Subjective sleep problems in patients with early Parkinson's disease

Background and objective Sleep problems are common in Parkinson's disease (PD) and increasingly so with disease progression. The frequency of these problems and the influence of dopaminergic treatment on sleep in early stages of PD remain unclear. We have therefore in this study examined the subjective experience of sleep problems in drug-naive patients with early PD and how these problems developed after 1 year on dopaminergic treatment using the Parkinson's Disease Sleep Scale (PDSS). Methods In all, 138 drug-naive patients with early PD derived from a population-based incident cohort and 138 age- and gender-matched control subjects were thoroughly assessed for Parkinsonism, cognition, depressive symptoms and sleep by structured interviews and clinical examination at the time of diagnosis and 1 year later on medication. Sleep problems were assessed using the PDSS. Results The total PDSS score for patients with PD was lower compared with controls, 119 vs. 127 (P < 0.05) at baseline and 121 vs. 128 (P < 0.005) after 1 year on drugs. Analyses of PDSS subdomains showed more nocturnal motor off symptoms both at baseline and after 1 year (P < 0.005) and increased daytime somnolence in patients compared with control subjects (P < 0.005 at baseline and P < 0.05 after 1 year). Only minor changes in sleep scores were seen after the introduction of dopaminergic treatment. Conclusion Patients with early PD report only modestly increased subjective sleep problems at the time of diagnosis compared with control subjects and dopaminergic treatment during the first year in general only slightly changed the experienced sleep problems.