A sutudy ob evaluation of brain death using electrically stimulted auditory veoked potentials and its pathology of temoral bone and brain

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For assissing comatose patints, the combination of audityry short, middle and long latency evoked potentials (auditory brain stem response (ABR), middle latency respones (MLR), and sloe vertez ersponse (SVR) and visual evoked rtesponse in more comprahensive than auditory granstem response (ABR) only or ABR with sloe vertex response (SVR). Seventy-three asutely comatose patients were stauied. Fourty-two of the patients had severe head injury and others had coma of vatied etiology. Within two moonths after asmission. 34 patiens survive, while 39 pariemts died. For comparison with auditory evoked potentials, caloric test, 3-3-9 grading sacle and EEG recording were performed simultaneously and quality of life of recovered cases were investigated after discharge. It was concluded that staging classification of auditory evoked potentials were very useful for assessing comtose patients' life and brain death.A case of brain death was pathologically stuied. Brain death of at least 48 hours' dur … More ation was demonstrated by neurological examination, flat electroencephalographic recording, and persistent absence of auditory evoked responses. The postrmorten examination was performed 3 hours after death. The parthological studies studies of the whole length of the auditory pathway reveled total autolysis of the organ of Corti, marked cell loss in the dorsal cochlear nucleus, and moderate cell loss in other nucle of the central auditory pathway. It should be considered that total antolysis of the organ of Corti and secere cell loss of the cochlear nucleus may occur if the auditory brain stem response becomes absent in comatose patients.Electrically stimulated auditory evoked potentials were studied for patinets who underwent cochelar implant surgery. E-ABRs were not observed in the early componets becasuse of setious interfere of electrical artifacts from cochlear implant device but E-MLR and E-SVR were well recorded. In addition, event related potentials of P300 for pure tone and words wrte recorded. In this study E-ABR was recvealed to br less useful for clinical evaluation of brain death but visual evoked response was demonstrated to be toughly present even if ABRs were sbaent in the condition of brain death. Less