The tau protein has been at the center of the hunt for a biomarker for concussions and traumatic brain injury, but a new study suggests it may be useful for more than just identifying a brain injury.
According to a report published in the journal Neurology, elevated levels of tau brain proteins six hours after a sports-related concussion are associated with a longer recovery period. The findings suggest that tau could act as a marker for predicting a person’s recovery length and assessing an athlete’s readiness to return to the field.
Tau proteins have also been linked to the development of chronic traumatic encephalopathy (CTE), frontotemporal dementia, and Alzheimer’s disease.
“This study suggests that tau may be a useful biomarker for identifying athletes who may take longer to recover after a concussion,” said Jeffrey Bazarian, M.D., M.P.H. of the University of Rochester Medical Center (URMC), professor of Emergency Medicine and Physical Medicine & Rehabilitation who treats patients at the UR Medicine Sports Concussion Clinic.
“Athletes are typically eager to get back to play as soon as possible and may tell doctors that they’re better even when they’re not. Tau is an unbiased measurement that can’t be gamed; athletes can’t fake it. It may be that tau combined with current clinical assessments could help us make more informed return-to-play decisions and prevent players from going back to a contact sport when their brains are still healing,” Bazarian said.
Returning to play while the brain is still vulnerable and healing from a traumatic brain injury increases the risk of long-term physical and cognitive problems, as well as increasing the risk of another more severe brain injury. However, there are no objective tools available to discern exactly when an athlete’s brain is ready for the athlete to start participating in the sport again.
Instead, this decision is currently based entirely on the opinions of physicians and trainers who must use subjective measures like self-reported symptom questionnaires and tests of memory and attention.
For the study, the team of researchers assessed changes in tau protein levels in 46 Division I and III college athletes who had experienced a concussion. The group included both male and female athletes from a variety of sports like soccer, football, and basketball.
The players had tau protein level samples taken before the season began and then again six hours after a concussion. The athletes were then split into two groups based on their recovery time.
Those included in the “long return to play group needed more than 10 days to recover from their concussion, while athletes in the “short return to play” group healed within 10 days of their injury.
The “long return to play” group consistently showed higher levels of tau in their blood after their concussion compared to those who healed within 10 days, leading the team to believe tau levels are predictive of recovery time.
While the change in tau proteins were consistent for both men and women in the “long return to play” group, the team did note significant differences between the sexes. Women accounted for 61% of the longer recovery group, but only 28 percent of the “short return to play” group. However, Bazarian said that is expected as women typically take longer to recover from brain injuries compared to men.
The team admits the research is limited by its small size, but they say the findings are promising. They intend to continue their research by testing blood samples immediately after a concussion to see if the spike in tau levels is immediately identifiable.