Cognition Declines Four Times Faster in People With Alzheimer's Disease Than Those With No Dementia

Researchers at the Rush Alzheimer's Disease Center and the Rush Institute for Healthy Aging set out to quantify the rates of cognitive decline in people who developed Alzheimer's disease and its precursor, mild cognitive impairment.

The study followed 1,168 older adults. All were participants in the Chicago Health and Aging Project, a longitudinal cohort study of older white and black people residing on the south side of Chicago.

The study found memory and thinking skills may decline rapidly for people who have mild cognitive impairment, which is the stage before Alzheimer's disease when people have mild memory problems but no dementia systems, and even more rapidly when dementia begins, which is when Alzheimer's disease is usually diagnosed.

In comparison to the no cognitive impairment group, the annual rate of cognitive decline was increased more than twofold in those with mild cognitive impairment and more than fourfold in those with Alzheimer's disease. The results did not vary by race, sex, or age.

"These results show that we need to pay attention to the time before Alzheimer's disease is diagnosed, when people are just starting to have problems forgetting things," said Robert S. Wilson, Ph.D, a neuropsychologist at the Rush Alzheimer's Disease Center.

"Part of understanding this disease is carefully quantifying what the consequences are in a defined population," Wilson said. "Such knowledge is especially important now with the prevalence of Alzheimer's disease expected to sharply increase by the middle of the 21st century."

Read more about the Rush Alzheimer's Disease Center.