Concussions among amateur and professional athletes who play competitive contact sports such as football and ice hockey have received a great deal of attention recently. Now, researchers believe they have found a protein detectable in blood that could be used to help rapidly diagnose a concussion, leading to better management of those affected.
A concussion, caused by a bump or blow to the head, is a type of traumatic brain injury (TBI). The brain is made of soft tissue that is cushioned by spinal fluid and surrounded by a hard skull. This allows the brain to move around inside the skull and even bang against it, which can lead to bruising, tearing of blood vessels, and injury to the nerves. That in turn can lead to a concussion, a temporary loss of normal brain function. Studies have shown that TBIs can have a long-lasting impact on cognitive abilities, including the development of dementia.
The signs and symptoms of concussions can be subtle and may not be immediate, varying from headache and confusion to loss of consciousness. This makes it difficult for health practitioners and coaches to determine when it is safe to return an athlete to play following a heady injury. A blood test that can detect a concussion would speed up diagnosis and allow more rapid treatment of the condition.
Researchers in Sweden recently reported that a blood test for a structural protein in the brain called tau (total tau or T-tau) shows promise as a test for concussions. The study analyzed blood levels of T-tau taken from a sample of Swedish Hockey League players who had concussions during the 2012-2013 season. The samples were tested at 1, 12, 36, and 48 hours following their injury as well as 6 days after the injury or when they returned to unrestricted competition.
Results showed that the injured players had significantly increased levels of T-tau compared with pre-season levels. The highest levels of T-tau were found in players at the first hour after a concussion. Values declined during the next 12 hours but remained elevated 6 days later when compared with pre-season samples. The T-tau level one hour after a concussion was also associated with the number of days it took for concussion symptoms to resolve and for players to be safely cleared for play.
The study also evaluated two other biomarkers, S-100 calcium-binding protein B (S-100B) and neuron-specific enolase (NSE), but found them to be less promising. While T-tau needs to be evaluated in larger studies, it raises hope that health practitioners may in the future be able to use blood tests to manage head injuries and make return-to-play decisions following a concussion.
Elsewhere on the web
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used. To access online sources, copy and paste the URL into your browser.
Shahim P, et al. Blood Biomarkers for Brain Injury in Concussed Professional Ice Hockey Players. JAMA Neurol 2014; DOI: 10.1001/jamaneurol.2014.367. Published online March 13, 2014. Available online at http://archneur.jamanetwork.com/article.aspx?articleid=1846623 through http://archneur.jamanetwork.com. Accessed March 23, 2014.
Gatson J and Diaz-Arrastia, R. Editorial: Tau as a Biomarker of Concussion. JAMA Neurol 2014; DOI: 10.1001/jamaneurol.2014.443. Published online March 13, 2014. Available online at http://archneur.jamanetwork.com/article.aspx?articleid=1846622 through http://archneur.jamanetwork.com. Accessed March 23, 2014.
Gever, J. Blood Test Diagnoses Concussion, Gauges Severity. Medpage Today. Published March 14, 2104. Available online through http://www.medpagetoday.com. Accessed March 25, 2014.
Zeltner, B. New blood test for concussion may help protect players, Swedish researchers report. Cleveland.com. Available online at http://www.cleveland.com/healthfit/index.ssf/2014/03/new_blood_test_for_concussion.html through http://www.cleveland.com. Accessed March 25, 2014.
Young, Kelly. Elevated Blood Biomarker Potentially Useful in Concussion Diagnosis. Journal Watch. March 14, 2014. Available online at http://www.jwatch.org/fw108594/2014/03/14/elevated-blood-biomarker-potentially-useful-concussion through http://www.jwatch.org. Accessed March 23, 2014.
Gever, J. Blood Test Accuracy Not Easily Measured. Medpage Today. Published March 17, 2014. Available online http://www.medpagetoday.com. Accessed March 25, 2014.
Centers for Disease Control and Prevention. Traumatic Brain Injury. Available online at http://www.cdc.gov/TraumaticBrainInjury/ through http://www.cdc.gov. Accessed March 25, 2104.
Mayo Clinic. Concussion: Symptoms. Available online at http://www.mayoclinic.org/diseases-conditions/concussion/basics/symptoms/CON-20019272 through http://www.mayoclinic.org. Accessed March 25, 2014.