and little (if any) procedural learning, whereas the
Mirror Drawing test involves fast and repetitive processing of visuospatial
stimuli but no acquisition of sequences. RESULTS: The children with DD were
impaired on both implicit learning tasks, suggesting that the learning deficit
observed in dyslexia does not depend on the material to be learned (with or
without motor sequence of response action) but on the implicit nature of the
learning that characterises the tasks. CONCLUSION: Individuals with DD have
impaired implicit procedural learning.
-----
J Fr Ophtalmol. 2005 Sep;28(7):713-23.
[Ocular proprioception and developmental dyslexia. Sixty clinical
observations.]
[Article in French]
Quercia P, Seigneuric A, Chariot S, Vernet P, Pozzo T, Bron A, Creuzot-Garcher
C, Robichon F.
Service d'Ophtalmologie, CHU de Dijon, Dijon.
PURPOSE: The objective of this study is to assess proprioception anomalies in
postural deficiency syndrome in a group of children suffering from reading
impairment. MATERIAL: and methods: Sixty male patients with an average age of 11
years and 9 months were included in the study. Initially, they were given a
standardized neuropsychological examination, which confirmed the diagnosis of
reading impairment. Then after filling out a questionnaire seeking a
proprioceptive anomaly, the patients were subjected to a clinical ocular and
postural examination consisting of nine precisely described steps. RESULTS: All
of the patients recruited for the study presented clinical signs confirming a
proprioception disorder found as a part of postural deficiency syndrome.
CONCLUSION: This study opens a new direction for research concerning the origin
and treatment of at least some reading-impaired children.
-----
Dyslexia. 2005 Aug;11(3):217-31.
Motor coordination difficulties in a municipality group and in a
clinical sample of poor readers.
Iversen S, Berg K, Ellertsen B, Tonnessen FE.
Section of Physiotherapy Science, Department of Public Health and Primary Health
Care, University of Bergen, Norway. syiverse@online.no
The purpose of the study was to investigate incidence, severity and types of
motor problems in two groups of poor readers compared to good reading controls.
A group of children with severe dyslexia referred to specialist evaluation, a
teacher selected municipality sample comprising the 5% poorest readers, and a
control group consisting of the 5% best readers were all assessed applying a
norm-based, standardized measure by Henderson and Sugden 1992; (The Movement
Assessment Battery for Children. Kent: The Psychological Corporation). The three
groups were compared with regard to total motor impairment scores as well as
motor function within the areas of manual dexterity, ball-skills and balance.
More than 50% of the children in both groups of poor readers showed definite
motor coordination difficulties at or below the 5th centile, for which motor
intervention is recommended. Children in both groups showed difficulties within
the sub-area of manual dexterity in particular and also performed significantly
worse than controls within the sub-area of balance, but not in ball-skills. The
high incidence of motor coordination problems in the two groups of poor readers
indicates that all children with reading difficulties should be screened for
possible motor difficulties.
-----
Ann Dyslexia. 2005 Jun;55(1):53-78.
The inadequacy of Individual Educational Program (IEP) goals for
high school students with word-level reading difficulties.
Catone WV, Brady SA.
University of Rhode Island, Kingston, Rhode Island 02883, USA. debbillcat1@yahoo.com
This investigation analyzed goals from the Individual Educational Programs (IEPs)
of 54 high school students with diagnosed reading disabilities in basic skills
(decoding and/or word identification). Results showed that for 73% of the
students, the IEPs written when they were in high school failed to specify any
objectives regarding their acute difficulties with basic skills. IEPs from
earlier points in the students' educations were also reviewed, as available. For
23 of the students, IEPs were present in the students' files for three time
points: elementary school (ES), middle school (MS), and high school (HS).
Another 20 students from the sample of 54 had IEPs available for two time points
(HS and either MS or ES). Comparisons with the IEPs from younger years showed a
pattern of decline from ES to MS to HS in the percentage of IEPs that commented
on or set goals pertaining to weaknesses in decoding. These findings suggest
that basic skills deficits that persist into the upper grade levels are not
being sufficiently targeted for remediation, and help explain why older students
frequently fail to resolve their reading problems.
-----
Exp Brain Res. 2005 Jul 26;:1-11 [Epub ahead of print]
Impaired balancing ability in dyslexic children.
Stoodley CJ, Fawcett AJ, Nicolson RI, Stein JF.
University Laboratory of Physiology, University of Oxford, Oxford, OX1 3PT, UK,
cjs@physiol.ox.ac.uk.
Children with developmental dyslexia struggle to learn to read and spell despite
adequate intelligence and educational opportunity. Several lines of research are
attempting to establish the neurobiological basis of dyslexia, and low-level
sensory and motor deficits have been found in dyslexic populations; furthermore,
behavioural and imaging data point to cerebellar dysfunction in dyslexia. To
investigate this, normal readers (n=19) and children with developmental dyslexia
(n=16) were asked to perform various cognitive, literacy, and balancing tasks.
Children balanced on the left or right foot, with eyes open or closed, for a
period of 10 s during which their movements were recorded with a motion-tracking
system. Dyslexic children were less stable than the control children in both
eyes-open conditions (left foot P=0.02, right foot P=0.012). While there were no
group differences during the eyes-closed conditions, the dyslexic children
dropped a foot to correct balance significantly more often than control children
(P<0.05). Incidence analysis showed that 50% of the dyslexic group fell into the
'impaired' category on the eyes-open balancing tasks; when the mean balancing
scores and the foot drops were considered, only three of our dyslexic children
showed no evidence of balancing difficulties. There were strong correlations
between reading and spelling scores and the mean eyes-open balancing score
(r=0.52 and 0.44, respectively). Thus, while not all children with developmental
dyslexia show impaired balancing skills, low-level motor dysfunction may be
associated with impaired literacy development. This could be due to several
factors, including the involvement of the cerebellum, the magnocellular system,
or more general developmental immaturity.
-----
CNS Drug Rev. 2005 Summer;11(2):169-82.
Piracetam: a review of pharmacological properties and clinical
uses.
Winblad B.
Karolinska Institutet, Neurotec, Huddinge, University Hospital B 84, S-14186
Stockholm, Sweden. bengt.winblad@neurotec.ki.se.
Piracetam, a derivative of the neurotransmitter gamma-aminobutyric acid (GABA),
has a variety of physiological effects that may result, at least in part, from
the restoration of cell membrane fluidity. At a neuronal level, piracetam
modulates neurotransmission in a range of transmitter systems (including
cholinergic and glutamatergic), has neuroprotective and anticonvulsant
properties, and improves neuroplasticity. At a vascular level, it appears to
reduce erythrocyte adhesion to vascular endothelium, hinder vasospasm, and
facilitate microcirculation. This diverse range of physiological effects is
consistent with its use in a range of clinical indications. Its efficacy is
documented in cognitive disorders and dementia, vertigo, cortical myoclonus,
dyslexia, and sickle cell anemia. While high doses are sometimes necessary,
piracetam is well tolerated.
-----
Biol Psychiatry. 2005 Jun 1;57(11):1301-9.
Dyslexia (specific reading disability).
Shaywitz SE, Shaywitz BA.
National Institute of Child Health and Human Development-Yale Center for the
Study of Learning and Attention, New Haven, Connecticut, USA. sally.shaywitz@yale.edu
Converging evidence from a number of lines of investigation indicates that
dyslexia represents a disorder within the language system and more specifically
within a particular subcomponent of that system, phonological processing. Recent
advances in imaging technology, particularly the development of functional
magnetic resonance imaging, provide evidence of a neurobiological signature for
dyslexia, specifically a disruption of two left hemisphere posterior brain
systems, one parieto-temporal, the other occipito-temporal, with compensatory
engagement of anterior systems around the inferior frontal gyrus and a posterior
(right occipito-temporal) system. Furthermore, good evidence indicates a
computational role for the left occipito-temporal system: the development of
fluent (automatic) reading. The brain systems for reading are malleable and
their disruption in dyslexic children may be remediated by provision of an
evidence-based, effective reading intervention. In addition, functional magnetic
resonance imaging studies of young adults with reading difficulties followed
prospectively and longitudinally from age 5 through their mid twenties suggests
that there may be two types of reading difficulties, one primarily on a genetic
basis, the other, and far more common, reflecting environmental influences.
These studies offer the promise for more precise identification and effective
management of dyslexia in children, adolescents and adults.
-----
Pediatrics. 2005 May;115(5):1360-6.
The Oxford-Durham study: a randomized, controlled trial of
dietary supplementation with fatty acids in children with developmental
coordination disorder.
Richardson AJ, Montgomery P.
University Laboratory of Physiology, Parks Road, Oxford OX1 3PT, United Kingdom.
alex.richardson@physiol.ox.ac.uk
BACKGROUND: Developmental coordination disorder (DCD) affects approximately 5%
of school-aged children. In addition to the core deficits in motor function,
this condition is associated commonly with difficulties in learning, behavior,
and psychosocial adjustment that persist into adulthood. Mounting evidence
suggests that a relative lack of certain polyunsaturated fatty acids may
contribute to related neurodevelopmental and psychiatric disorders such as
dyslexia and attention-deficit/hyperactivity disorder. Given the current lack of
effective, evidence-based treatment options for DCD, the use of fatty acid
supplements merits investigation. METHODS: A randomized, controlled trial of
dietary supplementation with omega-3 and omega-6 fatty acids, compared with
placebo, was conducted with 117 children with DCD (5-12 years of age). Treatment
for 3 months in parallel groups was followed by a 1-way crossover from placebo
to active treatment for an additional 3 months. RESULTS: No effect of treatment
on motor skills was apparent, but significant improvements for active treatment
versus placebo were found in reading, spelling, and behavior over 3 months of
treatment in parallel groups. After the crossover, similar changes were seen in
the placebo-active group, whereas children continuing with active treatment
maintained or improved their progress. CONCLUSIONS: Fatty acid supplementation
may offer a safe efficacious treatment option for educational and behavioral
problems among children with DCD. Additional work is needed to investigate
whether our inability to detect any improvement in motor skills reflects the
measures used and to assess the durability of treatment effects on behavior and
academic progress.
-----
J Pediatr Ophthalmol Strabismus. 2005 Mar-Apr;42(2):82-8.
A systematic review of the applicability and efficacy of eye
exercises.
Rawstron JA, Burley CD, Elder MJ.
Ophthalmology Department, Christchurch Hospital, Christchurch, New Zealand.
PURPOSE: To examine the current scientific evidence base regarding the efficacy
of eye exercises as used in optometric vision therapy. METHODS: A search was
performed of the following databases: Allied and Complementary Medicine
Database, Cochrane Database of Systematic Reviews, Cochrane Register of
Controlled Trials, EMBASE, and MEDLINE. Relevant articles were reviewed and
analyzed for strengths and weaknesses. Pertinent sections of classic texts were
studied to provide a historical basis and to serve as a source for additional
early references. RESULTS: Forty-three refereed studies were obtained. Of these,
14 were clinical trials (10 controlled studies), 18 review articles, 2
historical articles, 1 case report, 6 editorials or letters, and 2 position
statements from professional colleges. Many of the references listed by the
larger reviews were unpublished or published in obscure or nonrefereed sources
and therefore were not accessible. CONCLUSIONS: Eye exercises have been
purported to improve a wide range of conditions including vergence problems,
ocular motility disorders, accommodative dysfunction, amblyopia, learning
disabilities, dyslexia, asthenopia, myopia, motion sickness, sports performance,
stereopsis, visual field defects, visual acuity, and general well-being. Small
controlled trials and a large number of cases support the treatment of
convergence insufficiency. Less robust, but believable, evidence indicates
visual training may be useful in developing fine stereoscopic skills and
improving visual field remnants after brain damage. As yet there is no clear
scientific evidence published in the mainstream literature supporting the use of
eye exercises in the remainder of the areas reviewed, and their use therefore
remains controversial.
-----
Rev Neurol (Paris). 2005 Mar;161(3):299-310.
[Specific remedial therapy in a specialist unit: evaluation of 31
children with severe, specific language or reading disorders over one academic
year]
[Article in French]
Coste-Zeitoun D, Pinton F, Barondiot C, Ducot B, Warszawski J, Billard C; et
l'equipe du Service de Reeducation Neuropediatrique du Kremlin-Bicetre.
Service de Reeducation Neuropediatrique, CHU de Neuropediatrie, CHU de Biceetre,
78, rue du General-Leclerc, 94275 Le Kremlin-Bicetre, France.
delphine.coste-zeitoun@laposte.net
INTRODUCTION: Up to 3 percent of the children in France present severe and
specific language and/or reading disorders, despite regular remedial therapies.
Few studies have measured the effectiveness of treatment administered in a
specialist unit. PATIENTS AND METHOD: The aims of this study, focusing on
children diagnosed as dysphasic and/or dyslexic, were: During the academic year
2001-2002, 31 children (18 dyslexic and 13 dysphasic) were attending school in
our unit. The teaching program and intensive speech therapy (3 hours/week) were
tailored for each child according to his/her specific disorders. Reading,
spelling and numeracy developmental skills of each child were evaluated by
appropriate tools at the beginning and at the end of the year. Impairment was
defined by measuring the gap between the observed and the expected skills,
according to each child's age. Using a self-control method, progress achieved by
each child throughout the year was calculated with each tool, in each subject,
by subtracting the impairments disclosed at the beginning from those disclosed
at the end of the year. Progression was classified within three groups according
to the progress normally expected over an academic year (i.e. nine months) from
children with no disabilities attending school regularly; a progression fewer
than three months was considered as no progression. Uni- and multivariate
analyses including age (< or= or />9), type of pathology (dysphasia/dyslexia),
and intellectual quotient (IQ) as covariates was carried out to search for
independent prognosticators. RESULTS: The entire group demonstrated during the
year significant progress for reading (p = 0.0001), spelling (p = 0.0001) and
numeracy (p = 0.0001). Nineteen children (61 percent) showed more progress in
reading than normally expected over nine months. Out of the remaining 12
children, 10 demonstrated more progress in spelling and/or numeracy than
normally expected over nine months. All three reading evaluation tools disclosed
a progression although one was less efficient (p = 0.05). Multivariate analysis
disclosed age< or=9 and dysphasia as independent progress prognosticators.
CONCLUSION: Placement in a specialist unit allows children suffering from severe
dyslexia and dysphasia to lessen the gap in reading, spelling and numeracy. The
two prognosticators disclosed highlight the importance of early diagnosis (i.e.
before nine years old) and treatment of specific language and/or reading
disorders.
-----
Brain Cogn. 2005 Mar;57(2):135-42.
Tachistoscopic treatment of dyslexia changes the distribution of
visual-spatial attention.
Lorusso ML, Facoetti A, Toraldo A, Molteni M.
Unita di Psicologia e Neuropsicologia Cognitiva, IRCCS E. Medea, Bosisio Parini,
Lecco, Italy. mluisa@bp.lnf.it
Twelve children with developmental dyslexia underwent a four-month treatment
with tachistoscopic presentation of words, according to Bakker's methodology.
One group received standard lateral presentation of words on a PC screen, while
the other group received the same stimuli in random lateral position. The
spatial distribution of visual attention was measured by means of the
Form-Resolving Field (FRF; ), which was administered along with reading tests,
before and after treatment. The FRF of children who received random presentation
widened at -12.5 degrees on the left side, while the FRF in the group that
received standard lateral presentation narrowed at that position. Both groups
significantly improved in reading accuracy for both words and nonwords. Some
hypotheses are proposed concerning the mechanisms responsible for the changes in
the FRF and their correlation with improvements in word and nonword reading. The
results of the present study are also compared with data suggesting a left "minineglect"
in dyslexia.
-----
Otolaryngol Head Neck Surg. 2005 Mar;132(3):495-9.
Reading performance in children with otitis media.
Golz A, Netzer A, Westerman ST, Westerman LM, Gilbert DA, Joachims HZ,
Goldenberg D.
Department of Otolaryngology-Head and Neck Surgery, Rambam Medical Center and
Bruce Rappaport Faculty of Medicine-The Technion, Haifa, Israel. golz@netvision.net.il
OBJECTIVE: To examine whether middle ear diseases and the associated hearing
loss in early childhood affect reading performance later at school. STUDY DESIGN
AND SETTING: One hundred and sixty children, 6.5 to 8 years of age, were
enrolled in this study: 80 children with a history of recurrent infections
and/or prolonged periods of effusions of the middle ear before the age of 5
years, and 80 healthy children without any history of middle ear disease. Data
were collected from the medical records of the children. Every child underwent a
complete otological and audiological evaluation, followed by special reading
tests. RESULTS: The study group performed more poorly, in all reading tests, as
compared to the controls ( P < 0.001). CONCLUSION: Children with recurrent or
prolonged middle ear diseases during the first five years of life tend to be at
greater risk for delayed reading than aged-matched controls with no previous
middle ear diseases.
-----
Med Sci (Paris). 2005 Feb;21(2):216-21.
[Omega-3 fatty acids in psychiatry.]
[Article in French]
Bourre JM.
Laboratoire de Neuro-pharmacologie-nutrition, Inserm, Hopital Fernand-Widal,
200, rue du Faubourg Saint-Denis, 75475 Paris Cedex 10, France. jean-marie.bourre@
fwidal.inserm.fr.
The brain is one of the organs with the highest level of lipids (fats). Brain
lipids, formed of fatty acids, participate in the structure of membranes, for
instance 50 % fatty acids are polyunsaturated in the gray matter, 1/3 are of the
omega-3 family, and are thus of dietary origin. The omega-3 fatty acids (mainly
alpha-linolenic acid, ALA) participated in one of the first experimental
demonstration of the effect of dietary substances (nutrients) on the structure
and function of the brain. Experiments were first of all carried out on ex vivo
cultured brain cells, then on in vivo brain cells (neurons, astrocytes and
oligodendrocytes) from animals fed ALA deficient diet, finally on
physicochemical (membrane fluidity), biochemical, physiological, neurosensory
(vision an auditory responses), and behavioural or learning parameters. These
findings indicated that the nature of polyunsaturated fatty acids (in particular
omega-3) present in formula milks for human infants determines to a certain
extend the visual, neurological, and intellectual abilities. Thus, in view of
these results and of the high polyunsaturated fatty acid content of the brain,
it is normal to consider that they could be involved in psychiatric diseases and
in the cognitive decline of ageing. Omega-3 fatty acids appear effective in the
prevention of stress, however their role as regulator of mood is a matter for
discussion. Indeed, they play a role in the prevention of some disorders
including depression (especially post partum), as well as in dementia,
particularly Alzheimer's disease. Their role in major depression and bipolar
disorder (manic-depressive disease), only poorly documented, is not clearly
demonstrated. The intervention of omega-3 in dyslexia, autism, and schizophrenia
has been suggested, but it does not necessarily infer a nutritional problems.
The respective importance of the vascular system (where the omega-3 are actually
active) and the cerebral parenchyma itself, remain to be resolved. However, the
insufficient supply of omega-3 fatty acids in today diet in occidental (less
than 50 % of the recommended dietary intakes values for ALA) raises the problem
of how to correct inadequate dietary habits, by prescribing mainly rapeseed
(canola) and walnut oils on the one hand, fatty fish (wild, or farmed, but the
nature of fatty acids present in fish flesh is the direct consequence of the
nature of fats with which they have been fed), and eggs from laying hens fed
omega-3 fatty acids.
-----
J Child Neurol. 2004 Oct;19(10):759-65.
Using our current understanding of dyslexia to support early
identification and intervention.
Schatschneider C, Torgesen JK.
Department of Psychology and The Florida Center for Reading Research, Florida
State University, Tallahassee, FL 32301, USA. schatschneider@psy.fsu.edu
One of the major risk factors for reading disability is difficulty learning to
read words in text in an accurate and fluent manner. This is apparent when a
child at risk of dyslexia first starts to attempt to read. Dyslexic children
struggle to grasp and automate the alphabetic principle (ie, they cannot "sound
out" words or use phonemic decoding strategies) and therefore have difficulty
deciphering unfamiliar words that they have not encountered before. Even though
many of these words are part of the child's oral vocabulary, the child cannot
recognize them in printed form. As a result, reading can be extremely laborious
and time-consuming, fraught with errors, and altogether an unrewarding, aversive
experience. To be an efficient reader, one must be able to rapidly and
effortlessly recognize many words by sight, and for a child to acquire this
facility requires multiple exposures to these words. The difficulty that
dyslexic children have in developing reliable and efficient phonemic decoding
ability makes the acquisition of a lexicon of sight words a much slower process
than it is for the average reader. Several other factors can affect a child's
ability to read, which are reviewed herein. However, early recognition and
treatment of deficient phonologic awareness are an extremely important step in
the prevention of a reading problem in the child who is at risk of dyslexia.
-----
J Child Neurol. 2004 Oct;19(10):744-58.
Current status of treatments for dyslexia: critical review.
Alexander AW, Slinger-Constant AM.
The Morris Center, Department of Developmental Pediatrics, Gainesville, FL
32607, USA. admin_morrisctr@bellsouth.net
The acquisition of reading is a complex neurobiologic process. Identifying the
most effective instruction and remedial intervention methods for children at
risk of developing reading problems and for those who are already struggling is
equally complex. This article aims to provide the clinician with a review of
more current findings on the prevention and remediation of reading problems in
children, along with an approach to considering the diagnosis and treatment of a
child with dyslexia. The first part of the review describes interventions
targeted at preventing reading difficulties in the at-risk younger child. The
second part of the review discusses the efficacy of approaches to treat the
older, reading-disabled child ("intervention studies"). Factors that impact the
response to treatment are also discussed, as are neuroimaging studies that offer
insight into how the brain responds to treatment interventions. With appropriate
instruction, at-risk readers can become both accurate and fluent readers. In
contrast, although intensive, evidence-based remedial interventions can markedly
improve reading accuracy in older, reading-disabled children, they have been
significantly less effective in closing the fluency gap. Owing to the dynamic
course of language development and the changes in language demands over time,
even after a child has demonstrated a substantial response to treatment
interventions, his or her subsequent progress should be carefully tracked to
ensure optimal progress toward the development of functional reading and written
language skills.
-----
Behav Brain Res. 2005 Jan 6;156(1):95-103.
Auditory training improves neural timing in the human brainstem.
Russo NM, Nicol TG, Zecker SG, Hayes EA, Kraus N.
Auditory Neuroscience Laboratory, Northwestern University, 2240 Campus Drive,
Evanston, IL 60208, USA. n-russo@northwestern.edu
The auditory brainstem response reflects neural encoding of the acoustic
characteristic of a speech syllable with remarkable precision. Some children
with learning impairments demonstrate abnormalities in this preconscious measure
of neural encoding especially in background noise. This study investigated
whether auditory training targeted to remediate perceptually-based learning
problems would alter the neural brainstem encoding of the acoustic sound
structure of speech in such children. Nine subjects, clinically diagnosed with a
language-based learning problem (e.g., dyslexia), worked with auditory
perceptual training software. Prior to beginning and within three months after
completing the training program, brainstem responses to the syllable /da/ were
recorded in quiet and background noise. Subjects underwent additional auditory
neurophysiological, perceptual, and cognitive testing. Ten control subjects, who
did not participate in any remediation program, underwent the same battery of
tests at time intervals equivalent to the trained subjects. Transient and
sustained (frequency-following response) components of the brainstem response
were evaluated. The primary pathway afferent volley -- neural events occurring
earlier than 11 ms after stimulus onset -- did not demonstrate plasticity.
However, quiet-to-noise inter-response correlations of the sustained response (
approximately 11-50 ms) increased significantly in the trained children,
reflecting improved stimulus encoding precision, whereas control subjects did
not exhibit this change. Thus, auditory training can alter the preconscious
neural encoding of complex sounds by improving neural synchrony in the auditory
brainstem. Additionally, several measures of brainstem response timing were
related to changes in cortical physiology, as well as perceptual, academic, and
cognitive measures from pre- to post-training.
-----
Nutr Rev. 2004 Aug;62(8):295-306.
Nutrients for cognitive development in school-aged children.
Bryan J, Osendarp S, Hughes D, Calvaresi E, Baghurst K, van Klinken JW.
CSIRO, Health Sciences and Nutrition, GPO Box 10041, Adelaide BC, South
Australia, 5000.
This review considers the research to date on the role of nutrition in cognitive
development in children, with a particular emphasis on the relatively neglected
post-infancy period. Undernutrition and deficiencies of iodine, iron, and folate
are all important for the development of the brain and the emergent cognitive
functions, and there is some evidence to suggest that zinc, vitamin B12, and
omega-3 polyunsaturated fatty acids may also be important. Considerations for
future research include a focus on the interactions between micronutrients and
macronutrients that might be influential in the optimization of cognitive
development; investigation of the impact of nutritional factors in children
after infancy, with particular emphasis on effects on the developing executive
functions; and selection of populations that might benefit from nutritional
interventions, for example, children with nutrient deficiencies or those
suffering from attention deficit-hyperactivity disorder and dyslexia.
-----
Brain Cogn. 2004 Jul;55(2):341-8.
Hemispheric, attentional, and processing speed factors in the
treatment of developmental dyslexia.
Lorusso ML, Facoetti A, Molteni M.
Unita di Psicologia e Neuropsicologia Cognitiva, Istituto Scientifico "E. Medea"
di Bosisio P., Lecco, Italy. mluisa@bp.lnf.it
Aim of the study is to analyze the contributions of hemispheric, attentional,
and processing speed factors to the effects of neuropsychological treatment of
developmental dyslexia. Four groups of dyslexic children (M-type dyslexia) were
treated over a period of four months. A first group (n = 9) underwent Bakker's
Hemisphere-Specific Stimulation, with presentation of words in the right and
left visual field. A second group (n = 7) received the same stimuli randomly in
either visual hemifield. A third group (n = 8) received the same words presented
centrally at fixation point. A fourth group (n = 6) received central stimuli
with fixed presentation time (1500 ms). The children were tested before and
after treatment on reading and spelling measures. All groups improved
significantly after treatment on all variables. However, the group that was
treated with centrally presented stimuli improved more than the other groups in
spelling measures. A possible explanation is that rapid, simultaneous
presentation to both hemispheres enhances interhemispheric exchange, which could
produce an advantage in tasks requiring a high degree of integration between
left and right hemispheric functions, such as spelling. The absence of
significant differences in reading improvement may point to the role of memory
functions or strategic factors characterizing all the treatment programs,
possibly overweighing the effect of the other factors.
-----
Dyslexia. 2004 May;10(2):131-40.
The effects of an audio-visual training program in dyslexic
children.
Magnan A, Ecalle J, Veuillet E, Collet L.
Laboratoire d'Etude des Mecanismes Cognitifs, UMR-CNRS 5596 Universite Lumiere
Lyon 2, France. Annie.Magnan@univ-lyon2.fr
A research project was conducted in order to investigate the usefulness of
intensive audio-visual training administered to children with dyslexia involving
daily voicing exercises. In this study, the children received such voicing
training (experimental group) for 30 min a day, 4 days a week, over 5 weeks.
They were assessed on a reading task before and after the training. A
significant benefit to the experimental group was found after training. These
preliminary results underline the role of the phonological components of
dyslexia.
-----
Dyslexia. 2004 May;10(2):119-30.
The effect of practice on low-level auditory discrimination,
phonological skills, and spelling in dyslexia.
Schaffler T, Sonntag J, Hartnegg K, Fischer B.
Brain Research Group, Hansastr. 9, D-79104 Freiburg, Germany.
Phonological awareness is believed to play a major role in the auditory
contribution to spelling skills. The previous paper reports low-level auditory
deficits in five different subdomains in 33-70% of the dyslexics. The first
study of this paper reports the results of an attempt to improve low-level
auditory skills by systematic daily practice of those tasks that had not been
passed in previous diagnostic sessions. The data of 140 dyslexics indicate that
the average number of unsolved tasks can be reduced from 3 of 5 to 1 of 5. The
success rates have values of 70-80% for intensity and frequency discrimination
and for gap detection, but reach only 36% for time-order judgement and 6% for
side-order judgement. The second study reports that successful low-level
auditory training transfers completely to language-related phonological skills
and also to spelling with the largest profit in spelling errors due to poor
auditory analysis. Control groups (waiting and placebo) did not exhibit
significant improvements. It is concluded that low-level auditory deficits
should be considered and improved by practice in order to give the dyslexics
more phonological help when trying to transfer what they hear to spelling.
-----
Dyslexia. 2004 May;10(2):105-18.
On the development of low-level auditory discrimination and
deficits in dyslexia.
Fischer B, Hartnegg K.
Brain Research Group, University Freiburg, Germany. bfischer@uni-freiburg.de
Absolute auditory thresholds, frequency resolution and temporal resolution
develop with age. It is still discussed whether low-level auditory performance
is of clinical significance--specifically, for delayed maturation of central
auditory processing. Recently, five new auditory tasks were used to study the
development of low-level auditory discrimination. It was found that the
development lasts up to the age of 16-18 years (on an average). Very similar
tasks were now used with 432 controls and 250 dyslexic subjects in the age range
of 7-22 years. For both groups the performance in one of the tasks was not
related to the performance in another task indicating that the five tasks
challenge independent subfunctions of auditory processing. Surprisingly high
numbers of subjects were classified as low performers (LP), because they could
not perform one or the other task at its easiest level and no threshold value
could be assigned. For the dyslexics the incidence of LP was considerably
increased in all tasks and age groups as compared with the age matched controls.
The development of dynamic visual and optomotor functions and the corresponding
deficits in dyslexia are discussed in relation to the auditory data presented
here.
-----
Lancet. 2004 May 1;363(9419):1451-60.
Developmental dyslexia.
Demonet JF, Taylor MJ, Chaix Y.
INSERM U455, Hopital Purpan, IFR 96, Toulouse, France. demonet@toulouse.inserm.fr
Developmental dyslexia, or specific reading disability, is a disorder in which
children with normal intelligence and sensory abilities show learning deficits
for reading. Substantial evidence has established its biological origin and the
preponderance of phonological disorders even though important phenotypic
variability and comorbidity have been recorded. Diverse theories have been
proposed to account for the cognitive and neurological aspects of dyslexia.
Findings of genetic studies show that different loci affect specific reading
disability although a direct relation has not been established between symptoms
and a given genomic locus. In both children and adults with dyslexia, results of
neuroimaging studies suggest defective activity and abnormal connectivity
between regions crucial for language functions--eg, the left fusiform gyrus for
reading--and changes in brain activity associated with performance improvement
after various remedial interventions.
-----
Percept Mot Skills. 2004 Apr;98(2):587-93.
A cognitive-behavioral intervention program for students with
special reading disabilities.
Zafiropoulou M, Mati-Zissi H.
Laboratory of Developmental Psychology and Psychopathology, Department of
Preschool Education, University of Thessaly, Volos, Greece. mzafirop@uth.gr
Interaction among cognitive, meta-cognitive, and emotional factors seems to play
a determining part in achievement behavior and especially in scholastic
performance. In this study some preliminary results are presented of the
implementation of a multidimensional cognitive-behavioral psychoeducational
program especially designed for students with reading disabilities in which
parents and teachers also take part. The aim of the program was to provide
students with appropriate emotional and cognitive skills with which to address
their learning problems. First results on the efficacy of the implemented
program to 20 primary school boys and girls with special reading disabilities
encourage research on management of learning problems with focus on cognitive
and emotional aspects in which parents and teachers contribute. Research
including a control group is necessary.
-----
Prostaglandins Leukot Essent Fatty Acids. 2004 Apr;70(4):383-90.
Clinical trials of fatty acid treatment in ADHD,
dyslexia, dyspraxia and the autistic spectrum.
Richardson AJ.
University Laboratory of Physiology, Parks Road, Oxford OX1 3PT,
UK. alex.richardson@physiol.ox.ac.uk
Considerable clinical and experimental evidence now supports
the idea that deficiencies or imbalances in certain highly unsaturated
fatty acids may contribute to a range of common developmental
disorders including ADHD, dyslexia, dyspraxia and autistic spectrum
disorders (ASD). Definitive evidence of a causal contribution,
however, can only come from intervention studies in the form of
randomised, double-blind, placebo-controlled trials. Published
studies of this kind are still fairly few in number, and mainly
involve the diagnostic categories of ADHD and dyslexia, although
other trials involving individuals with dyspraxia or ASD are in
progress. The main findings to date from such studies are reviewed
and evaluated here with the primary aim of guiding future research,
although given that fatty acid supplementation for these conditions
is already being adopted in many quarters, it is hoped that some
of the information provided may also help to inform clinical practice.
-----
Rev Neurol. 2004 Feb 24;38 Suppl 1:47-52.
[Educational implications of the cognitive impairment
in developmental dyslexia]
[Article in Spanish]
Soriano Ferrer M.
Universidad de Almeria. Facultad de Humanidades y Ciencias de
la Educacion, La Canada de San Urbano, Espana.
Aims. In this study we review the main theories put forward
to account for developmental dyslexia, as well as the intervention
procedures deriving from these theories that enjoy the most empirical
support. Development. Developmental dyslexia is a complex disorder
that reflects cognitive impairment related to neurobiological
anomalies, although researchers still do not agree on fundamental
aspects regarding its aetiology. There are at present a number
of different theories that can be grouped in two antagonistic
lines of work. On the one hand, one of them considers that the
exclusive and direct cause of dyslexia is a specific cognitive
disorder. On the other hand, however, there are several theories
that consider the impairments experienced by dyslexic patients
to be part of a wide range of tasks and processes that are secondary
to an underlying primary deficit. As a consequence of the progress
made in the characterisation of dyslexia, an unprecedented effort
has been made in recent decades in the development of intervention
programmes and in the analysis of their effectiveness. Conclusions.
Research into the explanation for dyslexia finds itself faced
with the challenge of determining whether the different cognitive
problems identified in dyslexic patients represent different cognitive
routes towards the same dyslexic phenotype, whether they correspond
to different types of dyslexia or whether they refer to the sum
of the problems resulting from different comorbid conditions.
Until this issue is resolved, as educators, we must carry out
more comprehensive evaluations in order to determine the profile
of the difficulties that are experienced in each particular case
and to be able to tailor the interventions employed in this enigmatic
problem.
-----
Dyslexia. 2004 Feb;10(1):61-76.
Investigating learning deficits associated with
dyslexia.
Pothos EM, Kirk J.
Department of Psychology, University of Edinburgh, UK. e.pothos@ed.ac.uk
An artificial grammar learning task was used to define two
learning tasks of identical complexity at the symbolic level,
but which differed in terms of stimulus format. The stimuli in
one learning task were created so as to encourage participants
to perceive each stimulus as a whole, with less emphasis on the
stimulus constituent elements (the 'embedded' stimuli), while
in the second task the constituent elements of each stimulus were
emphasized by presenting them serially (the 'sequences' stimuli).
Using a between participants design, dyslexic participants performed
equally well in the two versions of the learning task. By contrast,
non-dyslexic participants performed as well as dyslexic ones with
the embedded stimuli but were impaired in the sequences stimuli.
This finding was interpreted as showing that dyslexic participants
were less able, compared to controls, to process individual stimulus
elements of both the sequences and the embedded stimuli, consistently
with recent work associating dyslexia with problems in attention
focusing and shifting.
-----
J Child Psychol Psychiatry. 2004 Jan;45(1):2-40.
Specific reading disability (dyslexia): what have
we learned in the past four decades?
Vellutino FR, Fletcher JM, Snowling MJ, Scanlon DM.
The State University of New York at Albany, Child Research and
Study Center, Department of Educational Psychology and Statistics,
New York 12222, USA. frv@csc.albany.edu
We summarize some of the most important findings from research
evaluating the hypothesized causes of specific reading disability
('dyslexia') over the past four decades. After outlining components
of reading ability, we discuss manifest causes of reading difficulties,
in terms of deficiencies in component reading skills that might
lead to such difficulties. The evidence suggests that inadequate
facility in word identification due, in most cases, to more basic
deficits in alphabetic coding is the basic cause of difficulties
in learning to read. We next discuss hypothesized deficiencies
in reading-related cognitive abilities as underlying causes of
deficiencies in component reading skills. The evidence in these
areas suggests that, in most cases, phonological skills deficiencies
associated with phonological coding deficits are the probable
causes of the disorder rather than visual, semantic, or syntactic
deficits, although reading difficulties in some children may be
associated with general language deficits. Hypothesized deficits
in general learning abilities (e.g., attention, association learning,
cross-modal transfer etc.) and low-level sensory deficits have
weak validity as causal factors in specific reading disability.
These inferences are, by and large, supported by research evaluating
the biological foundations of dyslexia. Finally, evidence is presented
in support of the idea that many poor readers are impaired because
of inadequate instruction or other experiential factors. This
does not mean that biological factors are not relevant, because
the brain and environment interact to produce the neural networks
that support reading acquisition. We conclude with a discussion
of the clinical implications of the research findings, focusing
on the need for enhanced instruction.
-----
Ann N Y Acad Sci. 2003 Nov;999:497-505.
Dyslexia and music. From timing deficits to musical
intervention.
Overy K.
Department of Neurology, Beth Israel Deaconess Medical Center
and Harvard Medical School, Boston, Massachusetts 02215, USA.
kovery@bidmc.harvard.edu
The underlying causes of the language and literacy difficulties
experienced by dyslexic children are not yet fully understood,
but current theories suggest that timing deficits may be a key
factor. Dyslexic children have been found to exhibit timing difficulties
in the domains of language, music, perception and cognition, as
well as motor control. The author has previously suggested that
group music lessons, based on singing and rhythm games, might
provide a valuable multisensory support tool for dyslexic children
by encouraging the development of important auditory and motor
timing skills and subsequently language skills. In order to examine
this hypothesis, a research program was designed that involved
the development of group music lessons and musical tests for dyslexic
children in addition to three experimental studies. It was found
that classroom music lessons had a positive effect on both phonologic
and spelling skills, but not reading skills. Results also indicated
that dyslexic children showed difficulties with musical timing
skills while showing no difficulties with pitch skills. These
apparent disassociations between spelling and reading ability
and musical timing and pitch ability are discussed. The results
of the research program are placed in the context of a more general
model of the potential relationship between musical training and
improved language and literacy skills.
-----
Dev Neuropsychol. 2003;24(2-3):613-39.
Interventions aimed at improving reading success:
an evidence-based approach.
Foorman BR, Breier JI, Fletcher JM.
Department of Pediatrics and Center for Academic Reading Skills,
The University of Texas-Houston Health Science Center, 77030,
USA. Barbara.R.Foorman@uth.tmc.edu
There is a consensus among researchers about the critical elements
for effective reading instruction. These elements are the integration
of explicit instruction in the alphabetic principle, reading for
meaning, and opportunity to learn. These critical elements are
present in classroom instruction that prevents reading difficulties
as well as effective small-group and one-on-one interventions.
Research on effective classroom instruction and reading interventions
is described, and the case is argued that the most effective intervention
is provided early--in kindergarten through 2nd grade--rather than
after 3rd grade, and allows for sufficient intensity, duration,
and supportiveness that no child is left behind. Policy implications
for changes in (a) the way learning disabilities are identified
and (b) the content of professional development of teachers are
discussed.
-----
Dyslexia. 2003 Feb;9(1):48-71; discussion 46-7.
Evaluation of an exercise-based treatment for
children with reading difficulties.
Reynolds D, Nicolson RI, Hambly H.
School of Education, University of Exeter, Heavitree Road, Exeter
EX1 2LU, UK.
An evaluation is reported of an exercise-based approach to
remediation of dyslexia-related disorders. Pupils in three years
of a Warwickshire junior school were screened for risk of literacy
difficulty using the Dyslexia Screening Test (DST). The 35 children
scoring 0.4 or over on the DST were divided randomly into two
groups matched for age and DST score. One quarter of the participants
had an existing diagnosis of dyslexia, dyspraxia or ADHD. Both
groups received the same treatment at school but the intervention
group used the DDAT exercise programme daily at home. Performance
on the DST and specialist cerebellar/vestibular and eye movement
tests were assessed initially and after six months. Cerebellar/vestibular
signs were substantially alleviated following the exercise treatment
whereas there were no significant changes for the control group.
Even after allowing for the passage of time, there were significant
improvements for the intervention group in postural stability,
dexterity, phonological skill, and (one-tailed) for naming fluency
and semantic fluency. Reading fluency showed a highly significant
improvement for the intervention group, and nonsense passage reading
was also improved significantly. Significantly greater improvements
for the intervention group than the control group occurred for
dexterity, reading, verbal fluency and semantic fluency. Substantial
and significant improvements (compared with those in the previous
year) also occurred for the exercise group on national standardized
tests of reading, writing and comprehension. It is concluded that,
in addition to its direct effects on balance, dexterity and eye
movement control, the benefits of the DDAT exercise treatment
transferred significantly to cognitive skills underlying literacy,
to the reading process, and to standardized national literacy
attainment tests.
-----
Dyslexia. 2003 Aug;9(3):140-5; discussion 167-76.
Reading intervention: a 'conventional' and successful
approach to helping dyslexic children
acquire literacy.
Hatcher PJ.
Department of Psychology, University of York, UK. ph20@york.ac.uk
The effectiveness of the 'conventional' approach to helping
children with dyslexia to acquire literacy has been questioned
by Reynolds et al. (Dyslexia 2003). Data are presented in this
reply to support the effectiveness of Reading Intervention, a
conventional approach to teaching reading delayed children.
-----
Ment Retard Dev Disabil Res Rev. 2003;9(3):196-204.
The development of reading impairment: a cognitive
neuroscience model.
McCandliss BD, Noble KG.
Sackler Institute for Developmental Psychobiology, Weill Medical
College of Cornell University, New York, New York 10021, USA.
Bdm2001@med.cornell.edu
This review discusses recent cognitive neuroscience investigations
into the biological bases of developmental dyslexia, a common
disorder impacting approximately 5 to 17 percent of the population.
Our aim is to summarize central findings from several lines of
evidence that converge on pivotal aspects of the brain bases of
developmental dyslexia. We highlight ways in which the approaches
and methodologies of developmental cognitive neuroscience that
are addressed in this special issue-including neuroimaging, human
genetics, refinement of cognitive and biological phenotypes, neural
plasticity and computational model-can be employed in uncovering
the biological bases of this disorder. Taking a developmental
perspective on the biological bases of dyslexia, we propose a
simple cascading model for the developmental progression of this
disorder, in which individual differences in brain areas associated
with phonological processing might influence the specialization
of visual areas involved in the rapid processing of written words.
We also discuss recent efforts to understand the impact of successful
reading interventions in terms of changes within cortical circuits
associated with reading ability. Copyright 2003 Wiley-Liss, Inc.
-----
Neurology. 2003 Jul 22;61(2):212-9.
Instructional treatment associated with changes
in brain activation in children with dyslexia.
Aylward EH, Richards TL, Berninger VW, Nagy WE, Field KM,
Grimme AC, Richards AL, Thomson JB, Cramer SC.
Departments of Radiology (Drs. Aylward and T.L. Richards, and
K.M. Field, A.C. Grimme, and A.L. Richards) and Bioengineering
(Dr. T.L. Richards), College of Education (Drs. Berninger and
Thomson), University of Washington, Seattle.
OBJECTIVE: To assess the effects of reading instruction on
fMRI brain activation in children with dyslexia. BACKGROUND: fMRI
differences between dyslexic and control subjects have most often
involved phonologic processing tasks. However, a growing body
of research documents the role of morphologic awareness in reading
and reading disability. METHODS: The authors developed tasks to
probe brain activation during phoneme mapping (assigning sounds
to letters) and morpheme mapping (understanding the relationship
of suffixed words to their roots). Ten children with dyslexia
and 11 normal readers performed these tasks during fMRI scanning.
Children with dyslexia then completed 28 hours of comprehensive
reading instruction. Scans were repeated on both dyslexic and
control subjects using the same tasks. RESULTS: Before treatment,
children with dyslexia showed less activation than controls in
left middle and inferior frontal gyri, right superior frontal
gyrus, left middle and inferior temporal gyri, and bilateral superior
parietal regions for phoneme mapping. Activation was significantly
reduced for children with dyslexia on the initial morpheme mapping
scan in left middle frontal gyrus, right superior parietal, and
fusiform/occipital region. Treatment was associated with improved
reading scores and increased brain activation during both tasks,
such that quantity and pattern of activation for children with
dyslexia after treatment closely resembled that of controls. The
elimination of group differences at follow-up was due to both
increased activation for the children with dyslexia and decreased
activation for controls, presumably reflecting practice effects.
CONCLUSION: These results suggest that behavioral gains from comprehensive
reading instruction are associated with changes in brain function
during performance of language tasks. Furthermore, these brain
changes are specific to different language processes and closely
resemble patterns of neural processing characteristic of normal
readers.
-----
Rev Neurol. 2003 Jun 1-15;36(11):1077-82.
[The neurobiology of developmental dyslexia: a
survey]
[Article in Spanish]
Lozano A, Ramirez M, Ostrosky-Solis F.
Universidad Nacional Autonoma de Mexico. Facultad de Psicologia
y Neuropsicologia, Mexico.
One of the most common disorders affecting the ability to read
is developmental dyslexia, which, unlike the alexia related to
a loss of the capacity to read associated with brain damage, refers
to a specific disorder in the acquisition of reading skills and
becomes apparent in reiterated persistent difficulties in learning
to read. A number of studies have attempted to detect structural
and functional abnormalities that might be the origin of problems
in learning to read. The use of functional neuroimaging techniques
such as positron emission tomography (PET), spectroscopic magnetic
resonance imaging (SMRI) and functional magnetic resonance imaging
(fMRI) enables us to measure changes in the metabolic activity
associated with alterations in the neuronal networks involved
in the reading process. In this review, different studies are
analysed in an attempt to identify alterations in the cortico
subcortical regions which could be the origin of the developmental
dyslexia. Results show that in dyslexics there is a temporoparietooccipital
disconnection, and a disconnection with the left frontal cortex
as regards the demands for fast auditory processing, as well as
abnormalities in the connections between the temporoparietal cortex
and the cerebellum with other regions of the brain. Such findings
suggest that the altered areas of the brain do not only show a
characteristic pattern of hypoactivation, but also that these
alterations could be the cause of this malady. We highlight the
importance of these findings in the diagnosis and rehabilitation
of this population.
-----
Neurol Clin. 2003 May;21(2):549-68.
Alexia and related reading disorders.
Bub D.
Department of Psychology, Faculty of Social Sciences, University
of Victoria, Victoria, BC V8W 3P5, Canada. dbub@uvic.ca
Peripheral dyslexias are the result of impairment to processes
that convert letters on the page into an abstract orthographic
representation. Many aspects of these disorders are difficult
to understand in depth. Invariably, there is evidence that some
type of word-level perception occurs rapidly in many patients
with LBL reading or neglect dyslexia, yet apparently contradictory
evidence indicates that part of the word has been misperceived
or that the letters must be analyzed laboriously for conscious
identification to occur. Current theories attempt to synthesize
these different aspects of the patients' performance, but their
development is at an early stage. Questions remain also about
the domain specificity of the perceptual impairment in LBL reading
and about the nature of spatial attention and spatial frames in
neglect dyslexia and other forms of attentional disorder. Current
understanding of central dyslexias has perhaps advanced further.
Well-developed computational models exist of these dyslexias,
as do plausible experimental techniques for revealing the activity
of semantic and non-semantic routes in normal readers. Nevertheless,
the difficult issue of domain specificity arises again with respect
to some of the mechanisms invoked, and in this regard, central
and peripheral dyslexias continue to pose the same challenge.
-----
Dyslexia. 2003 May;9(2):127-33; discussion 134-5.
A critique of claims from Reynolds, Nicolson &
Hambly (2003) that DDAT is an effective treatment for children
with reading difficulties--'lies, damned lies and (inappropriate)
statistics'?
Snowling MJ, Hulme C.
Department of Psychology, University of York, York, Hestington,
United Kingdom. m.snowling@psych.york.ac.uk
Reynolds, Nicolson and Hambly (Dyslexia 2003; 9: 48) report
a study to evaluate the effectiveness of dyslexia dyspraxia attention
deficit treatment (DDAT)-an exercise-based treatment for children
with reading difficulties. They claim that DDAT is an effective
treatment with positive effects on the cognitive skills underlying
literacy and the reading process. We outline the numerous methodological
and statistical problems with this study and conclude that it
provides no evidence that DDAT is an effective form of treatment
for children with reading difficulties.
-----
Psychol Rep. 2003 Apr;92(2):427-44.
A randomized trial of individual tutoring for
elementary school children with reading and
behavior difficulties.
Strayhorn JM Jr, Bickel DD.
Drexel University College of Medicine, USA. joestrayhorn@juno.com
Children in Grades K-5, selected for reading and behavior problems,
received individual tutoring in a program which aimed to detail
a hierarchy of reading skills, locate the point on the hierarchy
at which each child should work, and provide enthusiastic social
reinforcement for successes. Children were randomly assigned to
higher or lower frequency tutoring (one 45-min. session every
1.6 days vs every 8.3 days). The higher frequency group progressed
significantly faster in reading than the lower frequency group.
Both groups progressed much faster during the time of the intervention
than they had before tutoring. Before tutoring, both groups had
progressed at about 0.5 grade per year; during tutoring, the higher
frequency group progressed at 1.5 grade per year and the lower
frequency group at 1.1 grade per year. The subsets of children
with verbal ability scores one or two standard deviations below
the population mean, as assessed on the Peabody Picture Vocabulary
Test, still progressed at average rates of 1.2 grade per year
during tutoring. The amount of work students accomplished on a
sounding and blending drill predicted reading progress. The intervention
cost an average of 1,156 dollars per student per year.
-----
Pediatr Clin North Am. 2003 Feb;50(1):213-24.
Reading disorders in children.
Olitsky SE, Nelson LB.
Department of Ophthalmology, Children's Mercy Hospital, 2401 Gillham
Road, Kansas City, Missouri 64108, USA. seolitsky@cmh.edu
Reading difficulties are a complex set of disorders. Current
research indicates that these disorders are not caused by vision
abnormalities. Treatment of these disorders requires a multidisciplinary
approach involving educators, psychologists, and physicians. Parents,
physicians, and school officials should understand that there
are no quick cures for these children.
-----
Dyslexia. 2003 Feb;9(1):37-45.
Age-related improvements in auditory temporal
resolution in reading-impaired children.
Hautus MJ, Setchell GJ, Waldie KE, Kirk IJ.
Department of Psychology and Research Centre for Cognitive Neuroscience,
University of Auckland, Private Bag 92019, Auckland, New Zealand.
k.waldie@auckland.ac.nz
Individuals with developmental dyslexia show impairments in
processing that require precise timing of sensory events. Here,
we show that in a test of auditory temporal acuity (a gap-detection
task) children ages 6-9 years with dyslexia exhibited a significant
deficit relative to age-matched controls. In contrast, this deficit
was not observed in groups of older reading-impaired individuals
(ages 10-11 years; 12-13 years) or in adults (ages 23-25 years).
It appears, therefore, that early temporal resolution deficits
in those with reading impairments may significantly ameliorate
over time. However, the occurrence of an early deficit in temporal
acuity may be antecedent to other language-related perceptual
problems (particularly those related to phonological processing)
that persist after the primary deficit has resolved. This result
suggests that if remedial interventions targeted at temporal resolution
deficits are to be effective, the early detection of the deficit
and early application of the remedial programme is especially
critical.
-----
Rev Neurol. 2003 Feb;36 Suppl 1:S13-9.
[Intervention in dyslexic disorders: phonological
awareness training]
[Article in Spanish]
Etchepareborda MC.
Laboratorio para el estudio de las Funciones Cerebrales Superiores,
Buenos Aires, Argentina.
Taking into account the systems for the treatment of brain
information when drawing up a work plan allows us to re create
processing routines that go from multisensory perception to motor,
oral and cognitive production, which is the step prior to executive
levels of thought, bottom up and top down processing systems.
In recent years, the use of phonological methods to prevent or
resolve reading disorders has become the fundamental mainstay
in the treatment of dyslexia. The work is mainly based on phonological
proficiency, which enables the patient to detect phonemes (input),
to think about them (performance) and to use them to build words
(output). Daily work with rhymes, the capacity to listen, the
identification of phrases and words, and handling syllables and
phonemes allows us to perform a preventive intervention that enhances
the capacity to identify letters, phonological analysis and the
reading of single words. We present the different therapeutic
models that are most frequently employed. Fast For Word (FFW)
training helps make progress in phonematic awareness and other
linguistic skills, such as phonological awareness, semantics,
syntax, grammar, working memory and event sequencing. With Deco
Fon, a programme for training phonological decoding, work is carried
out on the auditory discrimination of pure tones, letters and
consonant clusters, auditory processing speed, auditory and phonematic
memory, and graphophonological processing, which is fundamental
for speech, language and reading writing disorders. Hamlet is
a programme based on categorisation activities for working on
phonological conceptualisation. It attempts to encourage the analysis
of the segments of words, syllables or phonemes, and the classification
of a certain segment as belonging or not to a particular phonological
or orthographical category. Therapeutic approaches in the early
phases of reading are oriented towards two poles based on the
basic mechanisms underlying the process of learning to read, the
grapheme phoneme transformation process and global word recognition.
The interventionalist strategies used at school are focused on
the use of cognitive strategy techniques. The purpose of these
techniques is to teach pupils practical strategies or resources
aimed at overcoming specific deficiencies.
-----
Rev Neurol. 2003 Feb;36 Suppl 1:S3-9.
[Developmental dyslexia]
[Article in Spanish]
Galaburda AM, Cestnick L.
Beth Israel Deaconess Medical Center, Boston, MA, EE.UU.
Developmental dyslexia makes up an important proportion of
the known learning disorders. Until the late 1970s most research
on dyslexia was carried out by educators and educational psychologists,
but soon after the publication of some dyslexic cases with focal
disorders of neuronal migration to the cerebral cortex, interest
in the neurobiological and neurocognitive underpinnings of dyslexia
grew, especially in Europe and North America. There are at least
two types of developmental dyslexia phonological and surface.
Surface dyslexia refers to a disorder in which the difficulty
lies in reading irregular words, whereas phonological dyslexia
is characterized by difficulty with pseudowords. Phonological
dyslexia is the more common of the two types. Surface dyslexia
does not present a major problem in a language such as Spanish,
where the number of irregular words is indeed very small. Still,
in languages such as English, where irregular words are common,
the phonological type of developmental dyslexia is much more common.
Phonologic dyslexics have problems with phonological awareness,
that is, the conscious knowledge and manipulation of speech sounds,
which is the most proximate explanation for their difficulty in
reading pseudowords. Many, but not all, phonologic dyslexics also
have problems processing rapidly changing sounds, even if not
linguistic, and some slow sounds, too. The same group tends to
have visual problems, especially involving the so called magnocellular
pathway of the visual system, which, among others, has the role
of analyzing movement. Accompanying these perceptual and cognitive
deficits, phonologic dyslexics also show abnormal brain activation
to phonological tasks, as shown in functional magnetic resonance
studies (figure). In addition, dyslexic brains show focal malformations,
ectopias and microgyria, of the cerebral cortex, involving mainly
the left perisylvian region and the word form area in the temporo
occipital junction. There are also changes in the composition
of neurons in the lateral and medial geniculate nuclei of the
thalamus. Experimental studies indicate that the thalamic changes
are a consequence of the focal malformations, and that they are
responsible for the sound processing deficits. None of these discoveries
have changed the therapeutic modalities in this condition, but
it is hoped that this will be the next area of progress.
-----
Brain Res Cogn Brain Res 2003 Jan;15(2):154-64
The role of visuospatial attention in developmental
dyslexia: evidence from a rehabilitation study.
Facoetti A, Lorusso ML, Paganoni P, Umilta C, Mascetti GG.
Dipartimento di Psicologia Generale, Universita degli Studi di
Padova, Via Venezia, 8, 35131, Padova, Italy
Shifting of visual attention induced by peripheral cues was
studied in 24 children with specific reading disorder (SRD) or
dyslexia and was compared with that of 19 normal readers by means
of a covert orienting paradigm. This paradigm presents participants
with valid, neutral and invalid spatial cues preceding the presentation
of a target stimulus. As compared to normal readers, in SRD children
the inhibition effect (i.e. the difference between neutral and
invalid cues) was absent. The 24 SRD children were divided into
two groups matched for age, IQ and reading ability to study the
efficacy of two different rehabilitation procedures. We assessed
the effects on reading accuracy and speed over a 4-month treatment
with visual hemisphere specific stimulation (VHSS; J. Learn Disabil.
25 (1992) 102) vs. traditional speech training. The VHSS program
trains participants to perform rapid endogenous attentional orienting
by presenting briefly flashed words in the peripheral visual field.
We found that children treated with VHSS showed significant changes
in their attentional inhibition process, as indicated by increased
costs for 'reorienting' the attentional focus. As this treatment
program also proved to be highly efficient in improving the children's
reading abilities, the possible causal relationship between reading
and inhibition mechanisms of visuospatial attention was discussed.
Copyright 2003 Elsevier Science B.V.
-----
J Child Psychol Psychiatry 2002 Oct;43(7):931-8
Auditory processing in children with dyslexia.
Heiervang E, Stevenson J, Hugdahl K.
Department of Psychiatry, University of Bergen, Norway. Heiervang@psyk.uib.no
BACKGROUND: It has been claimed that children with dyslexia
show a general impairment in the processing of rapid auditory
stimuli. However, most previous studies in this field have focused
on children with language impairment or children who do not meet
accepted criteria for dyslexia. METHODS: In the present study,
the processing of rapid non-verbal auditory stimuli (complex tones)
was examined in a population-based sample of 24 children with
dyslexia, 10 to 12 years of age, and a matched control group.
RESULTS: The dyslexia group showed reduced tone processing relative
to the control group, with significant main effects of tone duration,
inter-stimulus interval and task complexity. The deficit was not
specific for temporal order errors, and could not be explained
by differences in short-term memory or verbal IQ. However, correlations
between tone processing and reading ability were generally low
or absent. CONCLUSION: Although a general processing deficit for
rapid auditory stimuli in dyslexia was confirmed, its relevance
for reading problems and hence for treatment programmes for dyslexia
is questioned.
-----
Nat Neurosci 2002 Nov;5 Suppl:1080-4
The role of neuroscience in the remediation of
students with dyslexia.
Eden GF, Moats L.
Center for the Study of Learning, Georgetown University Medical
Center, Building D, 4000 Reservoir Road, Washington, DC 20057,
USA. edeng@georgetown.edu
Dyslexia is a specific learning disability that is neurobiological
in origin. It is characterized by difficulties with accurate and/or
fluent word recognition, spelling and decoding abilities. Research
findings agree that these and other observed behavioral manifestations
largely result from a deficit in the phonological component of
language. However, conflicting theories on the exact nature of
the phonological deficit have given rise to divergent treatment
approaches. Recent advances in functional brain imaging and genetics
have allowed these theories to be examined more closely. If implemented
appropriately, commercial programs can be effective in identifying
dyslexia. Treatment of dyslexia has been advanced through neuroscience,
yet further study is needed to provide rigorous, reproducible
findings that will sustain commercial approaches.
-----
Neuroreport 2002 Sep 16;13(13):1683-7
Temporal envelope perception in dyslexic children.
Rocheron I, Lorenzi C, Fullgrabe C, Dumont A.
SESAD, Le Mans, 219 Rue de la Bertiniere, 72100 Le Mans, France.
Speech intelligibility depends heavily on the accurate perception
of auditory temporal envelope cues, that is the slower amplitude
modulations present in the speech waveform. In a previous study,
McAnally and Stein demonstrated that dyslexics may show impaired
audibility (i.e. detectability) of these envelope cues. In the
present psychophysical study, the ability to process temporal
envelope cues was further investigated in dyslexic children by
measuring detection thresholds of sinusoidal amplitude-modulation
(SAM) and discrimination thresholds of SAM depth and SAM rate.
Each threshold was measured at slow and fast SAM rates of 4 and
128 Hz, respectively. Overall, SAM thresholds were higher in dyslexics
than in controls at both rates. The strongest deficit was observed
at 4 Hz in the SAM detection task, but a deficit was also apparent
at 128 Hz in the SAM discrimination tasks. Therefore, these results
reveal that, in addition to reduced audibility of slow and fast
envelope cues, some dyslexic children show poor encoding fidelity
for these cues (as measured by the discrimination tasks). Overall,
these findings are consistent with Tallal's hypothesis according
to which the speech and reading deficits in some dyslexics may
be caused by impaired temporal processes.
-----
Int J Lang Commun Disord 2002 Jul-Sep;37(3):289-308
Phonological training in children with dyslexia
using temporally modified speech:
a three-step pilot investigation.
Habib M, Rey V, Daffaure V, Camps R, Espesser R, Joly-Pottuz B,
Demonet JF.
Faculty of Medicine, CHU Timone, Marseille, France. rnp@univ-aix.fr
Three separate studies were successively carried out to investigate
the usefulness of intensively training children with dyslexia
with daily exercizes based on the temporal processing theory of
dyslexia, according to which these children would be specifically
unable to process brief and rapidly changing auditory stimuli.
The speech modification, similar for the three studies, was close
to that proposed by Merzenich et al. (1996) and Tallal et al.
(1996), including both artificial slowing of natural speech stimuli
and amplification of brief, unstable portions of the speech signal.
In the first study, 12 children, aged 10-12 years, received either
such modified speech or normal speech for 1 h a day, 5 days a
week, over 5 weeks, and they were assessed on phonological tasks
before, during and after training. A significant advantage for
the modified speech group was found both in pre-post-training
improvement and in day-to-day progression on phonological performance.
In a second study, 29 children with dyslexia, aged 5-12, received
a similar training, but for only 15 min a day, 7 days a week,
over 6 weeks, part at the speech therapist office, part in their
own homes. The finding of comparable improvement in a more 'natural'
environment and in children over a wider age range indicates both
the efficacy and feasibility of the method in usual clinical practice.
However, this study also showed that one of four children did
not improve as expected, prompting a third study where 23 other
children underwent specific tasks presumably exploring various
aspects of temporal processing in order to find predictors of
training efficacy. A 'temporal order judgement' (TOJ) task was
found best correlated with post-training improvement, suggesting
that one use this task for selecting the best candidates for temporo-phonological
training. Moreover, such correlation provided further argument
in favour of the temporal deficit theory of dyslexia, not only
by showing a link between a purely temporal task and ultimate
phonological performance, but also by demonstrating that TOJ performance
itself improves after phonological training. Finally, and taken
together, these studies provide further justification for a rational,
indication-based temporo-phonological treatment of dyslexia. Possible
neural substrates of the relevant mechanisms are discussed in
the light of recent experimental and brain-imaging studies.
-----
J Cogn Neurosci 2002 May 15;14(4):603-17
Abnormal auditory cortical activation in dyslexia
100 msec after speech onset.
Helenius P, Salmelin R, Richardson U, Leinonen S, Lyytinen H.
Helsinki University of Technology, Finlandia. paivi@neuro.hut.fi
Reading difficulties are associated with problems in processing
and manipulating speech sounds. Dyslexic individuals seem to have,
for instance, difficulties in perceiving the length and identity
of consonants. Using magnetoencephalography (MEG), we characterized
the spatio-temporal pattern of auditory cortical activation in
dyslexia evoked by three types of natural bisyllabic pseudowords
(/ata/, /atta/, and /a a/), complex nonspeech sound pairs (corresponding
to /atta/ and /a a/) and simple 1-kHz tones. The most robust difference
between dyslexic and non-reading-impaired adults was seen in the
left supratemporal auditory cortex 100 msec after the onset of
the vowel /a/. This N100m response was abnormally strong in dyslexic
individuals. For the complex nonspeech sounds and tone, the N100m
response amplitudes were similar in dyslexic and nonimpaired individuals.
The responses evoked by syllable /ta/ of the pseudoword /atta/
also showed modest latency differences between the two subject
groups. The responses evoked by the corresponding nonspeech sounds
did not differ between the two subject groups. Further, when the
initial formant transition, that is, the consonant, was removed
from the syllable /ta/, the N100m latency was normal in dyslexic
individuals. Thus, it appears that dyslexia is reflected as abnormal
activation of the auditory cortex already 100 msec after speech
onset, manifested as abnormal response strengths for natural speech
and as delays for speech sounds containing rapid frequency transition.
These differences between the dyslexic and nonimpaired individuals
also imply that the N100m response codes stimulus-specific features
likely to be critical for speech perception. Which features of
speech (or nonspeech stimuli) are critical in eliciting the abnormally
strong N100m response in dyslexic individuals should be resolved
in future studies.
-----
Neuroreport 2002 Apr 16;13(5):617-20
Dyslexia: verbal impairments in the absence of
magnocellular impairments.
Kronbichler M, Hutzler F, Wimmer H.
Department of Psychology, University of Salzburg, Hellbrunnerstr.
34, A-5020, Austria.
Sensitivity to dynamic visual and auditory stimuli was assessed
in dyslexic children (Grade 7) who at school entrance had suffered
from the well-established double-deficit of impaired phonological
sensitivity and deficient rapid naming performance. A visual magnocellular
deficit was assessed by the coherent motion detection task of
the Oxford group. An auditory magnocellular deficit was assessed
by the illusory sound movement perception task of Hari and Kiesila.
On both tasks our dyslexic subjects' performance was similar or
even better than the performance of normally reading controls.
Differences in the inclusion of ADHD cases in dyslexic samples
is discussed as a potential explanation of differences in results.
-----
Neuroreport 2001 May 8;12(6):1195-201
fMRI auditory language differences between dyslexic
and able reading children.
Corina DP, Richards TL, Serafini S, Richards AL, Steury K, Abbott
RD, Echelard DR, Maravilla KR, Berninger VW.
Department of Radiology, University of Washington, Box 357115,
University of Washington, Seattle, WA 98195-7115, USA.
During fMRI, dyslexic and control boys completed auditory language
tasks (judging whether pairs of real and/or pseudo words rhymed
or were real words) in 30 s 'on' conditions alternating with a
30 s 'off' condition (judging whether tone pairs were same). During
phonological judgment, dyslexics had more activity than controls
in right than left inferior temporal gyrus and in left precentral
gyrus. During lexical judgment, dyslexics were less active than
controls in bilateral middle frontal gyrus and more active than
controls in left orbital frontal cortex. Individual dyslexics
were reliably less active than controls in left insula and left
inferior temporal gyrus. Dyslexic and control children differ
in brain activation during auditory language processing skills
that do not require reading.
-----
Child Dev 2003 Mar-Apr;74(2):358-73
Family risk of dyslexia is continuous: individual
differences in the precursors of reading skill.
Snowling MJ, Gallagher A, Frith U.
Department of Psychology, University of York, Heslington, United
Kingdom. MJS19@york.ac.uk
The development of 56 children at family risk of dyslexia was
followed from the age of 3 years, 9 months to 8 years. In the
high-risk group, 66% had reading disabilities at age 8 years compared
with 13% in a control group from similar, middle-class backgrounds.
However, the family risk of dyslexia was continuous, and high-risk
children who did not fulfil criteria for reading impairment at
8 years performed as poorly at age 6 as did high-risk impaired
children on tests of grapheme-phoneme knowledge. The findings
are interpreted within an interactive model of reading development
in which problems in establishing a phonological pathway in dyslexic
families may be compensated early by children who have strong
language skills.
-----
J Vis 2003;3(1):95-105
Change detection is impaired in children with
dyslexia.
Rutkowski JS, Crewther DP, Crewther SG.
Brain Sciences Institute, Swinburne University of Technology,
Australia. arkadia@ihug.com.au
The severe deficits in rapid automatized naming demonstrated
by children with developmental dyslexia has usually been interpreted
in terms of a deficit in speed of access to the lexicon rather
than as a possible deficit in speed of visual object recognition.
Yet fluent reading requires rapid visual recognition and semantic
interpretation of new letters and words appearing in successive
fixations of the eyes. Thus we wondered whether change detection
performance was related to reading ability. We investigated whether
children with developmental dyslexia (DD) were less able to detect
change in a simple display-gap-display paradigm than normal reading
(NR) children of the same age and children with impaired reading
and mentation (LD). In a first experimental phase, the DDs required
a longer initial exposure of four letter items in order to detect
change of a single letter at a level of 71% correct, compared
with NRs performing at the same level. Thus the deficit in reading
in DD is associated with a deficit in early processes associated
with visual recognition. In a second experimental phase (using
the individual target display exposures measured in the first
phase), cues appeared during the 250 ms gap for a period of either
0 (no cue), 50 or 200 ms immediately prior to the presentation
of the second (comparison) display. Children of all groups showed
dependence on the presence of the cue to help make a judgement
of change (versus no change), with the NRs least affected. When
change was detected in the presence of a cue, the NRs were better
able to identify the new letter than either of the other groups.
However, only about 50% of the correct detections were accompanied
by a correct identification. Despite published reports of a mini-neglect
for left visual field in dyslexic adults, none of our groups showed
such an effect. However, a significant upper visual field (UpVF)
advantage in change detection performance was found across groups,
which we interpret in terms of the interactions of the ventral
and dorsal streams.
-----
Brain Res Cogn Brain Res 2003 Apr;16(2):185-91
Auditory and visual automatic attention deficits
in developmental dyslexia.
Facoetti A, Lorusso ML, Paganoni P, Cattaneo C, Galli R, Umilta
C, Mascetti GG.
Unita di Psicologia e Neuropsicologia Cognitiva, Istituto Scientifico
"E. Medea" di Bosisio Parini, Lecco, Italy
Several studies have provided evidence for a phonological deficit
in developmental dyslexia. However, recent studies provide evidence
for a multimodal temporal processing deficit in dyslexia. In fact,
dyslexics show both auditory and visual abnormalities, which could
result from a more general problem in the perceptual selection
of stimuli. Here we report the results of a behavioral study showing
that children with dyslexia have both auditory and visual deficits
in the automatic orienting of spatial attention. These findings
suggest that a deficit of selective spatial attention may distort
the development of phonological and orthographic representations
that is essential for learning to read.
-----
Dev Neuropsychol 2002;22(3):533-64
Fronto-central dysfunctions in reading disability
depend on subtype: guessers but not spellers.
van der Schoot M, Licht R, Horsley TM, Sergeant JA.
Department of Special Education Vrije Universiteit Amsterdam,
The Netherlands. M.van.der.Schoot@psy.vu.nl
The goal of this study was to test the hypothesis that the
inhibitory deficits previously found in children with the guessing
subtype of dyslexia (who read fast and inaccurately) can be attributed
to dysfunctions in the fronto-central brain areas. For this purpose,
the electrocortical correlates of the inhibition mechanism were
assessed in a stop task that was adapted for event-related brain
potential recording. It was found that in children with the spelling
subtype of dyslexia (who read slowly and accurately) and normal
readers, a positive component with a fronto-central scalp distribution
was related to processes engaged in the inhibition of a response.
Guessers did not show this "inhibition P300." Analyses
of the lateralized readiness potential (LRP) data suggested that
response inhibition in spellers depended (at least in part) on
their ability to inhibit the central activation of the response.
In guessers, the association between response inhibition and inhibition
of activity in the central motor structures was found to be weaker.
It was concluded that the inhibitory deficits in guessers can
be attributed to dysfunctions in the fronto-central brain structures
involved in selective motor inhibition (indicated by the LRP data)
and nonselective motor inhibition (indicated by the P300 data).
It was suggested that there may be an association between guessers
and attention deficit hyperactivity disorder children in that
both clinical groups may suffer from the same type of deficits
in executive functioning.
-----
Am J Med Genet 2003 Apr 1;118B(1):89-98
Continuing the search for dyslexia genes on 6p.
Grigorenko EL, Wood FB, Golovyan L, Meyer M, Romano C, Pauls D.
Yale University, New Haven, Connecticut.
This study is a continuation and extension of the work with
Orton Developmental Dyslexia (DD) pedigrees [Grigorenko et al.,
1997; 2000, Grigorenko et al., 2001]. This study utilized an extended
sample (N = 176) and a well-saturated map of chromosome 6p (30
markers). Six phenotypes were constructed to span a range of dyslexia-related
cognitive processes. These phenotypes were: (1) Phonemic Awareness
(of spoken words); (2) Phonological Decoding (of printed nonwords);
(3) Rapid Automatized Naming (of colored squares or object drawings);
(4) Single Word Reading (orally, of printed real words); (5) Phonemic
Awareness/Decoding/Single-Word Reading pathway; and (6) Phonemic
Awareness/Rapid Naming/Single-Word Reading pathway. The study
resulted in two major findings. First, considering the distributions
of the genetic linkage indicators across all phenotypes examined,
there appear to be three regions of interest (around markers D6S109,
D6S1261, and in the D6S105-D6S265 region). Any of these regions
could serve as a starting point in the search for specific gene
candidates contributing to the manifestation of DD, yet they all
might be echo peaks of a single peak, the boundary of which is
difficult to establish due to the limited power of this sample.
Second, the DD-related linkage in 6p21.3 appears to be most closely
related to the manifestations of DD through phonemic awareness
and single-word reading deficits. Copyright 2003 Wiley-Liss, Inc.
-----
Dyslexia 2003 Feb;9(1):48-71; discussion 46-7
Evaluation of an exercise-based treatment for
children with reading difficulties.
Reynolds D, Nicolson RI, Hambly H.
School of Education, University of Exeter, Heavitree Road, Exeter
EX1 2LU, UK.
An evaluation is reported of an exercise-based approach to
remediation of dyslexia-related disorders. Pupils in three years
of a Warwickshire junior school were screened for risk of literacy
difficulty using the Dyslexia Screening Test (DST). The 35 children
scoring 0.4 or over on the DST were divided randomly into two
groups matched for age and DST score. One quarter of the participants
had an existing diagnosis of dyslexia, dyspraxia or ADHD. Both
groups received the same treatment at school but the intervention
group used the DDAT exercise programme daily at home. Performance
on the DST and specialist cerebellar/vestibular and eye movement
tests were assessed initially and after six months. Cerebellar/vestibular
signs were substantially alleviated following the exercise treatment
whereas there were no significant changes for the control group.
Even after allowing for the passage of time, there were significant
improvements for the intervention group in postural stability,
dexterity, phonological skill, and (one-tailed) for naming fluency
and semantic fluency. Reading fluency showed a highly significant
improvement for the intervention group, and nonsense passage reading
was also improved significantly. Significantly greater improvements
for the intervention group than the control group occurred for
dexterity, reading, verbal fluency and semantic fluency. Substantial
and significant improvements (compared with those in the previous
year) also occurred for the exercise group on national standardized
tests of reading, writing and comprehension. It is concluded that,
in addition to its direct effects on balance, dexterity and eye
movement control, the benefits of the DDAT exercise treatment
transferred significantly to cognitive skills underlying literacy,
to the reading process, and to standardized national literacy
attainment tests.
-----
Dyslexia 2003 Feb;9(1):3-17
Monitoring dyslexics' intelligence and attainments:
a follow-up study.
Thomson M.
East Court School, Victoria Parade, Ramsgate, CT11 8ED, UK. dyslexia@eastcourt.school.co.uk
Intelligence (Wechsler Intelligence Scale for Children R and
III, 1992) and written language attainment (BAS Word Reading,
Neale Analysis of Reading, Vernon Graded Word Spelling) data for
around 250 children attending a specialist school for dyslexics
are presented. The Wechsler scales data show some evidence for
'ACID' and 'SCAD' profile effects on the subtests, with specifically
weak Index scores on Freedom from Distractibility and Processing
Speed. The relationship between intelligence and reading development
is also examined, with evidence for significant correlations between
intelligence and written language and a longitudinal study showing
that there is no 'Matthew' or drop-off effect in intelligence.
The attainments tests demonstrate that the widening gap between
a dyslexic's chronological age and his/her attainments can be
closed, and how attainments may be monitored within the context
of 'growth curves'. The results are discussed in relation to recent
reports (e.g. B.P.S. on Dyslexia, Literacy and Psychological Assessment)
on the relationship between intelligence and attainments and it
is concluded that this report could be seriously misleading for
practising educational psychologists.
-----
Proc Natl Acad Sci U S A 2003 Mar 4;100(5):2860-5
Neural deficits in children with dyslexia ameliorated
by behavioral remediation: evidence
from functional MRI.
Temple E, Deutsch GK, Poldrack RA, Miller SL, Tallal P, Merzenich
MM, Gabrieli JD.
Program in Neuroscience, Stanford University, Stanford, CA 94305,
USA. et62@cornell.edu
Developmental dyslexia, characterized by unexplained difficulty
in reading, is associated with behavioral deficits in phonological
processing. Functional neuroimaging studies have shown a deficit
in the neural mechanisms underlying phonological processing in
children and adults with dyslexia. The present study examined
whether behavioral remediation ameliorates these dysfunctional
neural mechanisms in children with dyslexia. Functional MRI was
performed on 20 children with dyslexia (8-12 years old) during
phonological processing before and after a remediation program
focused on auditory processing and oral language training. Behaviorally,
training improved oral language and reading performance. Physiologically,
children with dyslexia showed increased activity in multiple brain
areas. Increases occurred in left temporo-parietal cortex and
left inferior frontal gyrus, bringing brain activation in these
regions closer to that seen in normal-reading children. Increased
activity was observed also in right-hemisphere frontal and temporal
regions and in the anterior cingulate gyrus. Children with dyslexia
showed a correlation between the magnitude of increased activation
in left temporo-parietal cortex and improvement in oral language
ability. These results suggest that a partial remediation of language-processing
deficits, resulting in improved reading, ameliorates disrupted
function in brain regions associated with phonological processing
and produces additional compensatory activation in other brain
regions.
-----
Rev Neurol 2003 Feb;36 Suppl 1:S13-9
[Intervention in dyslexic disorders: phonological
awareness training]
[Article in Spanish]
Etchepareborda MC.
Laboratorio para el estudio de las Funciones Cerebrales Superiores,
Buenos Aires, Argentina.
Taking into account the systems for the treatment of brain
information when drawing up a work plan allows us to re create
processing routines that go from multisensory perception to motor,
oral and cognitive production, which is the step prior to executive
levels of thought, bottom up and top down processing systems.
In recent years, the use of phonological methods to prevent or
resolve reading disorders has become the fundamental mainstay
in the treatment of dyslexia. The work is mainly based on phonological
proficiency, which enables the patient to detect phonemes (input),
to think about them (performance) and to use them to build words
(output). Daily work with rhymes, the capacity to listen, the
identification of phrases and words, and handling syllables and
phonemes allows us to perform a preventive intervention that enhances
the capacity to identify letters, phonological analysis and the
reading of single words. We present the different therapeutic
models that are most frequently employed. Fast For Word (FFW)
training helps make progress in phonematic awareness and other
linguistic skills, such as phonological awareness, semantics,
syntax, grammar, working memory and event sequencing. With Deco
Fon, a programme for training phonological decoding, work is carried
out on the auditory discrimination of pure tones, letters and
consonant clusters, auditory processing speed, auditory and phonematic
memory, and graphophonological processing, which is fundamental
for speech, language and reading writing disorders. Hamlet is
a programme based on categorisation activities for working on
phonological conceptualisation. It attempts to encourage the analysis
of the segments of words, syllables or phonemes, and the classification
of a certain segment as belonging or not to a particular phonological
or orthographical category. Therapeutic approaches in the early
phases of reading are oriented towards two poles based on the
basic mechanisms underlying the process of learning to read, the
grapheme phoneme transformation process and global word recognition.
The interventionalist strategies used at school are focused on
the use of cognitive strategy techniques. The purpose of these
techniques is to teach pupils practical strategies or resources
aimed at overcoming specific deficiencies.
-----
Rev Neurol 2003 Feb;36 Suppl 1:S3-9
[Developmental dyslexia]
[Article in Spanish]
Galaburda AM, Cestnick L.
Beth Israel Deaconess Medical Center, Boston, MA, EE.UU.
Developmental dyslexia makes up an important proportion of
the known learning disorders. Until the late 1970s most research
on dyslexia was carried out by educators and educational psychologists,
but soon after the publication of some dyslexic cases with focal
disorders of neuronal migration to the cerebral cortex, interest
in the neurobiological and neurocognitive underpinnings of dyslexia
grew, especially in Europe and North America. There are at least
two types of developmental dyslexia phonological and surface.
Surface dyslexia refers to a disorder in which the difficulty
lies in reading irregular words, whereas phonological dyslexia
is characterized by difficulty with pseudowords. Phonological
dyslexia is the more common of the two types. Surface dyslexia
does not present a major problem in a language such as Spanish,
where the number of irregular words is indeed very small. Still,
in languages such as English, where irregular words are common,
the phonological type of developmental dyslexia is much more common.
Phonologic dyslexics have problems with phonological awareness,
that is, the conscious knowledge and manipulation of speech sounds,
which is the most proximate explanation for their difficulty in
reading pseudowords. Many, but not all, phonologic dyslexics also
have problems processing rapidly changing sounds, even if not
linguistic, and some slow sounds, too. The same group tends to
have visual problems, especially involving the so called magnocellular
pathway of the visual system, which, among others, has the role
of analyzing movement. Accompanying these perceptual and cognitive
deficits, phonologic dyslexics also show abnormal brain activation
to phonological tasks, as shown in functional magnetic resonance
studies (figure). In addition, dyslexic brains show focal malformations,
ectopias and microgyria, of the cerebral cortex, involving mainly
the left perisylvian region and the word form area in the temporo
occipital junction. There are also changes in the composition
of neurons in the lateral and medial geniculate nuclei of the
thalamus. Experimental studies indicate that the thalamic changes
are a consequence of the focal malformations, and that they are
responsible for the sound processing deficits. None of these discoveries
have changed the therapeutic modalities in this condition, but
it is hoped that this will be the next area of progress.
-----
J Child Neurol 2002 Dec;17(12):867-71
Atypical brain activation of reading processes
in children with developmental dyslexia.
Backes W, Vuurman E, Wennekes R, Spronk P, Wuisman M, van Engelshoven
J, Jolles J.
Department of Radiology, Maastricht University Hospital, Maastricht
University, Maastricht, The Netherlands. wbac@rdia.azm.nl
Brain activation differences of reading-related processes between
dyslexic and normal reading children were localized with functional
magnetic resonance imaging (MRI). The children performed tasks
that varied in visuospatial, orthographic, phonologic, and semantic
processing demands. Enhanced activation of the left extrastriate
cortex was found during all tasks in the dyslexic group. During
orthographic processing, dyslexic children predominantly showed
activation in the right prefrontal cortex, as also occurred during
the visuo-spatial task. Normal readers also showed activation
in the left prefrontal cortex. Dyslexic readers showed less activation
of both the temporal and the prefrontal cortex during phonologic
processing. The results suggest that dyslexic readers fail to
use brain areas that are normally specialized in language processing,
but rather use areas that underlie visuospatial processing.
-----
J Med Assoc Thai 2002 Nov;85 Suppl 4:S1097-103
Prevalence and clinical characteristics of dyslexia
in primary school students.
Roongpraiwan R, Ruangdaraganon N, Visudhiphan P, Santikul K.
Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital,
Mahidol University, Bangkok 10400, Thailand.
BACKGROUND: Dyslexia is the most common subtype of learning
disabilities with a prevalence ranging from 5-10 per cent. The
central difficulty in dyslexia is the phonological awareness deficit.
The authors have developed a screening test to assess the reading
ability of Thai primary school students. OBJECTIVE: 1. To study
the prevalence of dyslexia in first to sixth grade students at
Wat Samiannaree School. 2. To study the clinical characteristics
such as sex, neurological signs, verbal intelligence and comorbid
attention deficit hyperactive disorder (ADHD) of the dyslexia
group. METHOD: A total of 486 first to sixth grade students were
administered "Raven's progressive matrices test" for
estimation of intellectual functioning. Those who scored below
the fifth percentile were labeled as mental retardation and excluded
from the study. The students' reading ability was evaluated by
3 steps; first by classroom teachers using some items of the screening
test, second by the researchers examining some more items individually,
and third by the special educator assessing more details in reading
and phonology. The students who had a reading ability two-grade
levels below their actual grades and impairment in phonology were
diagnosed with dyslexia. RESULTS: The prevalence of dyslexia and
probable dyslexia were found to be 6.3 per cent and 12.6 per cent,
respectively. The male to female ratio of dyslexia was 3.4:1.
The dyslexia group had significantly lower Thai language scores
than those of the normal group (p < 0.05). All of the dyslexia
group had a normal grossly neurological examination but 90 per
cent showed positive soft neurological signs. Mean verbal intellectual
quotient score in the dyslexia group assessed by using Wechsler
Intelligence Scales for Children--Revised was 76 +/- 7. The comorbid
ADHD was 8.7 per cent in the dyslexia group. CONCLUSION: Dyslexia
was a common problem among primary school students in this study.
Further studies in a larger population and different socioeconomic
statuses are required to determine the prevalence of dyslexia
in the general population. The authors suggest evaluating the
reading ability carefully by using a test that can detect phonological
awareness deficit in all children who have learning problems.
-----
Z Kinder Jugendpsychiatr Psychother 2002 Nov;30(4):261-70
[Reliability, trainability and stability of auditory
discrimination performance in 2 computer-assisted assessment and
training methods]
[Article in German]
Bischof J, Gratzka V, Strehlow U, Haffner J, Parzer P, Resch F.
Abteilung fur Kinder- und Jugendpsychiatrie der Psychiatrischen
Klinik, Ruprecht-Karls-Universitat Heidelberg.
OBJECTIVES: The present study focuses on the possibilities
and effects of training dyslexic children in tone and phoneme
discrimination tasks. METHODS: A computer program was developed
to train dyslexic children to discriminate between tone and speech
stimuli. The correlation between auditory discrimination and reading
and orthography performance was then tested in a preliminary study
of n = 63 children. In a prospective study 44 children were assigned
to one of three paralyzed groups: tone training, phoneme training
or a control group. Upon completion of the initial diagnostics
for all groups, the two training groups received four weeks of
discrimination training, after which all three groups were immediately
re-tested for the first time. Parallel thereto all children underwent
specific training in reading and orthography at their school.
Six months later all were re-tested a second time. RESULTS: Both
test methods showed a high reliability (rn = .94; .95). Significant
correlations between auditory discrimination and reading and orthography
performance were confirmed. Auditory discrimination was significantly
trainable. Specific training effects, as well as independent developmental
effects were found. While the training effects of phoneme discrimination
were stable over six months, those of tone discrimination were
not. CONCLUSION: The central auditory discrimination between tone
and phoneme stimuli can be trained successfully in dyslexic children
and might also affect their reading and orthography performance.
-----
J Child Psychol Psychiatry 2002 Nov;43(8):1004-17
The long-term significance of teacher-rated hyperactivity
and reading ability in childhood: findings from two longitudinal
studies.
McGee R, Prior M, Willams S, Smart D, Sanson A.
Department of Preventive and Social Medicine, University of Otago
Medical School, Dunedin, New Zealand. rob.mcgee@stonebow.otago.ac.nz
BACKGROUND: The aims of this study were twofold: first, to
examine behavioural and academic outcomes of children with hyperactivity,
using data from two longitudinal studies; and second, to examine
comparable psychosocial outcomes for children with early reading
difficulties. METHODS: Measures of teacher-rated persistent hyperactivity,
and reading ability obtained during early primary school were
available for children from the Australian Temperament Project
and the Dunedin Multidisciplinary Health and Development Study.
Both samples were followed up to assess behavioural and academic
outcomes during the adolescent and early adult years. Family background,
antisocial behaviour and literacy were controlled in the first
set of analyses to examine the influence of early hyperactivity.
RESULTS: There were strong linear relationships between early
hyperactivity and later adverse outcomes. Adjustment for other
childhood variables suggested that early hyperactivity was associated
with continuing school difficulties, problems with attention and
poor reading in adolescence. Early reading difficulties, after
controlling for early hyperactivity, predicted continuing reading
problems in high school and leaving school with no qualifications.
CONCLUSIONS: The findings suggest that there are dual pathways
from early inattentive behaviours to later inattention and reading
problems, and from early reading difficulties to substantial impairments
in later academic outcomes.
-----
Dyslexia 2002 Oct-Dec;8(4):204-25
On the relationship between dynamic visual and
auditory processing and literacy skills; results from a large
primary-school study.
Talcott JB, Witton C, Hebb GS, Stoodley CJ, Westwood EA, France
SJ, Hansen PC, Stein JF.
Neurosciences Research Institute, Aston University, Birmingham,
UK. j.b.talcott@aston.ac.uk
Three hundred and fifty randomly selected primary school children
completed a psychometric and psychophysical test battery to ascertain
relationships between reading ability and sensitivity to dynamic
visual and auditory stimuli. The first analysis examined whether
sensitivity to visual coherent motion and auditory frequency resolution
differed between groups of children with different literacy and
cognitive skills. For both tasks, a main effect of literacy group
was found in the absence of a main effect for intelligence or
an interaction between these factors. To assess the potential
confounding effects of attention, a second analysis of the frequency
discrimination data was conducted with performance on catch trials
entered as a covariate. Significant effects for both the covariate
and literacy skill was found, but again there was no main effect
of intelligence, nor was there an interaction between intelligence
and literacy skill. Regression analyses were conducted to determine
the magnitude of the relationship between sensory and literacy
skills in the entire sample. Both visual motion sensitivity and
auditory sensitivity to frequency differences were robust predictors
of children's literacy skills and their orthographic and phonological
skills.
-----
Dyslexia 2002 Oct-Dec;8(4):189-203
Children with dyslexia are slow to articulate
a single speech gesture.
Fawcett AJ, Nicolson RI.
Department of Psychology, University of Sheffield, UK.
In addition to their well-established problems in phonological
processing, children with dyslexia show reduced speed of articulation.
Two groups of children with dyslexia, mean ages 13 and 16 years,
participated together with two groups of normally achieving children
matched for age and IQ, with 33 participants in total. Participants
were asked to articulate repeatedly, as fast as they could, either
a single articulatory gesture /p/ /t/ or /k/ or the sequence 'putuku'.
The waveforms generated were analysed in two ways; the time per
gesture excluding inter-articulatory pauses (articulatory duration);
and the mean time including the pauses (gesture duration). No
age effects were found, but dyslexic groups were significantly
slower on all tests. Deficits were greater in relative magnitude
for gesture duration than articulatory duration. The results suggest
that children with dyslexia have significant problems in articulation,
not only in gesture planning, but also in the speeded production
of single articulatory gestures.
-----
Rev Neurol 2002 Feb 28;34 Suppl 1:S13-23
[The early detection of dyslexia and approach
to treatment]
[Article in Spanish]
Etchepareborda MC.
Laboratorio para el estudio de las Funciones Cerebrales Superiores,
Buenos Aires, Argentina.
Introduction. The first sign of problems of dyslexia appears
in phonographic decoding when the child tries to associate graphic
signs with phonological sequences so as to pronounce words. During
this process the child tries to recognise words visually and associate
them with the names of objects. Development. Spatial agnosia is
a very common symptom in children with dyslexia and may be detected
at preschool age. This spatial disorientation is closely linked
with the notion of body, time and sometimes rhythm. Difficulty
in identifying colours is an early symptom of dyslexia. Drawing
up a plan of work, taking into account the systems for processing
cerebral information, allows us to recreate habits of multisensorial
perceptive processing; motor, oral and cognitive production, after
executive levels of thought, button up and top down systems for
processing. Fast For Word (FFW) training helps to achieve advances
in phonemic consciousness whilst other linguistic abilities such
as phonological, semantic, syntactic and grammatical consciousness,
working memory and sequencing of events are integrated. Hamlet
is a programme for working in phonological concepts based on classification
activities. It aims to favour the analysis of segments of words,
syllables or phonemes and the classification of a particular segment
as belonging to a particular phonological or orthographical category
or not.
-----
Rev Neurol 2002 Feb 28;34 Suppl 1:S7-S13
[Problems associated with dyslexia]
[Article in Spanish]
Artigas Pallares J.
Hospital de Sabadell. Corporacio Sanitaria Parc Tauli, Sabadell,
Espa a.
Objective. In this article we review the disorders of development
which affect learning and may be associated with dyslexia. Development.
Although the cognitive basis of dyslexia is a phonological deficit,
it is not uncommonly associated with other disorders whose deficit
is not necessarily related to the dyslexia from a physiopathological
point of view. The problems which usually accompany dyslexia are:
attention deficit with hyperactivity, dysgraphia, dyscalculia
and disorders of the development of coordination. The starting
point for understanding this comorbidity is finding broad, dysfunctional
areas of the brains of dyslexic patients beyond those theoretically
involved in dyslexia. Each of these disorders may or may not occur
together with dyslexia. There are even some subtypes which are
defined by being associated with dyslexia, leading to the conclusion
that in some cases there are underlying common mechanisms. It
is necessary to avoid confusion arising over dyslexia due to comorbidity
with other conditions.
-----
Rev Neurol 2002 Feb 28;34 Suppl 1:S1-7
[The contribution of neuropsychology to the diagnosis
and treatment of learning disorders]
[Article in Spanish]
Casta o J.
Introduction. In its broadest sense, the basic concept of Neuropsychology
is that all behaviour originates in the brain; according to Luria,
it depends on functional systems constituted by different areas
of the brain which are inter related. Each area deals with a particular
function which is part of the whole (for example, the cortical
area for vision deals with reading). Which cortical areas make
up the functional system depends on how the person acquired a
certain type of behaviour. Development. The neuropsychological
model, when applied to learning disorders, assumes that they are
the expression of specific cerebral dysfunction due to genetic
or environmental factors which have altered the development of
the nervous system. Pennington recognizes five functional systems
or nodules related to intellectual function. Each of these corresponds
to a clearly defined zone of the cerebrum and impaired function
of any zone causes specific learning disorders. Thus, the left
perisylvan region deals with neurolinguistic function and disorders
of this causes dyslexia. The hippocampal area of both hemispheres
is related to memory and changes in this lead to disorders of
memory. Right hemisphere dysfunction causes dyscalculia (posterior
right hemisphere) and behaviour disorders (anterior right hemisphere)
which may present together or separately. The dysexecutive syndrome
is due to frontal lobe changes and is characterized by attention
deficit, poor planning and anticipation, defective abstraction
and other behaviour disorders. Although these are the best defined
and most commonly seen syndromes in clinical practice, it would
be logical to expect that there may be as many types of disorder
as there are neural systems or subsystems involved in particular
types of learning or behaviour, which may be altered. In support
of these concepts we report four clinical cases seen by us in
the Italian Hospital, Buenos Aires.
-----
J Commun Disord 2002 Nov-Dec;35(6):501-31
Anatomical risk factors that distinguish dyslexia
from SLI predict reading skill in normal children.
Leonard CM, Lombardino LJ, Walsh K, Eckert MA, Mockler JL, Rowe
LA, Williams S, DeBose CB.
Department of Neuroscience, McKnight Brain Institute, University
of Florida, Gainesville 32611, USA. leonard@mbi.ufl.edu
These studies investigated whether anatomical measures could
separate phonologically-based reading disability (PD) from nonphonologically-based
learning disabilities such as specific language impairment (SLI).
In a previous study. four brain measures (cerebral asymmetry.
summed planum temporale and parietale asymmetry, anterior cerebellar
asymmetry, and a duplicated left Heschl's gyrus) distinguished
a group of PD adults from reading disabled adults without specific
phonological deficits (URD). Study 1 found that these measures
did not distinguish 14 reading disabled children from 21 children
with SLI. Instead, differences were found in cerebral volume,
planum temporale asymmetry, and the size of a single left Heschl's
gyrus. Study 2 demonstrated that including all seven measures
in a discriminant analysis separated the adults and children into
two groups: one with 100% of the PD adults and 75% of the reading
disabled children and the other with 72% of the SLI children and
75% of the URD adults. Study 3 demonstrated that an anatomical
risk factor index (ARF7) generated from the discriminant function
with seven brain measures predicted reading in normal children.
Children with ARF7 near 0 (normal anatomy) had superior verbal
ability and phonological decoding scores that improved with age.
Normal children with negative ARF7 the relatively s mall symmetrical
structures that characterize SLI)had deficits in verbal ability.
Children with positive ARF7 (the asymmetrical structures that
characterize PD) had phonological decoding scores that decreased
with age. These results suggest that PD and SLI are qualitatively
different disorders associated with anatomical deviations in opposite
directions from the population mean. LEARNING OUTCOMES: As a result
of this activity, the participant will be able to: (1) distinguish
the neuroanatomical features that characterize PD and SLI; (2)
recognize that PD is associated with large asymmetrical brain
structures while SLI is associated with smaller symmetrical brain
structures; (3) understand that children with moderate sized brains
and whose anatomy is intermediate between symmetry and extreme
asymmetry have an enhanced probability of developing good verbal
ability; (4) understand that reading disabilities depend on the
interaction of neurodevelopment and the environment.
-----
AJNR Am J Neuroradiol 2002 Nov-Dec;23(10):1678-85
Reproducibility of proton MR spectroscopic imaging
(PEPSI): comparison of dyslexic and normal-reading children and
effects of treatment on brain lactate levels during language tasks.
Richards TL, Berninger VW, Aylward EH, Richards AL, Thomson JB,
Nagy WE, Carlisle JF, Dager SR, Abbott RD.
Department of Radiology, University of Washington, Seattle, WA
98195, USA.
BACKGROUND AND PURPOSE: We repeated a proton echo-planar spectroscopic
imaging (PEPSI) study to test the hypothesis that children with
dyslexia and good readers differ in brain lactate activation during
a phonologic judgment task before but not after instructional
treatment. METHODS: We measured PEPSI brain lactate activation
(TR/TE, 4000/144; 1.5 T) at two points 1-2 months apart during
two language tasks (phonologic and lexical) and a control task
(passive listening). Dyslexic participants (n = 10) and control
participants (n = 8) (boys and girls aged 9-12 years) were matched
in age, verbal intelligence quotients, and valid PEPSI voxels.
In contrast to patients in past studies who received combined
treatment, our patients were randomly assigned to either phonologic
or morphologic (meaning-based) intervention between the scanning
sessions. RESULTS: Before treatment, the patients showed significantly
greater lactate elevation in the left frontal regions (including
the inferior frontal gyrus) during the phonologic task. Both patients
and control subjects differed significantly in the right parietal
and occipital regions during both tasks. After treatment, the
two groups did not significantly differ in any brain region during
either task, but individuals given morphologic treatment were
significantly more likely to have reduced left frontal lactate
activation during the phonologic task. CONCLUSION: The previous
finding of greater left frontal lactate elevation in children
with dyslexia during a phonologic judgment task was replicated,
and brain activation changed as a result of treatment. However,
the treatment effect was due to the morphologic component rather
than the phonologic component.
-----
Neuropsychologia 2003;41(1):108-14
Implicit learning deficit in children with developmental
dyslexia.
Vicari S, Marotta L, Menghini D, Molinari M, Petrosini L.
Servizio di Neurologia e Riabilitazione, IRCCS, Children's Hospital
Bambino Gesu, Lungomare Guglielmo Marconi 36, I-00058, Santa Marinella,
Rome, Italy. vicari@opbg.net
Several neuropsychological deficits have been reported as characteristic
of the cognitive profile of dyslexic children. Phonological and
visual processing are often impaired as well as auditory processing,
attention and information processing speed. We investigated whether
implicit learning, is impaired in dyslexic children and adolescents.
Tests of implicit and declarative learning were administered to
18 clinically defined dyslexics and 18 similar age controls. Dyslexics
showed a reduced learning rate in the implicit but not in the
declarative task, suggesting a specific deficit of implicit learning.
Although alternative hypothesis cannot be ruled out, considering
that implicit learning is a cognitive function primarily processed
by the cerebellum and that recent neurological and physiological
data suggest a cerebellar dysfunction in dyslexia, the present
results suggest an impairment of cerebellar system in reading
disabilities. Copyright 2003 Elsevier Science Ltd.
-----
Optometry 2002 Sep;73(9):553-75
Learning disabilities, dyslexia, and vision: a
subject review--a rebuttal, literature review, and commentary.
Bowan MD.
sparrow@nb.net
BACKGROUND: In 1998, the American Academy of Pediatrics, the
American Academy of Ophthalmology, and the American Association
of Pediatric Ophthalmology and Strabismus (AAP/AAO/AAPOS) published
a position paper entitled "Learning Disabilities, Dyslexia
And Vision: A Subject Review," intended to support their
assertion that there is no relationship between learning disabilities,
dyslexia, and vision. The paper presents an unsupported opinion
that optometrists (by implication) have said that vision problems
cause learning disabilities and/or dyslexia and that visual therapy
cures the conditions. The 1998 position paper follows two very
similar and discredited papers published in 1972 and 1981. METHOD:
This article critically reviews and comments on the many problems
of scholarship, the inconsistencies, and the false allegations
the position paper presents. Perhaps the foremost problem is that
the authoring committee has ignored a veritable mountain of relevant
literature that strongly argues against their assertion that vision
does not relate to academic performance. It is for this reason
that an overview, drawn from more than 1,400 identified references
from Medline and other database sources and pertinent texts that
were reviewed, is incorporated into this current article. The
AAP/AAO/AAPOS paper is also examined for the Levels of Evidence
that their references offer in support of their position. CONCLUSION:
The AAP/AAO/AAPOS paper contains errors and internal inconsistencies.
Through highly selective reference choices, it misrepresents the
great body of evidence from the literature that supports a relationship
between visual and perceptual problems as they contribute to classroom
difficulties. The 1998 paper should be retracted because of the
errors, bias, and disinformation it presents. The public assigns
great trust to authorities for accurate, intellectually honest
guidance, which is lacking in this AAP/AAO/AAPOS position paper.
-----
Neurosci Lett 2002 Oct 18;331(3):211-3
Children with dyslexia and right parietal lobe
dysfunction: event-related potentials in response
to words and pseudowords.
Wimmer H, Hutzler F, Wiener C.
University of Salzburg, Institute of Psychology, Hellbrunnerstrasse
34, A-5020 Salzburg, Austria. heinz.wimmer@sbg.ac.at
Hari and Renvall (Trends Cogn. Sci., 5 (2001) 525) proposed
that dyslexic children suffer from sluggish attention deployment
due to a right parietal lobe dysfunction. To examine this hypothesis,
good and poor readers (12, 11-year-old boys in each group) had
to read familiar words (low attentional demand) and pseudowords
(high attentional demand). The amplitude of the event-related
potential at around 100 ms post-stimulus (N1) in response to words
and pseudowords was used as measure of attention deployment. Consistent
with the attention deficit/right parietal lobe dysfunction hypothesis,
poor readers showed lower N1 amplitudes in response to pseudowords,
but not in response to words at central sites of the right hemisphere.
However, poor readers also showed lower N1 amplitudes to both
words and pseudowords at left frontal sites suggestive of an early
deficit in activating phonological codes.
-----
Clin Exp Optom 2001 Nov;84(6):346-353
Is there an association between functional vision
and learning to read?
Kiely PM, Crewther SG, Crewther DP.
School of Psychological Science, La Trobe University, Bundoora
VIC, 3086, Australia.
Background: Controversy exists about the role of visual parameters
and vision in learning to read. This study aims to determine whether
ocular parameters or performance on a dynamic test of visual function
differs for children of differing reading ability. Methods: Two
hundred and eighty-four children (mean age 9.9 +/- 1.8 years)
received a vision screening emphasising binocular anomalies associated
with discomfort at near (distance and near visual acuity, distance
vision challenged with binocular +1 D lenses, near heterophoria,
near point of convergence, stereopsis and accommodative facility).
Non-verbal mentation age and reading accuracy were assessed. One
hundred and six children performed a computerised task of motion
coherence detection. Children were classified as normal readers
(n = 195), children with dyslexia (n = 49) or learning disabled
children (n = 40) based on their mentation age and their reading
age. Results: There were no statistically significant differences
or correlations between visual parameters and reading performance.
Over thirty per cent of the children had accommodative facilities
below or equal to six cycles per minute. Children with learning
disabilities performed worst on the motion coherence task but
this was statistically significant only when compared to the performance
of dyslexics. Discussion: The lack of association between ophthalmic
parameters and poor reading ability supports the view of the Committee
on Children with Disabilities. However, 39 per cent of the children
might be expected to experience difficulty 'reading to learn',
as suggested by the American Academy of Optometry, as they showed
anomalies associated with visual discomfort with prolonged reading.
The motion coherence test did not differentiate dyslexics from
normal readers and was worst in children with learning disability.
Accommodative facility testing remained the most useful predictor
of potential visual discomfort.
-----
Semin Pediatr Neurol 2002 Sep;9(3):229-38
Contributions of magnetic source imaging to the
understanding of dyslexia.
Sarkari S, Simos PG, Fletcher JM, Castillo EM, Breier JI, Papanicolaou
AC.
Department of Neurosurgery, Vivian L. Smith Center for Neurologic
Research, University of Texas Health Science Center, Houston 77030,
USA.
The problem in dyslexia is difficulty learning how the printed
word maps onto spoken language. Magnetic Source Imaging protocols
were used in three studies. The first study with dyslexic children
showed greater activity in the right temporoparietal region. The
second study showed the aberrant neural circuit was present in
initial stages of reading acquisition. The third study demonstrated
that the aberrant profile could be normalized following intensive
instruction. These findings suggest that dyslexia represents a
functional deficit in the neural circuit that mediates the conversion
of print to sound, which is amenable to change given adequate
instruction.
-----
Semin Pediatr Neurol 2002 Sep;9(3):185-91
The prevention and identification of reading disability.
Mathes PG, Denton CA.
Department of Pediatrics, University of Texas, Houston Health
Science Center, 77030, USA.
There is abundant evidence that intervention for the prevention
of reading disability is effective in dramatically reducing the
prevalence of reading disability. This article explores the current
state of knowledge regarding the causation and prevalence of reading
disability, along with evidence that the incidence of this condition
can be dramatically reduced through quality intervention. Specifically,
we (1) explore what is known about the nature and causes of reading
disability, (2) examine how reading disability can best be identified,
and (3) estimate the percentage of children that have severe reading
difficulties that indicate the true presence of a disability.
-----
Br Med Bull 2002;63:135-46
Auditory processing and the development of language
and literacy.
Bailey PJ, Snowling MJ.
Department of Psychology, University of York, UK.
This paper considers evidence for basic auditory processing
impairments associated with dyslexia and specific language impairment,
against a back-drop of findings from studies of the normal development
of auditory and phonological processing. A broad range of auditory
impairments have been implicated in the aetiology of these language-learning
disorders, including deficits in discriminating the temporal order
of rapid sequences of auditory signals, elevated thresholds for
frequency discrimination and for detection of amplitude and frequency
modulation, impaired binaural processing and increased susceptibility
to backward masking. Current evidence is inconsistent, but suggests
that not all children with language difficulties have non-verbal
auditory processing impairments, and for those that do, the impact
on language development is poorly understood. Some implications
for clinical practice are discussed.
-----
Brain 2002 Oct;125(Pt 10):2272-85
Disabled readers suffer from visual and auditory
impairments but not from a specific
magnocellular deficit.
Amitay S, Ben-Yehudah G, Banai K, Ahissar M.
Departments of Neurobiology and Psychology, Interdisciplinary
Center for Neural Computation, the Hebrew University of Jerusalem,
Israel. sygal@ihr.mrc.ac.uk
The magnocellular theory is a prominent, albeit controversial
view asserting that many reading disabled (RD) individuals suffer
from a specific impairment within the visual magnocellular pathway.
In order to assess the validity of this theory we tested its two
basic predictions. The first is that a subpopulation of RD subjects
will show impaired performance across a broad range of psychophysical
tasks relying on magnocellular functions. The second is that this
subpopulation will not be consistently impaired across tasks that
do not rely on magnocellular functions. We defined a behavioural
criterion for magnocellular function, which incorporates performance
in flicker detection, detection of drifting gratings (at low spatial
frequencies), speed discrimination and detection of coherent dot
motion. We found that some RD subjects (six out of 30) had impaired
magnocellular function. Nevertheless, these RD subjects were also
consistently impaired on a broad range of other perceptual tasks.
The performance of the other subgroup of RD subjects on magnocellular
tasks did not differ from that of controls. However, they did
show impaired performance in both visual and auditory non-magnocellular
tasks requiring fine frequency discriminations. The stimuli used
in these tasks were neither modulated in time nor briefly presented.
We conclude that some RD subjects have generally impaired perceptual
skills. Many RD subjects have more specific perceptual deficits;
however, the "magnocellular" level of description did
not capture the nature of the perceptual difficulties in any of
the RD individuals assessed by us.
-----
Dyslexia 2002 Jul-Sep;8(3):143-59
Dyslexia: nature and nurture.
Olson RK.
Department of Psychology, University of Colorado, Boulder 80309,
USA. rolson@psych.colorado.edu
This paper explores the balance of genetic and environmental
influences on dyslexia in generally supportive educational environments.
Evidence from family studies suggests and research with identical
and fraternal twins confirms the presence of strong genetic influences
on dyslexia, though the way dyslexia is defined influences the
degree of genetic influence. The behavioural genetic evidence
is supported with molecular genetic evidence from DNA analyses
suggesting regions on several different chromosomes where genes
related to dyslexia are likely to be found. The behavioural and
molecular genetic analyses are also applied to different component
word reading skills (orthographic coding and phonological decoding)
as well as to related language skills (phoneme awareness) to better
understand the genetic and cognitive pathways to dyslexia.
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