[Clinical study on judgement of brain death by the nasopharyngeal lead with the aid of an automatic EEG analysis system].

We investigated the relationship between scalp electroencephalogram (EEG) and nasopharyngeal EEG using Automatic EEG Analysis System in 10 patients with the age between 17 and 66 who were clinically presumed brain death because of flat line EEG and loss of auditory brainstem response (ABR). Among 10 patients, nasopharyngeal lead EEG showed low voltage and slow waves of 10-20 microV in 4 cases and flat line EEG in 6 cases. However, Automatic EEG Analysis system-assisted analysis of EEGs recorded on a magnetic tape revealed that equivalent electric potentials in the scalp EEG from these patients were smaller than those of healthy volunteers, but those in the nasopharyngeal EEG from all patients showed low voltage within the range of distribution in normal volunteers (delta:6, theta 1:6, theta 2:2, alpha 1:1, alpha 3:10, beta 1:6 in 10 cases). The present results show that in addition to the routine scalp EEG, it is clinically useful to employ simple and easy nasopharyngeal lead EEG method and to analyze data using Automatic EEG Analysis System for the judgement of brain death.