The effect of repetitive subconcussive collisions on brain integrity in collegiate football players over a single football season: A multi-modal neuroimaging study

Neuroimage Clin. 2017 Mar 21;14:708-718. doi: 10.1016/j.nicl.2017.03.006. eCollection 2017.

Abstract

The cumulative effect of repetitive subconcussive collisions on the structural and functional integrity of the brain remains largely unknown. Athletes in collision sports, like football, experience a large number of impacts across a single season of play. The majority of these impacts, however, are generally overlooked, and their long-term consequences remain poorly understood. This study sought to examine the effects of repetitive collisions across a single competitive season in NCAA Football Bowl Subdivision athletes using advanced neuroimaging approaches. Players were evaluated before and after the season using multiple MRI sequences, including T1-weighted imaging, diffusion tensor imaging (DTI), arterial spin labeling (ASL), resting-state functional MRI (rs-fMRI), and susceptibility weighted imaging (SWI). While no significant differences were found between pre- and post-season for DTI metrics or cortical volumes, seed-based analysis of rs-fMRI revealed significant (p < 0.05) changes in functional connections to right isthmus of the cingulate cortex (ICC), left ICC, and left hippocampus. ASL data revealed significant (p < 0.05) increases in global cerebral blood flow (CBF), with a specific regional increase in right postcentral gyrus. SWI data revealed that 44% of the players exhibited outlier rates (p < 0.05) of regional decreases in SWI signal. Of key interest, athletes in whom changes in rs-fMRI, CBF and SWI were observed were more likely to have experienced high G impacts on a daily basis. These findings are indicative of potential pathophysiological changes in brain integrity arising from only a single season of participation in the NCAA Football Bowl Subdivision, even in the absence of clinical symptoms or a diagnosis of concussion. Whether these changes reflect compensatory adaptation to cumulative head impacts or more lasting alteration of brain integrity remains to be further explored.

Keywords: Accelerometers; Football; MRI; Repetitive impacts; Subconcussive.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Accelerometry
  • Brain / diagnostic imaging*
  • Brain Concussion / diagnostic imaging*
  • Brain Concussion / etiology*
  • Brain Mapping*
  • Cerebrovascular Circulation / physiology
  • Football / injuries*
  • Humans
  • Image Processing, Computer-Assisted
  • Male
  • Nerve Fibers / pathology
  • Neural Pathways / diagnostic imaging
  • Neuroimaging*
  • Seasons
  • Universities
  • Young Adult