Saliva MicroRNAs May Serve as Concussion Biomarker

Results of a multisite case-control clinical study published in Clinical and Translational Medicine show there may be biomarkers for concussion (mild traumatic brain injury; mTBI) in saliva. Differences in the levels of noncoding ribonucleic acid (ncRNAs) were found in people who experienced mTBI within 2 weeks of measurement (n=251) compared with people with anxiety, depression, attention-deficit hyperactivity disorder, exercise-related fatigue or chronic headache (n=287 across all conditions). Both mTBI and the other "control conditions" can cause changes in neuropsychologic performance, which is how mTBI is often assessed.

For the individuals with mTBI, saliva samples were taken at 5 different timepoints in the 2 months after injury occurred, and the first samples were compared to samples from individuals in the case-control group. Differences in 80% of the samples were used to create a diagnostic model that was able to accurately predict which of the remaining 20% of samples came from people with mTBI (n=50) or other conditions (n=58). 

In a subset of participants (n = 321; mTBI = 176 and control = 145) assessed for symptom burden  with the Post‐Concussion Symptom Scale and neurocognition and balance with the ClearEdge System, clinical measures cross‐validated the model with an area under the curve (AUC) measure of .835 (95% CI, .782‐.880) and .853 (95% CI, .803‐.899), respectively. In addition, a model to identify mTBI by symptom burden and 4 neurocognitive measures had a similar AUC (.888; CI, .845‐.925) as identification through symptom burden and 4 ncRNAs (.932; 95% CI, .890‐.965).

“Current methods rely on accurate symptom reporting and honest performance on neurocognitive testing,” said Steven Hicks, MD, associate professor of pediatrics, Penn State College of Medicine. “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. This method has lots of promising applications. A rapid, reliable diagnostic means that early, appropriate action can be taken to alleviate the symptoms of patients with concussions.”