Mental fatigue mediates the relationship between cognitive functions and return to productive activity following traumatic brain injury: a mediation analysis

Purpose: We performed a mediation analysis to investigate how mental fatigue mediates the relationship between cognitive functions and the return to productive activity following TBI. Methods: One hundred and one people (≥20 years) with first-time TBI more than 3 months who completed a series of cognitive tasks followed by Chinese versions of the Mental Fatigue Scale and Community Integration Questionnaire-Revised. Mediation analysis was used to test our hypotheses. Results: Recognition memory and information processing speed were the only cognitive functions correlated with mental fatigue (B = −0.56 and −0.37, P = .04 and < 0.001) and the return to productive activity (B = 0.69 and 0.19, both P < .001) after controlling for confounders. Mental fatigue partially mediated the associations of recognition memory and information processing speed with the return to productive activity (B = 0.15 and 0.08, P = .001 and < 0.001, proportion of mediation = 22% and 46%) after the adjustment of confounders. Conclusions: The findings suggest that mental fatigue can partially mediate the relationship between cognitive deficits and return to productive activity. Mental fatigue can be considered a crucial, treatable mediator of the adverse effects of cognitive impairment upon return to productive activity following TBI.