(CNN) A mobile game has revealed the navigational skills of people around the world in a bid to develop an accurate test for dementia.

The smartphone game, called " Sea Hero Quest, " asks players to set sail on a global adventure in search of precious artifacts -- in the form of memories -- which can be collected at different locations around the world.

As you progress through the game, scientists can use the data you generate to gain insight into your navigational abilities, which is one of the first skills people lose during the onset of dementia.

Initial results, presented at the Neuroscience 2016 conference in San Diego on Wednesday, found that our navigational skills deteriorate from early adulthood and for the rest of our lives, not just in older age, as previously thought.

More than 2.4 million people have played the game since its launch in May, generating the equivalent of more than 9,000 years of lab data. In addition to new insight into our navigational decline, the data revealed differences in spatial navigation abilities between genders as well as countries, with Nordic countries coming out on top.

The goal was to identify the normal range of navigation skills among humans in general, throughout the world, and to then use this to develop a test or chart to profile people and spot dementia early through any deviance from the norm.

"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," said Hugo Spiers , a neuroscientist at University College London , who led the research stemming from the game's data.

"The findings the game is yielding have enormous potential to support vital developments in dementia research," he said in a statement.

Deviating from the norm

The main finding from the game to date was the discovery that our ability to navigate declines as young as 19, which was the age when researchers began sampling, and continues to do so throughout life. This was highlighted by results from one particular aspect of the game in which gamers are spontaneously asked to shoot a flare in the direction they came from.

Nineteen-year-old users were 74% more likely to shoot the flare accurately on average, but by the age of 75, this had been cut to 46%. "We expected it to plateau, maybe in our 60s, but it was actually throughout our lifespan," Spiers told CNN.

Men performed this particular task 10% better than women, according to Spiers, but the researchers think this may be down to differences in strategies, in terms of how each gender navigates the seas during the game as a whole -- to find and collect the memories as tasked.

Another eye-opener was the differences in scores between countries. Some Nordic nations -- Finland, Sweden, Norway and Denmark -- were found to have notably better spatial navigation than participants from the other 189 countries.

"We're discovering some basic principles about humans," Spiers said, adding that this gender and cultural insight all feeds into identifying global norms and when people may be deviating from them due to dementia.

How big a problem is dementia?

The condition is a collection of symptoms, such as memory loss, difficulties in thinking or problem-solving, and reduced ability to navigate. It is caused by diseases including Alzheimer's and Parkinson's.

"Dementia is increasingly becoming one of the greatest medical challenges we face globally," said Hilary Evans, chief executive of Alzheimer's Research UK

"It is a disease you can prevent. ... It's not an inevitable part of aging."

Despite the high numbers affected, an accurate test for the condition remains unavailable. But this could be about to change -- depending the next stages of data analyzed from "Sea Hero Quest."

"(The game) can tell us, how do people get lost?" Spiers said.

"Fundamentally, people with dementia -- Alzheimer's dementia -- struggle to navigate, and on a scientific level, we don't know enough of how people navigate to help really pin down what's going wrong," he said.

Using global data

The team has completed one round of its data analysis and will continue to reveal more insight as it comes. All data are anonymous and available only to researchers at University College London.

"Step one is establishing this live database of, how do people navigate? ... That gives us the tool to develop that diagnostic," said Spiers.

Next, researchers will test the game on people known to have Alzheimer's dementia to see whether they can identify any key differences in they subjects' spatial navigation.

They then imagine a scenario in which people suffering from dementia can be identified early -- by playing the game -- and given relevant drugs to stop the disease taking full hold of their mind.

"You could give them (the game) and monitor if the drug is effective in a really powerful way," Spiers said.

Next step: Brain imaging

In the next stages of the project, Spiers would also like to have volunteers play the game while having their brains scanned in order to see which parts are active and link this to patterns seen in the population worldwide.

"I hope to collect neuroimaging data from people playing this game to really understand how the circuits are activated as people play the game," he said.

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This is not the first use of mobile games to crowdsource data for scientists. Cancer Research UK has launched five games , including " Play to Cure: Genes in Space " in 2014, which obtained data as people traveled through space and helped identify codes and patterns along their way -- unwittingly.

"Sea Hero Quest" became available on iOS and Android on May 4 and was created in a collaboration between Deutsche Telecom, Alzheimer's Research UK, scientists from University College London and the University of East Anglia, and game designers Glitchers

"These new insights into how humans navigate have only come as a result of a new kind of collaboration in dementia research," Evans said. "A health challenge as complex as dementia demands we approach studies innovatively."