NIH-funded study finds dyslexia not tied to IQ (NIH press release):

At left, brain areas active in typ­i­cally devel­op­ing read­ers engaged in a rhyming task. Shown at right is the brain area acti­vated in poor read­ers involved in the same task.

- “Regard­less of high or low over­all scores on an IQ test, chil­dren with dyslexia show sim­i­lar pat­terns of brain activ­ity, accord­ing to researchers sup­ported by the National Insti­tutes of Health. The results call into ques­tion the dis­crep­ancy model — the prac­tice of clas­si­fy­ing a child as dyslexic on the basis of a lag between read­ing abil­ity and over­all IQ scores.”

- “In many school sys­tems, the dis­crep­ancy model is the cri­te­rion for deter­min­ing whether a child will be pro­vided with spe­cial­ized read­ing instruc­tion. With the dis­crep­ancy model, chil­dren with dyslexia and lower-than-average IQ scores may not be clas­si­fied as learn­ing dis­abled and so may not be eli­gi­ble for spe­cial edu­ca­tional ser­vices to help them learn to read.”

Study Abstract

Although the role of IQ in devel­op­men­tal dyslexia remains ambigu­ous, the dom­i­nant clin­i­cal and research approaches rely on a def­i­n­i­tion of dyslexia that requires read­ing skill to be sig­nif­i­cantly below the level expected given an individual’s IQ. In the study reported here, we used func­tional MRI (fMRI) to exam­ine whether dif­fer­ences in brain acti­va­tion dur­ing phono­log­i­cal pro­cess­ing that are char­ac­ter­is­tic of dyslexia were sim­i­lar or dis­sim­i­lar in chil­dren with poor read­ing abil­ity who had high IQ scores (dis­crepant read­ers) and in chil­dren with poor read­ing abil­ity who had low IQ scores (nondis­crepant read­ers). In two inde­pen­dent sam­ples includ­ing a total of 131 chil­dren, using uni­vari­ate and mul­ti­vari­ate pat­tern analy­ses, we found that dis­crepant and nondis­crepant poor read­ers exhib­ited sim­i­lar pat­terns of reduced acti­va­tion in brain areas such as left pari­etotem­po­ral and occip­i­totem­po­ral regions. These results con­verge with behav­ioral evi­dence indi­cat­ing that, regard­less of IQ, poor read­ers have sim­i­lar kinds of read­ing dif­fi­cul­ties in rela­tion to phono­log­i­cal pro­cess­ing. Key­words: aca­d­e­mic achieve­ment, apti­tude mea­sures, dyslexia, neu­roimag­ing, reading.

–> To access study: click Here.

Related arti­cles:

• Unlock­ing dyslexia in Japanese
• Major grant to study brain basis of autism and dyslexia

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