Abnormal electrophysiological responses to successive stimuli in patients with cortical damage or multiple sclerosis

We studied the cortical potentials of normal subjects and patients with unilateral hemisphere damage to two simultaneous or successive stimuli. Both groups showed variations in the interaction between the signals evoked by the stimuli as a function of interstimulus interval. However, the anomalous stimulus-response function obtained from the patient group suggests pathological signal interaction. Data obtained from patients with multiple sclerosis were similar to those of the cortical-injury group suggesting that localized cerebral damage is not requisite for the disturbed profiles. We hypothesize that the results indicate abnormal temporal processing by these patients and propose that the defect may underlie visual illusions reported by patients with cerebral pathology.