dyslexia

Dyslexia Therapy

Older news items (pre-2010) brought over from the old website

Remedial reading program improves brain wiring in children

An imaging study involving 72 children aged 8 to 10 has provided the first evidence that intensive instruction to improve reading skills in young children causes the brain to physically rewire itself. The study found that the ability of white matter tracts to transmit signals efficiently improved substantially after the children received six months (100 hours) of remedial training. Moreover, those who showed the most white matter change also showed the most improvement in reading ability. Previous research has found that both children and adults with reading difficulty display areas of compromised white matter.

[963] Keller, T. A., & Just M A.
(2009).  Altering Cortical Connectivity: Remediation-Induced Changes in the White Matter of Poor Readers.
Neuron. 64(5), 624 - 631.

http://www.physorg.com/news179584529.html
http://www.npr.org/templates/story/story.php?storyId=121253104

Pre-school exercises can prevent dyslexia

A study comparing 107 children with either parent dyslexic and a control group of children without a hereditary predisposition to dyslexia has found that half the children with a dyslexic parent found learning to read more challenging than children in the control group. The predictors of reading and writing difficulties were evident primarily in two contexts: as a delayed ability to perceive and mentally process the subtleties of speech sound, and as a sluggishness in naming familiar, visually presented objects. The difficulties children experience when learning to read can be significantly reduced through training, and the CoE in Learning and Motivation Research has developed computer game-like learning environments to aid preventive training, and made them available on the internet free of charge. It’s recommended that the child start these exercises before school, if possible.  The exercises and tools are all available at www.lukimat.fi.

The results were presented at the Academy of Finland's science breakfast on 21 August.

http://www.eurekalert.org/pub_releases/2008-08/aof-pae082708.php

Remedial instruction can close gap between good, poor readers

A brain imaging study of poor readers has found that 100 hours of remedial instruction not only improved the skills of struggling readers, but also changed the way their brains activated when they comprehended written sentences. 25 fifth-graders who were poor readers worked in groups of three for an hour a day with a reading "personal trainer," a teacher specialized in administering a remedial reading program. The training included both word decoding exercises in which students were asked to recognize the word in its written form and tasks in using reading comprehension strategies. Brain scans while the children were reading revealed that the parietotemporal region — responsible for decoding the sounds of written language and assembling them into words and phrases that make up a sentence — was significantly less activated among the poor readers than in the control group. The increases in activation seen as a result of training were still evident, and even greater, a year later.
Although dyslexia is generally thought of as caused by difficulties in the visual perception of letters, leading to confusions between letters like "p" and "d", such difficulties occur in only about 10% of the cases. Most commonly, the problem lies in relating the visual form of a letter to its sound.

[702] Meyler, A., Keller T. A., Cherkassky V. L., Gabrieli J. D. E., & Just M A.
(2008).  Modifying the brain activation of poor readers during sentence comprehension with extended remedial instruction: A longitudinal study of neuroplasticity.
Neuropsychologia. 46(10), 2580 - 2592.

http://www.eurekalert.org/pub_releases/2008-06/cmu-cmb061108.php

Having right timing 'connections' in brain is key to overcoming dyslexia

New research has found that key areas for language and working memory involved in reading are connected differently in dyslexics than in children who are good readers and spellers. But, after the children with dyslexia went through a three-week instructional program, their patterns of functional brain connectivity normalized and were similar to those of good readers. The study looked specifically at activity in the left and right inferior front gyrus. The left inferior front gyrus may control the communication between the different areas involved in language, especially spoken language, while the right is thought to be involved in controlling the processing of letters in written words. Prior to the treatment these two areas were overconnected in the dyslexics, and the left inferior frontal gyrus also was overconnected to the middle frontal gyrus, which is involved in working memory that requires temporal coordination. It is not yet known how long the improvement in connectivity is maintained.

[844] Richards, T. L., & Berninger V. W.
(2008).  Abnormal fMRI Connectivity in Children with Dyslexia During a Phoneme Task: Before But Not After Treatment.
Journal of neurolinguistics. 21(4), 294 - 304.

http://www.eurekalert.org/pub_releases/2007-09/uow-hrt090407.php
http://www.sciencedirect.com/science/journal/09116044

New insight into brain and speech promises help for learning disabilities

Following a new understanding of the nature of certain language dysfunctions, researchers have devised a new non-invasive diagnostic tool called BioMAP that can quickly identify children with a subset of learning disabilities that results from a dysfunction in the way the brainstem encodes certain basic sounds of speech. Such children accounted for nearly a third of the language-disordered children the researchers studied. BioMAP measures whether a child's nervous system can accurately translate a sound wave into a brain wave. If it cannot, the affected individual demonstrates problems in discriminating speech sounds that interfere with normal learning. Once identified, children with these problems will be able to improve their speech discrimination skills through auditory training.

[789] Kraus, N., & Nicol T.
(2005).  Brainstem origins for cortical 'what' and 'where' pathways in the auditory system.
Trends in Neurosciences. 28(4), 176 - 181.

http://www.eurekalert.org/pub_releases/2005-04/nu-nii040405.php

Promise for helping adults with dyslexia

Recent studies have demonstrated that children with dyslexia can benefit from programs aimed at “retraining” the brain. Now a new study shows that adults with dyslexia can also benefit from tutoring in processing words, and their brains show changes that indicate neural modifications due to the training.

[454] Eden, G. F., Jones K. M., Cappell K., Gareau L., Wood F. B., Zeffiro T. A., et al.
(2004).  Neural Changes following Remediation in Adult Developmental Dyslexia.
Neuron. 44(3), 411 - 422.

http://www.eurekalert.org/pub_releases/2004-10/cp-pfh102204.php

Immature motion pathways in the brain associated with poor reading skills

An interactive computer game called MovingToRead (MTR) has significantly improved reading skills in poor second-grade readers within three months by practicing left-right movement discrimination for 5 to 10 minutes once or twice a week. It has been suggested that immature motion pathways — the circuit of neurons that helps readers determine the location of letters of a word and words on a page — may be related to reading problems in children. The therapy appears to be most effective with second-graders (age 7).

http://www.eurekalert.org/pub_releases/2003-11/sfn-ssb111103.php

Short-term dyslexia treatment strengthens key brain regions

A group of dyslexic children and a group of good readers of the same age underwent functional magnetic resonance imaging (fMRI) to map their brain activation patterns during two types of reading tests. Both groups of children were found to use the same specific parts of their brains to perform the reading tasks, however, the activation of these regions was much weaker in the dyslexic children. The children with dyslexia then received a three-week training program based on principles outlined by the National Reading Panel (http://www.nationalreadingpanel.org). After this program the levels of brain activation were found to be essentially the same in the two groups.

[261] Aylward, E. H., Richards T. L., Berninger V. W., Nagy W. E., Field K. M., Grimme A. C., et al.
(2003).  Instructional treatment associated with changes in brain activation in children with dyslexia.
Neurology. 61(2), 212 - 219.

http://www.eurekalert.org/pub_releases/2003-07/aaon-sdt071503.php
More background on dyslexia including initial steps toward identifying it in a child, how it may be treated, and additional resources can be found in Neurology's "Patient Page" at http://www.neurology.org.

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Dyslexia

For information on helping those with dyslexia, see Dyslexia therapy

Older news items (pre-2010) brought over from the old website

Unraveling the roots of dyslexia

There is some evidence that dyslexia is distinguished by a basic deficit in phonological processing, characterized by difficulties in segmenting spoken words into their minimally discernable speech segments (speech sounds, or phonemes). A new study investigating brain activity of dyslexics and normal adult readers when presented with letters, speech sounds, or a matching or non-matching combination of the two, has revealed that dyslexic adults showed lower activation of the superior temporal cortex when needing to integrate letter and speech sounds. The findings point to reading failure being caused by a neural deficit in integrating letters with their speech sounds.

Blau, V. et al. 2009. Reduced Neural Integration of Letters and Speech Sounds Links Phonological and Reading Deficits in Adult Dyslexia. Current Biology, 19 (6), 503-508.

http://www.eurekalert.org/pub_releases/2009-03/cp-utr030509.php

Chinese and English dyslexias stem from different brain abnormalities.

Dyslexia involves impairment in connecting the sight and sound of a word. In English, this is commonly seen in transpositions of letters, while in Chinese, the problem can affect how a person converts a symbol into both sound and meaning. Following an earlier study in which the brain areas involved in dyslexia were found to be different for English and Chinese readers, a new technique has confirmed and clarified the results. Chinese children with dyslexia had a significantly smaller left middle frontal gyrus than did Chinese children without the disorder, even though both groups had the same overall volume of gray matter. Intriguingly, this area is not associated with symbol recognition, but with working memory. Earlier research has found English-speaking dyslexics have less gray matter in the left parietal region. The findings also suggest that dyslexics in one language will probably not be dyslexic in the other.

[865] Siok, W T., Niu Z., Jin Z., Perfetti C. A., & Tan L H.
(2008).  A structural–functional basis for dyslexia in the cortex of Chinese readers.
Proceedings of the National Academy of Sciences. 105(14), 5561 - 5566.

http://www.nature.com/news/2008/080407/full/news.2008.739.html
http://sciencenow.sciencemag.org/cgi/content/full/2008/408/1?etoc

New evidence for the cause of dyslexia

A new study casts new light on the cause of dyslexia. Recent research has tended to focus on the magnocellular (M) pathway, one of two visual pathways in the brain that processes motion and brightness. The other visual channel, the parvocellular (P) pathway, processes detail and color. Although some studies have implicated an impaired M channel, showing that dyslexic children have trouble seeing rapidly changing or moving stimuli, results have been inconsistent. A new study suggests that the problem is rather a more general problem in basic sensory perception — an inability to shut out “noise”, that is, the sounds and patterns surrounding the target information.

[462] Sperling, A. J., Lu Z-L., Manis F. R., & Seidenberg M. S.
(2005).  Deficits in perceptual noise exclusion in developmental dyslexia.
Nat Neurosci. 8(7), 862 - 863.

http://www.eurekalert.org/pub_releases/2005-05/uow-sso052505.php

Dyslexia doesn't have a universal biological cause

While most of the latest research focuses on the biological causes of dyslexia, a new study reveals that the disorder affects the brains of Chinese and English speakers differently, suggesting that the neural basis of reading differs depending on the nature of the writing system. The findings have enormous implications for helping impaired readers in China, where 2% to 7% of children are dyslexic. The study also highlights the importance of paying attention to differences in languages, even languages as similar as English and Italian. It has been shown that the degree of impairment when reading can differ depending on the language.

[1058] Siok, W T., Perfetti C. A., Jin Z., & Tan L H.
(2004).  Biological abnormality of impaired reading is constrained by culture.
Nature. 431(7004), 71 - 76.

http://msnbc.msn.com/id/5888011/

Dyslexics have less gray matter in the brain's language centers

A new imaging study involving people with a family history of dyslexia confirms earlier research suggesting dyslexics have a significant reduction of gray matter in centers associated with language processing. The study lends credence to earlier studies that suggested intensive reading therapy activates parts of the brain needed for decoding words.

[1446] Brambati, S. M., Termine C., Ruffino M., Stella G., Fazio F., Cappa S. F., et al.
(2004).  Regional reductions of gray matter volume in familial dyslexia.
Neurology. 63(4), 742 - 745.

Brain development and puberty may be key factors in learning disorders

New research suggests that the brains of children with learning problems not only appear to develop more slowly than those of their unaffected counterparts but also actually may stop developing around the time of puberty's onset. In the study, children with impairments started out about three years behind, but their rate of improvement was very similar to that of the children without impairments — until around 10 years, when further development in the children with learning problems stopped. The researchers suggest that delayed brain development and its interaction with puberty may be key factors contributing to language-based learning disabilities such as dyslexia. This hypothesis suggests a completely new approach to the study of learning problems. It also points to the importance of early intervention.

[216] Wright, B. A., & Zecker S. G.
(2004).  Learning problems, delayed development, and puberty.
Proceedings of the National Academy of Sciences of the United States of America. 101(26), 9942 - 9946.

http://www.eurekalert.org/pub_releases/2004-06/nu-bda061604.php

Sensory processing different in people with dyslexia

An imaging study of dyslexics has found that dyslexic readers appear to process auditory and visual sensory cues differently than do normal readers. In the study 30 dyslexic readers and 30 normal readers performed three matching tasks — an auditory task, a visual task and a multisensory task — involving consonant-vowel pairs. During the auditory matching task the dyslexic readers showed increased activity in the visual pathway of the brain, while that same region deactivated in the normal readers. The dyslexic readers' increased activation patterns in the visual pathway corresponded to poorer performance on the matching task.

Burdette, J.H., Laurienti, P.J., Flowers, L., Kraft, R., Maldjian, J. & Wood, F.B. 2003. Report presented at the 89th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA).

http://www.eurekalert.org/pub_releases/2003-12/rson-fdm112403.php

Imaging study confirms theory of dyslexia

Functional magnetic resonance imaging (fMRI) has confirmed part of an eighty-year-old theory on the neurobiological basis of dyslexia. Dr Orton theorized that normally developing readers learn to suppress the visual images reported by the right hemisphere of the brain because these images potentially interfere with input from the left. The imaging study found that children do in fact "turn off" the right side of the visual parts of the brain as they become accomplished readers, and also demonstrated that different phonological skills relate to activity in different parts of the brain when children read. This observation lends support to the theory that there may be several neurobiological profiles that correspond to different subtypes of dyslexia, each associated with varying deficits in one or more of these different phonological skills.

[304] Turkeltaub, P. E., Gareau L., Flowers L. D., Zeffiro T. A., & Eden G. F.
(2003).  Development of neural mechanisms for reading.
Nat Neurosci. 6(7), 767 - 773.

http://www.eurekalert.org/pub_releases/2003-05/gumc-wor051603.php

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Twin studies shed light on relationship among ADHD, reading, math

January, 2011

While one twin study points to the common attribute of slow processing speed between those with ADHD and those with reading disabilities, another indicates a role for environment.

A twin study involving 457 pairs has found that ADHD on its own was associated with a reduced ability to inhibit responses to stimuli, while reading disabilities were associated independently with weaknesses on measures of phoneme awareness, verbal reasoning, and working memory. Both disorders were associated with a slow processing speed, and there was a significant genetic correlation between RD and ADHD.

However, just to remind us that genetics are rarely solely the answer, another twin study, involving 271 pairs of 10-year-old identical and fraternal twins, has found evidence that the associations between ADHD symptoms, reading outcomes and math outcomes are a product of both genetic and common environmental influences. The researchers speculate that such environmental influences may include aspects of the classroom and homework environment.

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Link between handedness and dyslexia

January, 2011

A genome study has found a gene variant that leads to greater right-hand skill in dyslexics, but not others. The gene is implicated in embryonic development.

While brain laterality exists widely among animal species, the strong dominance of right-handedness in humans is something of an anomaly. As this implies a left-hemisphere dominance for motor function, it’s been suggested that the evolution of language (also mainly a function of the left hemisphere) may be behind the right-handed bias, leading to a search for a connection between hand preference and language disorders. To date, no convincing evidence has been found.

However, a genetic study of 192 dyslexic children has now revealed a strong link between a variant of a gene called PCSK6 and relative hand skill in these children. Specifically, those who carried the variant in PCSK6 were, on average, more skilled with their right hand compared to the left than those not carrying the variant. However, among the general population, this gene variant is associated with less right-hand skill.

The findings provide evidence for a link between brain lateralization and dyslexia. The gene’s protein is known to interact with another protein (NODAL) that plays a key role in establishing left-right asymmetry early in embryonic development, suggesting that the gene may affect the initial left-right patterning of the embryo, with consequences for cerebral lateralization.

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Evidence that dyslexia 'uncouples' reading and IQ over time

January, 2010

A long-running study confirms that, as theorized, in typical readers, IQ and reading track together and influence each other, but neither of these things is true for children with dyslexia.

The ongoing 12-year Connecticut Longitudinal Study, involving a representative sample of 445 schoolchildren, has found that in typical readers, IQ and reading not only track together, but also influence each other over time. But in children with dyslexia, IQ and reading are not linked over time and do not influence one another. Although this difference has been assumed, this is the first direct evidence for it. It should also be noted that the language problem is not confined to reading: those with dyslexia take a long time to retrieve words, so they might not speak or read as fluidly as others.

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[550] Ferrer, E., Shaywitz B. A., Holahan J. M., Marchione K., & Shaywitz S. E.
(2010).  Uncoupling of reading and IQ over time: empirical evidence for a definition of dyslexia.
Psychological Science: A Journal of the American Psychological Society / APS. 21(1), 93 - 101.

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