An Physiological Survey on the Mechanism of Delirium in the Elderly

应用睡眠-觉醒节律强调节剂维生素B_(12)(甲钴胺)和安慰剂，连续14天静脉滴注治疗老年人术后妄想，并从生物节律的角度探讨其发生机制。在甲钴胺组(n=10)，从开始给药到神志不清缓解的时间明显短于安慰剂组(n=10)。服药后第3天至第7天，甲钴胺组的妄想评定量表总分(DRS)低于安慰剂组。甲钴胺组出现情绪不稳定、情绪昼夜变化、睡眠-觉醒节律紊乱、幻觉等DRS症状的时间明显短于安慰剂组。分析日间睡眠分布时，甲钴胺组在第3天至第9天的白天睡眠与夜间睡眠的比率显著小于对照组。此外，甲钴胺组还能抑制术后躁动缓解前两三天出现的高睡眠，从临床症状进程与睡眠-觉醒节律的关系以及甲钴胺的疗效判断，老年术后妄想可能是由于昼夜节律紊乱所致。此外，甲钴胺被认为可以增加夜间睡眠和/或增强白天的警觉性，从而稳定睡眠-清醒节奏。

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.