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IIR 11-358 – HSR&D Study

IIR 11-358
Identifying mTBI Subtypes and their Implications for Recovery and Reintegration
Terri Krangel Pogoda PhD
VA Boston Healthcare System Jamaica Plain Campus, Jamaica Plain, MA
Boston, MA
Funding Period: July 2012 - December 2016

Traumatic brain injury (TBI) is a signature condition of combat among returnees from the Iraq and Afghanistan wars. VA's goals regarding TBI are to (1) screen every Iraq and Afghanistan war Veteran for TBI; (2) evaluate each Veteran who screens positive, using the 22-item Neurobehavioral Symptom Inventory (NSI) in combination with a comprehensive history and physical examination; and (3) develop a treatment plan based on the assessment. The latter two elements constitute the comprehensive TBI evaluation (CTBIE).

The study's overall aim was to examine the course of persistent post-concussive symptoms and their impacts on Veterans' functioning at personal, family, and broader community levels. More specifically, we had three research objectives:
(1) Identify clusters of persistent post-concussive symptoms (syndromes) and their associated demographic, co-morbidity and etiological factors among Veterans with a CTBIE.
(2) Identify Veterans Health Administration (VHA) utilization and costs related to each syndrome.
(3) Assess the course of symptom severity within syndromes over time and relationships to short- and long-term reintegration in multiple domains, controlling for utilization.

To investigate these issues we used both secondary and primary data sources. We obtained the most recent update of the national CTBIE database (7/1/2009-9/30/2013) as well as VHA utilization data from VA administrative datasets. In terms of primary data, we administered a survey to a cohort of Iraq and Afghanistan Veterans at two points in time following their initial CTBIE. Primary analytic tools included cluster analysis, multiple linear regression, multiple analysis of variance (MANOVA), and chi-square. Objective 1 involved analysis of the national CTBIE data combined with data from other VA clinical databases. Based on prior work, we expected to identify distinct patterns of symptom severity -- syndromes -- across the four dimensions of the NSI: affective, cognitive, somatosensory, and vestibular. These syndromes were used for analyses of recovery and community reintegration over time, as measured by the Military to Civilian Questionnaire.

Objective 1: Using derivation and validation samples from the CTBIE, our cluster analyses of those with mild TBI (mTBI) identified four distinct and replicable patterns of symptom severity across the four NSI domains. The four mTBI clusters were: (1) High severity on all 4 domains (High); (2) High on Affective/ Cognitive/Vestibular (ACV); (3) High on Affective/Cognitive (AC); and (4) Low on all dimensions/high on Affective only (Low/A).

Objective 2: Due to staff attrition and loss of expertise, we could not analyze cost data. We analyzed VHA outpatient utilization up to 24-months post-CTBIE for 6 independent groups who responded to the patient survey: the 4 mTBI clusters: High(n=338), ACV(n=267), AC(n =285), Low/A(n=181); those with no TBI history (n=270); and moderate/severe TBI history (n=338). For VHA utilization there was a clear pattern whereby total number of clinic stops increased as a function of symptom or TBI severity. Those in the Low/A (M=30.63) and no TBI (M=34.30) clusters had the fewest clinic stops, and those in the moderate/severe TBI (M=56.16) and High (M=69.98) groups had the most clinic stops. This pattern was generally observed for Primary Care, Polytrauma, and Mental Health clinic stops.

Objective 3: Our survey respondents were predominately male (94%), White (62.7%), had diagnoses of mTBI (63.7%) and posttraumatic stress disorder (PTSD; 68.9%), and on average were 37.65 (SD=9.21) years old. The survey was completed approximately 3.5 years after the CTBIE. Embedded in the patient survey was the 5-item mild Brain Injury Atypical Symptoms Scale (mBIAS), which tests for symptom exaggeration. Individuals who did not pass (n=138) or complete (n=26) the screener were excluded from analysis. For the remaining sample (n = 1412) a multiple linear regression modeling community reintegration accounted for 49.3% of the variance. The significant predictors of poorer community reintegration were younger age (B= -.005, SE= .002), lower perceptions of having the best possible life (B= -.22, SE= .01), being unemployed/disabled/retired (B= .35, SE = .05) or unemployed/looking for work (B= .23, SE = .07) (versus being employed or a student); PTSD (B= .30, SE= .05) or depression (B= .17, SE= .04) diagnoses, and belonging to the mTBI ACV (B= .24, SE= .07) or High (B= .31, SE= .07) clusters (vs. the non-TBI group), all p <= .03. Having served in the Marines versus in the Army (B= -.18, SE= .06) and belonging to the Low/A cluster (B= -.16, SE= .07) (vs. no TBI) were associated with better community reintegration, all p < .03. The model also adjusted for gender, race, marital status, time between CTBIE and survey, VHA utilization, and percent service-connection; none were associated with community reintegration.

An unadjusted MANOVA found that mTBI cluster group was predictive of NSI symptom severity at 3.5-year follow-up. For each of the NSI domains, the High group reported the most severe symptom severity, followed by the ACV, AC, and Low/A clusters, for all post-hoc comparisons, p <= .02. This suggests that the extent to which NSI symptoms impacted these groups remained relatively stable as they relate to mTBI cluster membership. At 3.5-year follow-up, those with no TBI history reported NSI symptoms that were generally similar to the Low/A group. However, those with moderate/severe TBI consistently reported NSI symptom severity lower than the High group, for all post-hoc comparisons, p <=.0001.

The clinical presentation at the CTBIE was predictive of community reintegration at 3.5-year follow-up. Identifying a taxonomy of symptoms following TBI evaluation, and examining the course of symptom severity and community reintegration of individuals within those syndrome groups over time, could potentially improve VA's ability to design more effective treatment plans. These treatment plans might possibly include targeted early interventions that could hasten the mitigation of symptoms and achievement of community reintegration.

External Links for this Project

NIH Reporter

Grant Number: I01HX000794-01

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Journal Articles

  1. Amara JH, Stolzmann KL, Iverson KM, Pogoda TK. Predictors of Employment Status in Male and Female Post-9/11 Veterans Evaluated for Traumatic Brain Injury. The Journal of head trauma rehabilitation. 2019 Jan 1; 34(1):11-20. [view]
Conference Presentations

  1. Meterko MM, Pogoda TK, Stolzmann KL, Iverson KM, Krengel MH, Nealon Seibert M, Sayer N, Gormley K, Baker E. Are there symptom groupings associated with mild TBI? A cluster analysis of neurobehavioral symptom data among Operation Enduring Freedom/Operation Iraqi Freedom Veterans. Poster session presented at: AcademyHealth Annual Research Meeting; 2014 Jun 9; San Diego, CA. [view]

DRA: Mental, Cognitive and Behavioral Disorders, Acute and Combat-Related Injury, Brain and Spinal Cord Injuries and Disorders
DRE: Treatment - Observational
Keywords: none
MeSH Terms: none

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