Cognitive evoked potential (P300): a metric for cerebral concussion.

Cognitive impairment has been reported to occur in minor head injury (concussion). The value of the P300 evoked potential as a measure of cerebral concussion was studied in 20 patients with minor head injury and compared with the data from 20 normal subjects. Significant abnormalities of the P300 latency and amplitude were noted in these patients in the post-concussion period. The abnormalities improved completely on repeat testing. The correlation of the P300 to other parameters of head injury is discussed. The P300 constitutes a simple laboratory test that is sensitive measure of cerebral dysfunction in concussive head injuries.