Do you have a concussion? There presently is no objective diagnostic test to answer this question. Generally the question is answered through a series of subjective symptoms. This could all change with a non-invasive diagnostic test just reported in the British Journal of Sports Medicine.
The new study notes that through a simple saliva sample genetic markers can be identified to diagnose concussion with 94% accuracy. While the test results presently take some time to get back it is a safe guess that money will be thrown at this research to create a rapid result sideline test given the large market that would benefit from such a diagnostic tool.
In the study, titled Unique diagnostic signatures of concussion in the saliva of male athletes: the Study of Concussion in Rugby Union through MicroRNAs (SCRUM), researchers took samples from hundreds of rugby players including a control group. The researchers compared saliva samples collected before the season with samples collected after players were suspected to have a concussion. They found that markers in the saliva could objectively diagnose concussion with a high rate of accuracy.
The study’s full abstract reads as follows:
Objective To investigate the role of salivary small non-coding RNAs (sncRNAs) in the diagnosis of sport-related concussion.
Methods Saliva was obtained from male professional players in the top two tiers of England’s elite rugby union competition across two seasons (2017–2019). Samples were collected preseason from 1028 players, and during standardised head injury assessments (HIAs) at three time points (in-game, post-game, and 36–48 hours post-game) from 156 of these. Samples were also collected from controls (102 uninjured players and 66 players sustaining a musculoskeletal injury). Diagnostic sncRNAs were identified with next generation sequencing and validated using quantitative PCR in 702 samples. A predictive logistic regression model was built on 2017–2018 data (training dataset) and prospectively validated the following season (test dataset).
Results The HIA process confirmed concussion in 106 players (HIA+) and excluded this in 50 (HIA−). 32 sncRNAs were significantly differentially expressed across these two groups, with let-7f-5p showing the highest area under the curve (AUC) at 36–48 hours. Additionally, a combined panel of 14 sncRNAs (let-7a-5p, miR-143-3p, miR-103a-3p, miR-34b-3p, RNU6-7, RNU6-45, Snora57, snoU13.120, tRNA18Arg-CCT, U6-168, U6-428, U6-1249, Uco22cjg1,YRNA_255) could differentiate concussed subjects from all other groups, including players who were HIA− and controls, immediately after the game (AUC 0.91, 95% CI 0.81 to 1) and 36–48 hours later (AUC 0.94, 95% CI 0.86 to 1). When prospectively tested, the panel confirmed high predictive accuracy (AUC 0.96, 95% CI 0.92 to 1 post-game and AUC 0.93, 95% CI 0.86 to 1 at 36–48 hours).
Conclusions SCRUM, a large prospective observational study of non-invasive concussion biomarkers, has identified unique signatures of concussion in saliva of male athletes diagnosed with concussion.