Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

More evidence shows that children’s brains with dyslexia respond abnormally to language stimuli

27.10.2003


Imaging studies yield a potential core marker for reading problems, underscore neurological basis of difficulties



Researchers have additional evidence that reading problems are linked to abnormal sound processing, thanks to high-precision pictures of the brain at work. In a recent study, when children without reading problems tried to distinguish between similar spoken syllables, speech areas in the left brain worked much harder than corresponding areas in the right brain, whose function is still unknown. But when children with dyslexia made the same attempt, those right-brain areas actually worked harder, going into overdrive after a brief delay. These findings appear in the October issue of Neuropsychology, which is published by the American Psychological Association (APA).

Psychologists at The University of Texas Health Science Center at Houston targeted the suspect brain areas by isolating speech-processing sites from sites involved with other aspects of language, such as memory and meaning. As a result, they believe their research contributes to the identification of a central marker of the deficit that makes it hard for people with dyslexia to process similar but different sounds –- in both spoken and written form. The results parallel prior evidence gathered by the Houston team that brains of children with dyslexia also respond abnormally during reading.


The researchers studied the brain activity of 12 children with and 11 children without dyslexia during a simple speech perception task. The children were eight to 12 years old. Magnetoencephalography (MEG), a non-invasive, high-resolution form of functional imaging, highlighted precise activity in participants’ left and right temporoparietal (TP) language areas while the children discriminated between spoken pairs of syllables, such as /ga/ and /ka/. This kind of task, known as phonological processing, is fundamental to acquiring reading skill. The temporoparietal areas are on the surface in the back of the brain.

While distinguishing between sounds, the non-impaired readers showed more relative activity in the speech part of the left TP area. During the same task, after a slight delay, impaired readers showed a sharp peak of relative activation in corresponding (but functionally mysterious) areas on the right side. The poorer the child’s performance in phonological processing, the more their right brains "lit up" during that task.

The results, says co-author Joshua Breier, Ph.D., suggest that children with dyslexia "may lack the predominant involvement of left-hemisphere auditory association cortices" shown by children and adults without reading problems.

Dyslexia may affect up to 17 percent of the school-age population and can continue into adulthood. Reading experts have long suspected that many reading problems, especially in decoding letter sounds, are rooted in the brain and have more to do with sound than sight. Brain imaging studies have confirmed that suspicion and helped to put to rest any notion that dyslexia, although it can make a child feel "stupid" and be a problem in school, reflects visual problems or a lower overall intelligence.

"The neurological deficit appears to be specific to very restricted areas of the brain," says Breier, "and can occur in children with a wide range of general intellectual function."

Such findings are helping to shape national education policy. In fact, co-author Jack Fletcher, Ph.D., points out that most states, following federal guidelines, have for decades used a discrepancy between IQ and reading tests to determine eligibility for special education in the learning disability category, which accounts for more than half of all students in special education. However, several national bodies have, in the past year, proposed allowing states to use alternative means of establishing eligibility. Legislation is in progress. Breier explains that given the research, "The use of IQ in reading disability definitions, at least for these children, is not appropriate." Adds Fletcher, "It’s poor reading that’s important."

And, poor reading can improve. "The present study shows that reliable brain correlates can be identified in individual children," Breier points out. Given that effective teaching changes brain activation patterns, he says, "the brain in people with reading difficulties is responsive to intense intervention."

Further research will gauge the reliability of the findings, which were established with a participant number typical of a brain-imaging study, using high-precision measurements. In addition, the Houston researchers hope to determine under which treatment conditions MEG brain imaging might be associated with how well a child with dyslexia responds to intervention.



Article: "Abnormal Activation of Temporoparietal Language Areas During Phonetic Analysis in Children with Dyslexia," by Joshua I. Breier, Ph.D.; Panagiotis G. Simos, Ph.D.; Jack M. Fletcher, Ph.D.; Eduardo M. Castillo, Ph.D.; Wenbo Zhang, Ph.D.; and Andrew C. Papanicolaou, Ph.D.; The University of Texas Health Science Center at Houston; Neuropsychology, Vol. 17, No. 4.

(Full text of the article is available from the APA Public Affairs Office and at http://www.apa.org/releases/dyslexia_article.pdf)

Joshua Breier can be reached in Houston at The Institute for Rehabilitation and Research by email at Joshua.i.breier@uth.tmc.edu or by phone at 713-797-7570. His secretary is Michelle O’Neal.

The American Psychological Association (APA), in Washington, DC, is the largest scientific and professional organization representing psychology in the United States and is the world’s largest association of psychologists. APA’s membership includes more than 150,000 researchers, educators, clinicians, consultants and students. Through its divisions in 53 subfields of psychology and affiliations with 60 state, territorial and Canadian provincial associations, APA works to advance psychology as a science, as a profession and as a means of promoting human welfare.

Pam Willenz | EurekAlert!
Further information:
http://www.apa.org/
http://www.apa.org/releases/dyslexia_article.pdf

More articles from Studies and Analyses:

nachricht Graphene gives a tremendous boost to future terahertz cameras
16.04.2019 | ICFO-The Institute of Photonic Sciences

nachricht Mount Kilimanjaro: Ecosystems in Global Change
28.03.2019 | Julius-Maximilians-Universität Würzburg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Quantum gas turns supersolid

Researchers led by Francesca Ferlaino from the University of Innsbruck and the Austrian Academy of Sciences report in Physical Review X on the observation of supersolid behavior in dipolar quantum gases of erbium and dysprosium. In the dysprosium gas these properties are unprecedentedly long-lived. This sets the stage for future investigations into the nature of this exotic phase of matter.

Supersolidity is a paradoxical state where the matter is both crystallized and superfluid. Predicted 50 years ago, such a counter-intuitive phase, featuring...

Im Focus: Explosion on Jupiter-sized star 10 times more powerful than ever seen on our sun

A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter

  • Coolest and smallest star to produce a superflare found
  • Star is a tenth of the radius of our Sun
  • Researchers led by University of Warwick could only see...

Im Focus: Quantum simulation more stable than expected

A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.

Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...

Im Focus: Largest, fastest array of microscopic 'traffic cops' for optical communications

The technology could revolutionize how information travels through data centers and artificial intelligence networks

Engineers at the University of California, Berkeley have built a new photonic switch that can control the direction of light passing through optical fibers...

Im Focus: A long-distance relationship in femtoseconds

Physicists observe how electron-hole pairs drift apart at ultrafast speed, but still remain strongly bound.

Modern electronics relies on ultrafast charge motion on ever shorter length scales. Physicists from Regensburg and Gothenburg have now succeeded in resolving a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

Fraunhofer FHR at the IEEE Radar Conference 2019 in Boston, USA

09.04.2019 | Event News

 
Latest News

Marine Skin dives deeper for better monitoring

23.04.2019 | Information Technology

Geomagnetic jerks finally reproduced and explained

23.04.2019 | Earth Sciences

Overlooked molecular machine in cell nucleus may hold key to treating aggressive leukemia

23.04.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>