(CNN) -- Just a few minutes of playing a certain video game could help identify the earliest stages of Alzheimer's in ways existing medical tests can't, researchers have found.
A new study used a smartphone app called Sea Hero Quest to monitor how gamers with and without a genetic predisposition to Alzheimer's navigate the virtual world, using their thumbs to move a little boat through a series of maritime mazes.
This type of test was key because "spatial navigation is emerging as a critical factor in identifying preclinical Alzheimer's disease," authors of the study, just published in the Proceedings of the National Academy of Sciences, said.
Players with a high genetic risk for Alzheimer's took less efficient routes to reach checkpoints in the game, researchers found. What's more, the movement patterns were identified among players in the genetic risk pool who had not yet displayed any other memory problems, they said.
By casting an online global net for survey subjects, scientists also managed to reach their conclusions in what might be described as warp speed. They marked the equivalent of five hours' worth of lab research for every two minutes of game play, they said, because vast sums of data about each player are available in every second of play.
The findings offer wide-ranging possibilities, including aiding "the development of more personalized measures for future diagnostics and drug treatment programs," researcher Gillian Coughlan said.
'The largest dementia study in history'
Researchers set out to test the spatial navigation hypothesis in a novel way: They created Sea Hero Quest and engaged casual gamers around the globe.
Making their scientific purposes clear up front, developers focused on Apple and Android users in the United Kingdom, letting them decide whether to allow researchers to collect data about how they maneuvered through the game's virtual world. They ended up with 4.3 million players, setting the stage for what they call "the largest dementia study in history."
Scientists then homed in on data from more than 27,000 players between ages 50 and 75 -- the group at highest risk of developing Alzheimer's symptoms within a decade -- to create a global benchmark for how most people navigate the game, the study states.
Finally, they compared those results with the performance of 60 people in a lab setting: 31 with the gene APOE4 , which increases Alzheimer's risk, and 29 without it.
The cross-check revealed a clear difference in movement patterns among those in the risk pool -- who opted for less efficient paths -- and the other players, researchers said.
Memory tests are still the standard
By focusing on navigation as an early identifier of Alzheimer's, the Sea Hero Quest test differed from the memory and cognition tests typically used in clinics, scientists said.
"Current diagnosis of dementia is strongly based on memory symptoms, which we know now are occurring when the disease is quite advanced," Michael Hornberger, the lead researcher, said in a news release. "Instead, emerging evidence shows that subtle spatial navigation and awareness deficits can precede memory symptoms by many years."
Indeed, waning spatial awareness and navigation skills are often among the first clear signs that dementia is taking a toll on someone's life, said Hilary Evans, who heads Alzheimer's Research UK, which collaborated with the researchers.
Evans often ears heartbreaking stories about "people with dementia who get lost and can't find their way home," she said in a statement.
Sea Hero Quest was developed as a partnership between researchers at University College London, the University of East Anglia and Alzheimer's Research UK. It was created by the app developer Glitchers and funded by Deutsche Telekom.
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