The Canadian Sports Concussion Project

The Canadian Sports Concussion Project

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By: Nina Bahl

While a single concussion can resolve without issue, repeated head trauma may cause grave long-term consequences, including degenerative brain disease in the most severe cases. Given the prevalence of concussions in sports—especially in high-contact games like football and hockey—this problem is especially relevant for athletes. (For a full discussion of sports-related concussions, please see our Winter 2012 edition.)

Researchers involved in the Canadian Sports Concussion Project—based at the Krembil Neuroscience Centre at Toronto Western Hospital—are investigating a potential correlation between repeated concussive incidents in athletes and late deterioration of brain function. The project’s multidisciplinary team includes neurosurgeons, neurologists, neuropathologists, and neuroradiologists, among others, allowing for a unique clinical-MRI-neuropathological research analysis of the athletes studied. Specifically, the project encompasses two main studies: a clinical research arm and a brain donation component.

Of particular interest to the group is chronic traumatic encephalopathy (CTE), a posttraumatic neurodegenerative disease first described in boxers in the 1920s that is characterized by tau protein deposits, neurofibrillary tangles, and brain atrophy. Clinically, those suffering from CTE may exhibit personality changes, disordered motor control, and a progressive loss of cognitive function, which can ultimately develop into full-blown dementia. At present, there is no effective treatment for this condition and confirmation of the disease is generally only possible upon postmortem evaluation.

Currently, the clinical study is open to former Canadian Football League (CFL) players, in which participants undergo neurological, neuropsychiatric, and neuropsychological assessments, as well as an MRI scan. “[The] brain imaging arm [examines] the possible functional and structural brain abnormalities associated with repeated concussions,” explains Dr. Karen Davis, who runs the MRI component of the study and is Head of Toronto Western Research Institute’s Division of Brain, Imaging and Behaviour – Systems Neuroscience. “The definition of a concussion was not clear many years ago, and this certainly impacted record keeping in the past,” cautions Dr. Davis. “It can be a challenge to determine the exact concussion history of former players because [of this].” The project’s researchers encourage CFL alumni to participate in this study even if they have never received an official concussion diagnosis, but are currently experiencing head injury-related symptoms.

The second component of the Concussion Project involves postmortem brain evaluations of professional athletes and members of the public who have suffered multiple concussions. At present, brain donations can come from family members of deceased football and hockey players, as well as living donors who agree to provide their brains upon death. All donations are completed with full, informed consent, and privacy of donors is of utmost importance to the research group.

Thus far, six former CFL players have donated their brains for study, but autopsy results suggest that the relationship between repeated head injury and neurodegenerative disease is not so clear-cut. “All [players] had sustained multiple concussions—but three had CTE, and three did not,” reveals Dr. Charles Tator, Professor and Former Chair of Neurosurgery, and one of the project’s leading concussion experts. Indeed, the study’s initial results have generated more questions than answers regarding the long-term consequences of frequent concussions.

In a 2011 UHN media release, Dr. Tator emphasized the need to determine what causes CTE to develop in some athletes and not others, and to elucidate the number of concussions or level of trauma required to trigger the degenerative disease. Through both research arms of the Concussion Project, the hope is that investigators will be able to reveal the specific pathophysiology of CTE—knowledge that will certainly have tremendous impact on athletes in the future. “We want to be able to detect CTE antemortem, and to discover effective prevention and treatment strategies,” says Dr. Tator.

Results from this project and other recent studies have confirmed that CTE can develop in a number of different athletes who are exposed to repeated brain injury, but further research is needed to determine any concrete links between frequent concussions and neural degeneration. With endorsements from the Canadian Football League Alumni Association, the Canadian Football League, and the Professional Hockey Players Association, the Canadian Sports Concussion Project is well positioned to begin disentangling this complex relationship.

To learn more about the Canadian Sports Concussion Project, please visit www.donateyourbrain.ca. To support the project, please visit the Toronto General and Western Hospital Foundation at www.tgwhf.ca/giving/donate.asp.

References
University Health Network. (2012). The Canadian Sports Concussion Project at the Krembil Neuroscience Centre, Toronto Western Hospital.

University Health Network. (2011). Brain autopsies of four former football players reveal not all get chronic traumatic encephalopathy.

McKee AC, Cantu RC, Nowinski CJ, et al. (2009). Chronic traumatic encephalopathy in athletes: progressive tauopathy following repetitive head injury. J Neuopathol Exp Neurol, 68(7): 709-735.