How you MOVE could reveal an early sign of Alzheimer’s disease – long before memory loss

THE way you move through the world could be an early sign of dementia, scientists warn.

They say a simple test of navigation may expose risk of the devastating disease years before memory loss strikes.

Around 944,000 Brits are currently living with dementia and experts predict the numbers will exceed 1 million by the end of the decade.

Alzheimer’s is the most common form of the condition, and is thought to be caused by build-ups of proteins in the brain, including tau and amyloid.

Memory loss is the most commonly associated symptom of the disease, but now experts also think a waning sense of direction could be another warning sign.

Previous research has shown that people who rely on their sense of direction – like taxi and ambulance drivers – are less likely to die from Alzheimer’s than other workers.

Experts believe it’s because constantly memorising streets strengthens the hippocampus – the part of the brain that controls spatial memory and navigation.

The hippocampus is also one of the first areas to shrink in Alzheimer’s, so keeping it bigger for longer could help fend off the disease.

For the new study, an international team of researchers asked around 100 adults aged between 55 and 89 to take part in a virtual reality test, designed to challenge the brain’s built-in sense of direction. 

Volunteers strapped on VR headsets and found themselves in a completely empty digital world with no landmarks and no signposts.

They were told to follow a floating ball as it rolled along a winding path.

When the ball finally stopped, the participants were asked to point back to where they had started and turn to face the way they had been standing at the very beginning.

Everyone performed within the normal range on conventional memory and thinking tests.

But the results, published in Science Advances, showed that people who felt their memory was slipping, even though they passed tests, were far more likely to lose their bearings.

This group is known as having subjective cognitive decline (SCD).

Prof Thomas Wolbers, one of the authors, said: “People with subjective cognitive decline are known to be at an increased risk of developing Alzheimer’s dementia later in life.”

Researchers think the errors could come from a “memory leak”, where people struggle to keep track of the sequence of past positions needed to update their location in real time.

Another theory is a problem with “grid cells” – specialised neurons that act like the brain’s own sat-nav system, building a mental map of our surroundings.

A new diagnostic tool

Dr Vladislava Segen, lead author of the study, said: “These orientation difficulties did not arise from movement dynamics, such as walking faster or looking at the ground more often while walking. The causes were cognitive in nature.”

The team believes this type of navigation test could eventually be used alongside memory checks as a powerful new tool for diagnosing Alzheimer’s earlier, giving patients and families more time to plan and seek treatment.

Prof Wolbers added: “In the long term, I see potential for use in clinical routine, specifically in the early diagnosis of Alzheimer’s disease. However, this technique first needs to be further tested and simplified.”

Earlier this week, a separate study found that losing your sense of smell could be one of the first warning signs of dementia.

This is because the brain’s own immune system attacks key nerve fibres linked to detecting scent, scientists from Germany said..