Brainstem auditory evoked potentials following head injury

Brainstem auditory evoked potentials (BAEP) were examined in 40 patients with subjective disorders following closed head injury (CHI), with the established degree of recovery and performed CT-scan of the head. For all BAEP parameters the interval of normality was defined as 3 SD above and below mean value in the control group comprised of 20 healthy subjects. The upper limits of thus defined intervals of normality enabled the formation of four types of findings: type 1--normal finding that was registered in 23 (57.5%) patients; type 2 was a sum of individual findings with the prolonged interpeak latencies, but without the change of relative amplitude V:I--7 (17.5%) recordings; type 3--the findings where the fall of relative amplitude V:I was registered together with the prolongation of interpeak latency. It comprised of 4 (10%) recordings and the type 4 included 6 (15%) individual recordings with registered low RA V:I (0.8 or lower). The explanation of the most probable genesis of registered changes was presented.