PATTERN-ELICITED VISUAL EVOKED-POTENTIALS IN GOOD AND POOR READERS

1. The aim of this experiment was to determine if visual evoked potentials (VEP) obtained with sinusoidal grating stimuli differed systematically in good and poor readers. 2. The stimuli were vertical gratings and ranged in spatial frequency from 0.5 to 8.0 c/deg of visual angle (c/deg) in octave steps. The stimuli were viewed binocularly and occurred at a rate of 1.6 Hz. The stimulus duration (200 ms) allowed analysis of two components of the VEP elicited by stimulus onset and two components of the VEP elicited by stimulus offset. 3. The major findings indicated that poor readers had significantly lower amplitudes and significantly shorter latencies for components elicited by stimulus offsets when low spatial frequency stimuli were used. 4. These results are interpreted as support for the view that some reading disabled children have a sensory deficit characterized by a less vigorous transient visual system.