Research Reports - A model of fatigue following traumatic brain injury
J Head Trauma Rehabil. 2014 Apr 9
Ponsford J(1), Schönberger M, Rajaratnam SM
OBJECTIVE:: Fatigue is one of the most frequent sequelae of traumatic brain
injury (TBI), although its causes are poorly understood. This study investigated
the interrelationships between fatigue and sleepiness, vigilance performance,
depression, and anxiety, using a structural equation modeling approach.
METHODS:: Seventy-two participants with moderate to severe TBI (78% males) were
recruited a median of 305 days postinjury. They completed the Fatigue Severity
Scale, a vigilance task, the Epworth Sleepiness Scale, and Hospital Anxiety and
Depression Scale. A model of the interrelationships between the study variables
was developed, tested, and modified with path analysis.
RESULTS:: The modified model had a good overall fit (χ2 = 1.3, P = .54;
comparative fit index = 1.0; root-mean square error of approximation = 0.0;
standardized root-mean square residual = 0.02). Most paths in this model were
significant (P < .05). Fatigue predicted anxiety, depression, and daytime
sleepiness. Depression predicted daytime sleepiness and poor vigilance, whereas
anxiety tended to predict reduced daytime sleepiness.
CONCLUSIONS:: This model confirms the complexity of fatigue experience. It
supports the hypothesis that fatigue after TBI is a cause, not a consequence, of
anxiety, depression, and daytime sleepiness, which, in turn (especially
depression), may exacerbate fatigue by affecting cognitive functioning. These
findings suggest that to alleviate fatigue, it is important to address each of
these factors. However, the findings need to be confirmed with a longitudinal