Department of Ergonomics, Leibniz Research Centre for Working Environment and Human Factors Dortmund (IfADo), Dortmund, Germany.
Johanniter-Klinik am Rombergpark, Dortmund, Germany.
Psychophysiology. 2021 Jun;58(6):e13805. doi: 10.1111/psyp.13805. Epub 2021 Mar 8.
The phenomenon of mental fatigue has recently been investigated extensively by means of the EEG. Studies deploying spectral analysis consistently reported an increase of spectral power in the lower frequencies with increasing time-on-task, whereas event-related studies observed decreases in various measures related to task engagement and attentional resources. The results from these two lines of research cannot be aligned easily. (Frontal) theta power has been linked to cognitive control and was found to increase with time-on-task. In contrast, theoretical frameworks on mental fatigue suggest a decline in task-engagement as causal for the performance decline observed in mental fatigue. The goal of the present study was to investigate mental fatigue in time-frequency space using linear regression on single-trial data in order to obtain a better understanding about how time-on-task affects theta oscillatory activity. A data-driven analysis approach indicated an increase of alpha and theta power during the intertrial interval. In contrast, task-related theta activity declined. This reduction of stimulus-locked theta power may be interpreted as a reduction of task engagement with increasing mental fatigue. The increase of theta spectral power in the intertrial interval, moreover, could possibly be explained by an increased idling of cognitive control networks. Alternatively, it might be the case that the increase of theta power with time-on-task is a by-product an alpha power increase. As alpha peak frequency systematically decreases with time-on-task, the theta band might be affected as well.
最近，人们通过 EEG 广泛研究了心理疲劳现象。采用频谱分析的研究一致报告，随着任务时间的增加，频谱功率在较低频率下增加，而与事件相关的研究则观察到与任务参与和注意力资源相关的各种测量值下降。这两条研究路线的结果不容易协调。（额）theta 功率与认知控制有关，并且随着任务时间的增加而增加。相比之下，关于心理疲劳的理论框架表明，任务参与度的下降是导致心理疲劳中观察到的性能下降的原因。本研究的目的是使用单试次数据的线性回归在时频空间中研究心理疲劳，以更好地了解任务时间如何影响 theta 振荡活动。数据驱动的分析方法表明，在试验间间隔期间，alpha 和 theta 功率增加。相反，与任务相关的 theta 活动下降。刺激锁定 theta 功率的这种减少可以解释为随着心理疲劳的增加，任务参与度的降低。此外，试验间间隔中 theta 谱功率的增加可能可以通过认知控制网络的空闲增加来解释。或者，随着任务时间的增加，theta 功率的增加可能是 alpha 功率增加的副产品。由于随着任务时间的增加，alpha 峰值频率系统地降低，因此 theta 频段也可能受到影响。
