Alzheimer's Disease is named after Dr. Alois Alzheimer (1864-1915), a German neurologist, who in 1906 described changes in the brain tissue of a woman who died of an unusual mental illness. This disease is marked by the loss of cognitive (thought, memory, language) ability, generally over a period of 10 to 15 years.

Alzheimer's disease (AD) is a progressive condition in which nerve cells in the brain degenerate, and the size of the brain substance shrinks. AD is the single most common cause of dementia, i.e., a decline in all types of mental activity. Earlier, AD was classified as presenile dementia, but is now responsible for 75 percent of dementia cases in people over 65 years of age. In AD the progressive impairment of memory, and cognitive functions, ultimately leads to a vegetative state. Impairment of short-term memory (STM) is the first symptom of the disease, whereas, long-term memory (LTM), i.e., retrieval of distant memories remains relatively preserved.

AD is marked by atrophy of the cerebral cortical and subcortical neurones, labelled as dementia of Alzheimer's type. Senile plaques (Sheets) which are aggregates of beta-amyloid are evident in the brain. They are more abundant in the hippocampus and association areas of the cortex, leading to impairment of memory. It is proposed that deficiency of acetylcholine (a neurotransmitter) is responsible for the confusional state suffered by the subject. Additionally, there are changes in the brain glutamate, dopamine, noradrenaline and 5-hydroxytryptamine function.

Statistics are quite alarming. According to WHO estimates 3.7 million Indians suffer from AD, which is 22 percent of the global patient load. More than 50 percent people with AD live in the Developing World, which is expected to rise to over 70 percent by 2025. Seventy percent of all dementia patients can be attributed to AD. (Ref: India Today, Oct. 8, 2012). People with heart disease and diabetes are more prone to the disease. With gradual loss of memory, thought, and language the person is unable to carry out daily chores of life. The causes of AD are not fully known, Perhaps genetics and family history have a role to play.

Stages of the Disease

Three stages have been identified. However, the rate of progress, ranging from 2 to 10 years varies from person to person. Stage III is the stage of total dependence and inactivity. It is marked by losing control on body functions. One may be confined to a wheelchair or bed, with a vulnerability to infections.

Treatment

Presently there is no cure for Alzheimer's disease. Drugs employed to check further progress of the disease are: Denepezil, Galantamine, Memantine, and Rivastigmine. Symptomatic treatment for depression, insomnia, and agitation is desirable. Role of drugs like Seligiline, and efficacy of Vitamin E is under scrutiny.

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