Predictive value of short-latency somatosensory evoked potentials for awakening in long-term unconscious patients after severe traumatic brain injury with.

Objective To study the predictive value of short-latency somatosensory evoked potentials(SEP) for awakening of unconscious adult patients after severe TBI(traumatic brain injury,TBI).Methods Five prognostic factors including age,sex,mechanisms of injury,history of temporal craniectomy,and classification of SEP were selected and analyzed in 47 patients suffering from severe TBI(GCS 8) with duration of disorders of consciousnessness 2 weeks.SEP was classified into three grades according to the existence of N20-P25 complex wave and CCT(central conduction time,CCT) as following: GradeⅠ: Bilateral N20-P25 complex waves exist:(1)Bilateral CCT and amplitude of N20-P25 are normal and symmetrical;(2)Unilateral or bilateral CCT delays less than twice as long as normal,and at least unilateral amplitude of N20-P25 more than 0.8μV.Grade Ⅱ:(1) Bilateral CCT delays more than twice as long as normal;(2) Bilateral amplitudes of N20-P25 less than 0.8μV;(3) Unilateral N20-P25 complex wave exists,the other side absent.Grade Ⅲ: Bilateral N20-P25 complex waves absent.The outcome of awakening after the sixth month following injury was used as the criterion.Results The SEP classification significantly correlated with the probabilities of awakening(P=0.002) and the accuracy of predicting the outcome of awakening is 87.2%.Conclusions The SEP classification can objectively and accurately evaluate the patient's prognoses and predict the probabilities of patients' awakening.