a progressive, irreversible disease characterized by degeneration of the brain cells and commonly leading to severe dementia
See Alzheimer's disease in American Heritage Dictionary 4
(ältsˈhī-mərz, ăltsˈ-, ôltsˈ-, ôlzˈ-)
noun
A disease marked by the loss of cognitive ability, generally over a period of 10 to 15 years, and associated with the development of abnormal tissues and protein deposits in the cerebral cortex.