Evaluation of the Mental Fatigue Scale and its relation to Cognitive and Emotional Functioning after Traumatic Brain Injury or Stroke

Abstract

Objective: After traumatic brain injury (TBI) or stroke, long-term mental fatigue may occur with significant impact on work and social interactions. With the intention to measure mental fatigue irrespective of neurological illness, we developed the Mental Fatigue Scale (MFS). The scale incorporates affective, cognitive and sensory symptoms, duration of sleep and daytime variation in symptom severity. In this study, we evaluated the MFS and its relationship to cognitive and emotional functions. Participants: Healthy controls and well-rehabilitated subjects suffering from mental fatigue after mild TBI, TBI or stroke (age 19-69) were included in the study. Results: The results showed MFS to be invariant to age, gender and education. A cutoff score at 10.5 is suggested. Of the cognitive functions measured, information processing speed was found to be a significant predictor for the rating on MFS. We found that a significant effect on depression between controls and brain injured subjects can be a misleading conclusion if the effect of mental fatigue is not considered. Conclusions: We suggest MFS to be linked to mental impairment after brain injury. This study also demonstrated that mental fatigue must be treated as a separate construct and should not be mixed up with depression or anxiety.