Evoked potential assessment of mental function during recovery from severe head injury

Event-related potential recording and neuropsychologic testing were carried out on 18 severely head-injured patients and on a control group. At early stages of injury the patients had prolonged P3 latencies and reduced psychometric scores. In the assessment of individual patients the P3 latency proved to be a measure that diagnosed cognitive impairment with clinically acceptable levels of accurate classification. On retesting 4.6 +/- 1.6 months after trauma, normal values were found for the neuropsychologic measures and a residual latency prolongation for P3, indicating the P3 latency to be a sensitive index of subtle residual brain dysfunction due to head injury.