0930 Does Sleep Mediate the Relationship between Concussion Symptoms and Cognition in mildTBI Adults?

Abstract

Introduction: Mild Traumatic Brain Injury (mTBI) is characterized by a constellation of symptoms, including somatic, psychological, sleep and cognitive impairment. Although the effect of mTBI symptomatology on long-term sequelae has been studied, little is known about the mediating role of sleep disturbance between post-concussion symptom severity and cognitive deficits. We hypothesized that changes in sleep mediate the association between changes in concussion symptoms and cognition. Method(s): Fifty-eight individuals with mTBI, no history of concussions (34F;24M; aged: 42.60, SD=15.09) were evaluated (7 days to 1.5 years post-concussion). Average time between baseline and follow-up was 1.26 months(SD=0.48). The Rivermead Post-Concussive Questionnaire was used to assess psychological, somatic, and cognitive constructs. We assessed sleep disturbance by averaging four binary items: staying asleep,falling asleep, snoring, and rested in the morning. We analyzed score changes from baseline to follow-up. Structural equation modeling was used to estimate the mediation of sleep changes in the association between concussion symptoms (psychological and somatic) and changes in cognitive deficits. Model direct and indirect effects were evaluated using maximum likelihood estimation and bootstrapped confidence intervals. Result(s): Sleep changes did not mediate the association between changes in psychological and cognitive function (indirect effect: cognition-sleep-psychological:estimate=0.023;[-0.112, 0.176]), nor did sleep changes mediate the relationship between changes in somatic and cognitive deficits (indirect effect: cognition-sleep-somatic: estimate= 0.012;[-0.067, 0.106]). Interestingly, psychological changes had a significant effect on cognitive changes (estimate=0.462; [0.149, 0.775]) and sleep changes(estimate=0.643;[0.283, 1.003]). Therefore, improvements in psychological well-being had a positive effect on cognitive function and sleep quality. However, sleep changes did not affect the association between psychological and cognitive improvements. Improvements in somatic symptoms were associated with improvements in cognitive function (estimate= 0.532;[0.252, 0.812]) but not with sleep-quality changes (estimate= 0.326;[-0.073, 0.725]). Conclusion(s): Although results did not support the role of sleep changes as a mediator between changes in concussion symptoms and cognition, findings support the link between improvements in psychological or somatic symptoms and cognitive function. Rehabilitation therapies targeting post-concussion psychological and somatic symptoms may in turn reduce the impact of TBI on mental capacity complaints.