Clinical Study on Brain Death by the Nasopharyngeal Lead with the Aid of an Automatic EEG Analysis System

脑干脑电图是否呈平线是判断脑死亡的重要依据。因此，我不仅尝试从头皮表面记录脑电图，而且还尝试用鼻咽铅法从靠近脑干基底面的鼻咽壁记录脑电图。头皮脑电图电极分别放置在受试者仰卧位的顶叶区、颞叶区和枕叶区的左右两侧，电极采用国际联会10/20电极系统。鼻咽EEG的agcl电极针也插入外鼻腔上壁。在耳垂上放置参考电极，用参考蒙太奇法记录脑电图。采用自动脑电分析系统对头皮和鼻咽脑电进行分析。(1)研究健康受试者头皮和鼻咽脑电信号的差异。发现鼻咽脑电中δ、θ等慢波分量比头皮脑电多，α分量少。在光刺激下（频率为5 Hz，光强为0.6J），头皮脑电图出现α减少、θ增加的现象，而鼻咽脑电图无明显变化。因此，鼻咽脑电图与头皮脑电图有很大的不同，因此有望反映脑干脑电图。(2)以临床推定脑死亡的患者为研究对象，探讨头皮脑电与鼻咽脑电之间的关系。患者头皮脑电等效电位均小于健康志愿者，但鼻咽脑电等效电位均在正常受试者的分布范围内呈现低电压。

For the judgment of brain death, it is important to determine whether the brain-stem electroencephalogram (EEG) shows flat line or not. I have thus attempted to record EEG not only from the scalp surface but also from the nasopharyngeal wall quite close to the basal surface of brain stem by the nasopharyngeal lead method. The electrodes for the scalp EEG were placed on the right and left sides each of parietal, temporal and occipital regions of the subjects at supine position according to the 10/20 Electorode System of International Federation. AgCl-electorode needle for the nasopharyngeal EEG was also inserted into upper wall of the external nasal cavity. Reference electrodes were placed on the ear lobes and the EEG was recorded by reference montage. Both the scalp and nasopharyngeal EEGs were analyzed using Automatic EEG Analysis System.(1)The difference between the scalp and nasopharyngeal EEGs of the healthy subjects was investigated. It was found that the components of slow waves like delta and theta were observed more but the alpha component was less in the nasopharyngeal EEG than in the scalp EEG.By the photic stimulus (frequency : 5 Hz, strength of light : 0.6J), a decrease of alpha and an increase of theta occurred in the scalp EEG while there no specific changes of them in tha nasopharyngeal EEG.Consequently, the nasopharyngeal EEG was quite different from tha scalp EEG, and was thus expected to reflect the brain stem EEG.(2)The relationship between the scalp and nasopharyngeal EEGs was investigated from the patients who were clinically presumed brain death because of bothe flat-line scalp EEG and loss of auditory brain-stem response. The equivalent electric potentials in the scalp EEG from these patients were smaller than those of the healthy volunteers, but those in the nasopharyngeal EEG from all the patients showed low voltage within the range of distribution in normal subjects.