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Tuesday, 24 April, 2001, 10:28 GMT 11:28 UK
10-minute test for Alzheimer's
Scientists have developed a test which can detect the early stages of Alzheimer's disease in just 10 minutes.
The test can distinguish Alzheimer's sufferers from patients with depression and people without any neuropsychiatric disorder with 98% accuracy.
Professor Trevor Robbins and Dr Barbara Sahakian developed the test, called the CANTAB Paired Associates Learning Test, at Addenbrooke's Hospital in Cambridge.
The patients who made the most errors during the test were those over whom there was some doubt when they took the test, but whose mental abilities declined in the subsequent eight months.
Dr Sahakian said: "The CANTAB-PAL's sensitivity to Alzheimer's disease is related to the fact that the areas of the brain first affected in Alzheimer's disease are the same areas utilised when performing the test.
"We anticipate this test will be useful not only for early detection of Alzheimer's disease, but could also be used to measure the beneficial effects of current pharmacological treatments, such as the cholinesterase inhibitors, as well as future ones, including neuroprotective agents."
The test works by flashing up a series of patterns and images on a computer screen, and then asking patients to pinpoint whereabouts on the screen a particular image has just appeared.
It is designed to test the areas of the brain involved in controlling memory for places and events - known technically as episodic memory. It is this form of memory which is first to be damaged by Alzheimer's.
Dr Sahakian told BBC News Online that it was important to diagnose Alzheimer's disease as soon as possible.
She said: "The sooner you can act to diagnose somebody and give them treatment, the more likely it is to be of benefit to them."
This applies both to current treatments such as Aricept, a cholinesterase inhibitor, which is used to slow down the symptoms of the disease, and to newer drugs under development which will actively attack the disease process itself.
The Cambridge researchers hope that their test will eventually be available in GP surgeries. There has also been a lot of interest from the US.
Rebecca Gray, head of public affairs, Alzheimer's Society, said: "The study sounds very interesting. It is essential that people with suspected dementia are given as early and as accurate a diagnosis as possible.
"Development of drug treatments suitable for the early stages of dementia add to the importance of assessing the disease in its first stages."
Alzheimer's disease is a progressive, degenerative and irreversible brain disorder that causes intellectual impairment, disorientation and eventually death.
There is no cure. It is estimated that 2-5% of people over 65 years of age and up to 20% of those over 85 years of age suffer from the disease.
The exact cause of the disease is unknown. Alzheimer's disease is linked to gradual formation of plaques in the brain, particularly in the hippocampus and adjoining cortex.
As the disease develops, it destroys chemical messengers used by the cells of the brain to communicate with each other.
The results of early trials of the test are published in the journal Dementia and Geriatric Cognitive Disorders.