A poorer sense of direction or difficulty finding your way around places may be among the first indications that Alzheimer’s disease could affect you later on in life.
This is the preliminary result of The PREVENT project, an ongoing long-term study being carried out by experts seeking to uncover how dementia first affects the brain.
In this article, Dr Dennis Chan explains more about the findings and what it means for future Alzheimer's treatment. He also describes The Four Mountains test of spatial memory, used in the study to help experts pinpoint those in middle age at a high risk of developing Alzheimer's in later life.
Who does the study involve?
The PREVENT project, which is funded by the Alzheimer’s Society and based at Edinburgh University, aims to detect signs of Alzheimer’s in middle-aged people before symptoms appear later in life. Symptoms typically don't appear until people reach their 60s and unfortunately by this time, it has already done significant damage to the brain.
Loss of navigational skills
We usually consider Alzheimer’s to be a disease that affects memory in elderly patients. However, researchers believe that small changes begin in the brain when people are in their 40s and 50s, 10 to 15 years before symptoms arise.
So, how did researchers discover this?
The Four Mountains test
The PREVENT team works with volunteers who take part in various tests. One of these is The Four Mountains test - a test developed by my collaborators based at University College London and the University of York.
The ability to recognise places and visualise them from different points of view depends on the hippocampus, a region in the brain’s temporal lobe that is affected in the earliest stages of Alzheimer's disease. The Four Mountains Test can test this ability and we have previously found that patients with established dementia perform poorly on the test. During the test, people are shown a picture of four mountains and are asked to identify the correct picture when it is shown from a different perspective.
Researchers found that those who were at a higher risk of Alzheimer's did more poorly on this test, indicating poorer spatial memory. MRI studies have also shown that these people had a smaller hippocampus, which may be due to brain degeneration.
The test can therefore provide scientists and doctors with a potentially powerful tool to identify the earliest stages of Alzheimer’s disease before people develop symptoms.
Why is it important to identify those at risk early?
There are several important reasons for this. First, in the near future we will have drugs with the ability to slow the progression of dementia and these drugs will be most effective if given in the initial stages of the disease.
Second, separate research done by myself and others has shown that higher levels of engagement in physical, intellectual and social activities can maintain brain health into late life and reduce the risk of dementia. So detecting people at high risk would allow doctors to help people implement lifestyle changes to lower the risk of future dementia.
Third, it is important to have tests that can distinguish between different causes of memory decline. While some people with mild memory impairment may have early Alzheimer’s disease, in others it is due to other causes such as anxiety, depression, poor sleep and even medications. It is critically important that any such causes be identified and addressed, and that those affected do not labour under the misapprehension that they have Alzheimer’s disease.
If you are worried about dementia and would like to speak to a specialist, visit Dr Dennis Chan's Top Doctors profile and book an appointment with him.