Fatigue in the first year after traumatic brain injury: course, relationship with injury severity, and correlates.

The objectives of this study were to document the evolution of fatigue in the first year after traumatic brain injury (TBI), and to explore correlates of fatigue. Participants were 210 adults who were hospitalised following a TBI. They completed questionnaires 4, 8, and 12 months post-injury, including the Multidimensional Fatigue Inventory (MFI). Participants with severe TBI presented greater mental and physical fatigue, and reduced activity compared to participants with moderate TBI. For all MFI subscales except reduced motivation, the general pattern was a reduction of fatigue levels over time after mild TBI, an increase of fatigue after severe TBI, and stable fatigue after moderate TBI. Fatigue was significantly associated with depression, insomnia, cognitive difficulties, and pain at 4 months; the same variables and work status at 8 months; and depression, insomnia, cognitive difficulties, and work status at 12 months. These findings suggest that injury severity could have an impact on the course of fatigue in the first year post-TBI. Depression, insomnia, and cognitive difficulties remain strong correlates of fatigue, while for pain and work status the association with fatigue evolves over time. This could influence the development of intervention strategies for fatigue, implemented at specific times for each severity subgroup.