The Treatment of Alzheimer Disease

Alzheimer disease (AD) is a degenerative disease causing lesions in the brain, and is the principal cause of dementia. It is named after German neurologist Aloïs Alzheimer (1864–1915) who first described it in 1906. Certain brain cells shrink or disappear to be replaced by irregular dense patches called plaques, containing a protein, amyloid beta (Aβ). The Aβ molecule is a fragment derived from a protein called amyloid precursor protein (APP) which is embedded in the wall of a cell, and of which the outer fragment can be cut by enzymes. This is a normal cellular activity throughout the body, but it can degenerate. Aβ is not itself toxic, but is when it forms molecular aggregates. If the concentration of Aβ is too high, the molecules agglutinate to form the plaques that then stifle the neurons.

Although the disease causes loss of many functions it does not change the patient’s capacity to experience feelings of joy, anger, fear, sadness or love, and to react accordingly, at least in the early stages. It is impossible to restore normal function to the damaged brain cells, but nevertheless there exist forms of treatment and strategies that can help the patient and his entourage. Unfortunately the diagnosis is often made very late, for the patient does not realize he is ill, unlike in PD when the sufferer quickly notices his motor difficulties.

The commonest form of AD is sporadic, and accounts for 90 to 95% of cases. Its causes are unknown, but the greatest risk factor is age. In a rarer familial form, 5 to 10% of cases, there is genetic transmission from one generation to another. Estimates put the worldwide incidence of AD at 25 million, and this is set to triple by 2040. Some 10 to 15% of cases occur between 45 and 65 years of age. However after age 65 up to 5% of the world’s population are affected, and 20% after age 85. In developed countries AD is the fourth cause of death after cardiovascular disease, cancer and stroke. As the population of these countries is constantly increasing in age due to the progress of medicine in the prevention and treatment of other diseases, AD confronts us with a formidable challenge for the century to come, simply in terms of the costs involved for palliative care and other treatment.