Polysomnographic findings, video-based sleep analysis and sleep perception in progressive supranuclear palsy

Objectives: To compare subjective sleep perception, sleep architecture, rapid eye movement (REM) sleep without atonia, and REM sleep behavior disorder (RBD) in patients with progressive supranuclear palsy (PSP) to patients with Parkinson’s disease (PD).Methods: A comparative sleep study using the Parkinson’s Disease Sleep Scale (PDSS), the Mini-Mental State Examination (MMSE), and cardiorespiratory polysomnography on two consecutive nights with synchronized video recording. The study was undertaken in a sleep laboratory in a movement disorder center. Forty patients matched for age and cognition with probable PSP (n = 20, aged 71 ± 8 years, MMSE ? 24 in n = 7) and PD (n = 20, aged 69 ± 5 years, MMSE ? 24 in n = 8).Results: PDSS sum scores showed no difference between PSP and PD. PSP patients had significantly lower sleep efficiency (43.0 ± 15.0%) compared to PD patients (62.8 ± 19.1%) (p < 0.0008). Seventeen PSP patients and 19 PD patients had REM without atonia (RWA). Seven PSP patients and 13 PD patients had clinical RBD. The amount of RWA was lower in PSP (14.5 ± 17.3%) than in PD (44.6 ± 31.3%) (p < 0.0007). Eleven PSP and 11 PD patients were newly identified with sleep-disordered breathing (SDB).Conclusions: Polysomnographically recorded sleep is more severely impaired in PSP than in PD. PDSS ratings do not reflect the poorer sleep quality in PSP, possibly pointing to a specific neuropsychological profile. RWA and RBD are present in both neurodegenerative diseases. So far undetected SDB affects more than half of all patients in this study.     

Revisiting the impact of REM sleep behavior disorder on motor progression in Parkinson's disease

BackgroundEstimation of progression in Parkinson's disease (PD) is useful to guide clinical decisions and to enable patients to plan and manage their life with PD. Rapid eye movement (REM) sleep behavior disorder (RBD) and REM sleep without atonia (RWA) are recognized as early harbingers of neurodegeneration and may precede motor symptoms by years. However, their impact on motor progression remains elusive.MethodsWe retrospectively analyzed polysomnographic and clinical data of 59 PD patients, grouping them into patients with RBD (n = 15), RWA (n = 22) and those with normal muscle atonia (n = 22). We compared the three groups with regard to motor progression, defined as changes in Unified Parkinson's Disease Rating Scale (UPDRS) III values per year, and selected PD specific characteristics.ResultsMotor disability at first visit and time interval between first and last visits were similar between groups. We observed a significantly faster motor progression in PD patients with RBD and RWA than in those with preserved REM sleep atonia.ConclusionOur findings suggest that impaired muscle atonia during REM sleep might represent a marker of faster motor progression in PD.     

Two polysomnographic features of REM sleep behavior disorder: Clinical variations insight for Parkinson's disease

IntroductionLoss of REM sleep muscle atonia (RWA) and dream-enactment behavior (DEB) are two associated features of REM sleep behavior disorder (RBD), which is frequently associated with Parkinson's disease (PD). Few studies have examined both DEB and RWA simultaneously in patients with PD. This study aimed to evaluate relationships between RWA, DEB and clinical characteristics of PD.MethodsWe conducted overnight polysomnography in 145 patients with PD. DEB (motor behaviors and/or vocalizations during REM) and increased RWA (IRWA; tonic and phasic chin EMG density ≥ 30% and ≥15%, respectively) were identified. Patients were categorized as clinical RBD (DEB and IRWA), sub-DEB positive (DEB only), subclinical RBD (IRWA only), or normal REM sleep.ResultsPatients with DEB had higher Hoehn and Yahr (H&Y) stage, Unified Parkinson's Disease Rating Scale (UPDRS) III score, levodopa equivalent dose(LEDs), and worse cognition. RWA was associated with H&Y stage, LEDs, cognition, and sleep structure in all patients. PD duration was associated with RWA, but not DEB. The PD patients who exhibited clinical or subclinical RBD, compared to sub-DEB positive, had higher H&Y stage, UPDRS III score and LEDs, lower cognitive score, worse sleep structure than the PD + cREM group.ConclusionBoth DEB and RWA were associated with severity of PD illness. Subclinical RBD might have different disease progression from sub-DEB positive. DEB symptoms may fluctuate or disappear whereas RWA may continue to develop as PD progresses. Differences in the course of DEB and RWA may reflect the difference in the degeneration process of neurodegenerative disorders.     

Surface EMG activity during REM sleep in Parkinson's disease correlates with disease severity

ObjectivesOver 40% of individuals with Parkinson's disease (PD) have rapid eye movement sleep behavior disorder (RBD). This is associated with excessive sustained (tonic) or intermittent (phasic) muscle activity instead of the muscle atonia normally seen during REM sleep. We examined characteristics of manually-quantitated surface EMG activity in PD to ascertain whether the extent of muscle activity during REM sleep is associated with specific clinical features and measures of disease severity.MethodsIn a convenience sample of outpatients with idiopathic PD, REM sleep behavior disorder was diagnosed based on clinical history and polysomnogram, and severity was measured using the RBD sleep questionnaire. Surface EMG activity in the mentalis, extensor muscle group of the forearms, and anterior tibialis was manually quantitated. Percentage of REM time with excessive tonic or phasic muscle activity was calculated and compared across PD and RBD characteristics.ResultsAmong 65 patients, 31 had confirmed RBD. In univariate analyses, higher amounts of surface EMG activity were associated with longer PD disease duration (srho = 0.34; p = 0.006) and greater disease severity (p < 0.001). In a multivariate regression model, surface EMG activity was significantly associated with RBD severity (p < 0.001) after adjustment for age, PD disease duration, PD severity and co-morbid sleep abnormalities.ConclusionSurface EMG activity during REM sleep was associated with severity of both PD and RBD. This measure may be useful as a PD biomarker and, if confirmed, may aid in determining which PD patients warrant treatment for their dream enactment to reduce risk of injury.     

Relationship between I-MIBG scintigrams and REM sleep behavior disorder in Parkinson’s disease

BackgroundUptake of ¹²³I-labeled meta-iodobenzylguanidine (MIBG) in myocardial scintigrams has been shown to be as low in patients with idiopathic RBD as in Parkinson’s disease (PD) patients.Aim for studyTo clarify whether the existence of RBD accelerates autonomic dysfunction in PD, we investigated the association between MIBG scintigraphic findings and RBD measures among non-dementia PD patients.Subjects &; methodsWe conducted clinical interviews to assess REM sleep behavior disorder (RBD) symptoms, and performed polysomnograms (PSG) recordings and MIBG scintigrams on 49 PD patients. The patients were divided into three groups (PD with clinical RBD, PD with subclinical RBD, and PD with normal REM sleep).ResultsPD patients with clinical RBD had reduced MIBG uptake as determined by heart-to-mediastinum ratios of the delayed image compared to those with subclinical RBD and those with normal REM sleep. Multiple linear regression analysis revealed that only the existence of RBD symptoms was significantly associated with reduced MIBG uptake among PD patients without dementia after adjusting for demographic and PD symptom-related variables.ConclusionPD patients with clinical RBD might suffer from a wider α-synuclein pathology, including reduced cardiac sympathetic ganglia function as reflected by a lowered MIBG uptake.     

REM and NREM sleep enactment behaviors in Parkinson's disease, Parkinson's disease dementia, and dementia with Lewy bodies

Background/objectiveNocturnal sleep enactment behaviors (SEBs) are common in patients affected by Parkinson’s disease (PD), dementia associated with Parkinson’s disease (PDD), and dementia with Lewy bodies (DLB). We investigated the occurrence and neurobiological significance of abnormal SEBs in the context of PD without cognitive decline compared to PDD/DLB patients.MethodsWe evaluated a sample of 139 patients with PD, PDD, or DLB in a cross-sectional survey. One hundred and seventeen patients showing either no cognitive impairment (PD group) or meeting the diagnostic requirements for dementia (PDD/DLB group) underwent video-polysomnography. Seventy subjects (42 males) in whom a clear-cut diagnosis of abnormal sleep-related motor-behavioral episodes was possible were included in the final analysis.ResultsSEBs consisting of RBD or occurring on arousal from NREM or REM sleep were globally more frequent in the dementia group (PDD/DLB) than in the PD group (p = 0.001), the difference being statistically significant for arousal-related episodes (p = 0.002), while a trend emerged for RBD (p = 0.07). Male sex, daytime sleepiness, higher motor impairment, and lower mini-mental score were significantly more frequent with the occurrence of abnormal sleep-related motor-behavioral episodes.ConclusionSEBs in PD, PDD, and DLB may consist of RBD episodes or of arousal-related NREM and REM episodes. These latter are more frequent in patients with PDD/DLB and seem to be mainly related to more advanced stages of disease with a higher degree of cognitive decline.     

Quantitative assessment of isolated rapid eye movement (REM) sleep without atonia without clinical REM sleep behavior disorder: clinical and research implications

BackgroundRapid eye movement (REM) sleep without atonia (RWA) is observed in some patients without a clinical history of REM sleep behavior disorder (RBD). It remains unknown whether these patients meet the refined quantitative electromyographic (EMG) criteria supporting a clinical RBD diagnosis. We quantitatively evaluated EMG activity and investigated its overnight distribution in patients with isolated qualitative RWA.MethodsFifty participants with an incidental polysomnographic finding of RWA (isolated qualitative RWA) were included. Tonic, phasic, and ‘any’ EMG activity during REM sleep on PSG were quantified retrospectively.ResultsReferring to the quantitative cut-off values for a polysomnographic diagnosis of RBD, 7/50 (14%) and 6/50 (12%) of the patients showed phasic and ‘any’ EMG activity in the mentalis muscle above the respective cut-off values. No patient was above the cut-off value for tonic EMG activity or phasic EMG activity in the anterior tibialis muscles. Patients with RWA above the cut-off value showed higher amounts of RWA during later REM sleep periods.ConclusionsThis is the first study showing that some subjects with incidental RWA meet the refined quantitative EMG criteria for a diagnosis of RBD. Future longitudinal studies must investigate whether this subgroup with isolated qualitative RWA is at an increased risk of developing fully expressed RBD and/or neurodegenerative disease.     

Polysomnographic predictors of sleep,motor and cognitive dysfunction progression in Parkinson's disease: a longitudinal study

ObjectiveTo assess the predictive value of polysomnographic (PSG) data in the prospective assessment of cognitive, motor, daytime and nighttime sleep dysfunction in Parkinson's Disease (PD) patients.MethodsPD patients were assessed at baseline with video-PSG and with cognitive (MoCA), Sleep (SCOPA-Sleep Nighttime and Daytime scores) and Motor (UPDRSIII) function scales at both baseline and four years later. Linear regression analysis was used to assess the relation between PSG variables at baseline and change in symptoms scores.ResultsWe included a total of 25 patients, 12 with rapid eye movement (REM) sleep behavior disorder (RBD) (in 8 PSG was inconclusive, due to lack of REM sleep). MoCA scores decreased significantly at follow-up, while SCOPA-Sleep Daytime and SCOPA-Sleep Nighttime and UPDRSIII did not vary. Lower N3 percentage at baseline was significantly associated with MoCA decrease. Higher Periodic Limb Movements in Sleep index (PLMS) and the presence of RBD were significantly associated with SCOPA daytime score increase. Higher global severity of RBD, tonic RSWA and total number of motor events during REM sleep were associated with SCOPA Nighttime score increase.ConclusionsThe present work suggests that PSG data could be useful for predicting PD cognitive and sleep dysfunction progression. Reduced SWS could predict deterioration of cognitive function, while baseline PLMS could be useful to predict worsening of daytime sleep dysfunction. Severity of RBD could be used for estimating nighttime sleep symptoms progression.     

Loss of REM sleep features across nighttime in REM sleep behavior disorder

ObjectivesMelatonin is a chronobiotic treatment which also alleviates rapid eye movement (REM) sleep behavior disorder (RBD). Because the mechanisms of this benefit are unclear, we evaluated the clock-dependent REM sleep characteristics in patients with RBD, whether idiopathic (iRBD) or associated with Parkinson's Disease (PD), and we compared findings with PD patients without RBD and with healthy subjects.MethodsAn overnight videopolysomnography was performed in ten iRBD patients, ten PD patients with RBD (PD + RBD+), ten PD patients without RBD (PD + RBD−), and ten controls. The rapid eye movement frequency per minute (REMs index), the tonic and phasic electromyographic (EMG) activity of the levator menti muscle, and the duration of each REM sleep episode were evaluated. A generalized linear model was applied in each group, with the REM sleep cycle (four ordinal levels) as the dependent variable, as a function of REMs index, REM sleep duration, and tonic and phasic EMG activity.ResultsFrom the first to the fourth sleep cycle, REM sleep duration progressively increased in controls only, REMs index increased in subjects without RBD but not in patients with RBD, whether idiopathic or associated with PD, whereas tonic and phasic EMG activity did not change.ConclusionsPatients with PD or iRBD lost the physiologic nocturnal increase in REM sleep duration, and patients with RBD (either with or without PD) lost the increase of REMs frequency across the night, suggesting an alteration in the circadian system in RBD. This supports the hypothesis of a direct effect of melatonin on RBD symptoms by its chronobiotic activity.     

The relation between abnormal behaviors and REM sleep microstructure in patients with REM sleep behavior disorder

ObjectiveTo investigate the temporal relation between rapid eye movement (REM) sleep microstructure (REMs, EMG activity) and motor events in REM sleep behavior disorder (RBD).MethodsPolysomnographic records of eight patients with RBD were analyzed and compared with those of eight sex- and age-matched controls. We examined sleep microstructure for REM sleep with and without REMs and phasic chin EMG activity and their temporal relation to motor events on video.ResultsAll types of motor events were either more frequent in RBD patients than in controls (P ? 0.007) or present solely in RBD patients. In RBD, major motor events were significantly more frequent during REM sleep with REMs than during REM sleep without REMs (violent, 84.0% vs. 16.0%, P < 0.001; complex/scenic behavior, 78.1% vs. 23.2%, P < 0.001; major jerks, 77.5% vs. 20.3%, P < 0.001), whereas minor motor activity was evenly distributed (54.1% vs. 45.9%, P = 0.889). Controls showed predominantly minor motor activity with rare myoclonic body jerks. The distribution of motor events did not differ between REM sleep with and without REMs (40.9% vs. 59.1%, P = 0.262).ConclusionsIn RBD, major motor activity is closely associated with REM sleep with REMs, whereas minor jerks occur throughout REM sleep. This finding further supports the concept of a dual nature of REM sleep with REMs and REM sleep without REMs and implies a potential gate control mechanism of REM sleep with REMs for the manifestation of elaborate or violent behaviors in RBD.     

Parkinson’s disease and REM sleep behavior disorder result in increased non-motor symptoms

ObjectiveRapid eye movement (REM)-sleep behavior disorder (RBD) is often comorbid with Parkinson’s disease (PD). The current study aimed to provide a detailed understanding of the impact of having RBD on multiple non-motor symptoms (NMS) in patients with PD.MethodsA total of 86 participants were evaluated for RBD and assessed for multiple NMS of PD. Principal component analysis was utilized to model multiple measures of NMS in PD, and a multivariate analysis of variance was used to assess the relationship between RBD and the multiple NMS measures. Seven NMS measures were assessed: cognition, quality of life, fatigue, sleepiness, overall sleep, mood, and overall NMS of PD.ResultsAmong the PD patients, 36 were classified as having RBD (objective polysomnography and subjective findings), 26 as not having RBD (neither objective nor subjective findings), and 24 as probably having RBD (either subjective or objective findings). RBD was a significant predictor of increased NMS in PD while controlling for dopaminergic therapy and age (p = 0.01). The RBD group reported more NMS of depression (p = 0.012), fatigue (p = 0.036), overall sleep (p = 0.018), and overall NMS (p = 0.002).ConclusionIn PD, RBD is associated with more NMS, particularly increased depressive symptoms, sleep disturbances, and fatigue. More research is needed to assess whether PD patients with RBD represent a subtype of PD with different disease progression and phenomenological presentation.     

REM sleep behavior disorder in Parkinson's disease – Is there a gender difference?

BackgroundREM sleep behavior disorder (RBD) is common in Parkinson's disease (PD). While previous studies of idiopathic RBD have reported a striking male preponderance, little information exists about potential gender differences of RBD in PD.MethodsWe performed a cross sectional study of 107 PD patients. Probable RBD (pRBD) was diagnosed using the RBD Screening Questionnaire.ResultsMen had more fights (96% versus 54%, p < 0.001), violent behavior (71% versus 39%, p = 0.04) and awakening by own movements (89% versus 62%, p = 0.04). More women experienced disturbed sleep (85% versus 32%, p = 0.02). The frequency of pRBD was 31% in women and 43% in men (p = 0.2), total frequency 38%.ConclusionsWe found no clear differences in the frequency of pRBD among men and women with PD, but demonstrated significant gender differences in its clinical expression. Female PD patients reported significantly less fights and aggressive behavior during dreams, but had more disturbed sleep.     

Factors associated with the effect of pramipexole on symptoms of idiopathic REM sleep behavior disorder

BackgroundThe clinical effectiveness of pramipexole (PPX), a candidate treatment for idiopathic rapid eye movement sleep behavior disorder (iRBD), varies among individuals. This study investigates factors associated with PPX effectiveness for treating RBD symptoms.MethodsNinety-eight consecutive patients with RBD who had taken PPX or clonazepam (CNZP) for more than three months were enrolled. Factors associated with PPX effectiveness were examined: the ratio of REM sleep without atonia to total REM sleep (RWA/REM), length of RBD morbidity, frequency of vocalization or abnormal behavior, and Sniffin' Stick Test scores. These factors were also compared among the responders to PPX monotherapy, CNZP monotherapy, and PPX + CNZP combined therapy.ResultsPPX was efficacious in 61.7% (50/81) of the subject patients. RWA/REM was associated with PPX effectiveness. The cut-off rate of RWA/REM for predicting PPX effectiveness was estimated as 16.8%. Responders to PPX + CNZP combined therapy showed significantly higher RWA/REM and frequency of vocalization or dream enactment behavior than either responders to monotherapy with PPX or to CNZP.ConclusionPPX is probably applicable as an alternative to CNZP, especially for mild iRBD cases with a lower rate of RWA. Results of this study suggest that dopaminergic dysfunction can play a role in iRBD pathophysiology.     

Do patients with rapid eye movement sleep behavior disorder have a disease-specific personality?

ObjectivesRapid eye movement sleep behavior disorder (RBD) occurs idiopathically (iRBD), frequently representing a prodromal phase of Parkinson’s disease (PD). Previous reports have described that patients with PD have premorbid personality profiles such as industriousness, inflexibility, cautiousness, and lack of novelty seeking. As well, psychological stress often aggravates RBD symptoms. These phenomena encouraged us to investigate personality profiles in iRBD patients.MethodsIn this study, 53 patients with iRBD and 49 age and sex-matched healthy controls (HC) were enrolled. We used the revised version of the NEO Personality Inventory (NEO-PIR) to measure the personality of these subjects, and the 5 domains and the 30 facets of the NEO-PIR were compared between the two groups. Within the iRBD group, we investigated the association between RBD variables, e.g. the proportion of REM sleep without atonia (RWA/REM), length of RBD morbidity, frequency of vocalization or abnormal behavior, and the variables of NEO-PIR.ResultsIn the patients, olfactory function was significantly lower than that of healthy controls, but the inventory differences were not significant. The inventory showed no association with any RBD variable, or the existence of aggravation of these symptoms triggered by psychological stress, or olfactory dysfunction.ConclusionThese results suggest that RBD patients do not have a personality profile that might predict PD development. The personality profile itself cannot explain the psychological-stress-dependent aggravation of RBD symptoms.     

Reduced volume of the putamen in REM sleep behavior disorder patients

ObjectiveThe purpose of this study was to quantify volumes of specific subcortical gray matter nuclei implicated in Parkinson’s disease (PD) as a preliminary step for identifying a non-invasive clinical biomarker for PD. We hypothesized that REM sleep behavior disorder (RBD) patients, at risk for developing PD, will demonstrate a pattern of neuronal degeneration reflected in reduced striatal volumes on T1-weighted MRI.MethodsWe compared measures of RBD patients confirmed by polysomnography (PSG) with groups of age/gender-matched Control subjects and early PD (EPD) patients (Hoehn &; Yahr < 2). Clinical measurements included the Unified Parkinson’s disease Rating Scales (UPDRS), timed gait and finger tapping tasks, the Parkinson’s Disease Questionnaire (PDQ-39), and a time-synchronized video recorded single-night PSG. Volumetric measurements were derived from high-resolution T1-weighted 3 T MRI images.ResultsThe matched Control and EPD groups were statistically similar to the RBD group in age, gender, handedness, and total brain volumes. The RBD group had smaller bilateral putamen volumes (both raw and normalized by brain tissue volume), in addition to some clinical impairment on the UPDRS and PDQ-39.ConclusionsReduced putamen volumes may be a structural marker for RBD and reflect a pattern of neurodegeneration that predicts the development of PD.     

Decreased sleep spindle density in patients with idiopathic REM sleep behavior disorder and patients with Parkinson’s disease

ObjectiveTo determine whether sleep spindles (SS) are potentially a biomarker for Parkinson’s disease (PD).MethodsFifteen PD patients with REM sleep behavior disorder (PD + RBD), 15 PD patients without RBD (PD − RBD), 15 idiopathic RBD (iRBD) patients and 15 age-matched controls underwent polysomnography (PSG). SS were scored in an extract of data from control subjects. An automatic SS detector using a Matching Pursuit (MP) algorithm and a Support Vector Machine (SVM) was developed and applied to the PSG recordings. The SS densities in N1, N2, N3, all NREM combined and REM sleep were obtained and evaluated across the groups.ResultsThe SS detector achieved a sensitivity of 84.7% and a specificity of 84.5%. At a significance level of α = 1%, the iRBD and PD + RBD patients had a significantly lower SS density than the control group in N2, N3 and all NREM stages combined. At a significance level of α = 5%, PD − RBD had a significantly lower SS density in N2 and all NREM stages combined.ConclusionsThe lower SS density suggests involvement in pre-thalamic fibers involved in SS generation. SS density is a potential early PD biomarker.SignificanceIt is likely that an automatic SS detector could be a supportive diagnostic tool in the evaluation of iRBD and PD patients.     

Objective sleep data as predictors of cognitive decline in dementia with Lewy Bodies and Parkinson's disease

IntroductionParkinson's disease (PD) and Dementia with Lewy Bodies (DLB) prognosis depends on cognitive function evolution. Sleep disorders, as objectivated by polysomnography (PSG), are intimately connected with PD and DLB pathophysiology, but have seldomly been used to predict cognitive decline.Methods20 DLB and 49 PD patients underwent one-night in-lab video-PSG. Sleep variables were defined, including REM sleep motor events, Tonic and phasic REM sleep muscular tone and RBD diagnosis. Cognitive state (assessed with the Global Deterioration Scale (GDS) was collected from case files for 6 months intervals, for a maximum period of 3.5 years or until death/drop-out.). The relation between PSG data at baseline and variation of GDS scores over time was tested with mixed linear regression analysis.ResultsGDS scores were higher in DLB, than in PD. We confirmed significant cognitive decline in both disorders, but no significant differences in progression between them. There were no significant interactions between PSG data and GDS variation for the entire group and DLB separately. In PD patients, there was a significant interaction between RBD diagnosis and tonic excessive muscular tone and GDS increase.ConclusionOur data suggests that PSG data can be useful in predicting cognitive decline in PD but not in DLB patients. In PD patients, an RBD diagnosis is predictive of cognitive deterioration, confirming the notion that this non-motor symptom relates to a malignant sub-type. Tonic excessive muscular activity, but not other RBD features, had predictive value in this group, pointing to a specific relation with the disease pathophysiology.     

Association of rapid eye movement sleep behavior disorder with sleep-disordered breathing in Parkinson's disease

ObjectiveRapid eye movement (REM) sleep behavior disorder (RBD) and sleep-disordered breathing (SDB) are two major sleep disturbances observed in patients with Parkinson's disease (PD). However, prior studies exploring the clinical correlations between RBD and SDB in PD have been limited. We aimed to investigate the relationship between RBD and SDB in PD using a case–control study.MethodsA total of 46 PD patients with Hoehn–Yahr stages ranging from 1 to 3 participated in the present study. Participants underwent polysomnography to diagnose the presence of RBD and SDB, and were classified into groups, accordingly. SDB was defined as an apnea–hypopnea index greater than 5. Comparison of clinical and sleep-respiratory parameters was performed among them.ResultsSDB was more frequent in the RBD group than in the non-RBD group (51.4% vs 9.1%, p = 0.016). PD patients with RBD had significantly reduced mean SaO₂ and more severe sleep apnea–related parameters during total sleep and non-REM sleep in comparison with non-RBD PD patients. However, there were no differences on the REM-related apnea/hypopnea variables between participants with and without RBD (p > 0.05). Both the frequency of RBD and RBD screening questionnaire (RBDSQ) scores were higher in the participants with SDB than in the participants without SDB (p <0.05). Furthermore, a significant negative correlation was found between RBDSQ and mean SaO₂ in all participants.ConclusionsIn PD patients, SDB is more frequent and more severe in patients with RBD than in patients without, and RBD increases the risk of hypoxemia during sleep.