Rest-Activity Disturbances Correlate with Core Features in Dementia with Lewy Bodies.

Background: Sleep-wake disturbances are a clinically important and poorly studied feature of dementia with Lewy bodies (DLB) due to the challenges of in-laboratory polysomnography in this population.

Objectives: To compare rest-activity rhythms in DLB, Parkinson's disease (PD), and age-matched controls using home-based wrist actigraphy and examine their relationship with core clinical DLB features.

Methods: Eleven DLB patients, 12 PD patients, and 11 age-matched controls underwent clinical assessment. Actigraphy data were obtained over 14 days and analyzed using nonparametric methods.

Results: DLB patients demonstrated higher rest-activity rhythm fragmentation (P = 0.002) than controls and lower circadian amplitude (P = 0.011) than both PD and controls. Instability of rest-activity rhythm was positively correlated with hallucinations (P = 0.009) and cognitive fluctuations (P = 0.016) in DLB, and reduced daytime activity correlated with severity of motor parkinsonism (P = 0.013). No such correlations were observed in PD.

Conclusions: Actigraphy detects distinct rest-activity rhythm disruptions in DLB, differentiating it from PD and controls. These measures are associated with the severity of core clinical features in DLB.