Locus Coeruleus Pathology Indicates a Continuum of Lewy Body Dementia.

Background: Lewy body dementia (LBD) has two main phenotypes: Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB), separated by the 'one-year-rule'. They also show different symptom profiles: core DLB features include fluctuating cognition, REM-sleep behaviur disorder, and visual hallucinations. These symptoms are sometimes present in PDD, representing an intermediate 'PDD-DLB' phenotype.