January 16, 2017Neurology
Athletes who return to play before full recovery from concussions are at high risk for long-term symptoms like headaches, dizziness, and cognitive deficits with subsequent concussions. About half of college athletes see their post-concussive symptoms resolve within 10 days, but in others, the symptoms become chronic.
Despite the millions of sports-related concussions that occur annually in the United States, there is no reliable blood-based test to predict recovery and an athlete's readiness to return to play. Now, according to an article published online in Neurology (6 January 2017), NIH researchers have identified a blood biomarker that could better identify athletes who need more recovery time before safely returning to play after a sports-related concussion. The new study shows that measuring tau levels could potentially be an unbiased tool to help prevent athletes from returning to action too soon and risking further neurological injury. Tau is also connected to development of Alzheimer's and Parkinson's diseases, and is a marker of neuronal injury following severe traumatic brain injuries.
The new study evaluated changes in tau following a sports-related concussion in male and female collegiate athletes to determine if higher levels of tau relate to longer recovery durations. To measure tau levels, a group of 632 soccer, football, basketball, hockey, and lacrosse athletes from the University of Rochester first underwent pre-season blood plasma sampling and cognitive testing to establish a baseline. They were then followed during the season for any diagnosis of a concussion, with 43 of them developing concussions during the study. For comparison, a control group of 37 teammate athletes without concussions was also included in the study, as well as a group of 21 healthy non-athletes. Following a sports-related concussion, blood was sampled from both the concussed and control athletes at six hours, 24 hours, 72 hours, and seven days post-concussion.
Results showed that concussed athletes who needed a longer amount of recovery time before returning to play, (more than 10 days post-concussion) had higher tau concentrations overall at six, 24, and 72-hours post-concussion compared to athletes who were able to return to play in 10 days or less. These observed changes in tau levels occurred in both male and female athletes, as well as across the various sports studied. According to the authors, these findings indicate that changes in tau measured in as short a time as within six hours of a sports-related concussion may provide objective clinical information to better inform athletes, trainers, and team physicians' decision-making about predicted recovery times and safe return to play. The authors added that further research will test additional protein biomarkers and examine other post-concussion outcomes.