Correlation between brainstem auditory evoked potential findings and outcome in long-term unconscious patients with severe traumatic brain injury

Abstract

Objective To explore the correlation between brainstem auditory evoked potential (BAEP) findings and outcome in long-term unconscious patients with severe traumatic brain injury (TBI).Methods BAEP findings were recorded and analyzed in 63 patients suffering from severe TBI with duration of disturbance of unconsciousness for more than 2 weeks. The peak latency (PL) of wave Ⅰ, Ⅲ and Ⅴ, the interpeak latency (IPL) of wave Ⅰ-Ⅲ and Ⅲ-Ⅴ and the amplitude ratio of wave Ⅰ and Ⅴ were analyzed. Conscious or unconscious at 6 months after the injury was considered as the outcome criterion,and based on these, the patients were divided into conscious and unconscious groups; the significant indicators were chosen in the 2 groups using independent-sample t test. Results The probabilities of awakening in these patients were 34.9% (22/63) with abnormal index of BAEP indicators reaching 66.7%. Sixteen patients were sober at last in 21 patients with normal PL of wave Ⅰ, Ⅲ and Ⅴ, IPL of wave Ⅰ-Ⅲ and Ⅲ-Ⅴ, and amplitude ratio of wave Ⅰ and Ⅴ in bilateral side (the probabilities of awakening were 76.2%); 8 patients having abnormal PL of wave Ⅴ in bilateral side and 7 having abnormal IPL of wave Ⅲ-Ⅴ in bilateral side were unconscious; 2 patients having disappeared wave Ⅴ in unilateral side were unconscious. PL of wave Ⅴ and IPL of wave Ⅲ-Ⅴ in bilateral side were significantly different between the conscious group and the unconscious group. (P＜0.05). Conclusion BAEP findings (PL of wave Ⅴ and IPL of wave Ⅲ-Ⅴ in bilateral side) can objectively and accurately demonstrate the cerebral dysfunction and predict the outcome of the patients. Key words: Brainstem auditory evoked potential; Traumatic brain injury; Disturbance of consciousness