Alzheimer's disease (AD) is a mental disorder resulting from brain degeneration. It affects almost 1 in 10 individuals over the age of 65. The disease is characterised by confusion, personality and behavioural changes, impaired judgement and difficulty in following words and directions. Eventually, it robs its victims of volition. Identified by German physician Alois Alzheimer in 1912, the disease, which affects more than 20 million people worldwide, has no cure.

The only approved drug -- tacrine hydrochloride from the American company Warner-Lambert -- is of limited use and restricted to the early stages of the disease. Moreover, long-term tacrine therapy can lead to liver damage, abdominal discomfort and pneumonia.

In mid-1993, Joe Rogers of the Sun Health Research Institute in Arizona and Pat McGeer of the University of British Columbia in Canada reported that a drug called indomethacin might be able to stave off Alzheimer's. A trial on indomethacin is on in Arizona.

Recently, the hormone oestrogen was implicated in preventing Alzheimer's. At the University of Southern California in Los Angeles, a team led by Victor Henderson has looked at the occurrence of the disease in elderly women. They report that oestrogen lessened the risk of dementia by about 40 per cent. Galanthamine, a chemical found in the bulbs of daffodils and some other plants, also shows signs of promise in treating Alzheimer's. Trials show that the chemical has stabilised patients for up to a year.

A significant development in the last few months has been a breakthrough in diagnosing AD, for which the only certain diagnosis was a post-mortem examination of brain tissue. Now, a team led by Huntington Potter and Leonard Scinto of the Harvard Medical School, Boston, has reported a test that employs tropicamide, a drug which is widely used to dilate the pupils in eye examinations. The researchers claim that the pupils of Alzheimer's patients dilate 3 times more than those of healthy people in response to tropicamide. This test can predict the disease much before the symptoms develop.