Electric field distribution of event-related potentials in stroke patients.

Electrical field distributions of event-related potentials (ERP's) were recorded during an auditory "oddball paradigm" and were analyzed in terms of time and space. Fourteen normal subjects and 14 chronic patients were cerebral thrombosis were studied. For the components N1 and P3 of the ERP's to target stimuli, reference-independent measures (latency, global field power, location of maximal or minimal potential, and location of centroids) were determined. Stroke patients displayed P3 abnormalities in latency, amplitude, and electrical field on the scalp. In addition, N1 electrical fields were also abnormal. These ERP abnormalities correlated significantly with the extent of mental function impairment in the stroke patients, and they improved after administration of a cerebral metabolic enhancer (Nefiracetam: DM-9384). The ERP's seemed to be sensitive in indicating the effects of the drug. These data suggest that time-course analysis of the spatial distribution of the ERP electrical field might be useful for evaluation of the extent of mental function impairment and the efficacy of drugs.