Sleep disordered breathing in Parkinson's disease: a critical appraisal

Parkinson's disease (PD) is the second most common neurodegenerative disorder, characterized by resting tremor, rigidity, bradykinesia and postural instability, and is associated with non-motor features, including sleep abnormalities. The high prevalence of excessive daytime sleepiness and snoring in PD patients has led to the suggestion that sleep disordered breathing (SDB) is more common in these individuals than in normal subjects. We aimed to review the literature on SDB prevalence and its clinical repercussions in PD. A PubMed search was performed to identify controlled studies, published from January 1990 through October 2012, which addressed the prevalence of SDB diagnosed by polysomnography in idiopathic PD. From the seven studies included, five reported similar or lower prevalence of SDB in patients when compared to healthy age-matched controls. Two studies reported less oxyhemoglobin desaturation during sleep among patients. These results did not support the idea that PD patients are at increased risk of SDB and indicate that they may not present significant hypoxemia. The prevalence of obstructive sleep apnea syndrome and the long-term outcomes of disordered breathing events during sleep have not been adequately studied in PD.