An Physiological Survey on the Mechanism of Delirium in the Elderly

我们对老年人术后谵妄进行了<12>连续14天静脉注射强睡眠-觉醒节律调节剂维生素B_（甲钴胺）和安慰剂治疗的单盲对照研究，并从生物节律的角度对障碍的机制进行了评估。在甲钴胺组（n=10）中，从给药开始到谵妄缓解的时间显著短于安慰剂组（n=10）。从开始给药后第3天到第7天，与安慰剂组相比，甲钴胺组的谵妄评定量表（DRS）总分较低。甲钴胺组出现情绪不稳、情绪昼夜变化、睡眠-觉醒节律紊乱、幻觉等DRS症状项目的时间明显短于安慰剂组。甲钴胺组第3天至第9天白天睡眠与夜间睡眠之比明显小于对照组。此外，甲钴胺组术后谵妄缓解前2 ~ 3天内的嗜睡也受到抑制，从临床症状的病程与睡眠-觉醒节律的关系及甲钴胺的疗效来看，老年人术后谵妄的发生可能与昼夜节律紊乱有关。此外，甲钴胺被认为可以增加夜间睡眠和/或提高白天的警觉性，从而稳定睡眠-清醒节律。

We made a single blind controlled study on the treatment of postoperative delirium in the elderly with intravenous administration of Vitamin B_<12> (methylcobalamin), a strong regulator of sleep - awake rhythm and placebo for 14 consecutive days, and assessed the mechanism of the disorder from the aspect of biological rhythm. In the group administered with methylcobalamin (n=10), periods from the start of the administration to the remission of delirium were significantly shorter than the group with placebo (n=10). From 3rd day to 7th day after the initiation of the administration, sum of the points of delirium rating scale (DRS) were lower in the group with methylcobalamin compared with the group with placebo. The periods, in which the symptom items of DRS such as emotional instabilty, diurnal varition of the mood, disorder of sleep - awake rhythm and hallucination existed, were significantly shorter in the group with methylcobalamin than the group with placebo. When analyzing the diurnal distribution of sleep, daytime sleep to night time sleep ratio were significantly smaller from 3rd day to 9th day in the group with methylcobalamin. In addition to that, hypersomnolence which existed in two or three days period befor the remission of postoperative delirium were suppressed in the group with methylcobalamin.Judging from the relation between the course of clinical symptoms and sleep-awake rhythm as well as the efficacy of methylcobalamin, postoperative delirium in the elderly was suspected to occur as a result of the circadian rhythm disorder. And also, methylcobalamin was thought to increase nocturnal sleep and/ or enhance the alertness in the daytime leading to stabilize sleep - awake rhythm.