HONOLULU – Only a small correlation between the severity of early-morning motor symptoms and nocturnal sleep disturbances was observed in patients with Parkinson’s disease, results from a post hoc trial analysis demonstrated.
"Parkinson’s disease is defined by cardinal motor symptoms, but as we are discovering more and more, nonmotor symptoms are burdensome to patients with Parkinson’s disease," Dr. Todd Swick said at the annual meeting of the American Academy of Neurology.
The major motor symptoms are rest tremor, rigidity, bradykinesia, akinesia, and postural instability. Common nonmotor symptoms include sleep disorders, cognitive dysfunction, depression, and gastrointestinal disorders.
"Sleep disorders are recognized to be of considerable clinical importance," said Dr. Swick, medical director of the Houston Sleep Center. "These have been shown to precede the onset of motor symptoms by as long as 50 years."
In an effort to investigate the association between the severity of nocturnal sleep disturbances and early-morning motor symptoms in Parkinson’s disease, he and his associates conducted a post hoc analysis of 267 patients who participated in the RECOVER (Randomized Evaluation of the 24-Hour Coverage: Efficacy of Rotigotine) study.
Dr. Swick described RECOVER as the first large-scale, double-blind, randomized trial to investigate sleep outcomes and motor function in the early morning as coprimary outcome measures in this patient population.
Patients were randomized to placebo or to the rotigotine transdermal system (2-16 mg every 24 hours). The researchers titrated to the optimal dose over a period of 1-8 weeks and maintained the dose for an additional 4 weeks. Significant benefits in early-morning function and in the severity of nocturnal sleep disturbances were observed in patients treated with rotigotine but not in those treated with placebo (Mov. Disord. 2011;26:90-9).
For the current study, Dr. Swick and his associates conducted categorical and continuous value association analyses to determine United Parkinson’s Disease Rating Scale III (UPDRS III) total score (0-9, 10-19, 20-29, 30-39, and 40 or more, defined as categories 1, 2, 3, 4, and 5, respectively), as well as modified Parkinson’s Disease Sleep Scale (PDSS-2) total score in the study participants.
The mean age of the patients was 65 years, 66% were male, and 91% were white. Their mean UPDRS III and PDSS-2 total scores were 30.4 and 19.7.
Dr. Swick reported that the analyses showed only a modest correlation between severity of nocturnal sleep disturbances and early-morning motor symptoms in patients with Parkinson’s disease. "This is in line with previously published data," he said. "The data suggest that possibly nonmotor dysfunctions may influence the extent of sleep disorders. This may be due to changes within the central nervous system as evidenced by a significant deterioration in CNS functioning."
The data also suggest that, in the RECOVER study, "changes in PDSS-2 total score were unlikely to be entirely attributed to changes in UPDRS III scores," Dr. Swick said.
The study was supported by Schwarz Pharma, distributor of rotigotine. Dr. Swick disclosed that he has received personal compensation for speaking from Jazz Pharmaceuticals and research stipends from Jazz, Cephalon, Pfizer, Sanofi-Aventis, and Merck.