Event related potentials in adults diagnosed as reading disabled in childhood.

The purpose of this study was to identify electrophysiological correlates of reading disability (RD) in adults with psychometrically documented childhood reading histories. Specific a-priori hypotheses for these correlates were generated from the findings of Harter, Anllo-Vento, Wood & Schroeder (1988a); Harter, Diering & Wood (1988b). The subjects were 32 males with normal intelligence and no history of attention deficit disorder or current major psychopathology. Event related potentials were recorded over O1, O2, C3', C4', F3, and F4 to letter stimuli using an intralocation selective attention paradigm. Subjects with RD showed a general reduction in positivity starting at 150 ms and continuing up to 500 ms. The reduced positivity at left central P240 replicated the findings of Harter et al. (1988b) with children. However, adult RD was associated with more diffuse, bilateral reduction in electrophysiological response to all stimuli. A possible relationship between the bilaterality of the neural deficit and the severity of the dyslexia was proposed: that a bilateral deficit may be involved in severe cases.