[Correlation between EEG and auditory brainstem response (ABR) in comatose patients--diagnosis of brain death by ABR]

ABRs and EEGs were recorded from fifty comatose patients. Among them 21 patients were in deep coma and remaining 29 were in brain death that was diagnosed from clinical criteria. All the patients who showed some activity in EEG had ABR which showed waves I through V. However, there was no correlation between grade of EEG classification, dominant alpha, theta, or delta rhythm, and the inter wave latencies between waves I through V in the ABRs. Eleven of the twenty-nine patients who were diagnosed as brain death from clinical criteria and isoelectric EEG showed waves I through V potentials in ABR. Eight of these eleven patients even exhibited normal or nearly normal ABRs which had I to V latencies less than 4.4 ms. However, all the patients who showed isoelectric EEG and no response ABR died. Thus it is concluded that the ABR should be included for identification of brain death in addition to the clinical examination and EEG recordings.