Saliva test could take the guesswork out of concussion assessments
Detecting concussion can be tricky business, with doctors relying on subjective testing and evaluation of symptoms to reach a diagnosis. Scientists are working on techniques that can provide more definitive answers, and researchers at Penn State University have made an exciting advance in this area with a test they say can reveal tell-tale signs of brain injury through saliva.
From tools that track eye movements, to mouthguards that detect impacts in real time, to blood tests that reveal elevated levels of certain proteins, there are some promising possibilities on the horizon when it comes to detecting concussion. The hope is that these kinds of technologies can offer rapid and precise diagnoses of mild traumatic brain injuries, to help prevent athletes returning to the field of play when there is a real danger of further and long-lasting damage.
Similarly, the Penn State team was investigating how analysis of saliva could potentially reveal the occurrence of concussion, and remove the ambiguities for physicians and sideline medical staff making critical decisions on the health of an athlete. The research focuses on strands of genetic material called microRNA, which is widely abundant in the brain, leading the team to suspect that altered levels could not only indicate a concussion, but also be measured via cranial nerves in the mouth.
The study involved 538 subjects, with around half of those having experienced concussions within the two weeks prior. The other half of the subjects had not experienced concussions, but had symptoms associated with them such as anxiety, depression, fatigue and headaches.
First, RNA sequencing was used to evaluate the saliva samples from around half of these subjects, with statistical modeling and machine learning then used to tease out the differences between those with concussion and those without. With these distinct microRNA profiles in hand, the team then tested 200 more subjects and were successful in identifying which ones had indeed experienced concussions.
While still early days for the technology, and it’s a long way from making it into an on-the-spot test that could be used field-side by medical staff, the researchers say it already performs favorably compared to current testing methods. Work is now underway on larger clinical trials to validate and develop it further.
"Current methods rely on accurate symptom reporting and honest performance on neurocognitive testing," says Dr. Steve Hicks, principal investigator of the study. "Analyzing microRNA profiles in saliva following a head trauma is a non-invasive way to test for concussion that can't be influenced by a patient's feelings or motives."
The paper was published in the journal Clinical and Translational Medicine.