Electrophysiological methods in the diagnosis of dissociated brain death

Buchner H.; Schuchardt V.; Ferbert A.; Willmes K.

The definition of brain death used in the Federal Republic of Germany requires the irreversible loss of all brainstem and forebrain functions. The EEG, used to prove forebrain functioning, is part of the diagnostic criteria and is said to be necessary after primary infratentorial lesion. A review of the literture, as well as new data, case reports of isolated brainstem death and a intrarater-agreement and intrarater-stability study provide the basis for discussion of the definition of brain death, including validity and reliability of the EEG. The irreversible loss of all brainstem and forebrain functions can be detected only if an EEG is recorded in any case. Under usual conditions, recording of an isoelectric EEG is a valid indicator of brain death. The reliability and therefore the validity of the EEG is diminished by technical problems and limited inter- and interarater agreement. An expert system would be useful in order to increase the reliability of the EEG.