Activity-rest rhythm abnormalities in Parkinson's disease patients are related to dopaminergic therapy

To compare going to bed, waking-up, and immobility onset and offset times in Parkinson's disease (PD) patients receiving levodopa and/or dopamine agonists (i.e., dopaminergic therapy or DT) with "de novo" patients and healthy controls and to correlate these parameters with self-reported sleep disturbances.

Fifteen "de novo" and 60 PD patients on DT were included in the study. Twenty-three subjects without history of sleep complaints and similar age and sex distributions as the PD patients served as controls. Going to bed and waking-up times were registered in 7-day sleep logs. Nocturnal immobility onset and offset times were measured using actigraphy. Sleep disorders were assessed applying the PD sleep scale (PDSS).

Patients on DT showed earlier waking-up and immobility offset times (40 min) compared with controls and "de novo" patients. Multivariable regression analysis showed that DT but not Hoehn & Yahr score was a significant and independent predictor of early awakening time (OR = 4.0, 95% CI = 1.15-14.13). Patients manifesting more frequent nighttime psychotic symptoms and more frequent daytime somnolence showed earlier going to bed and waking-up times.

Results suggest that activity-rest rhythm alteration in PD may be a consequence of DT but not of disease stage. Altered sleep cycles correlated with diurnal somnolence and nocturnal psychosis.