Characterize Psychomotor Vigilance Task (PVT) performance across the Lewy body disease (LBD) spectrum (Parkinson’s disease (PD), PD dementia (PDD), and dementia with Lewy bodies (DLB)) and examine associations between PVT metrics and core disease features.

The cognitive impairment associated with LBD is often associated with impairment in tasks of sustained attention. The PVT and the NASA-PVT, a modified form adapted for touchscreen administration, are validated measures of sustained attention. The performance of the NASA-PVT in LBD and its associations with core clinical features have not previously been reported.

We assessed NASA-PVT performance for 5 minutes and derived mean reaction time (RT), mean reciprocal RT (RRT), RT variability defined as the standard deviation of RT, lapses defined as RT>500ms, slowest 10% RRT, and fastest 10% RT. Clinical measures included the Montreal Cognitive Assessment (MoCA), MDS Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), Northeast Visual Hallucination Inventory, and Clinician Assessment of Fluctuations. Group differences were assessed using the Kruskal-Wallis test for continuous variables with Dunn’s post hoc tests for pairwise comparisons. Spearman correlation tests were used for correlation analyses.

PDD (n=17) and DLB (n=18) exhibited significantly slower mean RT, greater RT variability, and more lapses than HC (n=9) and PD (n=19, all p < .05). LBD participants with cognitive fluctuations showed significantly greater RT variability (p = .006) and reduced slowest 10% RRT (p = .027). Mean RT, RT variability, number of lapses, and slowest 10% RRT were significantly correlated with MoCA score, MDS-UPDRS Part 3, visual hallucination burden, and daytime sleepiness (all p<0.05).

Psychomotor vigilance is impaired in PDD and DLB compared to PD and HC. The correlation of impaired psychomotor vigilance with global cognition, cognitive fluctuations, visual hallucinations, and greater sleepiness supports a shared underlying mechanism across these clinical features in LBD.