97 - The Presentation and Resolution of Neurobehavioral Symptoms Among Active-Duty Service Members Treated at Outpatient Traumatic Brain Injury Clinics within the Military Health System
Abstract Text: Introduction: Mild traumatic brain injury (mTBI) is the most prevalent brain injury among United States Service Members (SMs). These injuries can cause an array of physical, behavioral/emotional, and cognitive symptoms. Currently, the Neurobehavioral Symptom Inventory (NSI), a 22-item self-reported questionnaire, assists in the evaluation of these symptoms. As identified as a core outcome measure for post-concussion healthcare within the Department of Defense and the Veterans Administration, the NSI is often embedded within the comprehensive evaluation of mTBI at outpatient Military Treatment Facilities (MTFs). The main interventional approach at these outpatient traumatic brain injury clinics focuses on symptom management.
While previous research has identified the prevalence of common post-concussive symptoms, limited work has focused on TBI outpatient clinics within the Military Health System (MHS) and seldom incorporates multi-site data. As such, this analysis provides a thorough evaluation of the prevalence and resolution of symptoms experienced by SMs who have sought treatment at TBI outpatient clinics within the Military Health System.
MATERIALS AND Methods: This is a retrospective study of active-duty SMs with a history of concussion evaluated and treated at Category 1 or Category 2 outpatient TBI clinics within the Military Health System. NSI data was extracted from the TBI Portal, a Defense Health Agency enterprise platform that aggregates clinical information from disparate data systems. NSI questionnaires completed at Intensive Outpatient Program (IOP), Acute Concussion Clinic, and Brain Fitness Center were excluded. Participants were administered the NSI at initial intake and upon re-evaluation (15-120 days post intake), as part of usual care. Only NSIs completed after a participant's mTBI index data were included. Participants with at least two completed NSIs were included in the analyses. An NSI symptom was considered present if the participant rated the symptom as moderate(2), severe(3) or very severe(4), which suggests its negative impact on daily living. The NSI total score ranges from 0-88, with a high score indicating worse post-concussive symptoms. A reliable change index of eight points was used as the 90% confidence interval for the NSI total score. Frequency tables were used to summarize symptom prevalence. All statistical analyses were conducted in R (version 4.2.2).
Results: In total, 798 SMs with mTBI met the inclusion criteria for this analysis. This resulted in a sample population in which 79% were male, with the majority between the ages of 25-34 (37%). High representation by race were White, non-Hispanic (58%), followed by Hispanic (20%) and Black, non-Hispanic (15%). Examining military characteristics, 82% of the sample population was from the United States Army, while 51% were classified as Senior Enlisted.
At initial intake, the mean total NSI score was 34.8 (SD=16.4). Upon re-evaluation, the mean total NSI score was 25.7 (SD=18). For a clinically significant change in the total NSI score, 379 SMs (47%) made a clinically significant improvement and 189 SMs (24%) made a non-clinically significant improvement.
The most commonly reported NSI symptoms upon intake were headaches (78%), forgetfulness (75%), difficulty falling/staying asleep (75%), and poor concentration (70%). Least prevalent were symptoms related to changes in taste/smell (13%) and nausea (30%). Upon re-evaluation, 34% of SMs with headaches at intake exhibited a reduction in headache symptoms. Similarly, 37% of SMs saw a reduction in forgetfulness symptoms, while 37% saw a reduction in concentration symptoms. Among all reported symptoms, difficulty falling/staying asleep appeared to be most persistent, in which only 30% of those SMs reporting this symptom exhibited a reduction in severity.
Conclusions: The most commonly reported NSI symptoms in outpatient MTFs were headaches, forgetfulness, difficulty falling/staying asleep, and poor concentration. While there was a reduction in symptoms from intake, these symptoms remained the most commonly reported at re-evaluation. Further research is needed to understand the presentation and resolution of these symptoms and potential best practices for treating interrelated mTBI symptoms at outpatient MTFs.
Disclaimer: The views, opinions and/or findings expressed in this article are those of the authors and do not reflect the official policy of the Department of Army/Navy/Air Force, Uniformed Services University, Department of Defense, or the U.S. Government. In addition, the authors have no conflicts of interest to declare.
