Alzheimer’s is a crippling disease that is marked by a loss of cognitive function and, usually, massive memory loss and general confusion, but it starts many years before the symptoms become obvious. When it strikes, it hits hard, causing untold damage to the individual and his or her family. Anything that can potentially be an early warning of the disease would be eagerly welcomed by the medical fraternity.
The causes of Alzheimer’s disease, and dementia in general, are not yet fully understood, but recent research might just have unearthed a clue, and it lies in a simple eye test. Research at Lancaster University, and published in the Journal of the American Ageing Association, has indicated that people suffering with Alzheimer’s have problems with one particular eye-tracking test, and this could be the clue that indicates the onset of Alzheimer’s disease before it becomes apparent in other ways.
The research team studied four groups:
- 18 with Alzheimer’s
- 25 with Parkinson’s
- 17 healthy young people, and
- 18 healthy older people.
In the course of the tests, they were asked to follow the movement of light on a computer screen. At various times they were also asked to look away from the light. Their eye movements were tracked, and records showed striking differences in the groups’ performance.
The Alzheimer’s patients were unable to look away from the light as precisely as the others, and also had difficulty correcting the errors they made. This was the case although they had no difficulty when they were asked to look towards the light.
The errors made by the Alzheimer’s patients were ten times more frequent than in the other groups. Tests also indicated that their memory function was impaired, and this memory impairment correlated well with the difficulty encountered in looking away from the light.
The first test to indicate Alzheimer’s?
This seems to be the first time a test has shown something that correlates with the memory impairment usually seen in Alzheimer’s.
Dr Trevor Crawford, of the Department of Psychology and the Centre for Ageing Research at Lancaster University, said:
“The light tracking test could play a vital role in diagnosis as it allows us to identify and exclude alternative explanations of the test results,” he added.
A protein in the brain called beta amyloid is an indicator of the disease and can build up for several years before any obvious signs of dementia, such as memory loss or general confusion, become obvious.
The causes of Alzheimer’s
Dr Eric Karran, director of research at Alzheimer’s Research UK, is hopeful that this could constitute an important early warning sign:
“While it is unlikely Alzheimer’s could be diagnosed by a single eye test, the findings could help expand the battery of tests currently needed for diagnosis.”
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