Brain structure change in Posttraumatic Stress Disorder: A combined surface- and voxel-based study
Year: 2022
Type: other
Abstract: Studies examining gray matter (GM) change in Posttraumatic Stress Disorder (PTSD) have been limited to separate analyses using either voxel-based morphometry (VBM) or surface-based cortical thickness (CT) approaches. Since VBM is sensitive to multiple changes in GM such as thickness, volume, and cortical folding, the use of cortical thickness measurements combined with VBM may provide multi-modal validation of PTSD-related brain structure alterations. This study combines surface- and voxel-based approaches in correlating PTSD symptom severity with GM, in brain regions previously found to exhibit GM decrease in patients versus controls. 11 PTSD patients (females, mean age 39.4 yrs), with least one occurrence of a traumatic event since age 18, were assessed using a number of neuropsychiatric instruments. PTSD symptom severity was assessed with the PTSD Checklist (PCL) (Weathers, 1993). Individuals with current substance dependence, lifetime or current psychosis, bipolar disorder, current suicidality, and current psychoactive medications, were excluded. A T1-weighted 3D MPRAGE volume was used in analyses (Siemens 3T Tim Trio Scanner, 176 sagittal slices, TR/TE=1900/2.52ms, effective resolution 1mm3). Cortical thickness was calculated using Freesurfer and voxel-based morphometry was computed using SPM5. This study presents preliminary evidence of concordance between surface-based and voxel-based approaches to examine disease-associated GM change in PTSD, particularly in the parahippocampal gyrus. Our results extend prior findings of decreased cortical thickness in the parahippocampal gyrus (Woodward, 2009). The parahippocampal gyrus, involved in episodic memory encoding and retrieval, is thought to be disrupted in PTSD (e.g. in misperception of safe vs. threatening contexts), and is connected to the adjacent hippocampus, which has been previously shown to be volumetrically decreased in PTSD compared to healthy controls (Rauch, 2006). Results from prior GM studies have been mixed. A study of female PTSD patients versus controls reported no difference in cortical thickness and subcortical volume (Landré, 2010). The lack of group differences in this study could be due to variability within the PTSD group related to symptom severity. A study of males with combat-related PTSD, compared to controls, showed atrophy in cortical areas beyond the parahippocampal gyrus (Woodward, 2010). However, neither of these studies examined PTSD severity. Our results provide preliminary support for the idea that a disruption in memory (Rauch, 2006; Milad, 2009) with possible concomitant decrease in top-down contextual processing may be associated with PTSD severity.
Authors: Sheeva Azma, Rachel Thompson, Diana Bermudez, Rachael Renton, Adebanke Adeyemo, James Meyerhoff, Richard Amdur, Bonnie Green, Mary Ann Dutton, John VanMeter
Institution: Georgetown University Medical Center
Language: English
Subfield: Clinical Psychology
Field: Psychology
Domain: Social Sciences
Open Access status: gold
OpenAlex ID: W4416505460