Nerve protein in blood shows extent of brain damage following concussion

1 April 2014

Elevated blood levels of tau, a nerve cell protein, indicates the extent of brain damage from concussion, according to research at Sahlgrenska Academy in Sweden.

The researchers have now developed a method that can show just an hour after the injury how severe the concussion is, if there is a risk of long-term symptoms and when the player can return to the game.

They monitored and examined all of the players in Sweden's top hockey league in cooperation with Luleå University of Technology. Between September and December of the 2012/2013 season alone, 35 of 288 players in the Swedish Hockey League (SHL) had had a concussion — in three cases, it was so severe that the player was knocked unconscious.

The goal of the unique study was to find safer methods of diagnosing sports-related brain injuries, and to obtain a better basis for decisions about when the player can return to the game.

In the study, the players who had a concussion were asked to provide repeated blood samples, directly after the concussion and during the ensuing days. The results were compared with the pre-season samples from two full teams.

Professor Henrik Zetterberg and his colleagues identified the nerve cell protein, called tau, was at elevated levels in the blood following concussion. By measuring the tau levels in a regular blood test, the researchers could say how severe the concussion was just one hour after the injury, and with a high level of certainty could predict which players would have long-term symptoms and thereby needed to rest longer.

"In ice hockey and other contact sports, repeated concussions are common, where the brain has not finished healing after the first blow. This kind of injury is particularly dangerous, but there have not been any methods for monitoring how a concussion in an athlete heals," says Prof Zetterberg.

"In contact sports like ice hockey, boxing and American football, concussions are a growing international problem. The stakes for the individual athlete are high, and the list of players forced to quit with life-long injury is getting ever longer," says Henrik Zetterberg.

"We hope that this method will be developed into a clinical tool for club physicians and others in sports medicine, and is used as a basis for the decision on how long the player should rest after a blow to the head," says Henrik Zetterberg. “It could even be used in general in emergency medical care to diagnose brain damage from concussions regardless of how they happened.”

The study was conducted in cooperation with researchers at the Luleå University of Technology, Sahlgrenska University Hospital and the US biotech firm Quanterix Corporation.

Harry Wood

Reference

Shahim P, et al. Blood Biomarkers for Brain Injury in Concussed Professional Ice Hockey Players, JAMA Neurol. Published online March 13, 2014. doi:10.1001/jamaneurol.2014.367