Volumetric Brain Changes in Cortical and Subcortical Regions of Former American Football Players Years After Exposure to Repetitive Head Impacts

Omar John, BS

Brigham and Women’s Hospital – Research Assistant
John Omar poster

Scientific Abstract

Background: Exposure to repetitive head impacts (RHI) acquired from contact sports has been associated with neurological disorders including chronic traumatic encephalopathy (CTE), which currently can only be diagnosed post-mortem. American football players are at higher risk of developing CTE given their exposure to RHI. One promising approach for diagnosing CTE in vivo is to explore known neuropathological abnormalities at postmortem in living individuals at risk for CTE using structural magnetic resonance imaging. We compared volumetric changes in frontal lobe, temporal lobe, and subcortical structures known to be impacted by CTE pathology. We hypothesized that former American football players would show specific reduced volume in brain regions of interest (ROIs), observed to be abnormal in post-mortem studies, compared to unexposed controls.

Methods: We leveraged data from the DIAGNOSE CTE Research Project to compare the volumes of the CTE based ROIs in former American football players with a history of RHIs (n = 170) to unexposed controls (n = 58) with no history of RHI exposure. Brain segmentations and extractions of volume were performed in FreeSurfer using the Desikan-Killiany Atlas. Based on CTE pathology we focused on frontal lobe (superior frontal, caudal middle frontal, rostral middle frontal), temporal lobe (entorhinal, parahippocampal, temporal pole, and insula) and subcortical structures (amygdala, hippocampus, and hypothalamus). We used a generalized least square model to compare the groups while controlling for age, body mass index, education, race, imaging site, total intracranial volume, and Apolipoprotein E4 carrier status.

Results: Former American football players showed significant volumetric reductions compared to unexposed controls in the left hemisphere (hippocampus, amygdala, entorhinal, parahippocampal, insula, and superior frontal regions), the right hemisphere (hippocampus, amygdala, entorhinal, parahippocampal, insula, temporal pole, and superior frontal ROIs). Conclusion: These findings indicate long-term consequences of RHI exposure that can potentially be used as biomarkers for the in vivo detection of CTE.

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research Areas

Authors

Omar John, BS, Hector Arciniega, PhD, Zachary H Baucom, MA, Yorghos Tripodis, PhD, Tashrif Billah, MS, Michael J Coleman, MA, Ofer Pasternak, PhD, Michael Alosco, PhD, Inga K Koerte, MD, PhD, Alexander P Lin, PhD, Robert A Stern, PhD, Martha E Shenton, PhD, Sylvain Bouix, PhD

Principal Investigator

Martha E Shenton, PhD, Sylvain Bouix, PhD