Evaluation in prediction of outcome of awakening in unconscious patients after traumatic brain injury by new brainstem auditory evoked potential grading

Abstract

Objective To explore the value of new brainstem auditory evoked potential grading in prediction of awakening in unconscious patients after traumatic brain injury ( TBI ).Method BAEPs were recorded and analyzed in 93 patients suffering from TBI with duration of disturbance of unconsciousness.BEAPs were classified into three grades:Gradel-all BEAP findings were normal;Grade Ⅲ -bilateral PL of wave Vor IPL of wave Ⅲ ～ Ⅴ were abnormal,unilateral or bilateral wave Ⅴ were absent;Grade Ⅱ- any abnormal BAEPs except Grade Ⅲ,including unilateral or bilateral peak latency(PL) of waveⅠ,Ⅲ,inter peak latency(IPL) of wave Ⅰ ～ Ⅲ or amplitude ratio of waveⅠand Ⅴ were abnormal,or unilateral PL of wave Ⅴ or IPL of wave Ⅲ ～ Ⅴwere abnormal.Conscious or unconscious at the 6th month after injury was considered as the outcome criterion.Results The new grading standards showed grade Ⅰ,Ⅱ and Ⅲ have 79％,18％ and 0％ of patients awaking at the 6th month.The new BAEP grading standards had significant correlation with the probabilities of awakening( r =-0.662,P ＜0.001 ; The higher the grades,the lower the probability of awakening).The area under the ROC curve was 0.859 and 95％ confidence interval was (0.781 ～ 0.937 ) of awakening prediction using BAEP classification standard.Conclusions New BAEP grading could demonstrate cerebral dysfunction and probabilities of patients' awakening objectively and accurately. Key words: Craniocerebral trauma; Consciousness disorders; Awakening prediction; Brainstem auditory evoked potential