Acute plasma tau relates to prolonged return to play after concussion
Gill J, Merchant-Borna K, Jeromin A, Livingston W, Bazarian J. Neurology. 2017; 88:1-8.
Take Home Message: Elevated plasma tau concentrations within 6 hours of sport-related concussion was associated with prolonged return to play.
Many clinical tools used to diagnose and return concussed athletes to play rely on patient-reported information. An objective predictor, such as a blood test for tau protein, would provide an unbiased tool to determine an athlete’s diagnosis, prognosis and readiness for return to play. Therefore, the authors evaluated NCAA Division I and III contact-sport athletes between 2009-2014 to determine changes in tau following concussion compared to preseason. The authors also compared tau changes after a sports-related concussion (43 athletes) to both an athletic control group (no concussion; 37 athletes) and a healthy, nonathletic, control group (21 participants). All athletes gave blood samples during pre-season. Athletes that sustained a sports-related concussion also gave blood samples within 6 hours of injury, and then 2, 3, and 7 days post injury. Athletes that sustained concussions were then grouped into long return to play (> 10 days) or short return to play (< 10 days). Healthy athletes had blood draws at the same time points as the concussion group, and nonathletic participants had blood draws at an unrelated time point. Thirty-nine percent of the athletes with concussion returned in less than 10 days. Females were nearly 6 times more likely to be in the prolonged return to play group (61%). Both healthy and concussed athletes had higher mean tau during pre-season and all other times compared to nonathletic participants. The healthy athletes had higher mean tau concentrations compared to the concussed athletes at 24 and 72 hours. Athletes with long return to play had higher mean tau at 6 hours, 24 hours, and 72 hours post injury, after controlling for sex, compared to those with short return to play. The authors found that higher plasma tau 6 hours post-concussion was a good predictor of return to play in less than 10 days.
The authors presented that changes in tau from pre-season to 6 hours after a concussion was an accurate predictor of prolonged return to play following a concussion. Identifying biomarkers to better understand how an athlete may recover may protect athletes from neuronal damage, subsequent concussions, and sustaining further injuries (lower extremity injuries). Concussed athletes that took longer to recover typically had higher tau concentrations compared to those that took less than 10 days to recover. Therefore, the authors suggest that tau could be used as a prognostic biomarker. However, the mean tau levels at 24 and 72 hours were lower in the concussed athletes compared to the healthy athletes, which may suggest that physical activity can increase mean tau. This is supported by the finding that all athletes had higher levels of tau during pre-season compared with nonathletic participants. More research will need to be done to replicate and validate these findings in larger cohorts, while controlling for physical exertion. Currently, medical professionals should continue to use multiple clinical tests for concussion diagnosis and safe progression of athletes to play, and continue to be on the lookout for a reliable objective predictor such as a blood biomarker to use in his/her concussion protocol.
Questions for Discussion: Are biomarkers something you would be interested in implementing into your concussion protocol in the future? If not, what are your reservations?
Written by: Jane McDevitt, PhD
Reviewed by: Jeff Driban
Gill, J., Merchant-Borna, K., Jeromin, A., Livingston, W., & Bazarian, J. (2017). Acute plasma tau relates to prolonged return to play after concussion Neurology, 88 (6), 595-602 DOI: 10.1212/WNL.0000000000003587