“Fatigue of Brain Scale” for the Measurement of Cognitive and Behavioral States in Mental Health Problems: A Scale Development Study

Abstract Background To help workers balance work and personal life while experiencing illness, we developed a self-monitoring assessment tool for workers. We conceptualized " Fatigue of Brain" as a state of dysfunction of the central nervous system, such as decreased brain function and mental health problems, and attempted to measure it in a comprehensive, simple, and quantitative manner. We also developed cutoff points and provided indicators of conditions that would require a recommendation for medical examination. Methods We developed the items of the Fatigue of Brain Scale to measure the “Fatigue of Brain” state, and conducted factor analysis, comorbid validity, and retest reliability verification. The first survey (Survey 1) was conducted between February-March 2019, and the second survey (Survey 2) was conducted one month later. Men and women aged 18–64 years, who had experienced a leave of absence due to physical or mental health problems within the past 10 years were included in the survey. A total of 460 participants (211 men and 249 women, mean age 45.64 ± 9.62 years) were recruited for Survey 1, and 334 participants (161 men and 173 women, mean age 46.72 ± 10.11 years) for Survey 2. Receiver Operating Characteristic curve analysis was then used to examine the optimal cut-off value for this scale. Results A clear factor structure was obtained for 20 items consisting of four factors: "decline in role execution function," "social/daily function decline," "lack of sleep," and "maladaptive cognitive and behavioral responses," and sufficient reliability and validity were confirmed. In addition, cut-off values for “mild Fatigue of Brain,” “moderate Fatigue of Brain,” “severe Fatigue of Brain,” and “extreme Fatigue of Brain” were established. Conclusions If workers are aware of their current performance status and are able to self-manage their performance better, this would play an important part in trying to maintain good health, improve individual productivity, and contribute to company profits. The usefulness of this scale needs to be further verified by using it in actual workplaces in the future.