Dementia involves the loss of intellectual abilities, generally including memory, spatial skills, and executive functions (planning, abstract thought, self-monitoring, etc.). The two most common forms of dementia are Alzheimer’s disease and vascular dementia. The biology of Alzheimer’s is characterized by the buildup of amyloid plaques and neurofibrillary tangles in and around the neuron (brain cell). Alzheimer’s starts with memory impairment and then generalizes to a broad range of cognitive impairments, sufficiently severe to leave people unable to care for themselves. Vascular dementia is caused by cerebrovascular events, such as strokes, which involve major disruptions of the blood supply to the brain.

Dementia is fairly rare in the mid-sixties (about ten percent) but becomes quite common by the eighties and nineties. By some estimates, 50 percent of all people over 85 have Alzheimer’s disease. Consequently, virtually all families will be touched by dementia at some point. The social implications of this are enormous. People with severe dementia demand round-the-clock care, which puts tremendous strain on families, both emotionally and financially. Given the growing population of elderly people across the industrialized world, significant resources will be needed for elder care in the coming years.