Effects of Blast-and Impact-Related Concussion on Persistent Sleep Problems.

OBJECTIVE: Examine whether concussion mechanism of injury (high-level blast [HLB] vs impact) affects the likelihood of persistent sleep problems in a post-deployment military population. SETTING: Post-Deployment Health Assessment and Re-Assessment survey records completed upon return from deployment and approximately 6 months later. PARTICIPANTS: Active duty enlisted US Marines who completed both assessments (N = 64 464). DESIGN: This retrospective cohort study investigated US Marines deployed between 2008 and 2012. Logistic regression was used to examine persistent sleep problems 6 months after return from deployment. MAIN MEASURES: Self-reported sleep problems at reassessment were investigated as the outcome. Predictors included HLB-induced concussions (mbTBI vs none), impact-induced concussions (miTBI vs none), occupational risk of low-level blast, probable posttraumatic stress disorder (PTSD), depression, alcohol misuse, sleep problems upon deployment return, and relevant interactions, adjusting for sex and pay grade. RESULTS: With the exception of sex, all main effects in the model were associated with greater likelihood of reporting persistent sleep problems at reassessment. Sleep problems at return from deployment showed the strongest associations with likelihood of reporting sleep problems at reassessment, followed by mbTBI. The latter was exacerbated by PTSD and depression. CONCLUSION: mbTBI (vs miTBI) may be more strongly associated with persistent sleep issues that warrant additional monitoring and treatment, particularly among those with probable PTSD and/or depression.

The Effect of Concussion Mechanism of Injury on Sleep Problems in Active Duty Service Members Following Deployment.

INTRODUCTION: Sleep disruption is pervasive in the military and is generally exacerbated during deployment, partially due to increases in operational tempo and exposure to stressors and/or trauma. In particular, sleep disruption is a commonly reported symptom following deployment-related traumatic brain injury (TBI), though less is known about the prevalence of sleep disturbance as a function of whether the TBI was induced by high-level blast (HLB) or direct impact to the head. TBI assessment, treatment, and prognosis are further complicated by comorbidity with posttraumatic stress disorder (PTSD), depression, and alcohol misuse. Here, we examine whether concussion mechanism of injury is associated with differences in the prevalence of self-reported sleep disturbance following deployment in a large sample of U.S. Marines while accounting for probable PTSD, depression, and alcohol misuse. MATERIALS AND METHODS: This was a retrospective cohort study of active duty enlisted Marines with a probable concussion (N = 5757) who completed the Post-Deployment Health Assessment between 2008 and 2012. Probable concussion was defined as endorsement of a potentially concussive event with corresponding loss or alteration of consciousness. The presence of concussion-related sleep problems was assessed with a dichotomous item. Probable PTSD, depression, and alcohol misuse were assessed using the Primary Care PTSD Screen, the Patient Health Questionnaire-2, and the Alcohol Use Identification Test-Concise, respectively. Logistic regression models investigated the effects of mechanism of injury (HLB vs. impact), PTSD, depression, and alcohol misuse on the presence of sleep problems, adjusting for sex and pay grade. The study was approved by the Naval Health Research Center Institutional Review Board. RESULTS: Approximately 41% of individuals with a probable deployment-related concussion reported sleep problems following the event; 79% of concussed individuals reporting both HLB and probable PTSD reported sleep problems. All main effects were significantly associated with sleep disturbance in adjusted models. PTSD showed the strongest association with sleep disturbance (adjusted odds ratio [AOR] = 2.84), followed by depression (AOR = 2.43), HLB exposure (AOR = 2.00), female sex (AOR = 1.63), alcohol misuse (AOR = 1.14), and pay grade (AOR = 1.10). A significant HLB × PTSD interaction emerged (AOR = 1.58), which suggests that sleep disturbance was elevated among those with both HLB-induced (vs. impact-induced) concussions and presence (vs. absence) of PTSD. No other significant interactions emerged. CONCLUSION: To our knowledge, this is the first study to examine the prevalence of concussion-related sleep complaints following deployment as a function of the mechanism of injury in individuals with and without probable PTSD and depression. Individuals with HLB-induced concussion were twice as likely to report sleep problems as those with an impact-induced concussion. Future work should examine these effects longitudinally with validated measures that assess greater precision of exposure and outcome assessment (e.g., blast intensity and type of sleep disturbance).