Only Tau Will Tell...

With a bestselling novel and a Hollywood film to its credit (1), the subject of sports-related cranial trauma is finally receiving some long-overdue attention. American football is notorious for repeated concussion, and with the combined worth of National Football League teams being nearly $75 billion (2), safety of its stars – and protecting them from the probability of long-term neurological symptoms – is of great interest. To that end, researchers at the National Institutes of Health (NIH) have been investigating diagnostic markers to not only detect cases of concussion, but also to provide insight into prognosis and recovery (3).

Tau proteins have previously been linked to axonal damage after traumatic brain injuries (4) and, therefore, have potential as biomarkers of concussion. Indeed, the NIH team discovered that higher levels of tau observed six hours after a sport-related concussion correlate with an extended recovery period – findings that may eventually play a vital part in determining when an athlete can resume play.

There is a complicating factor, though; athletes generally have higher tau concentrations than non-sport playing controls, which must be taken into account. The researchers suggest that the elevated base level of tau may be caused by the general physical exertion of sports in conjunction with the increased blood-brain barrier permeability that occurs during sports-related activities. Although this natural elevation seems benign, it remains an important factor to consider – both for research into the association between tau and brain injury, and for any eventual diagnostic use.