A Neurologist's Guide to REM Sleep Behavior Disorder

Isolated rapid eye movement sleep behaviour disorder (iRBD) in the Island Study Linking Ageing and Neurodegenerative Disease (ISLAND) Sleep Study: protocol and baseline characteristics

Isolated rapid eye movement (REM) sleep behaviour disorder (iRBD) is a sleep disorder that is characterised by dream enactment episodes during REM sleep. It is the strongest known predictor of α-synuclein-related neurodegenerative disease (αNDD), such that >80% of people with iRBD will eventually develop Parkinson's disease, dementia with Lewy bodies, or multiple system atrophy in later life. More research is needed to understand the trajectory of phenoconversion to each αNDD. Only five 'gold standard' prevalence studies of iRBD in older adults have been undertaken previously, with estimates ranging from 0.74% to 2.01%. The diagnostic recommendations for video-polysomnography (vPSG) to confirm iRBD makes prevalence studies challenging, as vPSG is often unavailable to large cohorts. In Australia, there have been no iRBD prevalence studies, and little is known about the cognitive and motor profiles of Australian people with iRBD. The Island Study Linking Ageing and Neurodegenerative Disease (ISLAND) Sleep Study will investigate the prevalence of iRBD in Tasmania, an island state of Australia, using validated questionnaires and home-based vPSG. It will also explore several cognitive, motor, olfactory, autonomic, visual, tactile, and sleep profiles in people with iRBD to better understand which characteristics influence the progression of iRBD to αNDD. This paper details the ISLAND Sleep Study protocol and presents preliminary baseline results.

Rapid Eye Movement Sleep Behavior Disorder: Clinical Presentation and Diagnostic Criteria

Rapid eye movement (REM) sleep behavior disorder (RBD) classically presents with repetitive complex motor behavior during sleep with associated dream mentation. The diagnosis requires a history of repetitive complex motor behaviors and polysomnographic demonstration of REM sleep without atonia (RSWA) or capturing dream enactment behaviors. RSWA is best evaluated in the chin or flexor digitorum superficialis muscles. The anterior tibialis muscle is insufficiently accurate to be relied upon solely for RBD diagnosis. RBD may present with parkinsonism or cognitive impairment or may present in isolation. Patients should be monitored for parkinsonism, autonomic failure, or cognitive impairment.

Sex differences in rapid eye movement sleep behavior disorder: A systematic review and meta-analysis

Although rapid eye movement (REM) sleep behavior disorder (RBD) has been widely considered as a male-predominant parasomnia, the existing evidence for the sex difference in the risk of RBD in the general population was conflicting. The present study conducted a systematic review to explore the sex differences in the prevalence, comorbidities, clinical characteristics, and phenoconversion of RBD. One hundred thirty-five eligible studies were identified for the systematic review, and 133 were finally included in the meta-analysis. Males in the general population showed a trend for a higher risk of probable/possible RBD (pRBD), especially among the male older adults (aged ≥60). In the clinical populations, males showed a significantly higher risk of confirmed RBD, but not of pRBD. Among idiopathic RBD (iRBD) patients, males had a significantly earlier age onset of RBD compared with females. Male patients with Parkinson's disease (PD) had a higher risk of comorbid RBD. There was no significant sex difference in the risk of developing neurodegenerative diseases in iRBD patients. Large scale and prospective studies utilizing stringent diagnostic criteria for RBD are recommended to further verify the sex differences in RBD and to investigate the mechanism underlying the sex difference.

Pharmacological interventions targeting α-synuclein aggregation triggered REM sleep behavior disorder and early development of Parkinson's disease

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by elevated motor behaviors and dream enactments in REM sleep, often preceding the diagnosis of Parkinson's disease (PD). As RBD could serve as a biomarker for early PD developments, pharmacological interventions targeting α-synuclein aggregation triggered RBD could be applied toward early PD progression. However, robust therapeutic guidelines toward PD-induced RBD are lacking, owing in part to a historical paucity of effective treatments and trials. We reviewed the bidirectional links between α-synuclein neurodegeneration, progressive sleep disorders, and RBD. We highlighted the correlation between RBD development, α-synuclein aggregation, and neuronal apoptosis in key brainstem regions involved in REM sleep atonia maintenance. The current pharmacological intervention strategies targeting RBD and their effects on progressive PD are discussed, as well as current treatments for progressive neurodegeneration and their effects on RBD. We also evaluated emerging and potential pharmacological solutions to sleep disorders and developing synucleinopathies. This review provides insights into the mechanisms and therapeutic targets underlying RBD and PD, and explores bidirectional treatment effects for both diseases, underscoring the need for further research in this area.

Rapid eye movement sleep behavior disorder is associated with decreased quality of life and stigma in people with Parkinson's disease

BACKGROUND

Individuals with Parkinson's disease (PD) may present with rapid eye movement sleep behavior disorder (RBD). We therefore investigated the association between RBD and quality of life (QOL) in people with PD.

METHODS

Individuals with PD and a Mini-Mental State Examination score ≥ 24 were divided into two groups using the RBD screening questionnaire (RBDSQ): those with an RBDSQ score ≥ 5 were assigned to the "probable RBD" (pRBD) group, and those with a score < 5 to the "non-pRBD" group. Participants were then evaluated for motor symptoms (Movement Disorder Society-Unified Parkinson's Disease Rating Scale part III and modified Hoehn and Yahr Scale), cognitive functions (Montreal Cognitive Assessment and Frontal Assessment Battery [FAB]), anhedonia (Snaith-Hamilton Pleasure Scale), and QOL (Parkinson's Disease Questionnaire [PDQ]-39 total and subscores for mobility, activities of daily living, emotional well-being, stigma, social support, cognition, communication, and bodily discomfort). Each measure was compared between the two groups (Mann-Whitney U test/χ² test). Multiple regression analyses were performed to identify factors contributing to the total score and the subscore of the stigma domain of the PDQ-39.

RESULTS

Ninety-three individuals with PD were recruited (mean ± standard deviation age, 67.0 ± 10.6 years). The pRBD group exhibited a longer disease duration (P = 0.006), worse FAB (P = 0.015) and PDQ-39 total (P = 0.032) scores. RBDSQ scores correlated with higher scores in the PDQ-39 stigma domain (B = 2.44, P = 0.033).

CONCLUSION

RBD is associated with worse QOL and stigma in people with PD. The RBDSQ is a useful tool for the prediction of such disturbances in QOL.

Comparative efficacy of prolonged-release melatonin versus clonazepam for isolated rapid eye movement sleep behavior disorder

PURPOSE

Clonazepam and melatonin are recommended as first-line treatments for isolated rapid eye movement (REM) sleep behavior disorder (iRBD). This study aimed to compare their efficacy and safety in REM sleep without atonia (RWA) and RBD-related symptoms.

METHODS

This prospective, open-label, randomized trial included patients with video-polysomnography-confirmed iRBD. The patients were randomly assigned to receive either clonazepam 0.5 mg or prolonged-release (PR) melatonin 2 mg 30 min before bedtime for 4 weeks. The primary outcome was changes in RWA on follow-up polysomnography (PSG). Secondary endpoints were changes in other PSG parameters, clinical global improvement-impression scale (CGI-I) scores, and sleep questionnaire scores. The safety endpoint was adverse events.

RESULTS

Of 40 patients with probable RBD considered, 34 were enrolled in the study and randomized. Visual scoring parameters of RWA indices were reduced, and automatic scoring parameters tended to be improved after clonazepam treatment but not after PR melatonin treatment. The proportion of N2 sleep was increased, and N3 and REM sleep were decreased only in the clonazepam group. The clonazepam group tended to answer "much or very much improvement" on the CGI-I more frequently than the PR melatonin group (p = 0.068). Daytime sleepiness and insomnia symptoms were reduced after PR melatonin but not after clonazepam. Depressive symptoms increased after clonazepam. Four of the patients (13.3%) reported mild to moderate adverse events, which were similar between the two groups.

CONCLUSION

Four weeks of clonazepam, but not PR melatonin, improved RWA. RBD symptom improvement tended to be better after clonazepam than PR melatonin in exchange for increased depressive symptoms and daytime sleepiness.

CLINICALTRIALS

gov identifier: NCT03255642 (first submitted August 21, 2017).

Sleep and wakefulness disturbances in Parkinson's disease: A meta-analysis on prevalence and clinical aspects of REM sleep behavior disorder, excessive daytime sleepiness and insomnia

Sleep disorders (SDs) are common non-motor symptoms of Parkinson's disease (PD) with wide variability in their prevalence rates. The etiology of SDs in PD is multifactorial because the degenerative processes underlying the disease and their interaction with drugs and clinical features may promote REM sleep behavior disorder (RBD), excessive daytime sleepiness (EDS) and insomnia. Therefore, we designed a meta-analytic study to provide a reliable estimate of the prevalence and associated clinical and neuropsychiatric aspects of SDs in PD. A systematic literature search was performed up to February 2022. Pooled RBD prevalence was 46%, and its occurrence was associated with older age, lower education, longer disease duration, higher levodopa equivalent daily dose (LEDD), worse motor and autonomic manifestations, poorer quality of life and autonomy, and more severe neuropsychiatric symptoms. The pooled prevalence of EDS was 35% and was associated with older age, longer disease duration, worse motor and autonomic symptoms, higher LEDD, reduced autonomy, and more severe neuropsychiatric symptoms. Insomnia was reported in 44% of PD patients and was related to longer disease duration, higher LEDD, and more severe depression. SDs are associated with a more severe PD clinical phenotype; further studies should explore the pathophysiological mechanisms underlying SDs and develop targeted therapeutic strategies.

The Assessment of the Diagnostic Delay in Japanese People with Parkinson's Disease Using a Web-based Survey of Patients and Physicians

Objective Although diagnostic criteria of Parkinson's disease (PD) have been established, the details of the process by which patients notice symptoms, visit a physician, and receive a diagnosis of PD is unclear. We therefore explored factors influencing latency in diagnosing PD. Methods We performed an internet-based survey of patients with PD and their families as well as physicians treating patients with PD to identify any diagnostic latency and its determinants. Evaluated factors included motor and non-motor symptoms, the diagnosis history and symptoms, patients' feelings toward PD prior to the diagnosis, and physician-determined reasons for the diagnostic delay. Results Among the 186 eligible patient respondents (including 87 responses from family members of patients), 24% received a PD diagnosis >1 year after the onset of PD-related symptoms, 58.6% had mid- or late-stage PD at the diagnosis, and 29% of patients had initially thought their symptoms were common age-related phenomena. Tremor (42%) was the most frequent symptom that led patients to visit a medical institution, whereas gait disturbance (14%) was the least frequent. More patients diagnosed with early-stage PD than those diagnosed with mid- or late-stage PD consulted a neurologist at their first visit. Among the 331 eligible physicians, patients' misinterpretation of their symptoms as being age-related was deemed one of or the most common cause (s) of a diagnostic delay by 67% and 36%, respectively. Conclusion Patients' insufficient or misinterpreted information about PD may cause delays in accessing healthcare services, leading to diagnostic delay.

Body-First Subtype of Parkinson's Disease with Probable REM-Sleep Behavior Disorder Is Associated with Non-Motor Dominant Phenotype

BACKGROUND

The hypothesis of body-first vs. brain-first subtype of PD has been proposed with REM-Sleep behavior disorder (RBD) defining the former. The body-first PD presumes an involvement of the brainstem in the pathogenic process with higher burden of autonomic dysfunction.

OBJECTIVE

To identify distinctive clinical subtypes of idiopathic Parkinson's disease (iPD) in line with the formerly proposed concept of body-first vs. brain-first subtypes in PD, we analyzed the presence of probable RBD (pRBD), sex, and the APOEɛ4 carrier status as potential sub-group stratifiers.

METHODS

A total of 400 iPD patients were included in the cross-sectional analysis from the baseline dataset with a completed RBD Screening Questionnaire (RBDSQ) for classifying as pRBD by using the cut-off RBDSQ≥6. Multiple regression models were applied to explore (i) the effect of pRBD on clinical outcomes adjusted for disease duration and age, (ii) the effect of sex on pRBD, and (iii) the association of APOEɛ4 and pRBD.

RESULTS

iPD-pRBD was significantly associated with autonomic dysfunction (SCOPA-AUT), level of depressive symptoms (BDI-I), MDS-UPDRS I, hallucinations, and constipation, whereas significantly negatively associated with quality of life (PDQ-39) and sleep (PDSS). No significant association between sex and pRBD or APOE ɛ4 and pRBD in iPD was found nor did we determine a significant effect of APOE ɛ4 on the PD phenotype.

CONCLUSION

We identified an RBD-specific PD endophenotype, characterized by predominant autonomic dysfunction, hallucinations, and depression, corroborating the concept of a distinctive body-first subtype of PD. We did not observe a significant association between APOE ɛ4 and pRBD suggesting both factors having an independent effect on cognitive decline in iPD.

Isolated REM sleep behaviour disorder: current diagnostic procedures and emerging new technologies

Isolated REM sleep behaviour disorder (iRBD) is characterised by dream enactment behaviours, such as kicking and punching while asleep, and vivid/violent dreams. It is now acknowledged as a prodromal phase of neurodegenerative disease-approximately 80% of people with iRBD will develop dementia with Lewy Bodies, Parkinson's disease or another degenerative brain disease within 10 years. It is important that neurologists and other clinicians understand how to make an early accurate diagnosis of iRBD so that affected people can have the opportunity to take part in clinical trials. However, making a diagnosis can be clinically challenging due to a variety of reasons, including delayed referral, symptom overlap with other disorders, and uncertainty about how to confirm a diagnosis. Several methods of assessment are available, such as clinical interview, screening questionnaires and video polysomnography or 'sleep study'. This review aims to support clinical neurologists in assessing people who present with symptoms suggestive of iRBD. We describe the usefulness and limitations of each diagnostic method currently available in clinical practice, and present recent research on the utility of new wearable technologies to assist with iRBD diagnosis, which may offer a more practical assessment method for clinicians. This review highlights the importance of thorough clinical investigation when patients present with suspected iRBD and emphasises the need for easier access to diagnostic procedures for accurate and early diagnosis.

Predictors of rapid eye movement sleep behavior disorder in patients with Parkinson’s disease based on random forest and decision tree

Background and objectives

Sleep disorders related to Parkinson’s disease (PD) have recently attracted increasing attention, but there are few clinical reports on the correlation of Parkinson’s disease patients with rapid eye movement (REM) sleep behavior disorder (RBD). Therefore, this study conducted a cognitive function examination for Parkinson’s disease patients and discussed the application effect of three algorithms in the screening of influencing factors and risk prediction effects.

Methods

Three algorithms (logistic regression, machine learning-based regression trees and random forest) were used to establish a prediction model for PD-RBD patients, and the application effects of the three algorithms in the screening of influencing factors and the risk prediction of PD-RBD were discussed.

Results

The subjects included 169 patients with Parkinson’s disease (Parkinson’s disease with RBD [PD-RBD] = 69 subjects; Parkinson’s disease without RBD [PD-nRBD] = 100 subjects). This study compared the predictive performance of RF, decision tree and logistic regression, selected a final model with the best model performance and proposed the importance of variables in the final model. After the analysis, the accuracy of RF (83.05%) was better than that of the other models (decision tree = 75.10%, logistic regression = 71.62%). PQSI, Scopa-AUT score, MoCA score, MMSE score, AGE, LEDD, PD-course, UPDRS total score, ESS score, NMSQ, disease type, RLSRS, HAMD, UPDRS III and PDOnsetage are the main variables for predicting RBD, along with increased weight. Among them, PQSI is the most important factor. The prediction model of Parkinson’s disease RBD that was established in this study will help in screening out predictive factors and in providing a reference for the prognosis and preventive treatment of PD-RBD patients.

Conclusions

The random forest model had good performance in the prediction and evaluation of PD-RBD influencing factors and was superior to decision tree and traditional logistic regression models in many aspects, which can provide a reference for the prognosis and preventive treatment of PD-RBD patients.

Alterations of Regional Homogeneity in Parkinson's Disease with Rapid Eye Movement Sleep Behavior Disorder

OBJECTIVE

Patients with rapid eye movement (REM) sleep behavior disorder (RBD) in Parkinson's disease (PD-RBD) tend to have poor cognitive performance and faster cognitive deterioration, and the potential mechanism is still ambiguous. Therefore, this study aimed to detect the alterations in local brain function in PD-RBD.

METHODS

Fifty patients, including 23 patients with PD-RBD and 27 patients with PD without RBD (PD-nRBD), and 26 healthy controls were enrolled. All subjects were subjected to one-night polysomnography and underwent resting-state functional magnetic resonance imaging (rs-fMRI). The fMRI images of the three groups were analyzed by regional homogeneity (ReHo) to observe the local neural activity. Correlations between altered ReHo values and chin electromyographic (EMG) density scores and cognitive scores in the PD subgroups were assessed.

RESULTS

Compared with the patients with PD-nRBD, the patients with PD-RBD had higher ReHo values in the frontal cortex (the right superior frontal gyrus, the right middle frontal gyrus and the left medial superior frontal gyrus), the right caudate nucleus and the right anterior cingulate gyrus, and compared with the HCs, the patients with PD-RBD had lower ReHo values in the bilateral cuneus, the bilateral precuneus, the left inferior temporal gyrus and the left inferior occipital gyrus. For the patients with PD-RBD, the phasic chin EMG density scores were positively correlated with the ReHo values in the left medial superior frontal gyrus, and the tonic chin EMG density scores were positively correlated with the ReHo values in the right anterior cingulate gyrus.

CONCLUSION

This study indicates that increased ReHo in the frontal cortex, the caudate nucleus and the anterior cingulate gyrus may be linked with the abnormal motor behaviors during REM sleep and that decreased ReHo in the posterior regions may be related to the visuospatial-executive function in patients with PD-RBD.

Sleep Disturbances and Phenoconversion in Patients with REM Sleep Behavior Disorder

Objective: We aimed to investigate relationships between sleep disturbances and phenoconversion to neurodegenerative diseases in patients with REM sleep behavior disorder (RBD). Method: Using a comprehensive sleep database in a university-affiliated hospital between December 2014 and March 2021, we reviewed the data of 226 patients with RBD (182 patients with idiopathic RBD (iRBD) and 44 patients with symptomatic RBD (sRBD) with a neurodegenerative disease). Results: Among 226 patients with RBD (male, 61.5%), the mean age at RBD onset and mean disease duration were 59.4 ± 10.5 and 5.9 ± 5.6 years, respectively. Further, 111 (49.1%) patients had periodic limb movements during sleep (PLMS, PLM index ≥ 15/h), while 110 patients (48.7%) had comorbid obstructive sleep apnea (OSA, respiratory disturbance index ≥ 15/h). There was a positive correlation between age at RBD onset and the apnea-hypopnea index and Pittsburgh Sleep Quality Index. Compared to patients with iRBD, patients with sRBD showed a lower N3 sleep (3.3 ± 5.0 vs. 1.6 ± 3.1%, p = 0.004) and higher periodic limb movement index (36.3 ± 31.8 vs. 56.9 ± 47.5/h, p = 0.021) at the baseline. Among the 186 patients with iRBD, 18 (8.0%) developed neurodegenerative diseases (converters, mean follow-up duration: 2.5 ± 1.6 years) and 164 did not (non-converters, mean follow-up 2.4 ± 2.2 years). There was no significant between-group difference in the demographics and baseline clinical features. Continuous positive airway pressure (CPAP) therapy was prescribed in 101 patients with OSA; among them, 71 (70%) patients agreed to use it. CPAP improved dream enactment behaviors. Conclusion: In our study, 8.0% of patients with iRBD showed phenoconversion within a mean follow-up duration of 2.5 years. Polysomnographic parameters could not predict phenoconversion to neurodegenerative disease. However, approximately half of the patients with RBD presented with significant sleep disorders, including OSA or PLMS. CPAP therapy may alleviate RBD symptoms in patients with RBD-OSA.

Current Update on Clinically Relevant Sleep Issues in Parkinson's Disease: A Narrative Review

Sleep disturbances are among the common nonmotor symptoms in patients with Parkinson’s disease (PD). Sleep can be disrupted by nocturnal motor and nonmotor symptoms and other comorbid sleep disorders. Rapid eye movement sleep behavior disorder (RBD) causes sleep-related injury, has important clinical implications as a harbinger of PD and predicts a progressive clinical phenotype. Restless legs syndrome (RLS) and its related symptoms can impair sleep initiation. Excessive daytime sleepiness (EDS) is a refractory problem affecting patients’ daytime activities. In particular, during the COVID-19 era, special attention should be paid to monitoring sleep problems, as infection-prevention procedures for COVID-19 can affect patients’ motor symptoms, psychiatric symptoms and sleep. Therefore, screening for and managing sleep problems is important in clinical practice, and the maintenance of good sleep conditions may improve the quality of life of PD patients. This narrative review focused on the literature published in the past 10 years, providing a current update of various sleep disturbances in PD patients and their management, including RBD, RLS, EDS, sleep apnea and circadian abnormalities.

The Correlation Between Parkinson's Disease and Rapid Eye Movement Sleep Behavior Disorder: A Systematic Review

Parkinson's disease (PD) is a neurodegenerative disease caused due to the destruction of dopaminergic neurons and the deposition of α-synuclein proteins, known as Lewy bodies. Generally, the diagnosis of PD is centered around motor symptoms. However, the early recognition of non-motor symptoms such as autonomic dysfunction, sleep disturbances, and cognitive and psychiatric disturbances are gaining increased attention for the early diagnosis of PD. Rapid eye movement (REM) sleep behavior disorder or REM sleep behavior disorder (RBD) is described as parasomnia, which is a condition of loss of normal muscle atonia causing the person to act out vivid dreams and it has been seen to be associated with the misprocessing of intercellular α-synuclein leading to neurodegenerative diseases such as PD. This review's objective is to highlight the significance of RBD as a prodromal premotor marker for the early detection of PD. We used PubMed as our primary database to search for articles on May 2, 2021, and a total of 1849 articles were found in our initial search using keywords and medical subject heading (MeSH) keywords. Thereafter, we removed the duplicates, applied the inclusion/exclusion criteria, and did a quality appraisal to include 10 articles in this study. We concluded that the recognition and diagnosis of RBD are of paramount importance to detect early PD, and further longitudinal studies and clinical trials are of utmost importance to understand their correlation; also, treatment trials are needed to prevent the phenoconversion of RBD into PD.

Brainstem Quadruple Aberrant Hyperphosphorylated Tau, Beta-Amyloid, Alpha-Synuclein and TDP-43 Pathology, Stress and Sleep Behavior Disorders

Quadruple aberrant hyperphosphorylated tau (p-τ), amyloid-β peptide, alpha-synuclein and TDP-43 brainstem and supratentorial pathology are documented in forensic ≤40y autopsies in Metropolitan Mexico City (MMC), and p-τ is the major aberrant protein. Post-traumatic stress disorder (PTSD) is associated with an elevated risk of subsequent dementia, and rapid eye movement sleep behavior disorder (RBD) is documented in PD, AD, Lewy body dementia and ALS. This study aimed to identify an association between PTSD and potential pRBD in Mexico. An anonymous online survey of 4502 urban college-educated adults, 29.3 ± 10.3 years; MMC, n = 1865; non-MMC, n = 2637, measured PTSD symptoms using the Impact of Event Scale-Revised (IES-R) and pRBD symptoms using the RBD Single-Question. Over 50% of the participants had IES-R scores ≥33 indicating probable PTSD. pRBD was identified in 22.6% of the participants across Mexico and 32.7% in MMC residents with PTSD. MMC subjects with PTSD had an OR 2.6218 [2.5348, 2.7117] of answering yes to the pRBD. PTSD and pRBD were more common in women. This study showed an association between PTSD and pRBD, strengthening the possibility of a connection with misfolded proteinopathies in young urbanites. We need to confirm the RBD diagnosis using an overnight polysomnogram. Mexican women are at high risk for stress and sleep disorders.