Clinical evidence for a blood test that may be able to identify brain injuries quickly continues to grow, as Swedish researchers say the presence of high-levels of tau proteins in the blood indicate the breakdown of white matter in the brain.
The researchers are not the first to suggest the tau protein may be instrumental in creating a blood test for traumatic brain injuries. The tau protein is already of interest to Alzheimer’s disease researchers, and it has become the center of the hunt for a reliable and objective diagnostic test for brain injuries.
The latest study, published in the journal JAMA Neurology, shows that tau levels spiked in the blood in the hour immediately after suffering a traumatic brain injury, and then spiked a second time roughly 36 hours after the injury. While they declined slightly in between and after the 36 hours, blood samples compared to samples taken pre-season found the higher a hockey player’s tau levels are in the first hour after the injury, the longer it took for concussion symptoms to fade.
The researchers gathered blood samples and tracked blows to the head among the 288 professional players of the Swedish Hockey League for the first half of the 2012-13 season. Between September 13, 2012, and January 31, 2013, 35 players had suffered a concussion, and 28 of those injured players had blood samples taken 1, 12, 35, and 144 hours after their injury.
However, the tau protein may not be the holy grail it is made out to be. In an editorial accompanying the study, a pair of brain scientists cautioned the protein is only a sign of one kind of injury that occurs during a concussion: the twisting and stretching of axons, the fibers that carry electrical signals between cells and among different regions of the brain. In order for a blood test to identify all types of concussions, it may also have to look for markers the indicate injury to the brain’s blood vessels, as well as its specialized immune system.