中文摘要：

目的探讨体感诱发电位（SEP）对重型颅脑外伤（TBI）后长期意识障碍患者清醒预测的分级标准。方法记录46例重度TBI后意识障碍超过1周患者的SEP表现，根据SEP中N20-P25是否存在及中枢传导时间（CCT）是否正常，将SEP分为3级：I级为双侧N20-P25都存在（Ia：双侧CCT正常且对称，Ib：双侧CCT正常，但不对称）；Ⅱ级为一侧N20-P25存在．另一侧消失；Ⅱ级为双侧N20-P25都消失。预后以外伤后6个月患者是否清醒为标准。结果SEP分级与清醒的几率存在负相关关系（r=-0．591，P=0．000），分级越高，预后越差。结论SEP的分级可客观、准确地反映脑功能损伤程度和清醒的几率。

英文摘要：

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. ]I unilateral N20-P25 exist. ]＇he other side is absent, llI 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.