Researchers at the National Institutes of Health have found that measuring tau, a brain protein found in the blood, might help doctors identify athletes who need a longer recovery time after a sports-related concussion, according to a new report in the medical journal Neurology.
Tau is linked to the development of Alzheimer’s and Parkinson’s diseases and serves as an indicator of nerve cell damage following traumatic brain injuries, commonly referred to as concussion.
According to the Centers for Disease Control and Prevention, nearly 1.3 million concussions occur each year in the United States. Athletes who participate in contact sports have nearly a one in five chance of suffering a sports-related concussion per year of play.
Concussion damages the delicate tissues and blood vessels of the brain and can result in altered brain function that can last for days, weeks, or months. About 15 percent of concussed athletes experience symptoms as long as one year after their injury, a condition called persistent post-concussion syndrome, or PPCS—typically after returning to play too quickly.
Determining when an athlete can return to play presents many challenges. Doctors and athletic trainers currently rely on a variety of measures, including physical examination, cognitive performance, and interviews with the patient and his or her family. Balance tests and computer-generated assessments can gauge an athlete’s mental performance before and after a brain injury.
Some athletes, however, have found work-arounds for the tests, blaming poor ankle strength for failed balance tests and intentionally underperforming on the preseason computerized assessments so that their baseline test scores (what they’re compared against if they have a concussion) are falsely low.
Measuring tau levels could be an objective means of preventing athletes from returning to physical activity too soon and risking further brain injury.
In the study, researchers measured preseason tau levels in blood samples from more than 600 male and female University of Rochester athletes who participate in contact sports, including football, basketball, hockey, and lacrosse.
Then the researchers measured tau levels in those athletes who experienced a concussion during the season – 43 athletes in all – at multiple time points: within 6, 24, and 72 hours of the injury, and again at seven days post-injury and compared them with samples from uninjured athletes and non-athletes.
Tau was higher in the blood of male and female athletes who needed a longer recovery time, regardless of sport played. Measuring tau in concussed athletes might be a useful way to determine how long an athlete needs to be on the bench.
Current tests for measuring tau take weeks, not hours, to come back from the lab, however, and are expensive. Experts believe it might be many years before tau testing for concussion becomes routine.