Figure 2From: The clinical characteristics of dementia with Lewy bodies and a consideration of prodromal diagnosisNomenclature of Lewy body diseases. Parkinson’s disease dementia is diagnosed when cognitive impairment develops a year or more after the onset of parkinsonism. Dementia with Lewy bodies is diagnosed when cognitive symptoms appear without parkinsonism or less than 1 year after the onset of parkinsonism.Back to article page