Prognostic Indicators of Persistent Post-Concussive Symptoms after Deployment-Related Mild Traumatic Brain Injury: A Prospective Longitudinal Study in U.S. Army Soldiers

Abstract

Mild traumatic brain injury (mTBI), or concussion, is prevalent in the military. The course of recovery can be highly variable. This study investigates whether deployment-acquired mTBI is associated with subsequent presence and severity of post-concussive symptoms (PCS) and identifies predictors of persistent PCS among US Army personnel who sustained mTBI while deployed to Afghanistan. We used data from a prospective longitudinal survey of soldiers assessed 1-2 months before a 10-month deployment to Afghanistan (T0), on redeployment to the United States (T1), approximately 3 months later (T2), and approximately 9 months later (T3). Outcomes of interest were PCS at T2 and T3. Predictors considered were: sociodemographic factors, number of previous deployments, pre-deployment mental health and TBI history, and mTBI and other military-related stress during the index deployment. The study sample comprised 4518 soldiers, 822 (18.2%) of whom experienced mTBI during the index deployment. After adjusting for demographic, clinical, and deployment-related factors, deployment-acquired mTBI was associated with nearly triple the risk of reporting any PCS and with increased severity of PCS when symptoms were present. Among those who sustained mTBI, severity of PCS at follow-up was associated with history of pre-deployment TBI(s), pre-deployment psychological distress, more severe deployment stress, and loss of consciousness or lapse of memory (versus being "dazed" only) as a result of deployment-acquired mTBI. In summary, we found that sustaining mTBI increases risk for persistent PCS. Previous TBI(s), pre-deployment psychological distress, severe deployment stress, and loss of consciousness or lapse of memory resulting from mTBI(s) are prognostic indicators of persistent PCS after an index mTBI. These observations may have actionable implications for prevention of chronic sequelae of mTBI in the military and other settings.

Keywords: concussion; deployment; mental health; military; stress; traumatic brain injury.

Conflict of interest statement

Author Disclosure Statement Army STARRS was sponsored by the Department of the Army and funded under cooperative agreement number U01MH087981 with the U.S. Department of Health and Human Services, National Institutes of Health, National Institute of Mental Health (NIH/NIMH). The contents are solely the responsibility of the authors and do not necessarily represent the views of the Department of Health and Human Services, NIMH, the Veterans Administration, Department of the Army, or the Department of Defense. Dr. Stein has in the last 3 years been a consultant for Healthcare Management Technologies, Tonix Pharmaceuticals, Janssen, and Pfizer. In the past 3 years, Dr. Kessler has been a consultant for Hoffman-La Roche, Inc., Johnson & Johnson Wellness and Prevention, and Sonofi-Aventis Groupe. Dr. Kessler has served on advisory boards for Mensante Corporation, Plus One Health Management, Lake Nona Institute, and U.S. Preventive Medicine. Dr. Kessler owns 25% share in DataStat, Inc. For the remaining authors report, no competing financial interests exist.