Changes in hippocampal cerebral blood flow in moderate-severe traumatic brain injury

Poster Session C - Sunday, April 14, 2024, 5:00 – 7:00 pm EDT, Sheraton Hall ABC

Annick F. N. Tanguay¹ (annick.tanguay@vumc.org), Sophia Kekes-Szabo¹, Hillary Schwarb², Neal J. Cohen³, Binu P. Thomas⁴, Melissa C. Duff¹; ¹Vanderbilt University Medical Center, ²University of Nebraska-Lincoln, ³University of Illinois Urbana-Champaign, ⁴University of Texas Southwestern Medical Center

A reduction in cerebral blood flow (CBF) can occur in the chronic stage of traumatic brain injury (TBI) regardless of volumetric differences in brain structures. Thomas et al. (2021) showed that lower hippocampal CBF correlated with higher depression symptoms and greater sleep disturbance, but not cognitive changes in a sample with predominantly mild TBI. Here, we compared hippocampal CBF and hippocampal volume between 25 individuals with chronic moderate-severe TBI and 28 non-injured comparison participants (NC), and tested whether these measures related with symptoms of depression (Beck Depression Inventory-II), sleep quality (Pittsburgh Sleep Quality Index), and episodic memory ability (Auditory Verbal Learning Test). We found lower hippocampal CFB and volume bilaterally in the TBI group relative to the NC group. Higher hippocampal CBF and larger volume correlated with better episodic memory function, but did not correlate with symptoms of depression and sleep quality. Preliminary analyses with a subset of participants who received additional testing (NC: n = 8, TBI: n = 8) revealed that higher hippocampal CBF strongly correlated with better episodic memory on the Picture Sequencing task of the NIH toolbox (r = 0.68, p = .002), whereas hippocampal volume did not (r = 0.17, p = .504). Thus, hippocampal perfusion can predict cognitive function in moderate-severe TBI, even in the chronic phase of injury, and may supplement volumetric analyses to predict long-term outcomes. The predictive value of hippocampal CBF and volume may hinge on factors like TBI severity and sensitivity of the outcome measures.

Topic Area: LONG-TERM MEMORY: Episodic