The Impact of Moderate-Severe Traumatic Brain Injury on Hippocampal Structure and Function

Poster Session D - Monday, April 15, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Fatima Eldes¹, Annick F. N. Tanguay¹, Hillary Schwarb², Neal Cohen³, Melissa Duff¹; ¹Vanderbilt University, ²University of Nebraska-Lincoln, ³University of Illinois at Urbana-Champaign

Early imaging studies of the impact of traumatic brain injury (TBI) on the structure and function of the hippocampus focused on the volume of the whole structure. Attempts to associate volume and performance on neuropsychological tests of memory yielded inconsistent associations. Considerable new knowledge has since been gained about the architecture and organization of the hippocampus. We compared hippocampal volume along the longitudinal axis, taking measures of the head, body, and tail, in 24 individuals with moderate-severe TBI and 28 non-injured comparison participants. We also examined the relation between volume and performance on a measure of episodic memory, the Auditory Verbal Learning Test (AVLT). Volumetric measures were derived from FreeSurfer 7.2.0 and corrected for intracranial volume. We found significant group differences in volume for each hippocampal segment, with the largest effect for head volume, replicating work on the increased susceptibility of hippocampal head atrophy in TBI. The TBI group performed significantly lower on the AVLT (delayed recall score) than the comparison group. We found significant correlations between the volume of the entire hippocampus and the AVLT, in both hemispheres, in the TBI group, but not in the comparison group possibly due to restricted range. Correlations between all hippocampal segments and the AVLT were significant in the TBI group, but did not survive correction for multiple comparisons. Advances in the sensitivity of behavioral and neural measurement of hippocampal-dependent memory positions future work to generate new hypotheses on the impact of hippocampal pathology on behavioral outcomes in TBI and targeted rehabilitation approaches.

Topic Area: LONG-TERM MEMORY: Episodic