痴呆の重症度と脳幹聴性誘発電位—I, III, V波の振幅について

The Severity of Dementia and Brainstem Auditory Evoked Potentials : The Amplitude of Waves I, III and V

　痴呆の重症度と脳幹聴性誘発電位（BAEPs）の各振幅との関連について検討した。対象は痴呆性疾患78例（男子20例，女子58例）で，正常対照者9例（男子2例，女子7例）であった。結果の概要は以下の通りである。

　（1）個体差に関する要因として，①女性血管性痴呆患者のBAEPsの振幅は男性のそれより高値であったが，有意差はなかった，②女性血管性痴呆患者は女性変性疾患性痴呆患者のそれより低振幅で，特にV波では有意差が認められた，③III波の振幅が罹病期間の延長につれて低下していた。

　（2）痴呆の重症度とBAEPsの振幅との関係では，④女性血管性痴呆患者のV波の振幅が痴呆の重症度につれて低下し，痴呆検査の得点との間に有意な正の相関関係が認められた。

　以上の所見は，痴呆の重症化につれて脳幹障害が進行していることを示唆するものと考える。

The correlation between the severity of dementia and the amplitudes of brainstem auditory evoked potentials (BAEPs) was studied. The subjects were 78 patients with dementia (20 males, 58 females) whose mean age was 80.5±6.7 years. Normal sub-jects were 9 elderly persons (2 males, 7 females) whose mean age was 79.2±6.0 years. The ampli-tudes of wave- I, -III and -V were measured.

As for individual differences :① The amplitudes of BAEPs in the male group were lower than that in the female group, there was no significant difference.② The amplitudes of wave-V in female patients with vascular dementia were significantly lower than that of degenerative dementia.③ The amplitudes of wave-III reduced as the duration of illness prolonged.

Dividing the patients into three groups according to the severity of dementia which are mild, mode-rate and severe.④ The amplitudes of the wave-V reduced significantly as the severity of dementia advanced. There was a significantly positive corre-lation between the amplitudes of the wave-V and the Hasegawa's dementia scores (r=0.404759, p＜0.05)

Based upon the above results, the brainstem dysfunction might progress with the severity of dementia.