Following is a factfile on Alzheimer's disease:
WHAT IS IT? Alzheimer's disease is the commonest form of dementia, a degenerative disease of the brain that causes forgetfulness and disturbs thinking, emotions and behaviour.
HOW MANY PEOPLE HAVE IT? Twenty-four million people today have dementia, a figure likely to rise to 42 million by 2020 and 81 million by 2040. Alzheimer's accounts for between 50 and 60 percent of all dementia cases. The direct and indirect annual costs of caring for people in the United States alone are put at at least 100 billion dollars annually.
WHAT HAPPENS? Clumps of protein called amyloid plaques and tau tangles proliferate in the brain, especially the cortex and hippocampus, destroying brain cells and their connections. The onset of symptoms is gradual. Psychiatric, physical and neuro-imaging tests are needed to confirm diagnosis.
WHO IS AT RISK? Alzheimer's most commonly appears after the age of 65 and the risk increases with ageing. The precise cause is unclear but genes, environment and lifestyle may all play a role. On average, people live eight years after diagnosis, but this can range from as little as three to as many as 20 years.
IS THERE A CURE? No. If all goes well, the first drugs to slow or block the spread of Alzheimer's could be only a few years away. Present drugs have a temporary effect by inhibiting an enzyme that reduces acetylcholine, a vital chemical used in communication between brain cells.
OTHER TREATMENT: Antidepressants, anti-anxiety drugs and tranquillisers can ease sleeplessness, agitation, wandering, anxiety and depression, thus making the patient more comfortable and easing the burden of caregivers. Psychological, art and music therapy are also commonly used to try to stimulate the brain of Alzheimer's patients.
Sources: Alzheimer's Disease International (http://www.alz.co.uk/);
US National Institutes of Health (NIH) 2001-2 Alzheimer's Disease Progress Report; US National Institute of Ageing (http://www.nia.nih.gov/Alzheimers/Publications/adfact.htm); The Lancet (issue of December 17 2005).