Event related potential(ERP) can be evoked by psychological or cognitive internal events.

The purpose of this study was to determine the mean latency and mean amplitude of ERP as a property of P300 in 20 controls and 35 patients with traumatic brain injury(TBI) who were classified into three groups based on the Glasgow Coma Scale(GCS).

The mean latency and the mean amplitude of P300 were 309.9±21.0msec and 4.27±1.79 μV respectively in normal controls. The mean latency of P300 was prolonged with statistically significant in the moderate and severe TBI patients, but not in mild TBI patients. In all three groups of TBI patients, the mean amplitude was reduced, which is not statistically significant. The degree of severity of injury was positively correlated with the mean latency of P300 in patients with TBI.

In conclusion, these findings are suggestive that the latency of P300 may be useful in electrodiagnostic assessment of patients with TBI.