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    1 Comment for this article
    Comments on "Longitudinal Effects of Mild Traumatic Brain Injury and Posttraumatic Stress Disorder..
    Karen Schwab, PhD | Defense and Veterans Brain Injujry Center; Dept of Neurology, WRAMC,
    Comments on “Longitudinal Effects of Mild Traumatic Brain Injury and Posttraumatic Stress Disorder Comorbidity on Postdeployment Outcomes in National Guard Soldiers Deployed to Iraq,” Polusny et al, Arch Gen Psychiatry/Vol 68 (No 1) Jan 2011. Outcomes for individuals exposed to trauma during combat service in Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND), whether physical or psychological, have been examined in multiple articles.1-4 In their recent article, Polusny et al., state that postdeployment postconcussive symptoms and psychosocial outcomes were strongly associated with PTSD and that “…a history of concussion/MTBI alone does not contribute to long-term impairments in the health and well- being of OIF veterans.” They conclude that given these results and the doubling of self-reported concussion/mTBI history, current screening and treatment approaches for MTBI need to be rethought. However, given the survey based nature of the investigation, the small sample size of individuals who experienced mTBI/concussion, the design of the analyses, and their longitudinal data on one-year outcomes, their conclusions are not supported.
    The study addresses the important issue of one year outcomes, including chronic symptoms, depression, alcohol use, and quality of life. Our discussion point is not with the questions they ask, nor their point that PTSD is a serious issue for returning service members, but their methodology for examining the effects of mTBI and PTSD upon outcomes, and their incomplete reporting of their longitudinal findings.
    The analyses were based only on those individuals who participated in the survey at Time 1 (one month prior to return to the United States) and Time 2 (1 year later). This, along with a low injury rate in the sample of National Guard Soldiers returning from deployment to Iraq, limited the sample size for individuals with mTBI reported at Time 1 only (N=60) and may have limited the power to detect differential long-term outcomes in study participants. There was no control for multiple injuries or for the severity of the injury reported. In addition, they have analyzed data that is only by self report, without a clinically confirmed evaluation of concussion, the standard of care for diagnosing mTBI and subsequent post concussion symptoms or syndrome. The authors do not report whether individuals with self-reported TBI at Time 1 were disproportionately likely to drop out of the study before Time 2. Further, the manner in which the two time points were used in much of the analysis is not in line with a longitudinal analysis strategy. They use time 1 reports of MTBI versus time 2 reports of PTSD symptoms in order to compare the relative effects on one year outcomes for much of their analysis. The authors note that self-reported rates of in theater mTBI were 2.4 times higher at the second time point (one year after returning to the United States) than at time 1, and suggest that self-reported mTBI therefore has “limited reliability.” And though they found that rates of self-reported PTSD also increased over the same time period (1.8 times higher), they do not address reliability issues suggested by the increase of PTSD symptom reporting.
    Their conclusion that “…a history of concussion/MTBI alone does not contribute to long-term impairments in the health and well-being of OIF veterans.” overlooks their longitudinal findings. In fact, their study provides good preliminary evidence of the effect of mTBI on some (though not all) of outcomes measured 12 months post-deployment. In the portion of their analyses that provided a true longitudinal comparison of PTSD and MTBI (with both measured at Time 1) to subjects’ 12 month outcomes is of interest. As they note, previous civilian research indicates that problems after MTBI resolve quickly for most individuals. Nevertheless, despite the time period from injury to the assessment of continued symptoms and outcomes, they found that post-concussive symptoms, depression, and alcohol use (though not 4 other outcomes) were associated with MTBI, after controlling for Time 1 PTSD symptoms. It should be noted that they exclude depression as a finding due to p value of .03, but it is certainly worth exploring in future studies. And, a minor point, the blast question they used was not part of the Defense and Veterans Brain Injury Center’s (DVBIC) screening tool.
    The authors end with suggestions that TBI screening efforts in the Departments of Defense and Veterans Affairs are in place because of concerns that long-term disability and impairment can result. Their data suggest that some outcomes are affected by mTBI. As described in DoD/DVA Clinical Practice Guidelines on the Management of Concussion/mild Traumatic Brain Injury,5 the intention of the screening efforts by these two departments is very well in line with recent findings in the literature regarding the assessment and treatment of the constellation of symptoms experienced by our service members and veterans, to detect symptoms that are impairing individuals’ functioning (whether acute or longer term), and to provide care that allows them to participate fully in their work, home, and community.
    Karen Schwab, PhD [1] Alison Cernich, PhD [2, 3]
    [1]Defense and Veterans Brain Injury Center, Walter Reed Army Medical Center, Washington, DC. [2]VA Maryland Health Care System, Baltimore, MD [3]University of Maryland School of Medicine, Baltimore, MD
    1. McAllister TM, Stein MB, Effects of Psychological and Biomechanical Trauma on Brain and Behavior. Annals of the New York Academy of Sciences, October, 2010.
    2. Schneiderman AI, Braver ER, Kang HK, Understanding Sequelae of Injury Mechanisms and Mild Traumatic Brain Injury Incurred during the Conflicts in Iraq and Afghanistan: Persistent Postconcussive Symptoms and Posttraumatic Stress Disorder. Am J Epidemiol. 2008; 167: 1446-1452.
    3. Brenner LA, Terrio H, Homaifar BY, Gutierrez PM, Staves PJ, Harwood JEF, Reeves D, Adler LE, Ivins BJ, Helmick K, Warden D. Neuropsychological Test Performance in Soldiers with Blast-Related Mild TBI. Neuropsychology. 2010; 24(2): 160-167.
    4. Hoge CW, McGurk D, Thomas JL, Cox AL, Engel CC, Castro CA. Mild Traumatic Brain Injury in U.S. Soldiers Returning from Iraq. N Engl J Med. 2008; 358(5): 453-463.
    5. VA/DoD Clinical Practice Guideline for Management of Concussion/Mild Traumatic Brain Injury; Department of Veterans Affairs, Department of Defense, Version 1.0-2009.
    Disclaimer: The views expressed here are those of the authors and do not necessarily represent the official policy or position of Walter Reed Army Medical Center, the Defense and Veterans Brain Injury Center, University of Maryland School of Medicine, the Department of the Army, the Department of Defense, the Department of Veterans Affairs, or the US Government.

    Conflict of Interest: None declared
    Original Article
    January 3, 2011

    Longitudinal Effects of Mild Traumatic Brain Injury and Posttraumatic Stress Disorder Comorbidity on Postdeployment Outcomes in National Guard Soldiers Deployed to Iraq

    Author Affiliations

    Author Affiliations: Mental Health Patient Service Line (Drs Polusny, Nelson, Erbes, Arbisi, and Thuras) and Research Service (Dr Kehle), Minneapolis Veterans Affairs Health Care System, Center for Chronic Disease Outcomes Research (Drs Polusny and Kehle), and Departments of Psychiatry (Drs Polusny, Nelson, Erbes, Arbisi, and Thuras) and Psychology (Dr Arbisi), University of Minnesota Medical School, Minneapolis, Minnesota.

    Arch Gen Psychiatry. 2011;68(1):79-89. doi:10.1001/archgenpsychiatry.2010.172

    Context  Troops deployed to Iraq and Afghanistan are at high risk for exposure to combat events resulting in mild traumatic brain injury (MTBI) or concussion and posttraumatic stress disorder (PTSD). The longer-term impact of combat-related concussion/MTBI and comorbid PTSD on troops' health and well-being is unknown.

    Objective  To assess longitudinal associations between concussion/MTBI and PTSD symptoms reported in theater and longer-term psychosocial outcomes in combat-deployed National Guard soldiers.

    Design  Longitudinal cohort study. Participants were surveyed in Iraq 1 month before returning home (time 1) and 1 year later (time 2). Self-reports of concussion/MTBI and PTSD were assessed at times 1 and 2. Based on time 1 concussion/MTBI status (defined as an injury during deployment with loss of consciousness or altered mental status) and time 2 postdeployment probable PTSD status, soldiers were compared on a range of time 2 psychosocial outcomes.

    Participants  Nine hundred fifty-three US National Guard soldiers.

    Setting  The time 1 sample was assessed during redeployment transition briefings held at military installations in the Iraq combat theater. The time 2 sample was assessed using mailed surveys sent to the homes of US National Guard service members.

    Main Outcome Measures  Postconcussive, depression, and physical symptoms; alcohol use; social functioning; and quality of life assessed at time 2 using valid clinical instruments.

    Results  The rate of self-reported concussion/MTBI during deployment was 9.2% at time 1 and 22.0% at time 2. Soldiers with a history of concussion/MTBI were more likely than those without to report postdeployment postconcussive symptoms and poorer psychosocial outcomes. However, after adjusting for PTSD symptoms, concussion/MTBI was not associated with postdeployment symptoms or outcomes. Time 1 PTSD symptoms more strongly predicted postdeployment symptoms and outcomes than did concussion/MTBI history.

    Conclusions  Although combat-related PTSD was strongly associated with postconcussive symptoms and psychosocial outcomes 1 year after soldiers returned from Iraq, there was little evidence of a long-term negative impact of concussion/MTBI history on these outcomes after accounting for PTSD. These findings and the 2-fold increase in reports of deployment-related concussion/MTBI history have important implications for screening and treatment.