Conduct of the study. The sample resulting from the 1st part of the study should be at least composed of cognitively normal people, MCI and AD (grey circle). This sample should allow the prevalence and case-control studies. Arrows depict the different situations/ evolutions occurring over time. The dotted line shows a potential critical situation due to wrong classification of MCI. The sample resulting from the 2nd part of the study should offer the opportunity to obtain the incidence of MCI and/or AD as well as the progression rate between stages.
Perquin et al. BMC Public Health 2012 12:519 doi:10.1186/1471-2458-12-519