Jun 8, 2018Looking for Answers
Research has shown that subconcussive head impacts can cause neurophysical and neuropsychological changes in athletes. However, due to the absence of symptoms with a subconcussive hit, it’s hard to know when an athlete should be removed from competition because of it. According to an article for ScienceDaily, Jonathan Oliver, PhD, and a team of researchers set out to determine whether blood-based biomarker could change that.
“Given recent findings indicating a potential link between repetitive subconcussive impacts and the development of [chronic traumatic encephalopathy], efforts to determine the effect of subconcussive impacts throughout an athlete’s career may prove useful, especially if those efforts are feasible and cost effective,” said Dr. Oliver, who is an Assistant Professor of Kinesiology and Director of The Sport Science Center at Texas Christian University.
To do this, Dr. Oliver and researchers from The Sport Science Center at TCU, Texas Health Sports Medicine, and the University of Wisconsin-La Crosse engaged in a study to identify and monitor the accumulation of subconcussive head impacts. Published by the Journal of Neurosurgery, this study focused on two biomarkers of head trauma and brain injury — the tau protein and neurofilament light polypeptide (NF-L). The investigation began with taking seven blood samples from 35 NCAA football players — 20 starters and 15 nonstarters — over the course of the season. The tests were taken before the beginning of fall camp and three weeks before the season ended. During the season, they were taken 36 to 72 hours after a game or practice session.
Once the tests were taken, researchers examined any variations in plasma concentration of tau and serum concentrations of NF-L with the nonstarters serving as the control group. When it came to the tau concentration, researchers found that this number decreased over the season for both starters and nonstarters. However, due to the miniscule differences in concentration between the groups, it was found that tau protein would not be a good indicator of injury from subconcussive head impacts.
In the case of NF-L concentration, both groups saw an increase during the competitive season compared to their preseason numbers. Even though both groups experienced an increase, starters saw higher spikes at multiple points, while nonstarters had less significant increases. With this data, researchers showed that NF-L concentration during periods of repetitive head impact had fair-to-modest accuracy when differentiating between starters and nonstarters.
Overall, researchers found that NF-L could be a reliable biomarker for brain injury caused by repetitive subconcussive head impacts. But they also noted that this was only a preliminary study. In order to receive more conclusive results, they recommend performing a larger study.