Alzheimer's disease (AD) is by far the major cause of dementia accounting for approximately 60% of all demented individuals. First identified in 1906 by the German physician Alois Alzheimer, the disease is characterized by pathological hallmarks of neurofibrillary tangles and the accumulation of amyloid plaques.
AD is a disease that predominantly afflicts those over the age of 65. In 1900, the average life expectancy was 47 years, so AD occurred rarely. Since then, life expectancy in the United States has increased to 77.9 years driving up the incidence of Alzheimer's disease. This disease is now a major economic healthcare problem and is the most common neurodegenerative disease of the aging.