Alzheimer's test offers hope

The condition affects 600,000 people in the UK

Scottish scientists have discovered a test which could help improve the treatment of Alzheimer's disease sufferers.

The research team at Edinburgh University's department of neuroscience says the test can diagnose brain degeneration which is typical of the condition.

And it is hoped that, in conjunction with a vaccine being tested in the United States, it could lead to the development of drugs to reverse the effects of Alzheimer's.

The US vaccine - which is being tested on mice - appears to be working.

Patients in the early stages of Alzheimer's disease are often quite good at remembering events from early on in their lives

Professor Richard Morris

But researchers were still looking for a way of distinguishing between long and short-term memory.

That distinction is important because Alzheimer's initially affects short-term memory.

The Edinburgh test uses mice and a complicated water maze, in which exit routes keep changing, to show the difference.

The mice were used to analyse a protein, known as beta-amyloid, that collects in the brain.

As it grows the ability of people to learn and remember in particular ways declines.

Memory tests

Professor Richard Morris, who has been leading the research since 1995, said: "Patients in the early stages of Alzheimer's disease are often quite good at remembering events from early on in their lives.

"It is keeping track of things from more recent times that really poses the problem.

"Because of this, not all tests of memory are diagnostic, that is, just testing the memory in general doesn't prove anything."

When the mice in the test want to leave the water, they can rely on their short-term memories of the current location of the exits.

"If you just teach them one escape location the mice are fine," he said.

The team is based at Edinburgh University

"But when you keep changing where they have to go, the mice with the elevated beta-amyloid levels get confused."

But while results seem promising, the scientists say they still need to be interpreted with care.

The research follows the Dublin-based Elan Corporation's discovery in September 1999 of a vaccine to prevent and even clear amyloid plaques.

Two research teams in North America have also used the new variation of Professor Morris' water maze test to investigate whether vaccination against beta-amyloid is the key to improving memory.

Safety tests

One experiment conducted by a team at the University of Florida revealed that mice treated with the vaccine over several months show greatly improved memories.

A team at the University of Toronto reached similar conclusions.

Initial toxicological safety tests are being carried out on patients in Britain and the United States, and their progress is said to be promising.

However, Professor Morris said clinical trials may be a few years away.

An estimated 600,000 people in Britain suffer from Alzheimer's, the most common form of dementia.

The risk of contracting the disease increases with age, while it can also be caused by head injuries.