People with a history of concussion are more than twice as likely to develop a neurological disease, according to a new study that gathered the largest ever dataset on the syndrome in the UK. The study, from the team behind a new dementia screening app, Mindset4Dementia, has released its findings showing a significant correlation between concussion and brain disease after the Guardian revealed this week that a group of former professional rugby players are taking legal action against the sport’s governing bodies for negligence in their failure to protect them from long-term brain injuries caused by head trauma during their careers. The eight players, who include the England Rugby World Cup winner Steve Thompson along with the former Wales international Alix Popham and the 10-time capped England forward Michael Lipman, are among a group of 11 who have recently been diagnosed with early-onset dementia and probable chronic traumatic encephalopathy (CTE), a degenerative brain disease that can only be fully diagnosed postmortem. The legal firm representing the players says that it has have been in contact with as many as 100 retired players from across rugby union and rugby league who are suffering from some degree of neurological impairment. The only known cause for CTE is repeated head trauma, but because diagnosis is so tricky some experts insist the links between the disease and concussion are still unclear. In the study, a sample of 3,631 members of the general public who have already used the Mindset4dementia app, 12% reported having been previously diagnosed with a concussion. Among the 88% who had never had a concussion, 6.64% were living a neurological condition such as migraines, epilepsy or dementia. Among the 12% who did have a history of concussion, the figure living with a neurological condition more than doubled to 14.68%. When the groups were divided by age, the risk increased further still for people aged over 40, to 2.67 times more likely. The findings have been reviewed by an independent neurologist, and are being submitted for peer review next week. The team behind the study believe the app could develop into a crucial tool to help with the early diagnosis of both dementia and CTE. They have already approached the Rugby Football Union and the Football Association to collaborate on its development. The RFU has indicated it is keen to explore the new technology. Hamzah Selim, who devised the app, describes it as “a black and white correlation”. Selim, a 4th year medical student at UCL, developed the technology over the past two years in association with a group of clinicians and coders. The app condenses a battery of clinical tests for 20 different symptoms related to dementia into a single four-minute test that can be done on a phone. While it is not intended to replace an experienced neurologist, it will enable users to test themselves for the early signs and symptoms of dementia. The team is looking to develop sport-specific versions of the technology that can be used to diagnose concussions at pitch-side, from the amateur level up to the professional game. Selim was inspired to create the technology while he was using Snapchat in a lecture during his degree in neuroscience. “We were being shown how to perform a finger-tracking test for concussion, when you ask the patient to follow your finger, and I thought ‘Bloody hell, this is really difficult. And it is very hard to do unless you’re a top-level consultant, because you have to watch for a flicker of the pupil.’” He got bored, went on his phone, and started playing around on Snapchat. He used it to superimpose a photo-filter of a dog on his own face “And I saw that Snapchat was doing that by using eye-tracking software, and suddenly I thought why can’t we use the same technology to put filters on your face to track eye-movement?” The developers have also added clinical tests to check for signs of depression, anxiety, impulse-control and finger-tremors. “In four minutes it gives you an MOT of your own brain,” says Selim. As the app attracts more users, the AI behind it will improve too. “The general theory is that we’re picking up dementia too late. The earlier the pickup the better the chance of preserving cognitive health. So the end goal is for the technology to be able to become predictive, so that we can work out if patients are on a dangerous trajectory and help them put preventive measures and management plans in place sooner.”