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Degenerative brain disorder. It occurs in middle to late adult life, destroying neurons and connections in the cerebral cortex and resulting in significant loss of brain mass. The most common form of dementia, Alzheimer disease progresses from short-term memory impairment to further memory loss; deterioration of language, perceptual, and motor skills; mood instability; and, in advanced stages, unresponsiveness, with loss of mobility and control of body functions; death typically ensues in 5–10 years. Originally described in 1906 by the German neuropathologist Alois Alzheimer (1864–1915) with reference to a 55-year-old person and regarded as a presenile dementia, Alzheimer disease is now recognized as accounting for much of the senile dementia once thought normal with aging. The 10% of cases that begin before age 60 result from an inherited mutation. Neuritic plaques and neurofibrillary tangles in the brain on autopsy are the primary features used for diagnosis. No cure has been found. Most treatment targets the depression, behavioral problems, and sleeplessness that often accompany the disease.
This entry comes from Encyclopædia Britannica Concise. For the full entry on Alzheimer disease, visit Britannica.com.