Study finds marker of functional brain activity and vasculature more accurate than ImPACT testing
By Ella Gullickson. This article was initially published in our Concussion Update newsletter; please consider subscribing.
A study published in Brain Communications evaluated 50 athletes from English and Welsh rugby leagues using variability in blood oxygen levels measured with fMRI imaging to detect functional alterations in brain activity and changes in cerebral vascular status. Of the 50 athletes, 29 were recently diagnosed with a concussion, six were diagnosed with multiple concussions, and 15 had not recently experienced a concussion. The authors found that these measures of blood oxygen variability are significantly better at detecting concussion in athletes than widely used computerized cognitive diagnostic testing (i.e., ImPACT). Authors Evan D. Anderson et al. found that the ImPACT test was unreliable at distinguishing concussed athletes from healthy athletes. Additionally, the blood oxygen-based variability testing combined with ImPACT was even more reliable than the blood oxygen variability testing alone. Moreover, the blood oxygen variability testing was a “more sensitive predictor of post-concussion symptoms” and more accurately identified whether individuals had suffered more than one concussion.
Scott Schrange, writing for Medical Xpress, stated that single-concussion athletes had lower variability of blood oxygen levels. For multiple-concussion athletes, the blood oxygen variability was higher. Anderson et al. theorize that “unique neurovascular alterations may be induced in repetitive mTBI compared with single mTBI.” All of these results suggest that blood oxygen level variability in the brain is a promising candidate for use as a biomarker for concussion in the future. Additionally, the researchers state that this altered variability can “indicate sites of neural proliferation and synaptogenesis,” providing evidence of post-mTBI neuroplasticity that occurs during recovery.
These results are heartening because sport-related concussions (SRC) have been “among the most complex injuries in sports medicine to diagnose.” Due to a lack of reliable diagnostic tools, “athletes with minimal physiological and neurocognitive symptoms may…be cleared to return to play prematurely,” potentially exacerbating concussive symptoms, increasing the risk for severe secondary injuries, and complicating recovery. Aron Barbey, who directs the Center for Brain, Biology, and Behavior at the University of Nebraska-Lincoln, also studied the use of blood oxygen variability as a biomarker. In the article for Medical XPress, Barbey asserted, “We are indeed moving in the right direction to better understand and diagnose this complex injury.”
