Washington, Mar 23 (ANI): Cognitive abilities decline four times faster in Alzheimer's patients than those without any cognitive impairment, say researchers at Rush University Medical Center in Chicago.
The research is the second population-based study to quantify the rate of cognitive decline in Alzheimer's disease.
"Knowledge about the progressive cognitive decline in Alzheimer's disease is mainly based on studies of persons evaluated in clinical settings. In such studies, the full spectrum of the disease is unlikely to be represented. As a result, it has been difficult to securely determine the cognitive consequences of the disease and to test whether they vary in racial or ethnic subgroups of the population," said study author Dr. Robert S. Wilson.
The researchers aimed 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. At the beginning of the study, participants did not have dementia.
After a mean of five to six years, they had a detailed clinical evaluation and 614 persons were found to have no cognitive impairment, 395 had mild cognitive impairment, and 149 had Alzheimer's disease. They then completed brief cognitive testing at 3-year intervals for a mean of five and half years.
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.
"This study is especially significant because half of the participants are African Americans. Most of what we know about Alzheimer's disease is based on studies of Caucasians. Our study found no difference in how the disease played out in the two races," said Wilson.
The study is published in the latest issue of the journal Neurology, the medical journal of the American Academy of Neurology. (ANI)