Rapid Eye Movement-related Obstructive Sleep Research Articles

Positional obstructive sleep apnea in children prescribed continuous positive airway pressure therapy for obstructive sleep-disordered breathing.

Positional obstructive sleep apnea, in which there is a ≥ 2:1 predominance of obstructive events in the supine position, is a sleep-disordered breathing phenotype with a targeted treatment in the form of positional device therapy. We sought to determine the prevalence of positional obstructive sleep apnea in a cohort of children prescribed continuous positive airway pressure therapy, ascertain risk factors for the condition, and determine the associated continuous positive airway pressure treatment adherence rate. A retrospective cohort study of all children > 2 years old from a single tertiary paediatric centre prescribed continuous positive airway pressure therapy over an 8-year period was conducted. Positional obstructive sleep apnea prevalence was established by analysing positional and respiratory event data from the participants' original diagnostic polysomnography. Continuous positive airway pressure therapy adherence was determined using data from machine download. Univariable and multivariable logistic regression modelling was used to determine participant demographic and clinical factors associated with positional obstruction. Positional obstructive sleep apnea (defined by Bignold's criteria modified for paediatric use) prevalence in the cohort of 237 analysed participants was 38%. Suboptimal continuous positive airway pressure adherence was noted in 30% of this group based on initial machine download, performed a median of 96 days post-treatment initiation. Higher age and lower obstructive apnea-hypopnea index were independent predictors of positional obstructive sleep apnea, whereas neurodevelopmental diagnosis, presence/absence of rapid eye movement-related obstructive sleep apnea, overweight/obesity status and history of adenoidectomy/adenotonsillectomy were not. For children, positional device therapy is a treatment option worthy of further consideration and research.

Association between REM-related mild obstructive sleep apnea and common cardiometabolic diseases.

To explore the association between rapid eye movement-related obstructive sleep apnea (REM-OSA) and common cardiometabolic diseases (CMDs) in patients with mild OSA. This retrospective study was conducted by reviewing the medical records and polysomnograms (PSGs) of patients at Siriraj Hospital. The PSGs of patients diagnosed with mild OSA who had ≥ 15min of REM sleep were included. REM-OSA was defined if the apnea-hypopnea index (AHI) in REM was ≥ 2 times that of non-REM. Common CMDs included coronary artery disease, stroke, heart failure, diabetes mellitus, and hypertension. The data of 518 patients with a mean age of 48.3years, 198 males, and mean AHI of 9.8 events/h were analyzed in this study. When compared with the control group, the REM-OSA group (308 patients) were predominantly female (72%), overweight (62%), and had more severe oxygen desaturation, p-value < 0.001. CMDs were significantly more common in the REM-OSA group than in the controls [odds ratio (OR) 1.52, 95% confidence interval 1.04-2.21, p-value = 0.029]. Patients with a REM AHI of ≥ 20 events/h were significantly associated with hypertension compared to those with a REM AHI of < 20 events/h, p-value = 0.001. However, these associations were found not to be statisticallysignificant after controlling for age, sex, BMI, and prevalent coexistingCMD (OR = 1.13, 95% CI: 0.72-1.76, p-value = 0.605). Common CMDs, particularly HT, tend to show an association with REM-OSA in patients withmild OSA, but this association did not reach statistically significant levels.

The prevalence of rapid eye movement-related obstructive sleep apnea in a sample of Saudi population.

This study aimed to estimate the prevalence of rapid eye movement-related obstructive sleep apnea (REMrOSA) using common definitions. This was a retrospective cohort study that used three sets of criteria to identify patients with REMrOSA. These criteria were defined as strict, intermediate, and lenient depending on the apnea-hypopnea index (AHI), AHI during REM sleep/(AHI during non-REM sleep [NREM-AHI]), NREM-AHI and REM duration. The study included 609 patients with OSA and full sleep study. The prevalence of REMrOSA was 26%, 33%, and 52% using the strict, intermediate, and lenient criteria, respectively. There were no differences in the patients' general and demographic characteristics between the different groups of the three definitions. REMrOSA patients were more likely to be younger females than non-REMrOSA (NREMrOSA) patients. Comorbidities were more frequent in the REMrOSA group compared to NREMrOSA when using strict and intermediate definitions. In contrast, AHI, mean O2 saturation, and time spent <90% O2 saturation were significantly worse during NREMrOSA compared to REMrOSA, regardless of the criteria used. Our study reported higher AHI, lower mean oxygen saturation, lower minimum oxygen saturation, and longer time of desaturation during REMrOSA when lenient definition was used compared to when strict and intermediate definitions were used. REMrOSA is a common condition with a prevalence ranging between 26% and 52% depending on what definition is applied. Although OSA tends to be more severe with lenient definition, however, the clinical and polysomnographic features were similar among REMrOSA groups regardless of the definition used.

Clinical Characteristics of Rapid Eye Movement-Related Obstructive Sleep Apnea: An Experience in a Tertiary Medical Center of Taiwan.

PurposeObstructive sleep apnea (OSA) is characterized by intermittent hypoxemia and sleep fragmentation. While apnea is pronounced with severe desaturation during rapid eye movement (REM) sleep, REM-related OSA is a distinct phenotype of OSA associated with respiratory disturbances predominantly during REM sleep. In this study, we investigated the clinical features of REM-related OSA in Taiwan.Patients and MethodsAll patients diagnosed with OSA in the Taipei Veterans General Hospital from 2015 to 2017 were analyzed retrospectively and classified into REM-related OSA (REM-OSA) group, non-REM related OSA (NREM-OSA) group, and non-stage specific-OSA group. The clinical demographics, OSA-related symptoms, polysomnography results, and medical comorbidities of the three groups were analyzed.ResultsAmong 1331 patients with OSA, 414 (31.1%) were classified as REM-OSA, 808 (60.7%) as NREM-OSA, and 109 (8.2%) as non-stage specific-OSA. After being adjusted for OSA severity, the REM-OSA group was associated with less portion of males, longer desaturation duration, and lower nadir oxygen saturation (SpO2) compared with the NREM-OSA group in mild and moderate OSA. In moderate OSA, the non-stage specific-OSA group featured more OSA severity and more desaturation compared with the other groups. The Epworth Sleepiness Scale scores and the prevalence of comorbidities did not vary among the REM-OSA, NREM-OSA, and non-stage specific-OSA groups. High REM-AHI/NREM-AHI ratio was associated with young age, female gender, high BMI, and low AHI.ConclusionOSA patients with high REM-AHI/NREM-AHI ratio are related to young age, female gender, high BMI, and low AHI. Patients with REM-related OSA presented with longer desaturation duration and lower nadir SpO2 after being adjusted for OSA severity.

Characteristics of rapid eye movement-related obstructive sleep apnea in Thai patients

Obstructive sleep apnea (OSA) is a common sleep disorder that has been associated with cardiovascular consequences. Rapid eye movement (REM)-related obstructive sleep apnea (OSA) is a subtype of OSA which is characterized by apneas or hypopneas predominately during REM sleep. The factors associated with REM-related OSA are still unclear. We aimed to determine the prevalence and associated characteristics of REM-related OSA in Thai patients. A total of 408 patients’ charts were retrospectively reviewed. Demographic and anthropometric characteristics, comorbidities and polysomnographic data were obtained. The patients were divided into two groups: REM-related OSA and non-stage specific OSA. REM-related OSA was defined as an apnea–hypopnea index (AHI) ≥ 5 per hour, with a ratio of REM-AHI to NREM-AHI > 2, and NREM-AHI < 15 per hour. The prevalence of REM-related OSA was 21.6%. AHI and arousal index were both lower in REM-related OSA than in non-stage specific OSA. REM-related OSA was significantly associated with females (OR 2.35, 95% CI 1.25–4.42, p = 0.008), age < 60 years (OR 2.52, 95% CI 1.15–5.55, p = 0.021), and mild OSA (OR 17.46, 95% CI 9.28–32.84, p < 0.001). In conclusion, age < 60 years, female gender, and mild severity of OSA were associated with REM-related OSA.

Prevalence and Risk Factors for Rapid Eye Movement-Related Obstructive Sleep Apnea in Children.

ObjectivesDifferent pathophysiological mechanisms and the distribution of respiratory events among rapid eye movement (REM) and non-rapid eye movement (NREM) sleep modulate the effect of obstructive sleep apnea (OSA). We aimed to study the prevalence and risk factors for REM-related OSA in children.Study DesignRetrospective, cross-sectional study.MethodsWe recruited 366 children with OSA confirmed by polysomnography (PSG) over a 5-year period. REM-related OSA is defined by an obstructive apnea-hypopnea index (OAHI) in the REM sleep ≥2× than during NREM sleep.ResultsThe prevalence of REM-related OSA in children was 50.3%. Children with REM-related OSA were more likely to be female (P = 0.042), and had lower prevalence of adenotonsillar hypertrophy (P = 0.043) compared with children with other OSA subtypes. Children with REM-related OSA slept longer in the supine position (P = 0.003), had shorter duration of NREM1 sleep (P = 0.018), lower nadir SpO2 (P = 0.005), and a higher oxygen desaturation index 3% (ODI3%) (P = 0.014), and lower arousal index (P = 0.034) compared with other OSA subtypes. Female gender and supine sleep was the independent risk factors for REM-related OSA.ConclusionThe prevalence of REM-related OSA was 50.3%. OAHIREM should be considered as an important parameter in future clinical research studies done in children with OSA.

Nocturnal Blood Pressure Fluctuations in Patients with Rapid Eye Movement-Related Obstructive Sleep Apnea.

Rapid eye movement-related obstructive sleep apnea (REM-related OSA) is a polysomnographic phenotype. Nocturnal blood pressure (BP) fluctuations remain unclear in patients with REM-related OSA. We studied 27 patients with REM-related OSA, categorized as having REM-apnea-hypopnea index (REM-AHI) ≥ 5/h, REM-AHI/non-REM-AHI ≥ 2, and non-REM-AHI < 15/h. Beat-to-beat systolic BP (SBP) variability and nocturnal SBP fluctuation patterns using pulse transit time (PTT) were investigated. The maximum increase and average nocturnal SBP were significantly higher in males than in females (p = 0.003 and p = 0.008, respectively). The rate of non-dipping patterns in nocturnal SBP fluctuations was 63% in all patients (males, 70%; females, 50%). Epworth Sleepiness Scale (ESS) and Self-rating Depression Scale (SDS) scores in females were higher than those in males (8.4 ± 6.1 vs. 13.4 ± 5.4 points, p = 0.04; 43.8 ± 7.9 vs. 52 ± 11.6 points, p = 0.04, respectively). A high proportion of patients with REM-related OSA had a non-dipping pattern. Using PPT, we observed that in patients with REM-related OSA, SBP variability was greater in males. Despite clinical symptoms being slightly more severe in females, nocturnal SBP fluctuations should be considered in male patients with REM-related OSA.

Characteristics of patients with rapid eye movement-related obstructive sleep apnea: a retrospective review of 52 patients at a tertiary care center

Background: The term “rapid eye movement (REM)-related obstructive sleep apnea (OSA)” is commonly used to describe sleep disordered breathing that occurs exclusively in REM sleep. The prevalence of REM-related OSA ranges from 10% to 36%. Despite the presence of reports describing the features of REM-related OSA, there is still much more to be known about it.Methods: In this study we did retrospective review of 734 patients who had a diagnostic sleep study in a sleep lab at a tertiary center between January 2014 and August 2016 were reviewed.Results: We found that hypertension was found in the charts of 50 patients, 36 of them were diagnosed with hypertension and on medical therapy (72%), 11 patients (out of 50) had diabetes (22%) and 9 (out of 49) had dyslipidemia. 2 patients (out of 49) had Ischemic heart disease (4%), 1 patient (out of 49) had stroke (2%) and 3 patients (out of 49) had arrhythmias (6%). 8 patients (out of 49) had thyroid disease (16%).Conclusions: In conclusion Most patients had mild REM related OSA and most did not have subjective EDS. Hypertension was the most common comorbidity among our patients.

Insomnia as a Symptom of Rapid Eye Movement-Related Obstructive Sleep Apnea.

Rapid eye movement (REM)-related obstructive sleep apnea (OSA), a polysomnographic phenotype that affects 12–36% of OSA patients, is defined by apnea and hypopnea events that predominantly or exclusively occur during REM sleep. Recent studies indicated that REM-related OSA was associated with the development of nocturnal non-dipping of systolic and diastolic blood pressure, metabolic syndrome, diabetes, and depressive symptoms. However, to date, the association between REM-related OSA and insomnia still remains unclear. We investigated whether there was a difference between REM- and non-REM-related OSA in terms of insomnia-related sleep disturbance as measured by the Pittsburgh Sleep Quality Index (PSQI) in 1736 patients with OSA. REM-related OSA showed a significant association with increased PSQI in all adjusted models. In the subgroup analysis, the coefficients of all models were higher in female than in male patients with REM-related OSA. Insomnia should be considered an important complaint in patients with REM-related OSA, and its indicators, such as the PSQI, should be included in routine diagnostic testing.

Comparison of different criteria for the diagnosis of position and rapid eye movement-related obstructive sleep apnea syndrome and the value for the determination of prognosis

INTRODUCTION: Determination of clinical obstructive sleep apnea syndrome (OSAS) types is important for treatment decision. In the literature, there are two different criteria for the diagnosis of position and rapid eye movement (REM) related OSAS. One of them provides the criteria that nonsupine and/or non-REM apnea-hypopnea index (AHI) below 5, the other does not. In this study, these two definitions are named as “strict definition” and “loose definition.” This study is designed to identify which definition is more beneficial to use, and the prognostic value of the definitions by using OSAS severity according to AHI. This is the first study which investigates those issues. MATERIALS AND METHODS: This study is a retrospective cohort study. Obstructive AHI >5 of all adult patients admitted to our sleep disorders center between September 2012 and October 2014 were included to this study. The patients were grouped due to both strict and loose definitions. Patient groups were named as position related, REM related, REM + position related, pure OSAS due to loose definitions, and position dependent, aggravated by position, REM dependent, aggravated by REM, REM + position dependent, aggravated by REM + position, pure OSAS due to strict definitions. All these groups were compared for demographic and polysomnographic parameters. RESULTS: Two hundred and eighty (73.7%) of the patients were male, 100 (26.3%) were female, with a mean age of 49.9 ± 11.6, body mass index of 30.4 ± 5 and neck circumference of 43.2 ± 4.2. The patients had a mean Epworth Sleepiness Scale score: 13.5 ± 7, mean AHI: 32.3 ± 25.4, mean arousal index: 27.1 ± 19.6, mean peripheral capillary oxygen saturation (SpO2): 90.6 ± 4, and mean minimum SpO2: 78.7 ± 9.8. In OSAS aggravated by REM, position, REM + position total AHI, apnea index, hypopnea index, minimum SpO2 and desaturation percentage were all found significantly worse than REM dependent, position-dependent and REM + position-dependent OSAS patients (P CONCLUSION: In light of current findings, when evaluated with their effect on disease severity and complications, it is useful to predict prognosis of the disease when “strict definitions” are used for position- and/or REM-related OSAS cases.

Prevalence of Rapid Eye Movement-related Obstructive Sleep Apnea in Adult Narcolepsy

Objective The association between narcolepsy and rapid eye movement (REM)-related obstructive sleep apnea (OSA) has not been reported. This study aimed to examine the prevalence of REM-related OSA in narcolepsy patients. Methods From January 2013 to April 2018, 141 adult patients were diagnosed with narcolepsy using nocturnal polysomnography and the multiple sleep latency test. The prevalence of REM-related OSA in narcolepsy patients was retrospectively reviewed. Three criteria were used to determine REM-related OSA: Definition #1, an overall apnea-hypopnea index (AHI) ≥5 and AHI during REM (AHIREM)/AHI during non-rapid eye movement (NREM) (AHINREM) ≥2; Definition #2, an overall AHI ≥5 and AHIREM/AHINREM ≥2 and AHINREM <15; and Definition #3, an overall AHI ≥5 and AHIREM/AHINREM ≥2 and AHINREM <8 plus an REM sleep duration >10.5 minutes. Results Of the 141 narcolepsy patients, 26 were diagnosed with narcolepsy with cataplexy (NA-CA) and 115 with narcolepsy without cataplexy (NA w/o CA). Seventeen patients with NA-CA and 39 with NA w/o CA had OSA. According to Definition #1, the prevalence of REM-related OSA was 47.1% and 41.0%, respectively, in OSA patients with NA-CA and NA w/o CA; according to Definition #2, the respective prevalence was 47.1% and 38.5%, while that according to Definition #3 was 41.2% and 25.6%. No significant differences were found in the prevalence of REM-related OSA for each definition. Conclusion A high prevalence of REM-related OSA was confirmed in adult narcolepsy patients with OSA. Compared to previous reports, we noted a high frequency of REM-related OSA satisfying the relatively strict Definition #3. These results might reflect the pathophysiological characteristics of narcolepsy.

Effect of rapid eye movement-related obstructive sleep apnea on adherence to continuous positive airway pressure.

ObjectiveRapid eye movement (REM)-related obstructive sleep apnea (OSA) is characterized by respiratory events such as apnea and hypopnea predominately or exclusively during REM sleep. Several studies have revealed clinical predictors of adherence to the use of continuous positive airway pressure (CPAP). However, the effect of REM-related OSA on adherence to CPAP use remains unclear. Therefore, we investigated the effects of REM-related OSA on adherence to CPAP use 6 months after treatment initiation.MethodsWe enrolled 161 patients in this study and divided them into 3 groups: the good adherence, poor adherence, and dropout groups. We compared polysomnographic data and clinical findings, including those regarding morbidity of REM-related OSA, among the three groups to identify predictors of adherence to CPAP use.ResultsNone of the 43 patients in the good adherence group had REM-related OSA. Multivariate logistic regression analysis of the good adherence and dropout groups indicated that REM-related OSA was the only factor associated with adherence to CPAP use (odds ratio, 41.984; 95% confidence interval, 2.257–781.007).ConclusionsREM-related OSA is a reliable risk factor for dropout from CPAP therapy.

Gender differences of REM related obstructive sleep apnea-hypopnea syndrome

Objective: To explore the gender differences of rapid-eye-movement (REM) related obstructive sleep apnea-hypopnea syndrome (OSAHS). Methods: Consecutive patients with primary complaint of snoring from Sleep Medicine Center of West China Hospital between January 2016 and November 2016 were included in the study. All participants underwent one night polysomnography (PSG) and Epworth sleep scale (ESS) was estimated. The patients diagnosed with OSAHS were classified as REM related OSAHS (REM-OSAHS group) and non-rapid-eye-movement (NREM) related OSAHS (NREM-OSAHS group) based on the PSG parameters. And the gender differences of demographic and polysomnograpic characteristics in both groups were compared. The associations between apnea-hypopnea index (AHI) and body mass index (BMI), neck circumference and waist circumference among patients with OSAHS were explored by multiple linear regression analysis. Results: A total of 1 258 patients were diagnosed with OSAHS. There were 997 (79.3%) male and 261 (20.7%) female among these patients, the mean age was (46.4±12.0) years old and mean BMI was (26.6±3.4) kg/m(2). There were 236 patients (18.8%) classified into REM-OSAHS group, and 1 022 patients (81.2%) classified into NREM-OSAHS group; the proportion of REM-OSAHS in female was significantly higher than that in male (34.1% vs 14.7%, P<0.001). After controlling for age, drinking, smoking, hypnotics, coffee, strong tea and sleep related parameters, in NREM-OSAHS group, AHI was positively correlated with BMI, neck circumference and waist circumference (P<0.001) both in male and female. In REM-OSAHS group, AHI was positively correlated with BMI, neck circumference and waist circumference in female (P<0.05), but only significantly correlated with BMI and waist circumference in male (P<0.05). Conclusions: REM-OSAHS is commonly seen in female OSAHS patients. Evaluation of the influences of anthropometric data on the severity of REM-OSAHS should consider the impact of gender.

The prevalence of REM-related obstructive sleep apnoea is reduced by the AASM 2012 hypopnoea criteria.

The variations in reported prevalence of rapid eye movement-related obstructive sleep apnoea (REM-OSA) have been attributed to different definitions, although the effect of hypopnoea criteria has not been previously investigated. Within this retrospective study, 134 of 382 consecutive patients undertaking polysomnography (PSG) for the suspicion of OSA met the inclusion criteria. PSGs were scored using both the 2007 AASM recommended hypopnoea criteria (AASM2007Rec) and the 2012 AASM recommended hypopnoea criteria (AASM2012Rec). For each hypopnoea criteria, REM-OSA patients were grouped as REM-related [either as REM-predominant OSA (rpOSA) or REM-isolated OSA (riOSA)] or non-stage-specific OSA (nssOSA). Outcome measures (SF-36, FOSQ and DASS-21) were also compared between groups. Incorporation of the AASM2012Rec criteria compared to the AASM2007Rec criteria increased the apnoea-hypopnoea index (AHI) for NREM and REM sleep but decreased the AHIREM/AHINREM ratio from 1.9 to 1.3 (p<0.001). It also decreased the prevalence of riOSA [15.7 vs 2.2% (p<0.001) for AASM2007Rec and AASM2012Rec, respectively]. The prevalence of rpOSA remained the same for each hypopnoea criteria although the prevalence of nssOSA increased with the AASM2012Rec hypopnoea criteria [53.0 vs 66.4% (p<0.006) for AASM2007Rec and AASM2012Rec, respectively]. There were no differences in clinical symptoms between the groups, irrespective of hypopnoea criteria used. This study demonstrates that in comparison with AASM2007Rec, the AASM2012Rec hypopnoea criteria reduce the prevalence of riOSA but not rpOSA by reducing the ratio of REM respiratory events and NREM respiratory events.

Rapid Eye Movement-Related Obstructive Sleep Apnea: A Study on the Pathogenesis through Clinical and Polysomnographic Features

Purpose: The aims of this study were to evaluate the differences of clinical and polysomnographic features between rapid eye movement (REM)-related obstructive sleep apnea (OSA) and not-REM-related OSA, and to suggest the pathogenesis according to the REM dependency of OSA. Methods: One hundred ninety consecutive patients diagnosed with OSA were evaluated clinical features and performed full night polysomnography. The patients were divided into REMrelated (REM apnea-hypopnea index [AHI] at least two times higher than their non-REM AHI) and not-REM-related (a REM AHI less than two times higher than their non-REM AHI) OSA groups and evaluated the differences in age, body mass index (BMI), neck circumference, Epworth Sleepiness Scale score, and parameters of polysomnography. Results: REM-related patients were younger and showed higher sleep efficacy, low percentage of light sleep stage (stage 1 sleep), and low rate of positional OSA. Age was significantly associated with REM dependency of OSA and REM AHI were significant correlated with BMI, neck circumference, percentage of sleep in supine position, and percentage time of snoring. Conclusions: Our results showed that REM-related OSA patients showed less severe polysomnographic parameters than not-REM-related patients. However, significant risk factors were differed depending on the REM dependency and OSA severity, and the clinical features correlated with REM AHI and non-REM AHI were also showed differently. We suggest that the occurrence of OSA according to the REM dependency can be based on different mechanisms.

Multilevel surgery in patients with rapid eye movement–related obstructive sleep apnea

To compare the anatomic features and the results of a multilevel surgery in patients with rapid eye movement-related obstructive sleep apnea (REM OSA) and non-REM OSA. Cohort study of 90 consecutive mild or moderate OSA patients. The apnea-hypopnea index (AHI) was also calculated during REM sleep (AHI(REM)) and during non-REM sleep (AHI(NREM)), and patients were classified as having REM OSA if their AHI(REM)/AHI(NREM) ratio was >2, otherwise they were classified as non-REM OSA patients. All patients underwent concurrent uvulopalatopharyngoplasty and a radiofrequency tongue base reduction procedure. A total of 31.1 percent patients were classified as REM OSA and 68.9 percent patients as non-REM OSA. There were no differences in the anatomical features between two groups. However, the AHI, HI, and arousal index were significantly higher in the non-REM OSA group than in the REM OSA group. When a successful outcome was defined as a postoperative AHI <20 with at least a 50 percent reduction from the preoperative level, 50 percent of the patients with REM OSA and 35.5 percent of the patients with non-REM OSA met the criteria for a successful outcome. REM OSA patients had milder obstructive sleep apnea, and multilevel surgery might be more effective in REM OSA patients.

Clinical and Polysomnographic Characteristics in Rapid Eye Movement-Related Obstructive Sleep Apnea

Background and Objectives：To evaluate the clinical and polysomnographic features of rapid eye movement (REM)-related obstructive sleep apnea (OSA). Subjects and Method：185 consecutive OSA patients were classified as having REM and nonREM OSA. Subjective symptoms, anthropometric and polysomnographic characteristics between REM OSAS and non-REM OSAS patients were compared. Results：Thirty-eight of the 185 patients (20.5%) were classified as REM OSA, and 147 patients (79.5%) were classified as non-REM OSA. Ninety five percent of the REM OSA patients belonged to the mild or moderate OSA group. The dominant occurrence of apnea and hypopnea in REM sleep did notseem to affect subjective symptoms and daytime sleepiness. Anthropometric and polysomnographic features did not help to differentiate REM OSA from non-REM OSA. Conclusion：REM OSA may not be a separate and specific disease entity of OSA. (Korean J Otorhinolaryngol-Head Neck Surg 2009;52:36-40)