- Tau protein builds-up in the brain and causes spacial disorientation, experts say
- This symptom is experienced by many sufferers at the start of their dementia
- It’s the reason why three in five people with the condition wander off and get lost
- Experts say the findings could lead to an early test and possible treatments
Brain changes which cause people with Alzheimer’s to get lost could lead to a test for the disease before it strikes.
Scientists have found for the first time that a protein called tau caused by Alzheimer’s clogs up navigational cells in the brain.
It is the reason why three in five people with the condition wander off and get lost, because of damage to their memory and sense of direction.
As one of the first signs of illness, the finding means a brain scan for older people could detect Alzheimer’s early.
It could also save the more than 1,000 people with Alzheimer’s who are reported missing every year.
Scientists have found for the first time that a protein called tau caused by Alzheimer’s clogs up navigational cells in the brain (stock)
Scientists found in mice experiments that tau protein disables nerve cells in the entorhinal cortex – one of the parts of the brain responsible for navigation.
Animals with high levels of this protein perform worse in tests for spatial awareness.
The study by Columbia University Medical Centre could lead to people being diagnosed using an MRI scan before they first show signs of Alzheimer’s, by failing to return home or getting lost.
Its lead author has said brain scans could be made available to all elderly people, while the findings could in future provide new hope for treatment, through brain stimulation or light therapy to reactivate the cells damaged by tau.
Dr Karen Duff said: ‘The scientists knew that toxic tau builds up in the area of the brain where grid cells are located in people who died from Alzheimer’s. Doctors knew that people with Alzheimer’s tend to wander and get lost.
‘This is the first time we have found that both are connected. It means we could use tests of navigational ability or a functional MRI scan to help diagnose people with the earliest stage of Alzheimer’s disease.
‘This could be used to test people at risk, and even administered to everyone over the age of 65.’
In one of the most tragic cases of dementia patients becoming lost, the body of 88-year-old Janet McKay was found on wasteland in Clydebank, Scotland, after she vanished from her home in 2015.
Companies have come up with GPS technology allowing older people’s movements to be tracked by their relatives to keep them safe.
The latest study, published in the journal Neuron, shows how sense of direction is affected by the hallmark tangles of protein which Alzheimer’s causes in the brain.
It is the reason why three in five people with the condition wander off and get lost, because of damage to their memory and sense of direction, experts say
Researchers focused on excitatory grid cells, a type of nerve cell in the brain which fires in response to movement through space, creating a grid-like internal map of a person’s environment.
Mice engineered to have more tau protein in their brains were worse at finding their way in spatial tasks.
It is believed that, as in people, the protein affects their memory and ability to learn where they are going.
Eric Kandel, professor of brain science at Columbia University Medical Centre, said: ‘This study clearly shows that tau pathology, beginning in the entorhinal cortex, can lead to deficits in grid cell firing and underlies the deterioration of spatial cognition that we see in human Alzheimer’s disease.’
Previous research has suggested these problems with navigation could flag up the signs of Alzheimer’s long before people are usually diagnosed.
Scientists at University College London have invented a computer game, Sea Hero Quest, which involves navigating a boat around a fictional world, to gather feedback from online players into how dementia develops.
Dr Duff added: ‘Our findings suggest that it may be possible to develop navigation-based cognitive tests for diagnosing Alzheimer’s disease in its initial stages.
‘And if we can diagnose the disease early, we can start to give therapeutics earlier, when they may have a greater impact.’
Alzheimer’s Society research officer Louise Walker said: ‘Memory loss tends to be the most recognisable sign associated with Alzheimer’s disease, but people affected by the condition can also experience a range of other symptoms, including problems with navigation.
‘The results of this study have provided important information about how the tau protein, a key hallmark of Alzheimer’s disease, affects the area of the brain responsible for helping us to find our way.
‘As the study was in mice, the next step is to find out whether the tau protein has the same effect on this area of the brain in people.
‘Although any treatment to help people affected by Alzheimer’s navigate better is a long way off, this research is the first step in a journey that could help us to understand the reasons behind this often distressing symptom of the condition.’