Deployment-related mild traumatic brain injury, mental health problems, and post-concussive symptoms in Canadian armed forces personnel

Bryan G. Garber ,Mark A. Zamorski ,Corneliu Rusu

doi:10.1186/preaccept-4758297971370968

Abstract

Up to 20% of US military personnel deployed to Iraq or Afghanistan experience mild traumatic brain injury (mTBI) while deployed; up to one-third will experience persistent post-concussive symptoms (PCS). The objective of this study was to examine the epidemiology of deployment-related mTBI and its relationship to PCS and mental health problems (MHPs) in Canadian Armed Forces (CAF) personnel. Participants were 16153 personnel who underwent post-deployment screening (median =136 days after return) following deployment in support of the mission in Afghanistan from 2009 - 2012. The screening questionnaire assessed mTBI and other injuries while deployed, using the Brief Traumatic Brain Injury Screening Tool. Current MHPs and PCS were assessed using items from the Patient Health Questionnaire, the Patient Checklist for PTSD, and the Cognitive Failures Questionnaire. Log-binomial regression explored the association of mTBI, other injuries, and MHPs with PCS, using the presence of 3 or more of 7 PCS as the outcome. Results are expressed as adjusted prevalence ratios (PR). mTBI while deployed was reported in 843 respondents (5.2%). Less severe forms of mTBI (associated only with having been dazed or confused or having "seen stars") predominated. Blast was reported as a mechanism of injury in half of those with mTBI. Multiple PCS were present in 21% of those with less severe forms of mTBI and in 27% of those with more severe forms of mTBI (i.e., mTBI associated with loss of consciousness or post-traumatic amnesia). After adjustment for confounding, mTBI had no statistically significant association with PCS relative to non-TBI injury. In contrast, MHPs had a strong association with reporting 3 or more PCS (adjusted prevalence ratio (PR) =7.77). Deployment-related mTBI prevalence was lower than in many US reports; most of those who had had mTBI were free of multiple PCS. PCS was strongly associated with MHPs but not with mTBI. Careful assessment of MHPs is essential in personnel with a history of combat-related mTBI and PCS.

Highlights

Up to 20% of United States (US) military personnel deployed to Iraq or Afghanistan experience mild traumatic brain injury while deployed; up to one-third will experience persistent post-concussive symptoms (PCS)
The fundamental purpose of this study is to examine the epidemiology of mild traumatic brain injury (mTBI) in a different military population using data from a large population-based clinical screening program that employs the same case definitions and screening tools as most of the published US studies. It uses data collected during the mandatory Enhanced Post-deployment Screening process on Canadian military personnel deployed in support of the mission in Afghanistan to: 1) Determine the prevalence of self-reported mTBI while deployed; 2) Determine the prevalence of multiple PCS in the post-deployment period in those with and without a history of deployment-related mTBI; 3) Explore the role of a broader range of mental health problems and mTBI with PCS in the post-deployment period; and Respondents Respondents were 16193 Canadian Armed Forces (CAF) personnel who deployed in support of the mission in Afghanistan who completed a version of the Enhanced Post-deployment Screening (EPDS) questionnaire with questions on mTBI over the period January 2009 – July 2012
Combat exposure increased the risk of mTBI, with 12.61 (%) of those in the highest tertile reporting mTBI vs. 1.15 (%) in the lowest tertile. 1356 (8.8%) had symptoms of one or more of the three mental health problems assessed, with the prevalence of post-traumatic stress disorder (PTSD), depression, and panic disorder being 5.7%, 3.7%, and 1.9%, respectively

Summary

Introduction

Up to 20% of US military personnel deployed to Iraq or Afghanistan experience mild traumatic brain injury (mTBI) while deployed; up to one-third will experience persistent post-concussive symptoms (PCS). Prevalence estimates for deployment-related mTBI have ranged from 4.4% to 23%, with higher rates being seen in troops with heavy combat exposure [3,4] In both military personnel and civilians, a variety of acute, transient physical symptoms (e.g., headache, dizziness) and cognitive deficits can result from mTBI [5]. Persistence of those symptoms and/or cognitive impairments after deployment-related mTBI can erode quality of life, interfere with fitness for duty, and serve as a trigger for benefits for veterans [6]. In addition to these concerns about the public health impact of deployment-related mTBI, there has been concern that the pathophysiology and prognosis of blast-related mTBI (a common mechanism in deployment-related mTBI) may differ from that of other injury mechanisms [7,8]

Objectives

Methods

Results

Conclusion