Sleep episodes and daytime somnolence as result of individual susceptibility to different dopaminergic drugs in a PD patient: A polysomnographic study

The association between excessive daytime somnolence (EDS) and idiopathic Parkinson's disease (PD) is often reported but still debated. The possible role of antiparkinsonian therapy or primarily of PD on excessive diurnal sleepiness is controversial. We describe the case of a 61-year-old patient affected by PD who experienced sleep episodes (SE) occurring during pramipexole plus l-Dopa therapy. Polysomnographic sleep studies and subjective evaluations of daytime sleepiness (Epworth Sleepiness Scale) were carried out under administration of pramipexole plus l-Dopa, l-Dopa monotherapy and cabergoline plus l-Dopa. The polysomnography revealed two sleep events during pramipexole plus l-Dopa. Moreover, the polysomnographic data showed an increase of both diurnal and nocturnal sleep under pramipexole plus l-Dopa compared with cabergoline plus l-Dopa and l-Dopa as monotherapy. In addition, while Epworth Sleepiness Scale (ESS) Score showed a mild sleepiness under pramipexole (ESS score=11), ESS scores were normal under both l-Dopa and cabergoline plus l-Dopa. Sleep episodes also disappeared under both l-Dopa and cabergoline plus l-Dopa (2- and 12-month follow-up). We hypothesize that an individual susceptibility to specific antiparkinsonian drug may play a significant role in the genesis of sleepiness in our PD patient.