Abstract: Objective To assess the cognitive dysfunction in patients with the traumatic brain injury(TBI) by auditory P300. Methods Auditory P300 was recorded in the normal subjects and patients with TBI at the active(foot pedal) and passive task. Results In healthy persons, N2 and P3 in active task state showed higher amplitude than that in passive task state, and no significant prolongation of the latency. The ampli- tude of N1 and P2 at Cz was higher than that at Pz. In passive task state, N2 and P3 showed higher amplitude and longer latency in the patients than that in the healthy persons. N2 and P3 of the patients in the active task showed higher amplitude and longer latency than that in the passive task. Obvious change of P3 latency was observed in the patients with attention disorder. Conclusion The type of task mainly affect the amplitude of N2 and P3. The latency of N2 and P3 in passive task can be used as an indication for evaluating cognitive function in patients with diffuse brain injury.

Key words: forensic medicine, event-related potentials, P300, brain injuries, cognition