Institute of Sport Science, University of Rostock, Germany.
Department of Orthopaedics, University Medicine Rostock, Germany.
J Gerontol A Biol Sci Med Sci. 2018 May 9;73(6):792-797. doi: 10.1093/gerona/glx210.
Mental fatigue is a psychobiological state induced by sustained periods of demanding cognitive activity and is characterized by feelings of tiredness which are common in everyday life. Recently, it has been hypothesized that mental fatigue might have an impact on gait performance in old adults. Therefore, the effect of mental fatigue on gait performance under single- and dual-task conditions was investigated in young and old participants.
Spatio-temporal gait parameters of 16 young and 16 old healthy participants were measured using a photoelectric system during single- and dual-task walking before and after a randomly assigned mental fatigue (performing a stop-signal task for 90 minutes) and control intervention (watching a video for 90 minutes), respectively. Changes in subjective fatigue, wakefulness, mood, arousal, and psychophysiological workload (heart rate variability indices) were assessed.
Psychometric measures indicated increased subjective fatigue and arousal as well as decreased mood and wakefulness after the mental fatigue task. Heart rate variability indices revealed a higher psychophysiological workload during the mental fatigue intervention in old compared to young participants. Gait measures (coefficient of variation of speed, stride length, and stance time) revealed impaired dual-task walking performance following the mental fatigue intervention only in old participants.
Data indicate that mental fatigue, induced by sustained cognitive activity, can impair gait performance during dual-task walking in old adults. The susceptibility to mental fatigue could be a new intrinsic risk factor for falls in older people and should be taken into account when dual-task gait analyses are performed.
精神疲劳是一种由持续的高要求认知活动引起的心理生物学状态，其特征是疲劳感，这种疲劳感在日常生活中很常见。最近，有人假设精神疲劳可能会对老年人的步态表现产生影响。因此，本研究在年轻和老年参与者中分别考察了精神疲劳对单任务和双任务条件下步态表现的影响。
使用光电系统测量了 16 名年轻和 16 名健康的老年参与者在单任务和双任务行走期间的时空步态参数，分别在随机分配的精神疲劳（执行停止信号任务 90 分钟）和对照干预（观看视频 90 分钟）前后进行。评估了主观疲劳、觉醒度、情绪、唤醒度和心理生理工作量（心率变异性指数）的变化。
心理测量学指标表明，精神疲劳任务后主观疲劳和唤醒度增加，情绪和觉醒度降低。心率变异性指数显示，与年轻参与者相比，老年参与者在精神疲劳干预期间的心理生理工作量更高。步态测量（速度变异系数、步长和站立时间）仅在老年参与者中显示出精神疲劳干预后双任务行走表现受损。
数据表明，持续认知活动引起的精神疲劳会损害老年人在双任务行走中的步态表现。对精神疲劳的敏感性可能是老年人跌倒的一个新的内在风险因素，在进行双任务步态分析时应予以考虑。
