Study on occurrence of microsleep during psychomotor performance and criteria for its detection

背景：微睡眠通常被描述为第一阶段睡眠或超短睡眠的突然、短暂的突发性睡眠。随着临床观察，如睡眠过度患者的自动症状和抑郁症患者的情绪和精神运动表现，基础研究很少，微睡眠是否应该被认为是睡眠似乎仍然是一个开放的问题。方法：本研究的主要目的是通过精神运动表现来检测保持清醒状态时微睡眠的行为和生理特征，并探讨微睡眠的检测标准。15名受试者在下午持续记录脑电(EEG)、眼电(EOGs)和手指轻击次数超过40min。受试者被指示进行10次连续轻拍，主观估计间隔为1秒，力量约为1公斤。每只右手和左手都应该交替敲击十次(双交替Ta…手指敲击的SK更多)。在没有任何敲击动作持续70s后，出现了唤醒音。用最大熵法估计脑电功率谱。该方法基于移动线性回归分析，应用于眼球运动缓慢和轻拍的自动检测和测量。结果：微睡眠呈现出一种特殊的状态，表现为反复发生错误，包括用力降低、间隔延迟和失误，以及手指敲击的纠正。根据敲击间隔和手间交替间隙的分析，发现微睡眠的持续时间为2-7秒。在减力敲击前的几秒钟内，出现了生理上的显著变化：α频段的主要频率消失，α/β和α/β频段的脑电功率比降低，并出现缓慢的眼球运动。结论：1)用力敲击手指减半，2)α/theta功率比为1(中央脑电)和4(枕部脑电)，3)一次或多次眼球运动缓慢。较少

Background : Microsleep is usually described as a sudden, short-lasting burst of stage 1 sleep or ultrashort phase of sleep. With all clinical observations, such as automatic syndrome in hypersomniacs, and mood and psychomotor performance in depressed patients, few basic researches have been made and it seems to remain open whether microsleep should be considered as sleep or not.Method : The main aim of this study was to examine the behavioral and physiological features of microsleep during maintenance of wakefulness by psychomotor performance, and to explore the criteria for detection of microsleep. Electroencephalograms(EEGs), electrooculograms(EOGs) and finger tappings were continuously recorded over 40 min in the afternoon in 15 subjects. Subjects were instructed to perform 10-successive tappings with a subjectively estimated interval of 1 sec and a force of about 1 Kg. Ten-successive tappings were supposed to perform alternately on each of right and left hands (Dual Alternation Ta … More sk of Finger Tapping). Awakening tone was presented after no movement of tapping had lasted 70 sec. EEG power spectra were estimated by using maximum entropy method. The method, based on the application of a moving linear regression analysis, was applied to automatic detection and measurement of slow eye movements and tappings. Tap-by-tap analyses were made on EEG,EOG and tapping data.Results : A specific state to microsleep was present, behaviorally characterized as the repeated occurrence of mistakes, including lowered force, delayed interval and lapse, and corrections of finger tappings. Duration of microsleep was found to range from 2 to 7 sec on the basis of analysis of inter tap interval and alternation gaps between hands. Physiologically significant changes were seen during a few seconds before lowered-force tappings : disappearance of dominant frequency of alpha band, decreased EEG power ratios of alpha/theta and alpha/beta bands, and appearance of slow eye movements. These changes occurred even in normal train of tapping as well as in interrupted one.Conclusion : The following features might be help with detection of microsleep : 1)Finger tapping with force decreased by half, 2)Alpha /theta power ratio with a value of 1 (central EEG) and a value of 4 (occipital EEG), 3)One or more appearance of slow eye movements. Less