Human brains begin to lose their way before the age of 20, a game-based dementia study involving more than two million participants has shown.
The Sea Hero Quest project was set up to investigate spatial navigational ability, a key marker of Alzheimer’s disease progression.
Around the world, a total of 2.4 million people downloaded the smartphone app and played the game, which depicts a son’s sea journey to recover the memories lost by his ancient mariner father.
Different sections of the animated game involve navigating between buoy markers, shooting flares - a test of orientation - and chasing creatures.
Information about each anonymous player’s performance is saved and transmitted to the scientists.
One key early finding, presented at a meeting of neuroscientists in the US, was that navigational ability begins to decline much earlier than was previously thought - possibly from as young as 19.
It continues to deteriorate throughout life.
The study found that 19-year-old game players had a 74% chance of accurately hitting a navigational target. By the age of 75, this figure had fallen to 46%.
Evidence from the Sea Hero Quest study could pave the way to diagnosing dementia earlier by testing navigational skills rather than memory.
Lead researcher Dr Hugo Spiers, from University College London, said: “This is the only study of its kind, on this scale, to date. Its accuracy greatly exceeds that of all previous research in this area.
“The findings the game is yielding have enormous potential to support vital developments in dementia research.
“The ability to diagnose dementia at early stages, well before patients exhibit any signs of general memory loss, would be a milestone.”
Data from the study could be used to provide a benchmark showing the expected rate at which navigational ability drops off with age.
A significantly faster rate of decline might indicate the first sign of problems ahead.
Becoming completely disorientated is rare in healthy individuals, but very common in people suffering from dementia.
Dr Axel Wehmeier, managing director of German communications company Telekom Healthcare Solutions, which launched the game in April, said: “Research is at its most efficient when powered by innovative cross sector collaborations such as this one.
“Now we are excited to announce that we have taken this one step further and are now working with the scientists to adapt Sea Hero Quest for use in a clinical setting.”
The on-going research is expected to take another two years.
“Scientists will assess data on right or left handedness of players, the geographical environments in which they grew up, the number of hours they sleep, and the amount of time they spend travelling each day.
Hilary Evans, chief executive of the charity Alzheimer’s Research UK, which is co-funding the study, said: “The early data that has very quickly been generated by Sea Hero Quest should inspire other corporations to consider what assets they might bring to research into dementia or any of our most seemingly intractable medical conditions.”