Every year, an estimated 700,000 people visit emergency departments in the UK with head injuries – many of who obtained their injury while playing sport.
While concussion is the most common brain injury, it can be tricky to diagnose, with some symptoms not appearing for days or even weeks after the injury.
Now, scientists have paved the way for faster tests for concussion, having discovered distinct chemical ‘signatures’ for the condition in rugby players’ spit.
The researchers hope their findings could be used to develop pitch-side tests for concussion, and reduce the risk of long-term complications for athletes.
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Scientists have paved the way for faster tests for concussion, having discovered distinct chemical ‘signatures’ for the condition in rugby players’ spit (stock image)
At the moment, concussion diagnosis relies on a doctor’s interpretation of signs and symptoms, before a formal clinical assessment.
Key signs include dizziness, memory loss and trouble with balance – yet many symptoms do not appear immediately, making it tricky for doctors to diagnose rugby players with confidence.
In the study, researchers from the University of Birmingham set out to understand whether or not concussion could be diagnosed from rugby players’ spit.
The team obtained saliva samples from more than 1,000 male professional rugby players in the top two tiers of England elite rugby union from 2017-2019.
Spit samples were collected from 1,028 players before the rugby season began, and during standardised ‘gold standard’ head injury assessments at three time points – during the game, immediately afterwards, and 36-48 hours after the game ended in 156 players.
The researchers also took saliva samples from 102 uninjured players, and 66 who had muscle or joint injuries for comparison.
An analysis of the samples revealed that the players with concussion had 14 distinct chemical signatures called small non-coding RNAs (sncRNAs) in their saliva.
While the reason for this remains unclear, the researchers suggest that saliva may be able to receive cellular signals directly from cranial nerves in the mouth and throat, and so can rapidly register traumatic brain injury.
As a contact sport, rugby does involve frequent body impacts and a risk of accidental head impacts, and therefore a significant potential risk of concussion
If this is the case, it could make pitch-side saliva tests a viable option.
In their study, published in the British Journal of Sports Medicine, the researchers, led by Dr Valentina Di Pietro, wrote: ‘Concussion can be hard to diagnose and is often missed, especially where a structured evaluation by an expert clinician is not possible -for example, at grass-root level.
‘Small non-coding RNAs can provide a diagnostic tool that might reduce the risk of missing this type of injury at all levels of participation.’
Aside from rugby, the findings could also help doctors to understand the body’s response to brain injury over time, according to the researchers.
‘The detection of signatures of concussion at early time points in saliva (a non-invasively sampled biofluid) presents both at the pitch side, and in primary care and emergency medicine departments, an opportunity to develop a new and objective diagnostic tool for this common clinical presentation,’ they added.
The researchers have now patented a salivary concussion test, which is in the process of being transformed into an over-the-counter test for elite male athletes.