Testosterone and Resting State Connectivity of the Parahippocampal Gyrus in Men With History of Deployment-Related Mild Traumatic Brain Injury

• Published in: Military medicine 2020-09, Vol.185 (9-10), p.e1750-e1758
• Main Authors: Knutson, Kristine M, Gotts, Stephen J, Wassermann, Eric M, Lewis, Jeffrey D
• Format: Article
• Language: English
• Subjects: Adult; Brain; Brain Concussion - complications; Brain Concussion - diagnostic imaging; Humans; Magnetic Resonance Imaging; Male; Parahippocampal Gyrus; Post traumatic stress disorder; Retrospective Studies; Sleep; Testosterone; Traumatic brain injury
• ISSN: 0026-4075; 1930-613X
• DOI: 10.1093/milmed/usaa142

Abstract Introduction The purpose of this study was to explore the effect of low testosterone level on whole-brain resting state (RS) connectivity in male veterans with symptoms such as sleep disturbance, fatiguability, pain, anxiety, irritability, or aggressiveness persisting after mild traumatic brain injury (mTBI). Follow-up analyses were performed to determine if sleep scores affected the results. Materials and Methods In our cross-sectional design study, RS magnetic resonance imaging scans on 28 veterans were performed, and testosterone, sleep quality, mood, and post-traumatic stress symptoms were measured. For each participant, we computed the average correlation of each voxel’s time-series with the rest of the voxels in the brain, then used AFNI’s 3dttest++ on the group data to determine whether the effects of testosterone level on whole-brain connectivity were significant. We then performed follow-up region of interest-based RS analyses of testosterone, with and without sleep quality as a covariate. The study protocol was approved by the National Institute of Health’s Combined Neuroscience Institutional Review Board. Results Sixteen participants reported repeated blast exposure in theater, leading to symptoms; the rest reported exposure to a single blast or a nonblast TBI. Thirty-three percent had testosterone levels