The Relationship Between Hippocampal Volume and Declarative Memory in a Population of Combat Veterans With and Without PTSD

Abstract

Both reduced hippocampal volume and cognitive alterations have been found in posttraumatic stress disorder (PTSD). The purpose of this article was to examine the relationship between hippocampal volume, combat exposure, symptom severity, and memory performance in a sample of combat veterans with and without a history of PTSD. Subjects were 33 male veteran volunteers (16 PTSD+, 17 PTSD-) who underwent an MRI and neuropsychological testing with the California Verbal Learning Test (CVLT), a measure of declarative memory. Relationships between hippocampal volume (i.e., right + left hippocampal volume/whole brain volume) and performance on the CVLT were determined using partial correlational analysis controlled for age and Wechsler Adult Intelligence Scale, Third Edition (WAIS-III) vocabulary scores. Percent hippocampal volume for the entire sample was positively associated with several aspects of memory performance as reflected by the CVLT. In the PTSD+ group, CVLT performance was negatively correlated with lifetime, but not current CAPS symptoms. CVLT performance appears to be strongly correlated with hippocampal volume in a group of trauma survivors with and without PTSD. Insofar as CVLT performance in the PTSD group was negatively associated with worst episode, but not to current PTSD symptoms, memory performance in combat veterans may reflect some aspect of risk related to the magnitude of the psychological response to trauma, rather than current symptoms that may be interfering with cognitive performance. It will be of interest to study cognitive abilities that may relate to the likelihood of specific PTSD symptoms and to track changes in CVLT performance and hippocampal volume over time in persons with and without a history of trauma exposure.