Five to six years before their Alzheimer's diagnosis, the cognitive abilities of these 462 individuals had already started
declining, the researchers found. Specifically, the results of these individuals' annual cognitive examinations showed that,
on average, their semantic memory started deteriorating at 76 months before diagnosis, their working memory at 75 months,
their perceptual speed at 70 months, their visuospatial ability at 65 months, and their episodic memory at 63 months.