Getting lost and losing your ability to navigate could be an early red flag for dementia.
Scientists have concluded that changes in how we map our surroundings may provide an earlier sign of Alzheimer’s disease than memory loss.
They say healthy older people prefer to map objects and locations relative to where they are standing. But people showing early signs of dementia appear to use external cues, such as global landmarks and boundaries, instead.
Older people are worse at learning routes, spatial awareness and retracing their steps because of brain changes associated with ageing. The first time that people suspect an elderly relative has dementia often comes when they start ‘wandering’, or become lost when returning home.
Dr Thomas Wolbers, from the German Centre for Neurodegenerative Diseases, who led a review into how older people navigate, said: ‘It can take up to 10 years after the onset of Alzheimer’s for someone to show abnormal results on the standard cognitive tests that are available today, and that’s 10 years that you’ve lost for treating it, should an effective therapy come along down the road.
Getting lost and losing your ability to navigate could be an early red flag for dementia
Older people lose volume in their brain’s ‘memory centre’
He said: ‘This is where navigation-based diagnostics could contribute, by reducing that window.’
A research team, also including Bournemouth University, reviewed decades of human and animal studies on how people navigate as they age.
It is thought we get worse at finding our way over time because of changes to the vestibular system – which also make it harder to balance, so that older people suffer more falls. Judging direction is harder too, while altered eye movements affect navigation skills.
But there are also changes in the brain which may be linked to dementia. Older people trained to improve their navigation skills can reverse these changes and lose less volume in their hippocampus, the ‘memory centre’ of the brain, which is linked to dementia.
‘Navigational ability may provide key clues to changes underway in the brain’
Dr Laura Phipps, of Alzheimer’s Research UK, said: ‘We know there is more to dementia than memory loss, and this review of existing studies highlights that navigational ability may provide key clues to changes underway in the brain.
‘Once we understand how navigational skill is altered at different ages, scientists can then look to design ways to detect how this changes in dementia, with the hope of developing innovative ways to diagnose people much earlier than we are currently able to.’
The charity has been involved in creating a computer game called Sea Hero Quest, which involves sailing a boat around a cartoon world and has been used to judge people’s risk of Alzheimer’s.
Currently the disease is diagnosed based on an individual’s medical history, genetic risk factors, and performance on memory, language and reasoning tests.
The review, published in the journal Neuron, suggests people should be tested for how their ability to find their way changes over time.
For now, Dr Wolbers suggests that people train and use the navigational skills hardwired into their brains, especially in the age of sat nav technology.
He said: ‘There is growing evidence that if you rely too much on that technology it can have a detrimental effect on your navigational ability and in the long term may even be a risk to develop pathological conditions.’