Skip to content

    Brain & Nervous System Health Center

    Font Size
    A
    A
    A

    Brain Defect Underlies Reading Difficulties of Dyslexia

    By
    WebMD Health News

    Feb. 16, 2001 (San Francisco) -- A defect in a single part of the brain may underlie the reading difficulties of dyslexics, but intensive training can help them overcome their problems and allow them to read. The findings, presented Thursday at the annual meeting of the American Association for the Advancement of Science, could help researchers find a better way to diagnose and treat at-risk children before reading problems appear.

    For years, no one knew what caused dyslexia, which afflicts 10% of the population. They did know, however, that the difficulties of dyslexics are not caused by a poor education or low intelligence. Studies from the last few years have hinted at a biological cause, says Thomas Zeffiro, MD, PhD. But reading is a complex task performed by several parts of the brain, so no one was sure which part was malfunctioning, he says. Zeffiro is co-director of the Georgetown Center for the Study of Learning at Georgetown University Medical Center in Washington, D.C.

    To find out, Zeffiro, Guinevere Eden, DPhil, the other co-director of the Georgetown center, and their colleagues examined the brains of dyslexics and normal subjects using a brain-imaging method called functional magnetic resonance imagining -- a variant of the brain-scanning procedures doctors use to diagnose brain maladies that can detect changes in brain activity.

    Although it seems simple, reading is a complex task, says Eden. Readers must see symbols and deduce what they mean, sound out words in their head, and grasp what each sound means. "Children who are good at this succeed in reading," Eden says.

    Thirty-seven subjects -- 20 with dyslexia and 17 who read normally -- were monitored as they read and as they tried to detect moving dots on a computer screen. Dyslexics have problems with both tasks. An area of the brain called the left parietal lobe lit up for both tasks in both groups, but it lit up less for dyslexics. That meant that a single brain defect underlies both tasks, pointing to a common brain defect that goes awry in dyslexia.

    Today on WebMD

    nerve damage
    Learn how this disease affects the nervous system.
    senior woman with lost expression
    Know the early warning signs.
     
    woman in art gallery
    Tips to stay smart, sharp, and focused.
    medical marijuana plant
    What is it used for?
     
    senior man
    Article
    boy hits soccer ball with head
    Slideshow
     
    red and white swirl
    Article
    marijuana plant
    ARTICLE
     
    brain illustration stroke
    Slideshow
    nerve damage
    Slideshow
     
    Alzheimers Overview
    Slideshow
    Graphic of number filled head and dna double helix
    Quiz