Detecting Mild Traumatic Brain Injury after Combat Deployment: Agreement Between Veterans Health Administration Clinical System and LIMBIC-CENC Research Protocol

Identifying historical mild traumatic brain injury (TBI) is important for many clinical care reasons; however, diagnosing mild TBI is inherently challenging and utility of screening is unknown. This study compares a standardized research process to an established clinical process for screening and diagnosis of historical mild TBI during combat deployment in a military/Veteran cohort. Using validated instruments, the Long-term Impact of Military-relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC) prospective longitudinal study (PLS) screens for all potential concussive events (PCEs) and conducts structured concussion diagnostic interviews for each PCE. The Veterans Health Administration (VHA) systematically screens all Veterans with a post-9/11 combat deployment for historical TBI and offers a comprehensive TBI evaluation (CTBIE) for those who screen positive. This study evaluates the agreement between these two systems on both PCE and mild TBI identification during combat deployment and identifies features of Veterans who were negative clinically but positive in research. VHA TBI screen and CTBIE data were obtained from Veterans Affairs Informatics and Computing Infrastructure and linked to the LIMBIC-CENC PLS dataset. VHA screen positive for PCE was defined as a positive response for the first two VHA TBI screen questions of that query mechanism and immediate signs/symptoms of TBI. The PLS identified more positive PCE screens during combat deployment (86% vs. 41%) than the VHA PCE screen, and overall agreement was poor (kappa = 0.113). Participants had higher odds of being VHA negative/PLS positive on the PCE screen if they were of older age, female sex, had more years of military service, more months in combat deployment, officer rank, or <50% service-connected disability rating and lower odds if they had less education attainment, higher combat intensity, or higher Neurobehavioral Symptom Inventory scores. The LIMBIC-CENC PLS method also identified more Veterans with mild TBI during combat deployment compared with the VHA CTBIE (81% vs. 72%) with minimal overall agreement (kappa = 0.311). Participants had higher odds of being VHA negative/PLS positive for mild TBI diagnosis if they never married or were Air Force and had lower odds if they had higher combat intensity. The LIMBIC-CENC PLS research structured interview protocol identified higher rates of TBI than the VHA TBI assessment system both for positive PCE screens and positive mild TBI diagnosis during combat deployment. Agreement was far higher for TBI determinations compared with the PCE screening. Significant characteristics of PLS-positive/VHA-negative mismatches included demographic variables, military service variables, and current symptom levels. Further research is needed to better understand whether there is a clinical value to adjust the VHA TBI screening process and how these characteristics could be considered. Providers should be aware that some Veterans may have undocumented, positive mild TBI histories even if they underwent screening and/or CTBIE processes.