Impaired auditory gating and P50 nonsuppression following traumatic brain injury

Traumatic brain injury (TBI) can produce persistent attention and memory im pairment that may in part be produced by impaired auditory sensory getting. The P50 evoked waveform response to paired auditory stimuli appears to be a useful measure of auditory gating. The first controlled measurement of th e P50 ratio in TBI patients is described: when 20 patients with persistentl y symptomatic TBI were compared with 20 control subjects, the P50 ratio was significantly greater in the TBI group. The potential neurophysiologic and therapeutic implications of this finding in TBI patients who report sympto ms consistent with impaired auditory gating are discussed.