Alzheimerâs Shown to Develop in Four Distinct Patterns Source: Ariel Skelley/Getty Images May 3, 2021 Share  in Nature Medicine that shows how the tau protein spreads in AD according to four distinct patterns that lead to different symptoms with different prognoses of the affected individuals. âAlzheimerâs disease (AD) is characterized by the spread of tau pathology throughout the cerebral cortex. This spreading pattern was thought to be fairly consistent across individuals, although recent work has demonstrated substantial variability in the population with AD. Using tau-positron emission tomography scans from 1,612 individuals, we identified 4 distinct spatiotemporal trajectories of tau pathology, ranging in prevalence from 18 to 33%,â write the investigators.