The associations of psychological stress and pain with cognitive functioning in hospitalized individuals following mild traumatic brain injury

The influence of psychological distress and pain on cognitive outcome following mild traumatic brain injury (mTBI) has received little empirical attention. The current research explored the associations of psychological distress and pain with cognitive functioning in adults following mTBI. A systematic review (Study 1) and two empirical studies (Studies 2 and 3) were undertaken. A systematic review was conducted to identify and evaluate the existing evidence regarding the relationship between psychological distress and cognitive functioning following mTBI. The search yielded 17 relevant papers. Evaluation of the design and methodology of the studies revealed that the quality of the evidence was limited. A prospective longitudinal study of consecutive trauma patients suggested lower cognitive performance in the presence of depressive symptoms. In an empirical investigation, 57 consecutive mTBI patients admitted to a Level 1 trauma hospital were recruited. Within 14 days of injury, participants completed self-report measures of acute post-traumatic stress, depression, and pain, and neuropsychological measures of attention, memory, processing speed, reaction time, working memory, and verbal fluency. In Study 2, canonical correlation analyses explored whether acute post-traumatic stress, depression, and pain were related to cognitive performance in a number of domains. Acute post-traumatic stress and pain were significantly associated with speed and accuracy performance on an extended version of the Ruff 2 & 7 Selective Attention Test. Study 3 further analyzed performance on this task using repeated measures multivariate analyses of variance. Performance was tested under three conditions of increasing cognitive demand (standard, auditory distraction, and dual-task conditions). Acute post-traumatic stress was associated with lower accuracy while depression was associated with higher accuracy. Acute post-traumatic stress, depression, and pain were associated with differential changes in speed performance as cognitive demands increased. The results highlight the potential for complex associations of acute post-traumatic stress, depression, and pain with cognitive functioning in the acute to sub-acute phase of mTBI. Accurate differential diagnosis in neuropsychological assessment and rehabilitation efforts may benefit from understanding the nature of these relationships.