Results from a recent study appearing in Neurology are a big deal for anyone playing contact sports—or taking care of those who do. The study, out of St. Michael’s Hospital in Toronto, looked at college athletes who suffered concussions and tracked their brain health over an entire year. Results reveal that concussions may have prolonged effects on athletes’ brains, persisting up to a year after they are medically cleared to return to play.
This groundbreaking research, conducted by Dr. Nathan Churchill and colleagues at St. Michael’s Hospital in Toronto, challenges the conventional understanding of concussion recovery and underscores the need for more comprehensive return-to-play protocols.
Study Overview
The study tracked 187 varsity athletes from the University of Toronto, all screened to ensure no prior neurological disorders or sensory/motor impairments. Advanced MRI scans established baseline brain physiology for each participant. During the athletic season, 25 athletes sustained concussions and underwent follow-up MRIs at four intervals:1-7 days post-concussion; at medical clearance and return to play; 1-3 months after return to play; and 1 year after return to play. A control group of 27 non-injured athletes was also monitored to account for natural variations in brain physiology.
Key Findings
The research unveiled significant, enduring changes in the brains of concussed athletes:
Reduced Cerebral Blood Flow (CBF): Post-concussion MRIs indicated notable decreases in blood flow, particularly in the fronto-insular cortex, a region vital for cognitive functions such as thinking, memory, emotion, and social behavior. These reductions persisted up to a year after the athletes were cleared to play.
White Matter Integrity Disruptions: Signs of injury and inflammation were observed in the brain’s white matter, essential for efficient neural communication. These disruptions remained evident throughout the year-long study period.
Correlation with Recovery Time: Athletes exhibiting more significant changes in CBF tended to have longer recovery periods, suggesting that cerebral blood flow metrics could serve as potential indicators for recovery duration.
Implications for Sports Medicine
These findings challenge the prevailing assumption that clinical symptom resolution equates to full brain recovery. Dr. Churchill emphasized, “Our results provide strong evidence, suggesting incomplete recovery of brain function when returning to play and beyond.” This raises concerns about the potential cumulative effects of repeated concussions and the adequacy of current return-to-play criteria.
Recommendations for Athletes and Practitioners
Given the evidence of prolonged brain changes post-concussion, it’s imperative for athletes, coaches, and healthcare providers to adopt a more cautious approach:
- Extended Monitoring: Implementing longer-term follow-up assessments, including advanced neuroimaging, may help detect lingering physiological changes not apparent through standard clinical evaluations.
- Individualized Return-to-Play Protocols: Tailoring recovery plans to each athlete’s specific condition, rather than relying solely on symptom resolution, could enhance safety and long-term brain health.
- Education and Awareness: Raising awareness about the potential for extended brain recovery times can encourage athletes to report symptoms accurately and adhere to recommended rest periods.
Final Thoughts
The study from St. Michael’s Hospital provides compelling evidence that concussions can lead to brain changes lasting up to a year post-injury, even after clinical symptoms have subsided. This underscores the need for more comprehensive evaluation methods and cautious return-to-play strategies to safeguard athletes’ neurological health.
References
- Churchill, N. W., et al. (2025, March 12). Concussion-related changes in brain blood flow and structure may last up to a year. Neurology. American Academy of Neurology. https://www.aan.com/PressRoom/Home/PressRelease/5245
- Unity Health Toronto. (2025, March 12). Concussion changes in the brain last up to one year after return to play, athlete study finds. https://unityhealth.to/2025/03/athlete-concussion-study
