A study of event-related potential P300 in cerebral infarction.

N1, P2 and P300 potentials were studied in 20 cases of cerebral infarction and 47 healthy controls with the standard technique of auditory event-related potentials. Healthy controls of both sexes, different ages, education levels and cognitive capacity did not show apparent differences in the latency of P300 (P greater than 0.05, respectively). The patient group, however, revealed a significant (P less than 0.001) prolongation of latency of P300 (means = 409.6 +/- 50 ms) as compared with 28 well matched healthy subjects (means = 337.7 +/- 24 ms). Although there was a slightly lower amplitude of P300 in the patient group, the difference between control and patient groups was not significant (P greater than 0.05). There was a significant difference in the Cognitive Capacity Screening Examination findings between control and patient groups (P less than 0.01), but it seems that evaluation of the cognition-related latency of P300 may be more objective and sensitive in distinguishing between organic and cognitive distress (P less than 0.001).