Identifying a structural model for psychological distress symptoms following moderate to severe traumatic brain injury: A TBIMS Chronic Pain Collaborative Study

Oregon Convention Center 

Introduction
Depression, anxiety, and posttraumatic stress (PTS) symptoms are expected and common following a traumatic brain injury (TBI). These symptoms however have an often-overlapping presentation that can be challenging to address for rehabilitation researchers and clinicians. The current literature focuses on the relationship between these symptoms predominately after mild TBI. This study looks to evaluate several transdiagnostic, structural models to understand and better utilize reported psychological symptoms in the wake of moderate/severe TBI.
Methods
This study used 1,258 participants enrolled in both the TBI Model Systems and The Characterization and Treatment of Chronic Pain after TBI study. Confirmatory factor analysis (CFA) was initially conducted on the parent scales of the PHQ-9 (Patient Health Questionnaire-9), GAD-7 (General Anxiety Disorder-7), and PCL-5 (Posttraumatic Stress Disorder Checklist for DSM-5) to better understand the transdiagnostic relationship of these PTS measures. Exploratory factor analysis (EFA) was then performed to identify new structures of PTS and CFA to validate the model fit. EFA used a weighted least square mean and adjusted estimation with a Geomin or Bi-Geomin rotation. Global fit indices were calculated using the comparative fit index (CFI), Tucker-Lewis index (TLI), standardized root mean square residuals (SRMR), the root mean square error of approximation (RMSEA), and a chi-square test.
Results
The sample had an average age of 42 years and were mostly male and non-Hispanic white. The parent scales revealed evidence of a higher-order factor of psychological distress but these structures were found to be unstable. EFA then successfully identified a 3-factor, highly correlated single-order structure. The second-order structure of these factors revealed large factor loadings and evidence of the existence of a higher-order factor. The bifactor EFA identified a stable 4- and 5-factor structure. The CFA results of these structures found overall good model fit and internal consistency.
Conclusion
The transdiagnostic approach of this study revealed instability amongst our current PTS measures and also identified second-order and bifactor structural models of PTS symptoms for a moderate/severe TBI population. These findings may help improve statistical modeling, research, and treatment options for this population.

Structural equation modeling

Exploratory factor analysis

Confirmatory factor analysis

Bifactor Structure

Traumatic Brain Injury

Post-traumatic stress 

Mental Health Statistics Section