Sudden Mental Ability Decline Isn't Normal.

A sudden decline in mental ability is not a normal part of aging, but can signal the onset of Alzheimer's disease. According to researchers at Washington University School of Medicine in St. Louis (Mo.), cognitive performance in elderly adults remains stable over many years unless and until a dementing condition such as Alzheimer's develops. When such an illness attacks, there is a deterioration in cognitive performance that often is detectable over a relatively short period of time. "People without the disease can look forward to good mental function in old age." indicates Eugene H. Rubin, professor of psychiatry. "Unfortunately, those with Alzheimer's disease usually face a sharp decline."

Researchers studied 82 healthy people who were between the ages of 64 and 83 when the study began. Although 40% developed cognitive deterioration within 12 years of an initial examination, the other 60% remained stable. The majority demonstrating diminished cognitive abilities were in the beginning stages of an Alzheimer-type dementia.

Assessments consisted of a comprehensive clinical evaluation, including a neurological exam, and rigorous psychometric tests...