Definition

Alzheimer disease is a form of dementia caused by the destruction of brain cells. Dementia is the loss, usually progressive, of cognitive and intellectual functions. Alzheimer type dementia can be characterized by initial short-term memory loss, which eventually becomes more severe and finally incapacitating.

Diagnosis before death is based upon clinical findings of unexplained slowly progressive dementia and neuroimaging studies that show gross cerebral cortex atrophy (changes in the structure of the brain, usually in the form of shrinkage). Neuroimaging refers to the use of positron emission tomography (PET), magnetic resonance imaging (MRI), or computed topography (CT) scans. These are special types of pictures that allow the brain or other internal body structures to be...