Severity of idiopathic rapid eye movement sleep behavior disorder correlates with depression and alexithymia

BackgroundDepression and alexithymia often accompany early stages of Parkinson's disease (PD). However, these symptoms in idiopathic rapid eye movement sleep behavior disorder (iRBD) remain incompletely understood. The aim of this study was to compare depression and alexithymia between iRBD patients and healthy controls, and to evaluate the association between clinical RBD severity and severity of depression and alexithymia.MethodsPolysomnography-confirmed iRBD patients (n = 86) and healthy controls (n = 74) were enrolled. Clinical RBD severity was assessed using the RBD questionnaire-Hong Kong (RBDQ-HK). Depression and alexithymia were evaluated by the Beck Depression Inventory (BDI) and the 20-item Toronto Alexithymia Scale (TAS-20), respectively. Multivariate linear regression analysis was performed with adjustments for several covariates to determine the correlations between RBD severity and severity of depression and alexithymia.ResultsBDI scores were significantly higher in the iRBD group (10.6 ± 7.3) than in healthy controls (8.2 ± 6.0, p = 0.024). Higher total RBDQ-HK scores were associated with more severe depression in iRBD patients, even after controlling for confounding variables. iRBD patients exhibited significantly higher TAS-20 scores (45.7 ± 10.4) than healthy controls (42.1 ± 9.8, p = 0.026). Total RBDQ-HK scores were positively correlated with TAS-20 scores independent of BDI scores.ConclusionsPatients with iRBD were more depressed and had more severe alexithymia than healthy controls. Notably, as the clinical severity of RBD increased, both depression and alexithymia worsened.     

QT interval variability index and QT interval duration during different sleep stages in patients with obstructive sleep apnea

ObjectivesThe aim of the study was to investigate the impact of obstructive sleep apnea (OSA) on the QT interval variability and duration in patients during different sleep stages.MethodsPolysomnographic recordings of 28 (13 male, 15 female) patients with OSA and 30 (15 male, 15 female) patients without OSA were analyzed. The QT interval variability index (QTVI) and the corrected QT interval (QTc) analyses were performed using two awake, 3–4 non-rapid eye movement (NREM) and three rapid eye movement (REM) sleep episodes (each 300 s). The Bazett formula, linear, and parabolic heart rate correction formulas with two separate α values were used.ResultsQTVI was statistically higher in OSA than in non-OSA patients for males while awake (awake −0.7 ± 0.3 vs −1.2 ± 0.2, p = 0.001; NREM ‒0.9 ± 0.4 vs −1.1 ± 0.3, p = 0.110; REM ‒1.1 ± 0.3 vs −1.3 ± 0.2, p = 0.667) and for females in all wake–sleep stages (awake −0.3 ± 0.7 vs −0.9 ± 0.5, p = 0.001; NREM ‒0.3 ± 0.5 vs −0.8 ± 0.4, p = 0.002; REM −0.3 ± 0.5 vs −1.0 ± 0.4, p < 0.001). QTVI was significantly higher during awake compared to sleep stages in OSA males (p < 0.05); no difference between wake–sleep stages was found in females (p > 0.05). Significant gender differences in QTVI existed in OSA patients during sleep (p < 0.05) but not while awake. No significant differences in QTc between patients groups were observed.ConclusionsOSA is associated with increased QT variability. REM sleep per se does not increase QTVI. In OSA patients, QTVI might be a more useful measure to detect ventricular repolarization abnormality than measures of QTc.     

The role of pedunculopontine nucleus in isolated REM sleep behavior disorder and REM sleep without atonia

IntroductionThe aim of this study was to analyze the functions of pedunculopontine nucleus (PPN) in isolated REM sleep behavior disorder (iRBD) and REM sleep without atonia (RSWA) to investigate the role of PPN in dream-enacting motor behaviors in RBD. We evaluated the activity of PPN through the prepulse modulation (PPM) together with other brainstem reflexes to investigate the differences in changes at brainstem.MethodsWe included nine patients with isolated RSWA and 10 patients with iRBD. For diagnosis, all patients underwent polysomnography. None of the patients had parkinsonism or dementia. We also included 17 healthy participants with similar age and sex. Blink reflex (BR), PPM of BR, recovery excitability of BR, and auditory startle reflex (ASR) were recorded in all participants.ResultsThere was a prepulse inhibition deficit in iRBD and RSWA groups compared to healthy subjects. The BR-R2 recovery at 200 ms interval was also higher in patients with iRBD and RSWA. In ASR recordings, the response probabilities were higher in the RBD group compared to RSWA and control groups.ConclusionThe PPM was abnormal in both iRBD and RSWA whereas ASR was enhanced in iRBD. We suggest that there are certain similarities and differences in the pathophysiologies of iRBD and RSWA.     

Delayed emergence of a parkinsonian disorder or dementia in 81% of older men initially diagnosed with idiopathic rapid eye movement sleep behavior disorder: a 16-year update on a previously reported series

ObjectiveTo provide a 16-year update from the authors’ 1996 report documenting a 38% conversion from idiopathic rapid eye movement sleep behavior disorder (iRBD) to a parkinsonian disorder at a mean interval of nearly 13 years after the onset of iRBD in a series of 29 males ⩾50 years old.MethodsThe methods of evaluation, diagnosis and follow-up were previously described in the 1996 report. All patients had video-polysomnography (vPSG) confirmed RBD.Results80.8% (21/26) of patients who were initially diagnosed with iRBD eventually developed parkinsonism/dementia (three of the original 29 patients were lost to follow-up). The distribution of diagnoses was as follows: n = 13, Parkinson’s disease (PD); n = 3, dementia with Lewy bodies (DLB); n = 1, dementia (unspecified; profound); n = 2, multiple system atrophy (MSA); n = 2, clinically diagnosed Alzheimer’s Disease (AD) with autopsy-confirmed combined AD plus Lewy body disease pathology. Among the 21 iRBD “converters,” the mean age (±SD) of iRBD onset was 57.7 ± 7.7 years; mean age (±SD) of parkinsonism/dementia onset was 71.9 ± 6.6 years; and mean interval (±SD) from iRBD onset to parkinsonism/dementia onset was 14.2 ± 6.2 years (range: 5–29 years).ConclusionThe vast majority of men ⩾50 years old initially diagnosed with iRBD in this study eventually developed a parkinsonian disorder/dementia, often after a prolonged interval from onset of iRBD, with the mean interval being 14 years while the range extended to 29 years. Also, the specificity of iRBD converting to parkinsonism/dementia is striking. These findings carry important clinical and research implications in the convergent fields of sleep medicine, neurology, and neuroscience, and identify an optimal clinical group for conducting prospective research studies utilizing putative neuroprotective agents to delay the emergence of, or halt the progression to, parkinsonism and/or cognitive impairment as manifestations of either PD, DLB or MSA.     

Sleep bruxism and oromandibular myoclonus in rapid eye movement sleep behavior disorder: a preliminary report

Objective

We aimed to compare rhythmic masticatory muscle activity typical of sleep bruxism and oromandibular myoclonus (OMM) during rapid eye movement (REM) sleep in patients with idiopathic REM sleep behavior disorder (iRBD) and in Parkinson disease (PD) patients with RBD (PD-RBD).

Methods

Sleep polygraphic data were collected from 9 age-matched controls and 28 patients (mean ± standard error of the mean, 66.0 ± 1.7 y) with a clinical and sleep laboratory diagnosis of RBD. Patients were divided into two groups: 13 patients with iRBD and 15 patients with PD-RBD. Rhythmic masticatory muscle activity, a marker of sleep bruxism, and OMM were scored blind to subject’s diagnosis from jaw electromyographic recordings during sleep.

Results

The rhythmic masticatory muscle activity index was significantly higher during REM sleep in iRBD subjects compared to controls (P < .01) and was significantly higher during non-REM (NREM) sleep in both subject groups compared to controls (P ? .03). A positive sleep laboratory diagnosis of sleep bruxism was made in 25% of all patients. In iRBD, patients had more OMM during REM sleep than controls (2.4 times higher; P = .01).

Conclusion

In the presence of a high frequency of rhythmic masticatory muscle activity during REM sleep, RBD may be suspected and further neurologic assessment is recommended.     

The influence of sleep disordered breathing in REM sleep behavior disorder

Objectives/backgroundBecause both REM sleep behavior disorder (RBD) and Obstructive Sleep Apnea (OSA) can present with similar symptoms, it is important to understand the influence of OSA in the clinical manifestations of RBD and whether RBD modulates OSA severity. Our objectives were to compare: 1. the intensity of non-motor symptoms between RBD patients with (RBD-OSA) and without OSA (RBD-non-OSA), and 2. polysomnographic features between RBD-OSA and OSA without RBD (OSA-non-RBD) patients.Methods32 RBD cases were divided in two groups according to the presence of moderate to severe OSA [Apnea Hypopnea Index (AIH) > 14] (RBD-OSA vs. RBD-non-OSA). Non-motor symptoms were assessed with Montreal Cognitive Assessment Scale, SCOPA-Sleep and the Non-Motor Symptom Scale (NMSS) for Parkinson's disease. RBD-OSA patients were compared to 20 OSA-non-RBD patients matched for age, AHI and gender.ResultsCompared to RBD-non-OSA (n = 22) patients, RBD-OSA patients (n = 10) showed significantly higher scores in SCOPA-Sleep Daytime and NMSS Attention/Memory, Gastrointestinal and Urinary domains, as well as higher sleep fragmentation, more oxygen desaturation and higher AIH in NREM sleep. RBD-OSA patients presented with less O₂ desaturation, snoring, and BMI when compared to OSA-non-RBD patients.DiscussionOur data suggests that OSA contributes to hypersomnolence, gastro-intestinal, memory, and urinary complaints in RBD patients. RBD patients seem to have a milder OSA phenotype (possible reflecting a protective role conferred by the maintenance of muscle tone during REM sleep) and to be less prone to obesity and snoring than non-RBD patients.     

Sleep and libido in men with obstructive sleep apnea syndrome

ObjectivesThe objectives of this study were to investigate the relationship between a low libido and objective sleep parameters as well as mood disturbances in patients with obstructive sleep apnea syndrome (OSA).MethodsWe enrolled 436 untreated patients who were newly diagnosed with OSA (all male, mean age 42.8 years). Patients completed the Symptom checklist-90-Revised (SCL-90-R), Epworth Sleepiness Scale (ESS), Beck Depression Inventory-II (BDI), and Beck Anxiety Inventory (BAI). Patients were divided into low-libido and normal-libido groups according to their response to the statement “Loss of sexual interest or pleasure” on the SCL-90-R.ResultsApproximately 23% of patients reported a low libido. Patients with a low libido were older (47.5 ± 9.0 vs. 41.4 ± 11.1 years; p < 0.001), had more nocturia (33.3% vs. 16.6%; p < 0.001), higher BDI (9.0 (5.0–14.0) vs. 5.0 (2.0–9.0); p < 0.001) and BAI score (11.0 (6.3–16.8) vs. 5.0 (2.0–10.0); p < 0.001). These patients had a lower non-REM sleep stage 3 (N3) % (0.1 (0–4.0) vs. 2.3 (0.1–7.9); p < 0.001). Multivariate analysis revealed that older age and higher BDI score were independent factors associated with a low libido.ConclusionsMen with untreated OSA suffered from a low libido. Older age and depressed mood were the most important factors of low libido in middle-aged men with OSA.     

Somatosensory function is impaired in patients with idiopathic REM sleep behaviour disorder

BackgroundIdiopathic REM sleep behaviour disorder (iRBD) has been recognised as a significant biomarker for developing a neurodegenerative alpha-synucleinopathy, which is why iRBD is considered to be a prodromal state for alpha-synucleinopathies including Parkinson's disease (PD). Many patients with PD suffer from complaints of pain and present impaired somatosensory function. We hypothesized that pain perception and somatosensory function could be altered already in a preclinical stage of PD including iRBD. Hence, the objective of this study was to investigate pain perception and somatosensory function in patients with iRBD.MethodsQuantitative sensory testing (QST), laser evoked potentials (LEPs), and conditioned pain modulation (CPM) testing were performed in 13 iRBD patients without any clinical signs of PD or narcolepsy (11 males, 2 females, mean age 65.2 years) and 15 gender- and age-matched healthy control subjects (12 males, 3 females, mean age 65.8 years).ResultsThermal detection thresholds were higher in the iRBD group compared with the control group (cold detection threshold (CDT) p = 0.020, thermal sensory limen (TSL) p = 0.001), indicating an impaired temperature sensation in iRBD patients. The N2/P2 LEPs amplitude was smaller in iRBD patients than controls, but not statistically significant (p = 0.053).ConclusionsThis study found an impaired somatosensory function in iRBD patients, suggesting that somatosensory impairment might be an early feature in the neurodegenerative process of PD.     

Effects of long-term use of clonazepam on nonrapid eye movement sleep patterns in rapid eye movement sleep behavior disorder

ObjectiveWe aim to analyze in detail the characteristics of nonrapid eye movement (NREM) sleep in drug-free patients with idiopathic rapid eye movement sleep behavior disorder (iRBD). We compare drug-free iRBD patients to both normal controls and drug-free patients with narcolepsy/RBD and evaluate the changes following the long-term use of bedtime clonazepam.Participants and methodsForty-six participants were recruited: 15 with iRBD (13 men, 2 women; mean age, 65.8 ± 4.39 years), 13 with narcolepsy/RBD (10 men, 3 women; mean age, 63.0 ± 6.73 years), and 18 normal controls (10 men, 8 women; mean age 69.4 ± 7.72 years). Sleep was video polysomnographically recorded and the RBD severity scale (RBDSS) was obtained. Chin electromyography (EMG) amplitude was quantitatively assessed and the atonia index was computed. Additionally, NREM sleep instability was evaluated using an automatic quantitative analysis. Participants with iRBD were re-evaluated after 2.75 ± 1.62 years of regular therapy with 0.5 to 1-mg clonazepam at bedtime.ResultsSlow transient electroencephalography (EEG) events were increased in iRBD and decreased in narcolepsy/RBD, while fast transient events decreased in iRBD and increased in narcolepsy/RBD. During rapid eye movement (REM) sleep the atonia index was reduced in both iRBD and narcolepsy/RBD groups and during NREM sleep atonia index was increased in iRBD participants, remaining low in narcolepsy/RBD participants. After long-term therapy with clonazepam, wakefulness after sleep onset was decreased together with an increase in both slow-wave sleep (SWS) and sleep stage 2, in which the latter reached statistical significance; sleep stages 1 and 2 instability significantly decreased and the duration of EEG transients also slightly but significantly decreased. Finally, chin tone was not modified by clonazepam.ConclusionsOur study confirms that clonazepam modifies some aspects of NREM sleep in iRBD participants with a decrease in its instability. Moreover, we also show that a complex modification of sleep chin atonia exists in these participants, which also involves NREM sleep; for iRBD more complex neuropathologic models encompassing REM sleep and NREM sleep mechanisms are needed.     

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.     

Effect of low-intensity pure tone auditory stimulation on patients with rapid eye movement sleep behavior disorder

Objective: This study aimed to investigate the influence of low-intensity pure tone auditory stimulation on patients with rapid eye movement (REM), sleep behavior disorder (RBD), and attempt to identify a new method of RBD intervention.

Methods: Patients diagnosed with idiopathic RBD (iRBD) or symptomatic RBD (sRBD) were given auditory stimulation of low-intensity pure tones during their REM sleep. Sleep parameters including sleep process, sleep architecture as well as eye movements (EMs) frequency, and amplitude were recorded by polysomnography monitoring at pre-, intra-, and post-stimulation.

Results: Thirteen iRBD and 18 sRBD patients completed this study. Auditory stimulation significantly reduced the EMs frequency and amplitude in iRBD and sRBD patients (p < 0.05). In the iRBD group, the intra-stimulated FSL increased significantly than the pre-stimulated FSL (p < 0.05). After stimulation, patients had similar sleep latency (FSL), rapid eye movement sleep latency (RSL) and periodic limb movements in sleep (PLMS) compared with control. In the sRBD group, the intra-stimulated total sleep time, sleep efficiency was significantly increased, whereas the RSL and PLMS were significantly reduced compared with the pre-stimulated ones (all p < 0.05). The sRBD patients had similar time in bed, FSL and RBD episodes compared with control (all p < 0.05) in spite of significant difference before stimulation (all p < 0.05). However, the sleep architecture was not influenced by the stimulation despite the decrease in N3% in iRBD group (p < 0.05).

Conclusion: Low-intensity pure tone auditory stimulation may be a potentially effective intervention for RBD, especially for sRBD.     

Comparative study of the substantia nigra echogenicity and 123I-Ioflupane SPECT in patients with synucleinopathies with and without REM sleep behavior disorder

ObjectivesHyperechogenicity of the substantia nigra (SN) and abnormal dopamine transporter-single-photon emission computed tomography (DAT-SPECT) are biomarkers commonly used in the assessment of prodromal synucleinopathy. Our goals were as follows: (1) to compare echogenicity of SN in idiopathic rapid eye movement (REM) behavior disorder (iRBD), Parkinson's disease (PD) without RBD (PD-noRBD), PD with RBD (PD + RBD), and control subjects; and (2) to examine association between SN degeneration assessed by DAT-SPECT and SN echogenicity.Patients/methodsA total of 61 subjects with confirmed iRBD were examined using Movement Disorders Society-unified PD rating scale (MDS-UPDRS), TCS (transcranial sonography) and DAT-SPECT. The results were compared with 44 patients with PD (25% PD + RBD) and with 120 age-matched healthy subjects.Results and conclusionThe abnormal SN area was found in 75.5% PD, 23% iRBD and 7.3% controls. Median SN echogenicity area in PD (0.27 ± 0.22 cm²) was higher compared to iRBD (0.07 ± 0.07 cm²; p < 0.0001) and controls (0.05 ± 0.03 cm²; p < 0.0001). SN echogenicity in PD + RBD was not significantly different from PD-noRBD (0.30 vs. 0.22, p = 0.15).Abnormal DAT-SPECT was found in 16 iRBD (25.4%) and 44 PD subjects (100%). No correlation between the larger SN area and corresponding putaminal binding index was found in iRBD (r = −0.13, p = 0.29), nor in PD (r = −0.19, p = 0.22).The results of our study showed that: (1) SN echogenicity area in iRBD was higher compared to controls, but the hyperechogenicity was present only in a minority of iRBD patients; (2) SN echogenicity and DAT-SPECT binding index did not correlate in either group; and (3) SN echogenicity does not differ between PD with/without RBD.     

Severity of individual obstruction events increases with age in patients with obstructive sleep apnea

BackgroundAge is a risk factor of obstructive sleep apnea (OSA). It has been shown that OSA progresses over time, although conflicting results have been reported. However, the effect of age on the severity of OSA and individual obstruction events has not been investigated within different OSA severity categories by taking the most prominent confounding factors (i.e., body mass index, gender, smoking, daytime sleepiness, snoring, hypertension, heart failure, and proportion of supine sleep) into account.MethodsPolygraphic data of 1090 patients with apnea–hypopnea index (AHI) ≥5 were retrospectively reanalyzed. The effect of age on the severity of OSA and obstruction events was investigated in general, within different OSA severity categories, and in different age groups (age <40, 40≤ age <50, 50≤ age <60, and age ≥60 years).ResultsIn the whole population, AHI and durations of apneas, hypopneas, and desaturations increased with increasing age (B ≥ 0.108, p ≤ 0.010). In more detailed analysis, AHI increased with age only in the moderate OSA category (B = 0.075, p = 0.022), although durations of apneas increased in mild and severe OSA categories (B ≥ 0.076, p ≤ 0.038). Furthermore, durations of hypopneas increased with age in mild and moderate OSA categories (B ≥ 0.105, p ≤ 0.038), and durations of desaturations (B ≥ 0.120, p ≤ 0.013) in all OSA severity categories. AHI was not statistically significantly different between the age groups, although durations of obstruction events tended to increase towards older age groups.ConclusionAs obstruction event severity was more strongly dependent on the age than it was dependent on AHI, considering the severity of obstruction events could be beneficial while estimating the long-term effects of the treatments and prognosticating the disease progression.     

Cardiac sympathetic index identifies patients with Parkinson's disease and REM behavior disorder

ObjectiveTo compare circadian autonomic fluctuations in patients with Parkinson's Disease (PD) with or without REM sleep behavior disorder (RBD) by using heart rate variability (HRV) analysis.MethodsThis is a case-control study including 20 PD patients with RBD (PD-RBD) and 20 PD patients without RBD (PD). In all patients, we measured the components of HRV in the frequency domain during 24-h with daytime and night time recordings. Selected variables considered were low-frequency (LF) influenced by the sympathetic system and high-frequency (HF) influenced by the parasympathetic system. Moreover, we calculated night-to-day ratio for both LF (cardiac sympathetic index) and HF (cardiac parasympathetic index) spectral components. Video-polysomnography was performed in all patients to diagnose RBD.ResultsBoth nocturnal LF and HF spectral power values were significantly higher in PD-RBD patients than in PD patients (P < 0.001 and P = 0.004 respectively). Moreover, in PD-RBD patients LF and HF values were higher at night than during the day while no difference between night time and daytime values was observed in patients with PD. Cardiac sympathetic index value was significantly higher in PD-RBD patients (median 1.83, range 1.65–3.66) than in PD patients (median 0.93, range 0.44–1.3) without overlap of individual values between groups (accuracy 100%). By contrast, cardiac parasympathetic index had sensitivity of 45% and specificity of 100% for differentiating between PD groups.ConclusionsCardiac sympathetic index distinguishes PD-RBD patients from those with PD on an individual basis, thus representing a valid help in everyday clinical practice for screening of RBD in PD patients.     

Total durations of respiratory events are modulated within REM and NREM sleep by sleeping position and obesity in OSA patients

BackgroundSupine sleeping position and obesity are well-known risk factors for obstructive sleep apnea (OSA) and modulate the risk for OSA-related daytime symptoms. Although respiratory event durations are associated with OSA-related severe health consequences, it is unclear how sleeping position, obesity, and daytime sleepiness are associated with respiratory event durations during REM and NREM sleep. We hypothesize that irrespective of the apnea-hypopnea index (AHI), respiratory event durations differ significantly between various OSA subgroups during REM and NREM sleep.MethodsOne night in-lab polysomnographic recordings were retrospectively analyzed from 1910 untreated suspected OSA patients. 599 patients (AHI ≥ 5) were included in study and divided into subgroups based on positional dependency, BMI, and daytime sleepiness (Epworth Sleepiness Scale and Multiple Sleep Latency Test). Differences in total hypopnea time (THT), total apnea time (TAT), and total apnea-hypopnea time (TAHT) within REM and NREM sleep between the subgroups were evaluated.ResultsDuring REM sleep, positional OSA patients had lower THT (OR = 0.952, p < 0.001) and TAHT (OR = 0.943, p < 0.001) than their non-positional counterparts. Compared to normal-weight patients (BMI < 25 kg/m²), obese patients (BMI ≥ 30 kg/m²) had lower THT, TAT, and TAHT (ORs = 0.942–0.971, p ≤ 0.009) during NREM sleep but higher THT (OR = 1.057, p = 0.001) and TAHT (OR = 1.052, p = 0.001) during REM sleep. No significant differences were observed in THT, TAT, and TAHT between patients with and without daytime sleepiness.ConclusionRegardless of the AHI, respiratory event durations vary significantly between OSA sub-groups during REM and NREM sleep. Therefore, to personalize OSA severity estimation the diagnosis should be tailored based on patient's demographics, clinical phenotype, and PSG characteristics.     

Altered sensorimotor cortex noradrenergic function in idiopathic REM sleep behaviour disorder – A PET study

IntroductionNoradrenergic denervation is thought to aggravate motor dysfunction in Parkinson's disease (PD). In a previous PET study with the norepinephrine transporter (NART) ligand ¹¹C-MeNER, we detected reduced NART binding in primary sensorimotor cortex (M1S1) of PD patients. Idiopathic rapid-eye-movement sleep behaviour disorder (iRBD) is a phenotype of prodromal PD. Using ¹¹C-MeNER PET, we investigated whether iRBD patients showed similar NART binding reductions in M1S1 cortex as PD patients. Additionally, we investigated whether ¹¹C-MeNER binding and loss of nigrostriatal dopamine storage capacity measured with ¹⁸F-DOPA PET were correlated.Methods17 iRBD patients, 16 PD patients with (PD^RBD+) and 14 without RBD (PD^RBD−), and 25 control subjects underwent ¹¹C-MeNER PET. iRBD patients also had ¹⁸F-DOPA PET. Volume-of-interest analyses and voxel-level statistical parametric mapping were performed.ResultsPartial-volume corrected ¹¹C-MeNER binding potential (BP^ND) values in M1S1 differed across the groups (P = 0.022) with the iRBD and PD^RBD+ groups showing significant reductions (controls vs. iRBD P = 0.007; control vs. PD^RBD+ P = 0.008). Voxel-wise comparisons confirmed reductions of M1S1 ¹¹C-MeNER binding in PD and iRBD patients. Significant correlation was seen between putaminal ¹⁸F-DOPA uptake and thalamic ¹¹C-MeNER binding in iRBD patients (r² = 0.343, P = 0.013).ConclusionsThis study found altered noradrenergic neurotransmission in the M1S1 cortex of iRBD patients. The observed reduction of M1S1 ¹¹C-MeNER binding in iRBD may represent noradrenergic terminal degeneration or physiological down-regulation of NARTs in this prodromal phenotype of PD. The correlation between thalamic ¹¹C-MeNER binding and putaminal ¹⁸F-DOPA binding suggests that these neurotransmitter systems degenerate in parallel in the iRBD phenotype of prodromal PD.     

Mild cognitive impairment and abnormal brain metabolic expression in idiopathic REM sleep behavior disorder

BackgroundMild cognitive impairment (MCI) is a common feature of isolated rapid-eye-movement sleep behavior disorder (iRBD). Here, we assessed cognitive functions and MCI in a prospective iRBD cohort and investigated their association with disease-specific brain metabolic patterns.MethodsForty-four patients with polysomnography-confirmed iRBD performed a standardized battery of neuropsychological examinations every two years. We used previously established spatial covariance patterns from de novo drug-naïve Parkinson's disease with concomitant RBD (_denovoPDRBD-RP) and iRBD (iRBD-RP) using ¹⁸F-fluorodeoxyglucose PET scan. We compared those expressions between iRBD with normal cognition (iRBD-NC) and with mild cognitive impairment (iRBD-MCI), and evaluated whether they predict progressive cognitive deterioration.ResultsTwenty iRBD patients (45 %) had MCI at baseline and 12 patients (27 %, about 7 % per year) had clinically significant cognitive deterioration after 4 years. The iRBD-MCI and iRBD-NC groups showed similar rates of cognitive change, but iRBD-MCI consistently performed worse in the domains of verbal memory and executive function. Elevated _denovoPDRBD-RP expression predicted cognitive deterioration (hazard ratio = 5.98 [1.70–21.06]), whereas iRBD-RP did not.ConclusionsIncreased disease-specific brain metabolic patterns are associated with iRBD-MCI and impending cognitive deterioration with the risk of progression to Lewy body dementia.     

Rapid eye movement sleep disturbance in patients with refractory epilepsy: A polysomnographic study

Objective/BackgroundPatients with epilepsy have disrupted sleep architecture and a higher prevalence of sleep disturbance. Moreover, obstructive sleep apnea (OSA) is more common among patients with refractory epilepsy. Few studies have compared subjective sleep quality, sleep architecture, and prevalence of OSA between patients with refractory epilepsy and those with medically controlled epilepsy. Therefore, this study aimed to evaluate the differences in sleep quality, sleep architecture, and prevalence of OSA between patients with refractory epilepsy and patients with medically controlled epilepsy.PatientsThis retrospective case–control study included 38 patients with refractory epilepsy and 96 patients with medically controlled epilepsy. Sleep parameters and indices of sleep-related breathing disorders were recorded by standard in-laboratory polysomnography. The scores from sleep questionnaires on sleep quality and daytime sleepiness were compared between the two groups.ResultsPatients with refractory epilepsy versus medically controlled epilepsy had statistically significantly decreased rapid eye movement (REM) sleep (13.5 ± 6.1% vs. 16.2 ± 6.1%) and longer REM latency (152.2 ± 84.1 min vs. 117.2 ± 61.9 min). Further, no differences were found in the prevalence of sleep-related breathing disorders, subjective sleep quality, prevalence of daytime sleepiness, and quality of life. Although not statistically significant, patients with refractory epilepsy have a lower rate of OSA compared with those with medically controlled epilepsy (21.1% vs. 30.2%).ConclusionsPatients with refractory epilepsy had more disrupted REM sleep regulation than those with medically controlled epilepsy. Although patients with epilepsy have a higher risk of OSA, in this study patients with refractory epilepsy were not susceptible to OSA.     

Treating obstructive sleep apnea with continuous positive airway pressure reduces risk of recurrent atrial fibrillation after catheter ablation: a meta-analysis

IntroductionRecent studies have suggested that there is a strong relationship between obstructive sleep apnea (OSA) and atrial fibrillation (AF). However, they have not identified whether treating OSA with continuous positive airway pressure (CPAP) might reduce rates of recurrent AF.ObjectiveTo investigate the recurrent risk of AF after catheter ablation among patients with OSA who did receive or did nor receive CPAP therapy.MethodsA systematic review of PubMed, Embase, Medline, Cochrane library, China National Knowledge Infrastructure (CNKI) and Wan-fang databases was conducted to obtain relevant cohort studies and randomized controlled trials (RCTs). Study characteristics of AF patients were extracted, and their recurrent outcomes were recorded. A meta-analysis was then conducted using Review Manager software, version 5.3. In total, seven eligible cohort studies and three randomized controlled trials involving 1217 participants with AF after catheter ablation were included. These participants were divided into a CPAP group (n = 619, 50.86%) and non-CPAP group (n = 598, 49.14%).ResultsAfter a mean follow-up of 16.33 ± 10.34 months, 408 patients (33.52%) experienced recurrent AF, and the recurrence rate differed between the CPAP and non-CPAP groups (24.88% vs 42.47%; RR 0.60; 95% CI 0.51–0.70; p = 0.000). Overall, patients treated with CPAP had a lower risk of recurrent AF after catheter ablation than those who did not, and about 17.59% of cases with recurrent AF could be attributed to not receiving CPAP. Meanwhile, the results indicated that CPAP therapy decreased the left atrial diameter (LAD) (WMD –6.28; 95% CI –7.00 to −5.56; p = 0.000) and increased left ventricular ejection fraction (LVEF) (WMD 7.37; 95% CI 6.98–7.76; p = 0.000).ConclusionOSA had an increased risk of recurrent AF after successful catheter ablation, and CPAP treatment for AF patients with OSA might have significantly mitigated the recurrent risks.     

Seasonal effects on the continuous positive airway pressure adherence of patients with obstructive sleep apnea

ObjectiveThis study examined seasonal differences in continuous positive airway pressure (CPAP) therapy adherence among patients with obstructive sleep apnea (OSA).MethodsPatients aged ≥20 years with OSA who had used CPAP devices on the automatic setting for >12 consecutive months (n = 141) were included in this retrospective study from December 2015–2016. The information of CPAP use (pressure, hours of actual use) was extracted from database downloaded from patients’ CPAP devices. Patients were divided into adherent and non-adherent groups using the cutoff point of 70% CPAP use for ≥4 h daily over the 1-year study period. CPAP use data were averaged for each season.ResultsPatients in the adherent group were significantly older than those in the non-adherent group (p < 0.001). In the adherent group, the rate of ≥4 h daily CPAP use was significantly lower, the daily duration of CPAP use was significantly shorter, and the residual apnea–hypopnea index (AHI; events/hour) was significantly higher in summer than in other seasons (all p < 0.001). In the non-adherent group, the duration of daily CPAP use and the AHI differed significantly between winter and summer (p = 0.008 and p < 0.001, respectively).ConclusionsSeasonal changes were associated with the CPAP adherence of patients with OSA. The study findings suggest that there is possibility of increasing the duration of CPAP use by adjusting the bedroom environment in hot and humid seasons.