Background: Patients with Parkinson disease (PD) treated with the nonergot dopamine agonists pramipexole dihydrochloride and ropinirole hydrochloride have been reported to have sleep attacks without warning.
Objective: To perform a systematic evaluation of excessive daytime sleepiness using standard polysomnographic techniques.
Design: Two overnight studies and daytime sleep tests were performed on a prospective sample. Pathologic daytime sleep latency was indexed by a mean Multiple Sleep Latency Test score of no greater than 5 minutes or a mean Maintenance of Wakefulness Test latency of no greater than 20 minutes.
Patients and setting: Eighty nondemented, independent PD patients treated with dopamine agonists at the Toronto Western Hospital Sleep Research Unit, Toronto, Ontario.
Results: Patients treated with pramipexole dihydrochloride (n = 29), ropinirole (n = 28), or bromocriptine mesylate or pergolide mesylate (n = 23) did not differ with respect to mean Multiple Sleep Latency Test scores (overall, 12.1 minutes [SD, 5.1 minutes], F(2,77) = 0.11; P =.90) or mean Maintenance of Wakefulness Test latencies (overall, 26.7 minutes [SD, 5.4 minutes]; F(2,77) = 1.1; P =.29). Fifteen patients (18.8%) exhibited pathologic daytime sleep latencies. The main risk factor associated with pathologic daytime sleep latency was high levodopa dosage equivalents (>867.5 mg; odds ratio, 4.2; 95% confidence interval, 1.3-13.7). Subjective accounts of daytime sleep and wakefulness, as indexed by scores on the Epworth Sleepiness Scale, were not related to impaired daytime sleepiness or wakefulness (chi(2)(1) [n = 80], 0.13; P =.72).
Conclusions: Total dopaminergic drug dose rather than the specific dopamine agonist used is the best predictor of daytime sleepiness in PD patients receiving dopamine agonist therapy. Physicians concerned with daytime hypersomnolence in PD patients treated with dopamine agonists and receiving high levodopa dosage equivalents should consider polysomnographic monitoring for impaired daytime sleep latency.