Impact of Somatic Vulnerability, Psychosocial Robustness and Injury-Related Factors on Fatigue following Traumatic Brain Injury—A Cross-Sectional Study

Abstract

Fatigue is a common symptom after traumatic brain injuries (TBI) and a crucial target of rehabilitation. The subjective and multifactorial nature of fatigue necessitates a biopsychosocial approach in understanding the mechanisms involved in its development. The aim of this study is to provide a comprehensive exploration of factors relevant to identification and rehabilitation of fatigue following TBI. Ninety-six patients with TBI and confirmed intracranial injuries were assessed on average 200 days post-injury with regard to injury-related factors, several patient-reported outcome measures (PROMS) of fatigue, neuropsychological measures, and PROMS of implicated biopsychosocial mechanisms. Factor analytic approaches yielded three underlying factors, termed Psychosocial Robustness, Somatic Vulnerability and Injury Severity. All three dimensions were significantly associated with fatigue in multiple regression analyses and explained 44.2% of variance in fatigue. Post hoc analyses examined univariate contributions of the associations between the factors and fatigue to illuminate the relative contributions of each biopsychosocial variable. Implications for clinical practice and future research are discussed.

Stability and Change in Biopsychosocial Factors Associated With Fatigue 6 and 12 Months After Traumatic Brain Injury: An Exploratory Multilevel Study

“…In a previous cross-sectional analysis of the first wave (6 months post-injury) of the current study, 15 we found 3 factors underlying biopsychosocial correlates of fatigue. Pain, somatic symptoms, daytime sleepiness, and insomnia were related to fatigue through a factor termed "somatic vulnerability."…”

“…In a previous cross-sectional analysis of the first wave (6 months post-injury) of the current study,15 we found 3 factors underlying biopsychosocial correlates of fatigue. Pain, somatic symptoms, daytime sleepiness, and insomnia were related to fatigue through a factor termed “somatic vulnerability.” Psychological distress, personality traits (neuroticism, extraversion, conscientiousness, and optimism), behavioral inhibition, and loneliness were associated with fatigue through a factor termed “psychosocial robustness.” Third, we demonstrated injury severity and neuropsychological variables to be associated with fatigue, although the effects were small.…”

“…Our study employed several fatigue measures, and in an earlier study we found a single, reliable factor underlying items from these PROMs in our sample 15. Fatigue was therefore measured with a factor analytic regression score, with factor loadings constrained across time (ie, assuming no time-related measurement invariance), using items from several fatigue PROMs.…”

“…Furthermore, several injury severity indices from the acute phase were included, e.g., Abbreviated Injury Scale–Head (AIS-head) 26. A variable was calculated for those patients discharged directly to rehabilitation from the neurosurgical department (direct pathway to rehabilitation), which was associated with fatigue in an earlier cross-sectional study on data from the first measurement 15. Finally, performance-based assessment with neuropsychological subtests from the Delis-Kaplan Executive Function System27 (Trail Making Test & Color Word Interference Test), Wechsler's Adult Intelligence Scale IV28 (Digit Span), Wechsler's Abbreviated Scale of Intelligence29 (Matrix Reasoning & Similarities), and Conners Continuous Performance Task III (CPT-III) were included.…”

“…Our study employed several fatigue measures, and in an earlier study we found a single, reliable factor underlying items from these PROMs in our sample. 15 Fatigue was therefore measured with a factor analytic regression score, with factor loadings constrained across time (ie, assuming no time-related measurement invariance), using items from several fatigue PROMs. The Fatigue Severity Scale 22 has been extensively used in the measurement of fatigue following TBI, and consists of 9 items pertaining to perceived impact of fatigue on various functional domains, of which only items 3 to 9 were included in the factor due to nonsalient loadings from items 1 and 2.…”