Prevalence and prognosis of prodromal A lzheimer's disease as assessed by magnetic resonance imaging and 18 F ‐fluorodeoxyglucose‐positron emission tomography in a community: reanalysis from the O saki‐ T ajiri P roject

Background Dubois et al . proposed the criteria for prodromal A lzheimer's disease ( AD ) to detect dementia in its very early stage. Because detection requires magnetic resonance imaging and 18 F ‐fluorodeoxyglucose‐positron emission tomography ( PET ), the prevalence and prognosis have not been fully investigated. Methods Our database included 346 healthy participants ( C linical D ementia R ating ( CDR ) 0), 119 with questionable dementia ( CDR 0.5), and 32 dementia participants ( CDR 1+) and was applied to investigate the prevalence of prodromal AD . Forty‐four CDR 0.5 participants (37%) were randomly selected to undergo 18 F ‐fluorodeoxyglucose ‐PET . The same percentage was applied to select 128 CDR 0 and 12 CDR 1 + participants (total: n = 184) to calculate the prevalence. A neuroradiologist classified the PET images in a blinded manner based on the criteria of Silverman et al . Participants were considered to have prodromal AD if they exhibited ‘parietal/temporal +/− frontal hypometabolism’ ( PET ) with hippocampal atrophy (magnetic resonance imaging). Results Eighteen CDR 0.5 participants (40.9%) met the criteria for prodromal AD , which was a prevalence rate of 9.8% among older adults aged ≥65 years. Thirteen prodromal AD participants (72%) converted to AD during the 5‐year follow‐up period. Discussion The concept and criteria for prodromal AD are useful for predicting which subjects in a community will convert to AD .