Wright Nicola, McGown Amanda
Human Performance Enhancement Group, Centre for Human Sciences, QinetiQ Ltd., Farnborough, Hampshire, UK.
Aviat Space Environ Med. 2004 Jan;75(1):37-45.
During air operations, aircrew may encounter sleepiness that can arise from the length of duty periods, working during the circadian low of alertness, and circadian dysrhythmia arising from time-zone change. A previous study investigated physiological and physical measures that could be used to identify sleep and provide the basis of an alertness alarm. Eye movements were sensitive indicators of sleepiness and sleep, and wrist inactivity identified sleep episodes lasting longer than 5 min.
Wrist inactivity can provide the basis of a practical alertness device for use by aircrew.
The electrical activity of the brain (electroencephalogram, EEG), eye movements, and wrist activity were recorded continuously from the Captain and First Officer during six return flights between London and Chicago. The route comprised an outward daytime and overnight return flight, each lasting approximately 9 h. The EEG and eye movements were used to identify sleepiness and sleep, and these episodes were correlated with periods of wrist inactivity. A software simulation based on the data collected during the study was conducted in order to determine the number of errors generated by an alertness alarm based on wrist inactivity lasting 3, 4, or 5 min.
Sleepiness or sleep was observed in 8 of the 12 subjects. All periods of sustained sleep in excess of 5 min were associated with at least 5 min of wrist inactivity. The simulated alertness alarm using a wrist inactivity setting of 5 min gave only one false alarm, and in this respect performed better than a device based on a shorter time interval (3 or 4 min).
An alertness device based on wrist inactivity would prevent sustained periods of sleep lasting longer than 5 min. It would not, however, reliably detect sleepiness and brief episodes of sleep. The anticipated use of the device is in support of the management of alertness in aircrew, where it could be used to ensure that unintended or unauthorized napping does not occur or is detected in a timely manner.
在执行空中任务期间，机组人员可能会出现困倦，这可能源于执勤时间的长短、在昼夜警觉性低谷期工作以及因时区变化引起的昼夜节律失调。先前的一项研究调查了可用于识别睡眠并为警觉性警报提供依据的生理和身体指标。眼球运动是困倦和睡眠的敏感指标，手腕静止不动可识别持续超过5分钟的睡眠时段。
手腕静止不动可为机组人员使用的实用警觉性设备提供依据。
在伦敦和芝加哥之间的6次往返航班上，对机长和副驾驶的大脑电活动（脑电图，EEG）、眼球运动和手腕活动进行了连续记录。航线包括一次白天的去程和一次夜间的返程航班，每次持续约9小时。脑电图和眼球运动用于识别困倦和睡眠，这些时段与手腕静止不动的时段相关联。基于研究期间收集的数据进行了软件模拟，以确定基于持续3、4或5分钟手腕静止不动的警觉性警报产生的错误数量。
12名受试者中有8名观察到困倦或睡眠。所有持续超过5分钟的睡眠时段都与至少5分钟的手腕静止不动相关。使用5分钟手腕静止不动设置的模拟警觉性警报仅产生一次误报，在这方面比基于更短时间间隔（3或4分钟）的设备表现更好。
基于手腕静止不动的警觉性设备可防止持续超过5分钟的睡眠时段。然而，它不能可靠地检测困倦和短暂的睡眠时段。该设备的预期用途是支持机组人员的警觉性管理，可用于确保不会发生意外或未经授权的小睡，或能及时检测到小睡情况。
