Dyslexia: Research reports

Helping dyslexics

June 2008

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.
The findings are available online in the August issue of Neuropsychologia.  Full reference
http://www.eurekalert.org/pub_releases/2008-06/cmu-cmb061108.php

September 2007

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.
The study was published online August 17 in the Journal of Neurolinguistics.    Full reference 
http://www.eurekalert.org/pub_releases/2007-09/uow-hrt090407.php
http://www.sciencedirect.com/science/journal/09116044

April 2005

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.
The report appeared in the April issue of Trends in Neurosciences. Full reference
http://www.eurekalert.org/pub_releases/2005-04/nu-nii040405.htm

October 2004

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.
The study appeared in the October 28 issue of Neuron. Full reference
http://www.eurekalert.org/pub_releases/2004-10/cp-pfh102204.htm

November 2003

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.htm

July 2003

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.
The study was published in the July 22 issue of Neurology.Full reference
http://www.eurekalert.org/pub_releases/2003-07/aaon-sdt071503.htm
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.

Causes of dyslexia

April 2008

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.
The study was published in the April 8 issue of the Proceedings of the National Academy of Sciences.  Full reference
http://www.nature.com/news/2008/080407/full/news.2008.739.html
http://sciencenow.sciencemag.org/cgi/content/full/2008/408/1?etoc

May 2005

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.
The report appeared in the May 29 issue of Nature Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2005-05/uow-sso052505.htm

September 2004

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.
The study appeared in the 2 September issue of Nature. Full reference
http://msnbc.msn.com/id/5888011/

August 2004

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.
The finding was published in the August 24 issue of Neurology. Full reference

June 2004

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.
The article appeared in the June 29 issue of the Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2004-06/nu-bda061604.htm

December 2003

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.
The report was presented at the 89th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA). Reference
http://www.eurekalert.org/pub_releases/2003-12/rson-fdm112403.htm

May 2003

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.
The findings were published online on May 18 in Nature Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2003-05/gumc-wor051603.htm