Merriam-Webster Collegiate Dictionary - alzheimer's disease

 noun  Etymology: Alois Alzheimer died 1915 German physician  Date: 1912 a degenerative brain disease of unknown cause that is the most common form of dementia, that usually starts in late middle age or in old age, that results in progressive memory loss, impaired thinking, disorientation, and changes in personality and mood, and that is marked histologically by the degeneration of brain neurons especially in the cerebral cortex and by the presence of neurofibrillary tangles and plaques containing beta-amyloid — called also Alzheimer's