VISUAL-EVOKED POTENTIALS IN DYSLEXICS AND NORMALS - FAILURE TO FIND ADIFFERENCE IN TRANSIENT OR STEADY-STATE RESPONSES

We measured transient and steady-state checkerboard contrast-reversal visual evoked potentials (VEPs) in ten dyslexics, five patient control s, and 11 normals over a range of contrasts and luminances. Latency, a mplitude, and phase measurements failed to distinguish the responses o f dyslexics from those of normals or patient controls. Decreases in lu minance or contrast resulted in an increased latency of the transient VEP in all groups, but these changes also did not distinguish the resp onses of dyslexics from those of the controls. Response variability wa s similar in dyslexics and normals, but was increased in subjects with attention deficit-hyperactivity disorder (ADHD). Performance on stand ardized psychometric testing did differentiate the dyslexics from cont rols, but did not correlate with VEP responses.