Summary: Changes in microRNA levels in saliva can indicate a recent concussion. This new saliva-based test offers a low-cost, non-invasive way to support concussion identification.
Source: Penn State
Penn State College of Medicine researchers report that measuring specific molecules in saliva could help clinicians diagnose concussions more accurately. A recent multi-site clinical study found that saliva microRNA profiles can distinguish people with recent mild traumatic brain injury (mTBI) from those without, offering an objective, non-invasive diagnostic tool.
The research team analyzed saliva samples from more than 500 participants to measure tiny strands of genetic material known as micro ribonucleic acids (microRNAs). MicroRNAs regulate cellular processes and are abundant in nervous tissue. Because cranial nerves connect the brain and the oral cavity, investigators hypothesized that concussion-related changes in brain physiology might be reflected in saliva microRNA levels.
Concussions result from head trauma and commonly cause symptoms such as headache, dizziness and confusion. Current diagnosis relies heavily on self-reported symptoms and neurocognitive testing, which can be subjective and susceptible to bias—for example, athletes may underreport symptoms to return to play sooner. Researchers sought an objective biomarker that does not depend on patient reporting or effort during testing.
“Current methods rely on accurate symptom reporting and honest performance on neurocognitive testing,” said Dr. Steve Hicks, associate professor of pediatrics and principal investigator. “Analyzing microRNA profiles in saliva after head trauma provides a non-invasive test that is not affected by a patient’s motivation or subjective reporting.”
To develop and validate the saliva-based diagnostic approach, the team enrolled 538 participants across 11 clinical sites. About half the participants had sustained a concussion within two weeks of enrollment. The remainder served as controls but included individuals with conditions that might mimic concussion symptoms—such as anxiety, depression, attention deficit hyperactivity disorder (ADHD), exercise-related fatigue or chronic headache—so the test’s specificity could be assessed.
Researchers performed RNA sequencing on saliva samples from a large subset of participants to identify candidate noncoding RNAs (ncRNAs) that differed between mTBI and control groups. They applied statistical modeling and machine learning to discover patterns that differentiated concussed patients. After identifying promising ncRNA markers in a training set, the team tested the diagnostic model on an independent validation cohort of more than 200 additional participants and successfully identified which patients had concussions.
The saliva RNA approach showed diagnostic performance comparable to, and in some comparisons favorable against, existing clinical tools such as balance and reaction-time testing. Results of the study were published in Clinical and Translational Medicine.
Dr. Hicks noted that this work builds on an earlier pilot study that indicated saliva microRNA patterns could also predict how long concussion symptoms might last. The researchers emphasize that further development is needed to translate this biomarker into a portable, rapid test usable on the sidelines by athletic trainers, at accident scenes by emergency responders, or by military medics in field settings. Hicks is collaborating with Quadrant Biosciences, which received a grant to support a larger clinical study to validate and commercialize the technology.
Contributors to the research include Cayce Onks, Raymond Kim, Kevin Zhen, Jayson Loeffert, Andrea Loeffert and Robert Olympia of Penn State College of Medicine; Gregory Fedorchak, Samantha DeVita and Aakanksha Rangnekar of Quadrant Biosciences; John Leddy and Mohammad Haider of State University of New York; Zofia Gagnon, Callan McLoughlin, Jason Randall and Miguel Madeira of Marist College; Aaron Yengo-Kahn and Justin Wenzel of Vanderbilt University Medical Center; Matthew Heller and Hallie Zwibel of New York Institute of Technology College of Osteopathic Medicine; Aaron Roberts and Samantha Johnson of Adena Regional Medical Center; Chuck Monteith, Colgate University; Michael Dretsch, Walter Reed Army Institute of Research; Thomas Campbell, Old Dominion University; Rebekah Mannix, Harvard Medical School; and Christopher Neville and Frank Middleton of State University of New York Upstate Medical University.
Funding: This project was supported by a sponsored research agreement between Quadrant Biosciences and the Penn State College of Medicine. The National Center for Advancing Translational Sciences through the Penn State Clinical and Translational Science Institute (UL1 TR002014) also supported the work. Dr. Hicks is a scholar in the institute’s Early Stage Investigator Training Program (KL2 TR002015). The content is the responsibility of the authors and does not necessarily represent the official views of the NIH.
Disclosures: Steve Hicks is a paid consultant for Quadrant Biosciences. Steve Hicks and Frank Middleton serve on Quadrant Biosciences’ scientific advisory board and are co-inventors on saliva RNA biomarker patents related to concussion, owned by the Penn State Research Foundation and the SUNY Upstate Research Foundation and licensed to Quadrant Biosciences. Samantha DeVita, Gregory Fedorchak and Aakanksha Rangnekar are employees of Quadrant Biosciences. Christopher Neville is on the scientific advisory board and holds equity in Quadrant Biosciences Inc. Material was reviewed by the Walter Reed Army Institute of Research with no objection to presentation or publication. The opinions expressed are the authors’ private views and not official positions of the Department of the Army or Department of Defense. The investigators followed human subject protection policies prescribed in AR 70-25.
About this neurology and concussion research news
Source: Penn State
Contact: Barbara Schindo – Penn State
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Original Research: Open access. “Diagnosing mild traumatic brain injury using saliva RNA compared to cognitive and balance testing” by Steve Hicks et al., Clinical and Translational Medicine.
Abstract
Diagnosing mild traumatic brain injury using saliva RNA compared to cognitive and balance testing
Background
Early, accurate diagnosis of mild traumatic brain injury (mTBI) can improve patient outcomes, but current practice depends largely on subjective symptom reports and performance-based tests. An objective, biologic biomarker could increase diagnostic accuracy and guide timely care. This study assessed whether salivary noncoding RNAs (ncRNAs) can serve as a diagnostic adjunct to symptom scales, neurocognitive testing, and balance assessment, with the hypothesis that saliva ncRNA levels would demonstrate comparable diagnostic accuracy.
Methods
This case-control study enrolled 538 individuals, including 251 participants with mTBI enrolled within 14 days of injury from 11 clinical sites. A total of 679 saliva samples were collected across up to five time points (≤3, 4–7, 8–14, 15–30, and 31–60 days post-injury). Levels of ncRNAs—including microRNAs, small nucleolar RNAs, and piwi-interacting RNAs—were quantified by RNA sequencing. The first sample from each mTBI participant was compared with saliva from 287 controls. Samples were split into training and test sets to identify diagnostic ncRNA candidates and to build and validate a predictive model.
Results
A diagnostic model using seven ncRNA ratios plus participant age and chronic headache status differentiated mTBI and control participants with strong accuracy: cross-validated area under the curve (AUC) of 0.857 (95% CI, 0.816–0.903) in the training set and 0.823 in the independent test set. In a subset assessed with symptom scales (Post-Concussion Symptom Scale), neurocognitive testing and balance measures, those clinical tools produced comparable AUCs. Models combining symptom burden with either select neurocognitive measures or with a subset of ncRNAs showed similar or improved diagnostic performance.
Conclusion
Salivary ncRNA levels provide a noninvasive, biologic measure that can assist objective and accurate diagnosis of mild traumatic brain injury, supporting clinical decision-making and potentially enabling more timely treatment and safer return-to-activity decisions.