Neural based assessment of mind wandering during a fatigueinducing motor task: Is task failure due to fatigue or distraction?

This study developed a method for investigating mind wandering (MW) in a fatigue-inducing motor task. To develop research protocols to assess fatigue in clinical cohorts, it is important that participants perform the task at hand to the best of their ability and with their complete attention. Therefore, it is important to know if the participant fails in the task due to fatigue or lack of sustained attention as a result of MW. Two cohorts of 12 healthy controls and Chronic Fatigue Syndrome (CFS) subjects performed a hand-grip fatigue-inducing motor task while EMG and EEG were simultaneously recorded. Frontal midline theta (FMT) and parietal alpha power were calculated throughout the task. While no significant differences were obtained in the FMT power for both cohorts, significant differences in parietal alpha power for the healthy subjects across the task shows they may have experienced MW unlike CFS subjects, who had to put in consistent effort to sustain attention during the task, which could imply fewer MW events. Assessing MW using EEG can serve as an objective marker for evaluating performance in a task and, for assessing the impact of fatigue on the ability to sustain attention.