Reliability of electroencephalogram in the diagnosis of brain death.

The definition of brain death includes the irreversible loss of all brainstem and forebrain functions. The electroencephalogram (EEG), used to test forebrain functions, is part of the diagnostic armamentarium and is considered necessary even after primary infratentorial lesions. A review of both the current literature as well as new data on an interrater agreement and intrarater stability study provide the basis for a discussion on the reliability of EEG recording in this context and on the definition of brain death. Under normal conditions, the presence of an electrocerebrally inactive EEG is a valid indicator of brain death. However, the reliability and accordingly the validity of the EEG is restricted by technical problems and limited intrarater stability and interrater agreement.