Longitudinal motor decline in dementia with Lewy bodies, Parkinson disease dementia, and Alzheimer's dementia in a community autopsy cohort

INTRODUCTIONWe examined the progression of extrapyramidal symptoms and signs in autopsy-confirmed dementia with Lewy bodies (DLB), Parkinson's disease dementia (PDD), and Alzheimer's disease dementia (AD). METHODSLongitudinal data were obtained from Arizona Study of Aging and Neurodegenerative Disease, with PDD (n = 98), AD (n = 47) and DLB (n = 48) further sub-grouped as with or without parkinsonism (DLB+ and DLB-). Within-group Unified Parkinson's Disease Rating Scale (UPDRS) -II and UPDRS-III trajectories were analyzed using non-linear mixed effects models. RESULTSIn DLB, 65.6% had parkinsonism. Baseline UPDRS-II and III scores (off-stage) were highest (P < 0.001) for PDD (mean & PLUSMN; SD 14.3 & PLUSMN; 7.8 and 27.4 & PLUSMN; 16.3), followed by DLB+ (6.0 & PLUSMN; 8.8 and 17.2 & PLUSMN; 17.1), DLB- (1.1 & PLUSMN; 1.3 and 3.3 & PLUSMN; 5.5) and AD (3.2 & PLUSMN; 6.1 and 8.2 & PLUSMN; 13.6). Compared to PDD, the DLB+ group had faster UPDRS-III progression over 8-years (Cohen's-d range 0.98 to 2.79, P < 0.001), driven by gait (P < 0.001) and limb bradykinesia (P = 0.02) subscales. DISCUSSIONMotor deficits progress faster in DLB+ than PDD, providing insights about expected changes in motor function. HighlightsDementia with Lewy bodies has faster motor progression than Parkinson's disease dementiaLinear and non-linear mixed modeling analysis of longitudinal data was utilizedFindings have implications for clinical prognostication and trial design