Background: In Parkinson's disease (PD), there is entanglement of disease-inherent and treatment-induced sleep abnormalities. So far, there has been no study specifically investigating the influence of diurnal dopaminergic medication (DM) on nocturnal slow wave sleep (SWS).
Methods: Polysomnographic analysis in 62 PD patients.
Results: PD patients had a sleep efficiency of 70 +/- 17% and an SWS amount of 16 +/- 11%. Linear regression analysis showed no significant correlation between the amounts of SWS and DM. However, patients with a medium DM dosage (300-600 mg of levodopa equivalents) preserved a SWS percentage >25% (p = 0.035, chi(2) test) more frequently than patients with higher or smaller DM. The DM dosage had no effect on other main sleep parameters. Psychotropic comedication had no effect on SWS percentage. In contrast, SWS amount was inversely correlated with both disease duration and age. It was independent of rapid eye movement sleep amount. The natural female bonus effect on SWS amount was absent in women with PD.
Conclusion: Diurnal dopaminergic treatment has no major impact on SWS in PD, which, however, decreases with disease duration. Disease-dependent, but treatment-independent decrease in SWS suggests primary degeneration of sleep-regulating systems in PD.