Patient's with Parkinson's Disease often have difficulty staying asleep. They are also sleepy. This can be due to the disease or some of the Parkinson's medications. Obstructive sleep apnea (OSA) is also common in Parkinson's Disease. This may be due, in part, to loss of neuromuscular control of the upper airway muscles - allowing the throat to collapse easier.
This study looked at patients with Parkinson's Disease that had OSA. They gave the patients CPAP and placebo CPAP, monitored nightly use, and measured sleepiness objectively. The results showed that CPAP deepened sleep and reduced daytime sleepiness. Patients were able to use the CPAP consistently despite having the motor control problems common in Parkinson's Disease. Interestingly, CPAP use did not reduce the amount of time spent awake after initially falling asleep. The authors point out that this points to the inherent sleep difficulties of Parkinson's patients, even after their OSA is treated.