Evaluation of somatosensory evoked potential grading in prediction of outcome of awakening in long-term unconscious patients after severe traumatic brain injury

Objective To explore the somatosensory evoked potential grading in prediction of awakening in unconscious patients after severe traumatic brain injury. Methods SEPs were recorded and analyzed in 46 patients suffering from severe TBI with duration of disturbance of unconsciousness more than one week. SEPs were classified as following according to the existence of N20-P25 and the central conduction time (CCT): Ⅰ bilateral N20-P25 are normal; Ⅰ a bilateral CCT are normal and symetrical; Ⅰ b bilateral CCT are normal,but asymmetrical, Ⅱ unilateral N20-P25 exist. The other side is absent, Ⅲ bilateral N20-P25 are absent. The awakening after the sixth month from injury was used as the criterion. Results SEP grading has significant correlation with the probabilities of awakening (P< 0.05): The higher the SEP grades, the lower the probabilities of awakening is. Conclusion SEP grading can objectively and accurately demonstrate cerebral dysfunction and probabilities of patients' awakening. Key words: Craniocerebral trauma;  Disturbance of consciousness;  Awakening prediction; Somatosensory evoked potential