Effects of a Disengagement Intervention on Cognitive Performance in Those with a Mild Head Injury

Abstract

Mild head injury (MHI) is a major public health concern and cognitive fatigue following injury is one of the most commonly reported and debilitating symptoms that interfere with everyday life. The ventromedial prefrontal cortex (vmPFC) is especially susceptible during injury and is an important brain region in the context of traumatic brain injury; the vmPFC is responsible for regulating physiological arousal and the neuropathology following MHI has been shown to lead to physiological underarousal. Dampened physiological arousal has been shown to precede and give rise to cognitive fatigue, and that more severe injuries lead to both worsened physiological arousal and fatigue outcomes. The frontal regions most susceptible during injury are also largely involved in attentional processes, such that attentional processes are compromised following the neuropathology associated with MHI as well as from the onset of cognitive fatigue. Attentional deficits then arise in those with a history of MHI as a function of injury as well as cognitive fatigue compounding together; these attentional deficits then go on to impair overall cognitive functions which then present as poor performance on cognitively demanding tasks and, or, as a lessened ability to make optimal decisions in everyday life. Due to this, physiological arousal may then reflect cognitive resources available to individuals, and an opportunity to replenish these cognitive resources (i.e., a disengagement intervention) may lead to better performance outcomes on cognitively demanding tasks as well as improved fatigue ratings. This study sought to examine the effects of a disengagement intervention on cognitive performance across cognitively demanding tasks (i.e., Go/No-Go Task and Mental Rotation Task [MR Task]) in those with, and without, a history of MHI. It was found that those with a history of MHI exhibited lower physiological arousal as a function of injury severity, higher fatigue, and required more effort to meet task demands. It was also found that the Go/No-Go Task reliably induced cognitive fatigue as evidenced by diminished performance as a function of time on task, and that the stimulus-driven Go/No-Go Task slowly depleted cognitive resources while the goal-directed MR Task quickly exhausted cognitive resources. It was also found that having the opportunity to disengage from the task for a short period of time buffered performance decrements and lead to requiring less effort across cognitively demanding tasks. Additionally, it was also found that physiological arousal was dampened and fatigue was heightened as a function of the lockdowns imposed by the COVID-19 pandemic.