(ˈɑlts haɪ mərz, ˈælts-, ˈɔlts-) n. a common form of dementia of unknown cause, usu. beginning in late middle age, characterized by progressive memory loss and mental deterioration associated with brain damage. [after Alois Alzheimer (1864–1915), German neurologist, who described it in 1907]MedicalSeeAlzheimer's disease