The Influence of Sleep Apnea Syndrome on Cognitive Functions in Patients with REM Sleep Behavior Disorder

ABSTRACT

OBJECTIVES: We investigated the effects of sleep apnea syndrome (SAS) on cognitive functions in patients with REM sleep behavior disorder (RBD). We also studied correlations between sleep variables related with SAS and parameters of cognitive function tests. METHODS: Twenty two RBD patients with SAS and 20 RBD patients without SAS participated in the study. The diagnoses of RBD and SAS were confirmed on polysomnography. All the participants performed neuropsychological tests by the Korean version of the Consortium to Establish a Registry for Alzheimer's disease (CERAD-K) Assessment Packet. RESULTS: There were no differences between two groups in age and sex, education, body mass index, and results of the Beck depression inventory (BDI) and the Epworth sleepiness scale (ESS). No difference was found in any of parameters of the CERAD-K between two groups. The cognitive functions were not correlated with BDI, ESS, or variables related with SAS. CONCLUSION: SAS had no influence on cognitive functions of RBD patients. The result could be explained by negligible effects of SAS on cognitive functions among aged population and no difference in daytime sleepiness between the RBD patients with and without SAS.