Simple test predicts Alzheimer's six years early, say scientists

Published on Monday 15 October 2007 00:04

THOUSANDS of people in Scotland who develop Alzheimer's disease each year could be offered more effective treatment thanks to a new test that claims to predict the onset of symptoms up to six years ahead.

The simple blood test has been created by an American biotech company and is said to be 90 per cent accurate.

Experts say that, if its effectiveness is confirmed, the test could revolutionise the diagnosis and treatment of dementia within a few years.

Currently, there is no simple way of telling whether signs of mild forgetfulness mark the beginning of severe mental decline. Alzheimer's is diagnosed by testing for other causes of memory loss and mental impairment, such as strokes and tumours, and ruling them out.

Jim Jackson, chief executive of Alzheimer's Scotland, said the test - which has been developed by San Francisco-based company Satoris, working with colleagues from US and European universities - could allow patients to be targeted with effective early treatment.

He added that the "early warning" test would also help people with Alzheimer's come to terms with the disease, and allow them to make plans for the future, such as drawing up a will.

He said: "The hope is that we can develop a treatment that stops Alzheimer's in its tracks, instead of merely delaying its progress. An early-diagnosis test would potentially help a lot.

"It's very difficult coming to terms with having such an illness. It would be somewhat easier if you have got your full mental capacity when you are diagnosed."

But he urged caution over the new findings, saying much larger-scale research is needed.

People most likely to be offered the test would be those with close relatives who have had the disease, and who may be starting to experience memory lapses.

The test, outlined in the journal Nature Medicine, takes the radical approach of "listening" to the way blood cells communicate with signalling proteins.

A study of a small group of people with mild cognitive impairment indicated that the test could predict the onset of Alzheimer's.

Over a period of two to six years, 91 per cent of those whose blood tested positive went on to develop the disease and had their condition confirmed after death.

The company hopes to introduce the test for research use as early as next year. A commercial diagnostic test would follow later.

But first, the effectiveness of the technique will have to be proven by larger studies.

More than 700,000 people in the UK - about 65,000 in Scotland - are living with dementia, 62 per cent of whom have Alzheimer's. As people continue to live longer, the number is expected to rise to nearly one million in less than 20 years.

Dr Susanne Sorensen, head of research at the Alzheimer's Society, said: "The race is on to develop an effective test to diagnose Alzheimer's disease as early as possible.

"A blood test for detecting Alzheimer's disease would provide clinicians with a simple, non-invasive tool that could help them diagnose people with the disease. This would be a huge breakthrough."

'IT WOULD HAVE GIVEN ME A LOT MORE PEACE OF MIND'

LYNDA Hogg is convinced early diagnosis would have provided her with peace of mind in her struggle against Alzheimer's disease.

The 53-year-old, from Edinburgh, was diagnosed with dementia in April last year, after a brain scan finally ended the uncertainty over an illness that had been steadily worsening for years.

She had been getting increasingly tired and suffering memory loss. But despite the intervention of a neurologist, she says she was left to "struggle on" not knowing the cause.

"I kept working but had to cut my hours as I was really beginning to struggle. The worst thing was I didn't know what the problem was," she says.

"I think this early test would be a great thing. It would have given me a lot more peace of mind. I would have been able to relax and enjoy life more."

She says some people with Alzheimer's would benefit from knowing they have the disease at an early stage, by allowing them to plan the coming years and make the most of life while their mental faculties are still strong.

"But there is also a downside. I think a lot of people wouldn't want to know they have the disease. I don't think a test would be for everyone."

She moved house two years ago - before her diagnosis - and has found it difficult to settle in. "Had I known earlier, I would have decided to leave city life and get a quiet place in the country. That would have been my dream."