Abstract
Rarely in recent medical history has a previously obscure disorder so rapidly engaged the attention of the biomedical and lay communities alike as has Alzheimer's disease. This surge of interest arises from two fundamental developments. First, the prolongation of life expectancy that has occurred in this century has increased the portion of the population subject to degenerative diseases of the brain that occur late in life. Second, students of the aging nervous system have gradually evolved a major reinterpretation of the pathologic basis of common senile dementia. It is now known that most patients, at least in Western countries, who . . .