Alzheimer's decline could start much earlier

People with Alzheimer's disease could start going downhill years before they develop the condition. Researchers from the Rush Alzheimer's Disease Center in Chicago studied 2,071 older adults who were all free of dementia at the beginning of the study. Over the course of the study the participants were tested on working memory, perceptual speed and visuo-spatial ability. Over 16 years 462 people developed Alzheimer's disease. The researchers found that Alzheimer's disease was preceded by an average of five to six years of cognitive decline during which the rate of cognitive decline accelerated more than 15-fold. Mild cognitive impairment - the precursor to Alzheimer's disease - was also preceded by about six years of cognitive decline.