Severe or very severe postconcussive symptoms, including sleep difficulties and forgetfulness, persist at 1-year follow-up in service members with mild traumatic brain injuries (mTBIs), according to a study in the American Journal of Epidemiology.
Soldiers with ≥1 postdeployment mTBI were recruited from 2 US Army bases within <1 week of their return from Afghanistan or Iraq (ClinicalTrials.gov identifier: NCT01847040). The Brief Traumatic Brain Injury Screen was used to identify mTBI in this cohort. Patients were categorized as either TBI screen negative (n=1010) or TBI screen positive (n=557), which was defined as any soldier who had injury exposure in theater that resulted in immediate loss of consciousness, forgetting the injury, or altered loss of consciousness.
At 3-, 6-, and 12-month in-person and telephone follow-up, investigators assessed changes on the 22-item Neurobehavioral Symptom Inventory, which assessed symptoms associated with concussion. Symptom severity was rated on the 5-item Likert scale with concurrent use of the Validity-10 Scale to determine potential symptom exaggeration.
A significantly greater number of patients with mTBI were more likely to have ≥1 postconcussive symptom at either severe or very severe levels and at all time points (47% vs 21% baseline; adjusted risk ratio [aRR]=1.7; 95% CI, 1.51-1.93; P <.0001). These findings remained significant when the investigators adjusted for the incidence of posttraumatic stress disorder (aRR=1.34; 95%CI, 1.41-1.82). The most frequently reported postconcussive symptoms at baseline for participants who were positive and negative for mTBI included sleeping difficulties, forgetfulness, irritability, and headaches.
Compared with those who were negative for mTBI, those with mTBI had a higher risk for ≥1 severe or very severe baseline Neurobehavioral Symptom Inventory symptom (RR=1.94; 95% CI, 1.71-2.19). Additionally, more patients with mTBI had a higher risk for severe or very severe sleep scores at each follow-up compared with patients without mTBI (RR=2.19; 95% CI, 1.83-2.62). Over the 1-year follow-up period, the prevalence of postconcussive symptoms remained constant.
Limitations of the study include the self-reported nature of the collected and analyzed data as well as the inclusion of only soldiers who served in Afghanistan or Iraq, which may limit generalizability across the entire US military patient population.
Based on their findings, the investigators suggest that “health systems may consider targeting some of the more highly prevalent and highly elevated symptom burden over time in formats readily accessible to” military personnel with mTBI.
Ferdosi H, Schwab KA, Metti A, et al. Trajectory of postconcussive symptoms 12 months after deployment in soldiers with and without mild traumatic brain injury: warrior strong study [published online September 7, 2018]. Am J Epidemiol. doi: 10.1093/aje/kwy199