REM Sleep Behavior Disorder Patients Research Articles

0679 Impaired Visual Processing In Rbd Patients: A Visual Search Task Study

Rapid Eye Movement (REM) sleep Behavior Disorder (RBD) is a REM sleep parasomnia known to be strongly associated with the development of neurodegenerative disorders. Cognitive deterioration has been shown to be a common issue in RBD patients, in particular impairments in visuo-spatial abilities. However, little is known about the effect of RBD on visual processing. The aim of this study was to evaluate the basic mechanisms of stimulus analysis in RBD patients by a visual search paradigm. 12 RBD patients (mean age: 68.25 ± 9.63, 9 males) and 12 age-matched healthy controls (HC) were enrolled in the study. After a nocturnal video-polysomnographic recording, patients performed a visual search task in which they had to detect the presence/absence of a target (letter T) embedded in the 50% of trials into a set of distractors (letters Os, Xs, or Ls). Target’s salience and distractors’ numerosity were manipulated as independent variables, whereas accuracy and reaction times (RT) were recorded as dependent variables. Typical effects of visual search were confirmed: RT increased with distractors’ number and decreased with targets’ salience. RBD patients showed significantly slower RT in comparison with HC. Furthermore, analyzing RT of stimuli containing the target in comparison to RT of stimuli in which the target was absent, patients differed from controls only in the condition of target absent. This result indicates a perceptual impairment specifically related to the exhaustive visual analysis, according to the Sternberg’s model. These results experimentally demonstrates a perceptual impairment revealed by the more demanding conditions of the visual search task. This impairment seems to be in line with previous neuropsychological researches that showed the presence of a visuo-spatial deficit in RBD patients. none.

0682 A Novel, Highly Efficient REM Sleep without Atonia Visual Analysis Method for REM Sleep Behavior Disorder Diagnosis

Polysomnographic REM sleep without atonia (RSWA) is requisite for REM sleep behavior disorder (RBD) diagnosis, yet traditional scoring criteria for phasic muscle bursts (requiring minimum duration of 100ms) are tedious and labor intensive, and overlap with state-independent excessive fragmentary myoclonus. Furthermore, traditional quantitative RSWA metrics have created confusion and further limited adaption of RSWA quantification by sleep clinicians. We aimed to simplify phasic RSWA scoring criteria and derived RSWA metrics to expedite RSWA analysis while maintaining high diagnostic precision. Fifteen iRBD patients and 30 OSA controls who have been previously reported underwent manual RSWA analysis utilizing a 1 second minimum phasic muscle duration cutoff (maximum 14.9 seconds). RSWA was analyzed in the submentalis (SM) and anterior tibialis (AT) muscles. The total duration of REM sleep with phasic muscle activity was divided by total non-artifact REM time, yielding a “density of muscle activity” during REM sleep. Parametric mean comparison and receiver operating characteristic (ROC) curves were used to determine the best diagnostic cutoff thresholds for RBD and compared with previously published cutoffs from this cohort. Mean RSWA densities were significantly higher in RBD patients vs. OSA controls, for both SM (11% vs. 0.4%, p<0.01) and AT (10% vs. 1.3%, p<0.01), with best diagnostic cut-offs for SM of 4.0% (AUC = 0.92) and AT of 4.3% (AUC = 0.94), which were highly similar to previously determined diagnostic discrimination using shorter phasic burst duration scoring criteria. Increasing minimum phasic duration criteria to 1 second, with calculation of a unitary RSWA metric greatly simplifies and expedites manual RSWA analysis without sacrificing diagnostic sensitivity and specificity, yielding an approach to RSWA analysis that is both more intuitive and easily employed in busy clinical sleep laboratory settings. Support (If Any):

Effect of Rapid Eye Movement Sleep Behavior Disorder on Obstructive Sleep Apnea Severity and Cognition of Parkinson's Disease Patients

Background:Rapid eye movement (REM) sleep behavior disorder (RBD) and obstructive sleep apnea (OSA) are the most common sleep disorders in Parkinson's disease (PD). The aim of this study was to identify whether RBD could alleviate OSA severity in PD patients and its effect on cognitive impairment.Methods:From February 2014 to May 2017, we recruited 174 PD patients from the Second Affiliated Hospital of Soochow University, all of whom underwent polysomnography (PSG). We collected clinical data, PSG results, and compared information between patients with and without RBD or OSA by analysis of covariance. We also investigated the effect of these sleep disorders on cognitive impairment using linear regression.Results:We grouped participants as follows: PD only (n = 53), PD + OSA (n = 29), PD + RBD (n = 61), and PD + RBD + OSA (n = 31). Minimum oxygen saturation (SaO2) during whole sleep and in REM sleep was higher in PD + RBD + OSA patients than that in PD + OSA patients. PD + RBD patients had worse Mini-Mental Status Examination and Montreal Cognitive Assessment (MoCA) scores than those in the PD group (P < 0.001), especially in visuospatial/executive, attention, and memory functions. The PD + OSA group performed worse than the PD group in the delayed recall domain. After adjusting for age, sex, body mass index, education, disease severity, and other sleep disorders, MoCA was negatively associated with OSA (β = −0.736, P = 0.043) and RBD (β = −2.575,P < 0.001). The severity of RBD (tonic/phasic electromyography activity) and OSA (apnea-hypopnea index/oxygen desaturation index/minimum SaO2) were also associated with MoCA. The adjusted β values of RBD-related parameters were higher than that for OSA.Conclusions:We found that RBD alleviated OSA severity; however, RBD and OSA together exacerbated PD cognitive impairment. Further studies are needed to evaluate whether OSA treatment can improve cognition in PD.

REM Sleep Behavior Disorder and Alzheimer’s Disease: Definitely No Relationship?

Rapid eye movement (REM) sleep behavior disorder (RBD) is a REM sleep parasomnia characterized by the loss of the typical muscular atonia present during healthy REM sleep. RBD can occur in the absence of other neurological conditions or in association with a neurodegenerative disorder. It is now well established that RBD is a strong predictor of neurodegeneration, in particular synucleinopathies, such as Parkinson's disease, Lewy body dementia (LBD), or multiple system atrophy. However, some longitudinal studies report that a minority of patients develop either overlapping form of dementia or Alzheimer disease's (AD). Although AD is reported as a possible development in patients with RBD, it is in a limited number of cases and there are concerns about the accuracy of the diagnostic criteria. Neuropsychological impairments identified in cross-sectional studies of RBD patients describe a profile similar to that observed in dementia related to synucleinopathies. However, only deficits in executive function predict the development of neurodegeneration. Longitudinal studies reported the development of AD in RBD patients in about 7% of cases with variability ranging from 3% and 11%. Since the majority of longitudinal investigations do not report AD as a possible development for RBD patients the proportion may be overestimated. The study of the relationship between RBD and AD may be confounded by two factors that lead to misdiagnosis: the use of clinical criteria alone and the overlap between the clinical features and neuropathology of AD and LBD. Future studies to investigate this association must use updated diagnostic criteria incorporating ancillary investigations.

Ventromedial medulla inhibitory neuron inactivation induces REM sleep without atonia and REM sleep behavior disorder

Despite decades of research, there is a persistent debate regarding the localization of GABA/glycine neurons responsible for hyperpolarizing somatic motoneurons during paradoxical (or REM) sleep (PS), resulting in the loss of muscle tone during this sleep state. Combining complementary neuroanatomical approaches in rats, we first show that these inhibitory neurons are localized within the ventromedial medulla (vmM) rather than within the spinal cord. We then demonstrate their functional role in PS expression through local injections of adeno-associated virus carrying specific short-hairpin RNA in order to chronically impair inhibitory neurotransmission from vmM. After such selective genetic inactivation, rats display PS without atonia associated with abnormal and violent motor activity, concomitant with a small reduction of daily PS quantity. These symptoms closely mimic human REM sleep behavior disorder (RBD), a prodromal parasomnia of synucleinopathies. Our findings demonstrate the crucial role of GABA/glycine inhibitory vmM neurons in muscle atonia during PS and highlight a candidate brain region that can be susceptible to α-synuclein-dependent degeneration in RBD patients.

Electromyography Analysis of Rapid Eye Movement Sleep Behavior Disorder

Polysomnography (PSG), which records physiological phenomena including brain waves, breathing status, and muscle tonus, is useful for the diagnosis of sleep disorders as a gold standard. However, measurement and analysis are complex for several specific sleep disorders, such as rapid eye movement (REM) sleep behavior disorder (RBD). Usually, brain waves during REM sleep indicate an awakening pattern under relaxed conditions of skeletal and antigravity muscles. However, these muscles are activated during REM sleep when patients suffer from RBD. These activated muscle movements during REM, so-called REM without atonia (RWA) recorded by PSG, may be related to a neurodegenerative disease such as Parkinson's disease. Thus, careful analysis of RWA is significant not only physically, but also clinically. Commonly, manual viewing measurement analysis of RWA is time-consuming. Therefore, quantitative studies on RWA are rarely reported. A software program, developed from Microsoft Office Excel®, was used to semiautomatically analyze the RWA ratio extracted from PSG to compare with manual viewing measurement analysis. In addition, a quantitative muscle tonus study was carried out to evaluate the effect of medication on RBD patients. Using this new software program, we were able to analyze RWA on the same cases in approximately 15 min as compared with 60 min in the manual viewing measurement analysis. This software program can not only quantify RWA easily but also identify RWA waves for either phasic or tonic bursts. We consider that this software program will support physicians and scientists in their future research on RBD. We are planning to offer this software program for free to physicians and scientists.

A study in 184 consecutive idiopathic REM sleep behavior disorder patients in a single Japanese center

A study in 184 consecutive idiopathic REM sleep behavior disorder patients in a single Japanese center

Phenoconversion of Czech idiopathic REM sleep behavior disorder patients

Phenoconversion of Czech idiopathic REM sleep behavior disorder patients

Dreaming frequency in REM sleep behavior disorder patients: analysis of questionnaire and polysomnographic data

Dreaming frequency in REM sleep behavior disorder patients: analysis of questionnaire and polysomnographic data

Envelope analysis of electromyogram in REM sleep behavior disorder patients

Envelope analysis of electromyogram in REM sleep behavior disorder patients

Hyposmia Is Associated with RBD for PD Patients with Variants of SNCA.

Objective: Hyposmia may occur simultaneously with REM sleep behavior disorder (RBD) as a specific phenotype in Parkinson's Diseases (PD), of which the disease progression is fast. In the study, we tried to identify whether the genotypic characteristics could participate in the co-occurrence of hyposmia and RBD in PD patients.Methods: 152 PD patients were recruited from the Department of Neurology, Ruijin Hospital affiliated to Shanghai JiaoTong University School of Medicine from 2011 to 2016, with comprehensive clinical assessment performing. Two SNPs of SNCA (rs11931074 and rs894278) in 105 patients were also analyzed.Results: Overall, 84 of 152 PD patients (55.3%) were diagnosed with RBD after PSG evaluation. After regression analysis, higher levels of three parts of UPDRS and SCOPA-AUT scores were all associated with increased risk of RBD in PD patients, respectively. While for olfactory function, we didn't find significant correlation between hyposmia and RBD in PD patients. However, we found that in the group of minor G allele of rs894278, patients with lower score of SS-16 had a 4.76-fold risk of suffering from RBD in patients (95% CI: 1.39–16.67; p = 0.013). Furthermore, we analyzed SNP associated gene expression by eQTL analysis in Genevar database and found that GG genotype of rs894278 was associated with higher levels of α-synuclein in Nerve tissue (p = 1.5E-8) while TT genotype of rs11931074 was associated with higher levels of α-synuclein in Brain (p = 0.0082), which suggesting a potential functional relevance with different symptoms of PD.Conclusions: Hyposmia was associated with RBD in PD patients with the minor G allele of rs894278, which represent one specific subtype of PD. This study could provide more detail information about PD subtype of RBD with hyposmia in the future.

REM sleep behavior disorder, autonomic dysfunction and synuclein-related neurodegeneration: where do we stand?

From newfound parasomnia to a marker of future synucleinopathy, since its first description in 1986, REM sleep behavior disorder (RBD) has been systematically tackled from virtually many viewpoints in basic, translational, and clinical studies. The time delay between RBD and synucleinopathy onset offers an exceptional window for observation and design of neuroprotective trials. In the last few years, research has focused on characterizing possible differences within RBD patients in order to draw potential profiles more or less susceptible to further neurodegeneration. Attention has been drawn towards autonomic dysfunction in RBD as one of such variables. In this review, REM sleep physiology and relevant brain anatomy is briefly mentioned and integrated with neuroanatomical and physiological concepts regarding the central autonomic network. A detailed summary of works showing the presence of autonomic dysfunction in RBD is provided, and clinical and electrophysiological features of RBD in synucleinopathies are discussed. A short overview of RBD in other neurodegenerative diseases is also provided.

P365 Automated chin EMG analysis for quantification of REM sleep without atonia

Objectives REM sleep without atonia (RSWA) is a key feature of REM sleep behavior disorder (RBD). However, detailed visual scoring of EMG on 30 and 3 s intervals is highly time demanding. A computer program with automated scoring algorithm would thus be a valuable asset for sleep professionals scoring RBD. Methods Criteria’s for tonic (2xRMS baseline for >15 s per 30 s epoch), phasic (max amplitude >4 × RMS baseline (or 2 × Tonic), 3 s epochs) and any (tonic and/or phasic) chin EMG activity were implemented in a software algorithm. Sleep stages, respiratory-, arousal- and artifact events were visually scored and imported into the software. Visual scoring of EMG activity done by a blinded board-certified sleep professional was compared to the software algorithm by regression analysis and Kappa statistics. A total of 31989 3 s epochs in 19 patients with Parkinson’s disease (PD) were evaluated (mean age 65.2 ± 9.7, 10 RBD+, 9 RBD−). Results Total percentages of tonic, phasic and any muscle activity correlated strongly between the software algorithm and visual scoring ( R 2 > 0.97 for all activities). Cohen’s Kappa indicated very high agreement on individual events (0.73 for tonic, 0.80 for phasic, 0.83 for any activity). A cut-off value of 10% of any activity separated both groups correctly. Bouts of phasic activity were longer in patients with RBD compared non-RBD (375.4 ± 61.1 versus 478.3 ± 88.9, p = 0.014). Conclusion/significance Our software reliably detects altered chin muscle activity in PD patients when excluding artifact corrupted epochs, providing a fast tool for detecting RBD patients and metrics for correlation analysis with clinical variables.

Changes in the symptom frequency of rapid eye movement sleep behavior disorder according to disease duration

BackgroundThis descriptive study was conducted to examine the changes in the symptom frequency in patients with rapid eye movement (REM) sleep behavior disorder (RBD) without medical intervention, in order to determine the association of RBD symptom frequency with disease duration.MethodsData were collected from 70 consecutive RBD patients who visited the Sleep Clinic in Shiga University of Medical Science. RBD symptom frequencies at the first visit to the clinic were quantified based on the reports by the patients and their family members. For quality assurance, patients living alone or those with cognitive decline were excluded. Finally, 50 patients with family-confirmed symptom history were enrolled. The symptom frequencies were converted to a unit that reflects the estimated number of nights in a year affected by RBD (NAR). Using NAR, we observed the relation between RBD symptom frequency and the disease duration.ResultsOf the 50 patients, 41 were male and 9 were female, consistent with the male-dominant nature of this disease. The mean age at RBD onset was 62.2 ± 9.1 years, and the mean disease duration at the time of visit was 6.0 ± 4.9 years. The median symptom frequency was 50 NAR, with a 1st quantile value of 24 NAR and a 3rd quantile value of 115 NAR. When RBD symptom frequency was plotted against disease duration, we found that the frequency was lowest in the first 2 years of RBD (median, 18; range, 2–29 NAR), and higher frequencies were found in 2-year bin groups from 2 to 8 years after RBD onset (median, 60; range, 50–150 NAR). Intriguingly, after 8 years of RBD, the frequency returned to a level comparable to that in the first 2 years of RBD (median, 50; range, 12–100 NAR).ConclusionsThere was no association between RBD symptom frequency and disease duration. RBD clinical symptoms could be less prominent when neural damage becomes severe. Therefore, a natural decrease in RBD symptom frequency may be indicative of progression of neurodegeneration.

REM Sleep Behavior Disorder and Other Sleep Disturbances in Non-Alzheimer Dementias

The study aimed to review recent updates of our understanding of REM sleep behavior disorder (RBD) and other sleep disorders in non-Alzheimer’s disease (AD) dementias. Numerous recent discoveries have provided insight into the role of RBD and sleep in patients with non-AD dementias. Imaging modalities such as DaTscan and cerebral blood flow may be useful for monitoring phenoconversion in idiopathic RBD patients to Parkinson’s disease (PD) or dementia with Lewy bodies (DLB). Patients with isolated REM sleep without atonia have non-motor signs of neurodegenerative disease. Colon mucosal biopsies in iRBD patients have shown presence of α-synuclein aggregates. Recent genetic models of RBD and neuroimaging have furthered evidence for the locus subcoeruleus/sublateral dorsal nucleus as the center for the generation and maintenance of REM muscle atonia. Circadian rhythm disturbances likely play a large role in nighttime insomnia, daytime sleepiness, autonomic symptoms, motor variations, and hallucinations in PD and DLB. Early onset stridor in patients with multiple system atrophy (MSA) portends a worse prognosis than late onset stridor, and treatment of stridor is associated with survival. Our ability to predict phenoconversion in idiopathic RBD is improving and will be highly important as “high risk” phenoconverters are identified for enrollment in neuroprotective clinical trials. Treatments of RBD improve but do not fully eliminate DEB; therefore, the risk for sleep-related injury remains a concern even among seemingly well-treated patients. Excessive daytime sleepiness (EDS) secondary to neuropathology, sedating medications, sleep disordered breathing (SDB), restless legs syndrome (RLS), and circadian rhythm alterations are common in the non-AD dementias, leading to significant caregiver burden and worsening of cognition. Addressing primary sleep disorders is the mainstay of treatment for EDS. RLS is a frequent co-morbidity in non-AD dementias. Initial management of RLS includes ensuring serum a ferritin level of >75 μg/L and therapy with gabapentin encarbil (which is less likely to cause augmentation than dopamine agonists). All MSA patients should be evaluated for the presence of nocturnal stridor, which should be treated if present. Therapies targeting the circadian system are often an underutilized therapeutic avenue in the management of sleep, motor, autonomic, and psychiatric symptoms in PD and DLB patients.

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.

REM Sleep EEG Instability in REM Sleep Behavior Disorder and Clonazepam Effects.

We aimed to analyze quantitatively rapid eye movement (REM) sleep electroencephalogram (EEG) in controls, drug-naïve idiopathic REM sleep behavior disorder patients (iRBD), and iRBD patients treated with clonazepam. Twenty-nine drug-naïve iRBD patients (mean age 68.2 years), 14 iRBD patients under chronic clonazepam therapy (mean age 66.3 years), and 21 controls (mean age 66.8 years) were recruited. Power spectra were obtained from sleep EEG (central derivation), using a 2-second sliding window, with 1-second steps. The power values of each REM sleep EEG spectral band (one every second) were normalized with respect to the average power value obtained during sleep stage 2 in the same individual. In drug-naïve patients, the normalized power values showed a less pronounced REM-related decrease of power in all bands with frequency <15 Hz than controls and an increase in the beta band, negatively correlated with muscle atonia; in patients treated with clonazepam there was a partial return of all bands <15 Hz toward the control values. The standard deviation values of the normalized power were higher for untreated patients in all EEG bands and were almost completely normalized in patients treated with clonazepam. The REM sleep EEG structure changes found in this study disclose subtle but significant alterations in the cortical electrophysiology of RBD that might represent the early expression of the supposed neurodegenerative processes already taking place at this stage of the disease and might be the target of better and effective future therapeutic strategies for this condition.

0718 7 TESLA IMAGING OF MICROSTRUCTURAL BRAINSTEM CHANGES IN REM SLEEP BEHAVIOR DISORDER

REM-sleep-behavior-disorder (RBD) is characterized by the absence of muscle-atonia during REM-sleep, and represents a prodromal clinical manifestation of evolving Parkinsons’s disease (PD) and other synucleinopathies. Interestingly, RBD is hypothesized to be related to a dysfunction of brainstem-nuclei (Bn) of the arousal/motor networks based on: (i) lesion/connectivity studies in animals, and a few human studies in-vivo; (ii) ex-vivo human staging models of PD progression. Yet, a precise identification of the Bn involved in living humans is still missing, thus limiting our understanding of idiopatic-RBD/prodromal PD. We investigated the presence of microstructural brainstem changes in idiopatic-RBD in humans by high-resolution multi-contrast 7 Tesla MRI and our recently developed stereotaxic probabilistic structural atlas of 11 Bn of the arousal/motor networks, which included two subregions of the substantia nigra (SN) and three raphe nuclei. At 7 Tesla, on 6 patients with idiopathic-RBD (5m/1f, age 70 ± 1) under IRB-approval, we aquired .75mm-isotropic M2PRAGE and multi-echo GRE images. We computed a T1-map from the MP2RAGE. Multi-echo GRE images were coregistered to the T1-map. Regions of interest (ROI) displaying T1 hyperintensity (T1>2500ms) within a brainstem mask were automatically detected. To determine the location of these ROIs with respect to the 11 Bn, we precisely coregistered T1-maps to the Bn atlas space. In 5 out of 6 RBD patients we detected ROIs with T1 hyperintensity (i.e. microstructural changes) in the ventro-caudal part of the right SN-subregion 1 (compatible with SN pars-reticulata) and in a paranigral region (rostro-medial to the caudal part of SN-subregion1). These ROIs colocalized to T2*-weighted hyperintensity and had a volume of .4-1.2mm3. The other 10 Bn displayed normal appearing gray matter. These results provide compelling empirical evidence for the hypothesized role of specific Bn nuclei in the pathogenesis of RBD. Interestingly, the observed contrast (hyperintensities in T1 and T2*-weighted MRI) in the detected ROIs is compatible with the presence of small lacunar infarcts (i.e. parenchymal spaces filled with CSF/interstitial-fluid) in the nigral and peri-nigral region of RBD patients. This original result differs from recent findings of iron accumulation in the SN pars-compacta of idiopatic-RBD patients. NIH-NIBIB: K01-EB019474, P41-RR014075.

Muscle Activity During Sleep in Human Subjects, Rats, and Mice: Towards Translational Models of REM Sleep Without Atonia.

Rapid-eye-movement (REM) sleep without atonia (RSWA) is a marker of REM sleep behavior disorder (RBD) and is common in narcolepsy. Available techniques for electromyogram (EMG) analysis are species-specific, limiting translational research on RSWA. We developed an automated technique based on distributions of normalized EMG values (DNE) to overcome this limitation. With DNE, we tested whether the control of neck and tibialis anterior (TA) muscles during sleep in wild-type rats and mice validly models the control of submentalis (chin) and TA muscles in healthy humans. We then applied DNE to REM sleep recordings of patients with idiopathic RBD and of mouse models of narcolepsy, testing for a common DNE signature of RSWA. Retrospective analysis of sleep recordings from 20 idiopathic RBD patients, 34 control subjects, 8 wild-type rats, 21 orexin-neuron deficient mice, 8 orexin knock-out mice, and 22 wild-type mice. Neck EMG of rats and mice and human chin EMG progressively decreased from wakefulness to non-REM sleep and REM sleep, whereas the effects of sleep on TA EMG differed between rats, mice, and humans. DNE discriminated idiopathic RBD patients from controls based on higher median values of normalized chin EMG during REM sleep. The same parameter, computed on neck muscle EMG, discriminated narcoleptic mice from wild-type mice. These results support the application of DNE in translational research on RSWA. Increased median values of normalized EMG of chin (humans) and neck (rats and mice) muscles may be a signature of RSWA in different species and pathological conditions.

Diagnostic Value of Isolated Mentalis Versus Mentalis Plus Upper Limb Electromyography in Idiopathic REM Sleep Behavior Disorder Patients Eventually Developing a Neurodegenerative Syndrome.

To compare two electromyographic (EMG) montages, isolated mentalis muscle versus mentalis in combination with upper limb muscles in the baseline diagnostic video-polysomnography (V-PSG) of patients with idiopathic REM sleep behaviors disorder (IRBD) who eventually were diagnosed with a clinically defined neurodegenerative syndrome. Forty-nine patients were included. At baseline, diagnosis of RBD was based on a typical history of dream enactment behaviors plus V-PSG showing REM sleep with qualitative increased EMG activity and/or abnormal behaviors. Quantification of EMG activity (tonic, phasic and "any") in the mentalis and upper limb muscles (biceps brachii-BB, n = 36 or flexor digitorum superficialis-FDS, n = 13) was performed manually and compared with published cut-offs. Nine (18.4%) patients had either tonic or phasic EMG below the cut-offs for the isolated mentalis and four of them (11.1 %) also had values below the cut-off for the mentalis combined with BB. All 13 patients recorded with the FDS were above the mentalis combined with FDS cut-off. For the diagnosis of IRBD, sensitivity of isolated mentalis was 81.6% and of the combination of mentalis plus upper limb muscles was 91.8% (p = .03). Audiovisual analysis showed abnormal REM sleep behaviors in all nine patients with values below the cut-offs. Quantification of EMG activity in the upper limbs combined with the mentalis increases the ability to diagnose IRBD when compared with the isolated measurement of the mentalis. Detection of typical abnormal behaviors during REM sleep with audiovisual analysis is essential for the diagnosis of IRBD in patients with EMG values below the published cut-offs.