Comparing phenotypic features between Parkinson’s disease dementia and dementia with Lewy bodies

BACKGROUND: Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB) are two synucleinopathies that share considerable overlap in their clinical and pathological characteristics. OBJECTIVE: This study aimed to evaluate the profile of phenotypic features across PDD and DLB to highlight their shared and distinctive features to explore any possible neurobiological underpinnings. METHODS: Patients diagnosed with Parkinson's disease dementia (PDD) (n=31) and dementia with Lewy bodies (DLB) (n=30) underwent evaluation for motor and non-motor symptoms using the International Parkinson and Movement Disorder Society -Unified Parkinson's Disease Rating Scale, the Scales for Outcomes in Parkinson's Disease-Psychiatric Complications, the Montreal Cognitive Assessment, the Hospital Anxiety and Depression Scale and the Epworth Sleepiness Scale. RESULTS: Patients with PDD showed a more severe phenotype than those with DLB, with higher scores in motor severity, hallucinations, delusions, somnolence, and urinary dysfunction (all p≤0.01). The correlations between neuropsychiatric symptoms differed between groups. In both PDD and DLB, depression correlated with anxiety (PDD ρ=0.54; DLB ρ=0.65; both p