Concordance of clinician judgment of mild traumatic brain injury history with a diagnostic standard.

INTRODUCTION Mild traumatic brain injury (mTBI), or concussion, is a defining injury of U.S. servicemembers who have served in the Iraq and Afghanistan wars. Recent estimates indicate self-reported or clinician-confirmed traumatic brain injury (TBI) ranging from 6.8 to 22.8 percent of Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) servicemembers and Veterans [1-6]. Blast (e.g., from bombs or improvised explosive devices [IEDs]) is the most prevalent mechanism of mTBI for OIF/OEF servicemembers [7-9], and vehicular accidents and falls [4,6] are other common etiologies of TBI among OIF/OEF servicemembers. Symptoms following mTBI typically resolve within hours or days, and usually last less than 12 mo, but can emerge or persist over time and interfere with daily functioning [10-11]. However, there is uncertainty as to whether symptoms that appear to be persistent are directly related to an mTBI incident [6,11-13]. Due to the prevalence and health consequences of mTBI, accurate determination of mTBI is important so that appropriate treatment is delivered and progress is evaluated. Identifying an mTBI event can be challenging. On the battlefield, moderate to severe forms of TBI can be recognized by obvious physical signs or functional limitations [14-15]. However, mTBI symptoms in their acute stage may go undetected for many reasons, including confounding mental (e.g., posttraumatic stress disorder [PTSD]) or physical (e.g., amputation) health conditions requiring more immediate attention [16-18], fast-paced battlefield situations in which mTBI and resulting change in consciousness or memory is unnoticed or undocumented, or servicemembers' reluctance to report injuries while deployed [16]. Imaging and neurological examinations for mTBI, if performed, may appear normal [11,17]. Because of these contextual factors, Veteran self-report, in conjunction with a medical examination [1], has become standard for identifying mTBI history in the Department of Veterans Affairs (VA) [11]. TRAUMATIC BRAIN INJURY SCREENING AND EVALUATION In April 2007, the VA mandated a TBI screening clinical reminder system for all OIF/OEF Veterans seeking VA healthcare [4,19-20]. Patients who report a prior TBI diagnosis upon screening are offered a referral for follow-up treatment. Patients without a prior TBI diagnosis are asked four sets of TBI screening questions regarding (1) events that increase TBI risk, (2) immediate symptoms following the event, (3) new or worsening symptoms postevent, and (4) current symptoms. Patients endorsing one or more questions in each of the four sections screen positive and are offered a referral for a VA comprehensive TBI evaluation (CTBIE) [11,19,21-22]. VA's standard for identifying TBI is a medical examination and in-depth clinical interview by a clinician assessing possible TBI events and current symptoms. The VA and Department of Defense (DOD) define TBI as a structural injury and/or disruption in brain function caused by an external force resulting in the onset or worsening of clinical signs immediately postevent [11]. These signs include loss of consciousness (LOC) or decreased level of consciousness, loss of memory for events immediately prior to or following the injury (posttraumatic amnesia [PTA]), and altered mental state (alteration of consciousness [AOC]) [11]. TBI is further categorized as mild, moderate, or severe based on the duration of these sequelae [11]. The VA/DOD clinical practice guidelines adopted criteria based on those of the American Congress of Rehabilitation Medicine (ACRM) for classifying mTBI. According to ACRM criteria, mTBI is defined as a physiological disruption in brain function that is manifested by at least one of the following: LOC [less than or equal to] 30 min, AOC [less than or equal to] 24 h, PTA