A new technology that could pave the way for an objective test to diagnose concussion at pitchside has been hailed as a “gamechanger” by researchers. The test, performed on saliva samples, has the potential to be used in high-impact sports such as elite rugby and football where head injuries are common, and also at grassroots level and in other areas of life.
The research team, led by the University of Birmingham and part‑funded by the Rugby Football Union, has published the study in the British Journal of Sports Medicine. The identification of the biomarkers in saliva creates the possibility of a non-invasive clinical test for concussion.
According to the report’s first author, Dr Valentina Di Pietro, technology to make the test available at pitchside could be developed within three to five years. Dr Simon Kemp, chief medical officer at the RFU, says that samples, which currently require analysis in a lab, could return results for practical use in the elite men’s game as early as next season.
“For the first time we have successfully identified that these specific salivary biomarkers can be used to indicate if a player has been concussed,” Professor Antonio Belli, the report’s senior author, said. “We now have a laboratory-based, non-invasive diagnostic test using saliva, which is a real gamechanger, and provides an invaluable tool to help clinicians diagnose concussion more consistently and accurately.
“The test could be used not only in sport, from grassroots to professional levels, but also in healthcare and military settings. In community sports, these biomarkers may provide a diagnostic test that is comparable in accuracy to the level of assessment available in a professional sports setting.”
The study’s breakthrough is the identification of these biomarkers in saliva, but practical use of the technology in live situations will depend on further tests and ratification by players’ unions and governing bodies. Kemp said: “The best-case scenario is that we could see some real-time results being fed back next season in the elite men’s game.”
What the study has nothing to say about, though, is the levels of damage to a player’s brain incurred in any given event, let alone from participation in any given game, still less any season or career. Definitive answers to these questions remain decades away, but if the sort of science revealed by the Birmingham study can begin to lend objectivity to the detection of brain injury in a timely fashion the benefits could resound throughout sport and beyond.
The issue of brain injury in rugby has been brought centre-stage by a group of former players who are suing the game’s authorities after being diagnosed with early-onset dementia, which they believe was caused during their rugby careers.
The biomarkers identified are called microRNAs, discovered in 1993. These are of interest because the changes in them observed following injury are precursors to the production of the sort of protein molecules usually tested for as biomarkers. They are also much smaller. This renders them a more sensitive gauge of neurotrauma.
“They work differently from protein biomarkers,” Belli said. “MicroRNAs are messages the cells transmit in response to an event, like a brain injury. These are codes the cells send to each other to say: ‘You don’t need these genes,’ or: ‘You do need these other genes,’ as a response. And the place where you find microRNAs most abundantly is saliva. Salivary glands are connected directly to the brain by nerves. We’re seeing this response within minutes of injury.”
The study will now expand into further areas, investigating the role of these biomarkers in women, youth and community sport.
There are also plans to collect further samples from two as-yet unidentified elite men’s competitions, subject to ratification at World Rugby’s next welfare symposium at the end of this month and by the applicable players’ unions.
The report’s lead authors, Belli and Di Pietro, are founding members of a company called Marker Diagnostics, which is in the process of trying to develop an over-the-counter test. This would revolutionise the safety of the sport at community level, but there remain significant barriers.
Many more factors feed into the challenge of making the test available at pitchside. The saliva samples are analysed by the polymerase-chain-reaction method, as in tests for Covid-19, which means they must be sent to a lab. Di Pietro notes the speed with which the lateral flow test was developed for Covid-19. That was achieved in a national emergency, but she maintains the prospects for the similar development of a pitch-side test are realistic. “I think the technology will be there in the next three to five years.”
Meanwhile, the definition of when a player has sustained a brain injury remains inexact. The parameters of the Birmingham study mean the “correct answer” to whether or not a player had sustained a brain injury is supplied by the HIA, a test that rests solely on the symptoms presented by a player. These can vary from individual to individual, and there is no way of assessing how they might relate to the wider crisis in certain sports regarding neurodegenerative conditions in later life. The current study, for now, takes its lead from this old-fashioned investigation of symptoms. The hope is that one day those roles will be reversed.