Alzheimer's Disease :



I INTRODUCTION Alzheimer's Disease, progressive degenerative disease of the brain and the leading cause of dementia in the elderly. Symptoms of sufferers include loss of recent memory, disorientation for place and time, and a progressive loss of capacity for thought, learning, planning tasks, and maintaining attention to what is going on around them.


II OCCURRENCE It was first described by the German neuropathologist Alois Alzheimer in 1906. It is estimated that 20 per cent of people over 80 in the United Kingdom will develop dementia and that Alzheimer's disease is by far the main contributing cause. The number of individuals with this condition is estimated to rise to over 1 million by the year 2010. Percentage rates (cases per 100 individuals of 65 years and over) worldwide vary considerably between 0.6 in China to 10.3 in Massachusetts in the United States. The prevalence of the disease increases with advancing age, but there is no evidence that it is caused by the ageing process.


III CAUSES AND DIAGNOSIS The cause of this disease has not been discovered. However, the ability of doctors to diagnose Alzheimer's disease has improved in recent years, but remains a process of elimination. Final diagnosis can still only be positively confirmed by post-mortem examination. Computerized tomography and magnetic resonance imaging scanning can show the brain shrinkage characteristic of the disease.
During a post-mortem, Alzheimer's patients show massive nerve cell loss in all parts of the brain. The hallmark lesions of Alzheimer's disease include abnormal proteins known as neurofibrillary tangles and neuritic plaques. The nature of these abnormal proteins and the location of the gene for producing the precursor protein have been identified; and excess amounts of amyloid protein have been discovered in pathological examinations of the brains of Alzheimer's patients. Alzheimer's disease is also characterized by profound deficits in the brain's neurotransmitters (chemicals that transmit nerve impulses, particularly acetylcholine), which have been linked with memory function.
The important scientific issue concerning the disease revolves around the question of why particular classes of nerve cells are vulnerable and subject to cell death. Many researchers are actively pursuing an answer to this question in studies examining the potential effects of genetic factors, toxins, infectious agents, metabolic abnormalities, and a combination of these factors. Recent findings indicate that a percentage of Alzheimer's cases are inherited. The average life expectancy of people with the disease is between 5 and 10 years, although many patients now survive 15 years or more because of improvements in care and medical treatment. Palliative therapy (relief of symptoms) is still the only treatment available.