Assessment of traumatic brain injury patients by WAIS-R, P300, and performance on oddball task.

The present research investigates factors that prevent traumatic brain injury patients from returning to work. Participants included 40 patients and 40 healthy individuals. Participants' intelligence quotients and the P300 component of event-related potentials elicited during an auditory oddball task were compared. The patients' mean intelligence quotient was significantly lower than that of the control group. However, some patients had normative intelligence, suggesting that the WAIS-R test results could not fully explain their inability to return to work. The peak of the P300 component could not be determined from recordings of 9 patients. When compared to the control group, the mean latency and amplitude for the remaining 31 patients were significantly longer and smaller, respectively. The mean reaction time of the patients was significantly longer than that of the controls. Omission errors were significantly more frequent in the patient group than among controls, suggesting that the patients were suffering from deficits in the allocation and maintenance of attention. Based on the number of omission errors, patients were divided into a group comprising individuals who committed fewer than two omissions (n=26) and a group comprised of individuals who committed more than three omissions (n=14). The frequent omission errors observed among individuals in the latter group may indicate their inability to sustain an adequate level of vigilance. This deficit would be a factor preventing the patients' return to work.