Exploring the factor structure of a battery of neuropsychological assessments among the CENC cohort

ABSTRACT

Objective: The goal of the Chronic Effects of Neurotrauma Consortium (CENC) study is to explore the effects of concussions among Service Members and Veterans. A factor model was fit to selected neuropsychological measures to identify potentially useful relationships between assessments collected on CENC-enrolled participants.

Method: 492 post-9/11 participants with combat exposure were enrolled across four VA study sites. Participants completed assessments including concussion history, neurocognitive functioning, and self-report questionnaires. Exploratory factor analyses (EFA) using four different methods with varimax and promax rotations were used to analyse the cognitive variables. Final model selection was based on factor loadings towards simple structure.

Results: The scree plot suggested the number of factors to be extracted was between 4 and 5. EFA produced a 5-factor MINRES model with promax rotation that resulted in a factor loading with variables loading on only one factor with a predefined threshold (0.40). Variables loaded on five cognition domains: list learning, working memory/executive skills, cognitive control, fluency, and memory.

Conclusion: These results provide reasonable evidence that data collected from the CENC neuropsychological battery can be reduced to five clinically useful factors. This will enable us to use the factors for further study of the impact of concussion on neurodegeneration.

KEYWORDS:

• Exploratory factor analysis
• Neuropsychology
• Traumatic brain injury
• Cognition

Acknowledgements

The CENC Observational Study Group members include: Study leadership: William C. Walker MD (CENC Observational Study Chairman), David X. Cifu MD (consortium PI); Site PIs or co-PIs: Heather G. Belanger PhD (Tampa), Randall Scheibel PhD (Houston), Blessen C. Eapen MD (San Antonio), Carlos Jaramillo MD (San Antonio), Ajit Pai MD (Richmond), Melissa Geurra MD (Fort Belvoir), Terri Pogoda PhD (Boston), Scott Sponheim PhD (Minneapolis) and Kathleen Carlson PhD (Portland). The authors also acknowledge the efforts of the entire CENC Observational Study Leadership Working Group and Core Team members who also include: Justin Alicea, Jessica Berumen, Cody Blankenship, Jennifer Boyce, Linda Brunson, Katrina Burson, William Carne, Julia Christensen, Margaret Clarke, Sureyya Dikmen, Esra Doud, Connie Duncan, Stephanie Edmunds, Robyn Endsley, Elizabeth Fogleman, Cheryl Ford-Smith, George Gitchel, Katelyn Gormley, Brenda Hair, Jim Henry, Shawn Hirsch, Nancy Hsu, Caitlin Jones, Sunchai Khemalaap, Valerie Larson, Henry Lew, Tiffany Lewis, Scott McDonald, Tamara McKenzie-Hartman, Frank Mierzwa, Alison Molitor, Joe Montanari, Johnnie Mortenson, Lauren Nagusuki, Nicholas Pastorek, Judy Pulliam, Risa Richardson, Callie Riggs, Rachel Rosenfield, Sara Salkind, Robert Shin, James K. Sickinger, Taylor Swankie, Nancy Temkin, Doug Theriaque, Maya Troyanskaya, Rodney Vanderploeg, Carmen Vasquez and Rick Williams (consortium Co-PI).

This material is based upon work supported with resources and the use of facilities at: Hunter Holmes McGuire Veterans Affairs Medical Center (VAMC) in Richmond, VA; James A. Haley Veterans Hospital (VH), Tampa, FL; Audie L. Murphy Memorial VH, San Antonio, TX; and Michael E. DeBakey VA Medical Center, Houston, TX and is based upon work supported in part by the Defense and Veterans Brain Injury Center, US Army Medical Research and Material Command (USAMRMC).

Declaration of Interest

This work was supported by grant funding from: Department of Defense, Chronic Effects of Neurotrauma Consortium (CENC) Award W81XWH-13-2-0095 and Department of Veterans Affairs CENC Award I01 CX001135. The authors report no conflicts of interest. The views, opinions and/or findings contained in this article are those of the authors and should not be construed as an official Veterans Affairs or Department of Defense position, policy or decision, unless so designated by other official documentation.