[Change of brainstem auditory evoked potential with different stimulating frequencies after closed diffuse brain injuries of rat].

UNLABELLED:OBJECTIVE To investigate the change of peak latency (PL), interpeak latency (IPL) and peak latency ratio (PL ratio) of brainstem auditory evoked potential (BAEP) with different stimulating frequencies after closed diffuse brain injuries of rat,and provide experimental evidence for clinical diagnosis of traumatic brain injury in early stage and also for Forensic practice. METHODS:A rat model for closed diffuse brain injury was successfully constructed by hit the parietal bone with a spring-driven steel stick. The auditory brainstem response (ABR) evoked by clicking with low stimulating frequency of 10 Hz and high stimulating frequency of 50 Hz were respectively recorded at 6 h, 12 h, 2 d, 4 d after brain injury. The results of experimented group were compared with those of control group. RESULTS:The 2 d, 4 d V PL and the 6 h, 12 h, 2 d, 4 d III-V IPL of BAEP with 50 Hz stimulating frequency of model group became longer than those of control group (P < 0.05), but there was no significant difference observed between model and control group experimented with low stimulating frequency of 10 Hz (P > 0.05). The PL ratio of III/I, IV/I, V/I, IV/III and V/III with different stimulating frequencies had no significant postinjury changes. Conclusion The high stimulating frequency of BAEP is a reliable test for diagnosis of TBI in early period. Its sensitivity is superior to the low simulating frequency.