Repeated Head Impacts Disrupt Brain's Waste Clearance System
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A new study examining cognitively impaired professional boxers and mixed martial arts fighters reveals that the brain's waste-clearing system, known as the glymphatic system, weakens after repeated head impacts.
These findings, set to be presented at the annual meeting of the Radiological Society of North America on December 1, 2023, highlight the risks associated with sports-related traumatic brain injuries, which account for up to 30 percent of all brain injury cases.
The study, led by Dhanush Amin, M.D., from the University of Alabama at Birmingham and Cleveland Clinic Nevada, utilized diffusion tensor imaging along the perivascular space, or DTI-ALPS, to assess how water moves in and around channels linked to glymphatic flow, a crucial process for flushing waste and maintaining brain health.
The study analyzed data from roughly 900 active fighters tracked in Cleveland Clinic's Professional Athletes Brain Health Study, focusing on 280 athletes, including 95 with cognitive impairment and 20 healthy controls.
Surprisingly, impaired athletes initially displayed higher glymphatic activity, which sharply declined with increased knockouts, suggesting that the brain initially responds to repeated injuries by enhancing waste clearance, but eventually becomes overwhelmed.
Dr. Amin noted the pattern of glymphatic function varied significantly between impaired and non-impaired fighters, emphasizing the importance of early detection of glymphatic changes to protect long-term brain health.
By identifying these changes before symptoms arise, athletes might receive recommendations for rest or medical care, potentially impacting their career decisions and safeguarding their cognitive future.
The study underscores the pressing need for better protective measures in contact sports and raises awareness about the long-term neurological effects of repeated head impacts, as highlighted by co-authors Gaurav Nitin Rathi, M.S., Charles Bernick, M.D., and Virendra Mishra, Ph.D.