Effects of rate of repetitive stimulus presentation on the visual evoked brain potentials of young adults with Down's syndrome.

Visual evoked brain potentials (VEP) to repeated stimuli of several interstimulus intervals (ISI) were recorded from young adults with Down's syndrome (DS). The following results were obtained: (i) An ISI effect previously observed in normals: VEP amplitudes increased with increase in ISI; some ISI effect on latency was also observed; (ii) VEP amplitudes of DS subjects were larger than VEP amplitudes of normals; (iii) VEP peak latencies of DS subjects were longer than VEP peak latencies obtained from normals; (iv) ISI had a more pronounced effect on VEP amplitudes of DS than normal subjects. These results are discussed with respect to CNS differences and issues of attention and information processing.