P4‐216: Reduction in Hippocampal Volume is Associated With Age and Memory Deficits in Retired Professional Football Players

Abstract

Background: Repeated concussions are associated with postconcussive symptoms including memory impairment. Professional athletes in contact sports seem to be at greater risk of persistent symptoms due to repeated concussions. We used volumetric analysis to test whether repeated concussions have delayed effects in terms of decreased hippocampal volume and poor memory performance in former professional football players. Methods: Participants were 38 retired Canadian Football League (ex-CFL) players (age=56.0+12.9 years) and 21 healthy male controls (age=48.3+10.7 years) without history of concussion. Controls from the Alzheimer's Disease Neuroimaging Initiative database (ADNI) (N=179) were used for validation because of our small control sample size. The number of self-reported concussions in the ex-CFL group ranged from 0-48. Participants underwent a 3T T1-weighted structural MRI scan and a Rey Auditory Verbal Learning Test (RAVLT) to assess verbal memory. Scans were pre-processed using a standard pipeline: image intensity non-uniformity correction, intensity range normalization (0-100), stereotaxic registration and non-linear warping to an average template brain (Montreal Neurological Institute ICBM-152). Volumetric analysis was performed and hippocampal volumes were correlated with age, adjusting for intracranial volume, and with RAVLT word recall scores, adjusting for age. Results: The ex-CFL players showed a significant association between age and left hippocampal (LH) (r=-.60, p