title: Multiple Past Concussions Are Associated with Ongoing Post-Concussive Symptoms but Not Cognitive Impairment in Active-Duty Army Soldiers.
abstract: The extent to which multiple past concussions are associated with lingering symptoms or mental health problems in military service members is not well understood. The purpose of this study was to examine the association between lifetime concussion history, cognitive functioning, general health, and psychological health in a large sample of fit-for-duty U.S. Army soldiers preparing for deployment. Data on 458 active-duty soldiers were collected and analyzed. A computerized cognitive screening battery (CNS-Vital Signs(®)) was used to assess complex attention (CA), reaction time (RT), processing speed (PS), cognitive flexibility (CF), and memory. Health questionnaires included the Neurobehavioral Symptom Inventory (NSI), PTSD Checklist-Military Version (PCL-M), Zung Depression and Anxiety Scales (ZDS; ZAS), Perceived Stress Scale (PSS), Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and the Alcohol Use and Dependency Identification Test (AUDIT). Soldiers with a history of multiple concussions (i.e., three or more concussions) had significantly greater post-concussive symptom scores compared with those with zero (d=1.83, large effect), one (d=0.64, medium effect), and two (d=0.64, medium effect) prior concussions. Although the group with three or more concussions also reported more traumatic stress symptoms, the results revealed that traumatic stress was a mediator between concussions and post-concussive symptom severity. There were no significant differences on neurocognitive testing between the number of concussions. These results add to the accumulating evidence suggesting that most individuals recover from one or two prior concussions, but there is a greater risk for ongoing symptoms if one exceeds this number of injuries.
authors.affiliation: 1 U.S. Army Aeromedical Research Laboratory, Fort Rucker, Alabama; National Intrepid Center of Excellence, Walter Reed National Military Medical Center , Bethesda, Maryland.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Dretsch
authors.affiliation: 2 Division of Physical Medicine and Rehabilitation, University of British Columbia and GF Strong Rehab Centre , Vancouver, British Columbia, Canada .
authors.forename: Noah D
authors.initials: ND
authors.lastname: Silverberg
authors.affiliation: 3 Department of Physical Medicine and Rehabilitation, Harvard Medical School and Red Sox Foundation and Massachusetts General Hospital Home Base Program, Boston, Massachusetts; Defense and Veterans Brain Injury Center , Bethesda, Maryland.
authors.forename: Grant L
authors.initials: GL
authors.lastname: Iverson
mesh_terms: D000328:Adult; D001924:Brain Concussion / Q000150:complications* / Q000453:epidemiology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008889:Military Personnel / Q000706:statistics & numerical data*; D038223:Post-Concussion Syndrome / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: PTSD; concussion; military; neurocognitive; post-concussion symptoms