Table 1.

Definitions of rapidly progressive dementia

Study	Type of RPD	Definition of RPD	Additional diagnostic characteristics
Geschwind (2016)2	General definition of RPD	Symptom onset to dementia: <1 or 2 years	NA
Degnan and Levy (2014)22	General definition of RPD	Symptom onset to dementia: <6 months	NA
Josephs et al. (2009)19	Rapidly progressive neurodegenerative dementia	Symptom onset to death: <4 years	Neuropathological diagnosis of neurodegenerative disease
Soto et al. (2008)5	Rapidly progressive AD	Reduction of ≥3 points per 6 months in MMSE score	Clinical diagnosis of AD
Schmidt et al. (2011)20	Rapidly progressive AD	Reduction of ≥6 points per year in MMSE score	Clinical diagnosis of AD
Gaig et al. (2011)21	Rapidly progressive DLB	Symptom onset to death: ≤1.5 years	Neuropathological diagnosis of diffuse Lewy body disease
Garcia-Esparcia et al. (2017)23	Rapidly progressive DLB	Symptom onset to death: ≤2 years	Neuropathological diagnosis of diffuse Lewy body disease
Zerr et al. (2009)18	Possible sporadic CJD	Total duration <2 years	CJD typical clinical syndrome

AD, Alzheimer disease; CJD, Creutzfeldt–Jakob disease; DLB, dementia with Lewy bodies; MMSE, Mini-Mental State Examination; NA, not applicable; RPD, rapidly progressive dementia.