Rapid eye movement sleep behavior disorder: a window on the emotional world of Parkinson disease

The correlation between rapid eye movement sleep behavior disorder and the progress of Parkinson's disease: a systematic review and meta-analysis

Background

This meta-analysis was conducted to evaluate potential differences in symptoms between PD patients with or without RBD.

Methods

A systematic search was conducted in PubMed, Cochrane, Embase, and Web of Science databases (as of August 16, 2023), to identify relevant studies on PD and RBD. Statistical analysis was performed using Stata 15.0. Continuous variables were analyzed using the standardized mean difference (SMD) and 95% confidence interval (95% CI), while count data were assessed using the odds ratio (OR) and 95% CI as statistical effect sizes. Heterogeneity among all included studies was tested; for studies with low heterogeneity (I2 < 50%), a fixed-effects model was used to calculate statistical results. For studies with relatively high heterogeneity (I2 > 50%), a random-effects model was applied, followed by sensitivity and subgroup analyses to identify sources of heterogeneity.

Results

A total of 5,672 subjects were involved in this study. Compared to the NRBD group, the UPDRS-III score in the RBD group was significantly higher (SMD = 0.20, 95% CI: [0.11, 0.29], P < 0.001), and the Hoehn-Yahr score in the RBD group was also significantly higher (SMD = 0.29, 95% CI: [0.03, 0.55], P < 0.001). Patients with PD in the RBD group had more severe cognitive impairments than those in the NRBD group (SMD = -0.30, 95% CI: [-0.48, -0.11], P < 0.001). The incidence of hallucination in PD patients in the RBD group was 3.0 times that of the NRBD group (OR = 3.0, 95% CI: [2.15, 4.20], P = 0.110). PD patients in the RBD group also experienced more severe anxiety symptoms (SMD = 0.13, 95% CI: [-0.26, 0.51], P < 0.001), had higher scores in depression scales (SMD = 0.22, 95% CI: [0.02, 0.43], P < 0.001), and higher scores in sleep disorder scales than those in NRBD group (SMD = 0.10, 95% CI: [-0.11, 0.31], P < 0.001).

Conclusion

Results show PD patients with co-occurring RBD have more severe motor and non-motor symptoms likely due to overlapping affected regions in RBD and PD-related pathology, plus broader neurodegeneration seen in PD patients with RBD.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/#searchadvanced, identifier CRD42023476331.

Isolated REM Sleep without Atonia Is Not Equivalent to REM Sleep Behavior Disorder in Early-Stage Parkinson's Disease

BACKGROUND

In early-stage Parkinson's disease (PD), rapid eye movement (REM) sleep behavior disorder (RBD) predicts poor cognitive and motor outcome. However, the baseline significance and disease evolution associated with isolated REM sleep without atonia (iRWA, ie, enhanced muscle tone during 8.7% of REM sleep, but no violent behavior) are not well understood.

OBJECTIVES

The objective is to determine whether iRWA was a mild form of RBD and progressed similarly over time.

METHODS

Participants with early PD (<4 years from medical diagnosis) were included from 2014 to 2021 in a longitudinal study. They underwent interviews and examinations in the motor, cognitive, autonomous, psychiatric, sensory, and sleep domains every year for 4 years along with a video polysomnography and magnetic resonance imaging examination of the locus coeruleus/subcoeruleus complex (LC/LsC) at baseline. The clinical characteristics were compared between groups with normal REM sleep, with iRWA and with RBD, at baseline and for 4 years.

RESULTS

Among 159 PD participants, 25% had RBD, 25% had iRWA, and 50% had normal REM sleep. At baseline, the non-motor symptoms were less prevalent and the LC/LsC signal intensity was more intense in participants with iRWA than with RBD. Over 4 years, participants with normal REM sleep and with iRWA had a similar cognitive and motor trajectory, whereas participants with RBD had greater cognitive and motor decline.

CONCLUSIONS

We demonstrated that iRWA is frequent in early PD, but is not a milder form of RBD. Both groups have distinct baseline characteristics and clinical trajectories. They should be distinguished in clinical routine and research protocols. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Traditional uses, chemical compounds, pharmacological activities and clinical studies on the traditional Chinese prescription Yi-Gan San

ETHNOPHARMACOLOGICAL RELEVANCE

A widely used traditional prescription, Yi-Gan San (YGS) is a remedy for neurodegenerative disorders. The formulation consists of seven Chinese medicinal materials in specific proportions, namely Uncariae Ramulus cum Uncis (Uncaria rhynchophylla (Miq.) Miq. ex Havil.), Bupleuri Radix (Bupleurum chinense DC.), Angelicae Sinensis Radix (Angelica sinensis (Oliv.) Diels), Chuanxiong Rhizoma (Ligusticum wallichii Franch.), Poria (Poria cocos (Schw.) Wolf), Atractylodis Macrocephalae Rhizoma (Atractylodes macrocephala Koidz.) and Glycyrrhizae Radix et Rhizoma (Glycyrrhiza uralensis Fisch.). Using YGS has been shown to alleviate various behavioural and psychological symptoms of dementia (BPSD).

AIM OF THIS REVIEW

The goal of this review is to give up-to-date information about the traditional uses, chemistry, pharmacology and clinical efficacy of YGS based on the scientific literature and to learn the current focus and provide references in the next step.

MATERIALS AND METHODS

The database search room was accessed using the search terms "Yi-Gan San" and "Yokukansan" to obtain results from resources such as Web of Science, PubMed, Google Scholar and Sci Finder Scholar. We not only consulted the literature of fellow authors for this review but also explored classical medical books.

RESULTS

YGS has been used to cure neurosis, sleeplessness, night weeping and restlessness in infants. Its chemical components primarily consist of triterpenes, flavonoids, phenolics, lactones, alkaloids and other types of compounds. These active ingredients displayed diverse pharmacological activities to ameliorate BPSD by regulating serotonergic, glutamatergic, cholinergic, dopaminergic, adrenergic, and GABAergic neurotransmission. In addition, YGS showed neuroprotective, antistress, and anti-inflammatory effects. The majority of cases of neurodegenerative disorders are treated with YGS, including Alzheimer's disease and dementia with Lewy bodies.

CONCLUSIONS

Based on previous studies, YGS has been used as a traditional prescription in East Asia, such as Japan, Korea and China, and it has diverse chemical compounds and multiple pharmacological activities. Nevertheless, few experimental studies have focused on chemical and quantitative YGS studies, suggesting that further comprehensive research on its chemicals and quality assessments is critical for future evaluations of drug efficacy.

Dreaming in Parasomnias: REM Sleep Behavior Disorder as a Model

Sleep parasomnias have drawn the interest of sleep experts because they represent a valuable window to directly monitor dream activity and sleep mentation associated with nocturnal events. Indeed, parasomnias and their manifestations are helpful in investigating dream activity and features, overcoming methodological limits that affect dream study. Specifically, REM sleep Behavior Disorder (RBD) is a parasomnia characterized by enacted dream episodes during Rapid Eye Movements (REM) sleep, caused by the loss of physiological atonia. Patients suffering from RBD report a peculiar oneiric activity associated with motor episodes characterized by high Dream Recall Frequency (DRF) and vivid dreams. Additionally, isolated RBD (iRBD) represents a prodromal stage of neurodegeneration preceding the development of α-synucleinopathies. This narrative review aims to combine evidence describing dream activity in RBD and similarities and differences with other NREM parasomnias. Moreover, a special focus has been reserved for those conditions in which RBD is associated with α-synucleinopathies to clarify the potential role of dreams in neurodegenerative processes.

Research progress on neuromolecular imaging of REM sleep behavior disorder

Idiopathic rapid eye movement sleep behavior disorder (iRBD) is an important non-motor complication of Parkinson's disease. At the same time, iRBD is considered to be the prodromal stage of α-synucleinopathy. This high risk of conversion suggests that iRBD becomes a nerve It is a window for early research on degenerative diseases and is the best candidate for neuroprotection trials. A wide range of neuroimaging techniques has improved our understanding of iRBD as a prodromal stage of the disease. In addition, neuroimaging of abnormal iRBD is expected to be a potential biomarker for predicting clinical phenotypic transformation. This article reviews the research progress of neuromolecular imaging in patients with iRBD from the perspective of iRBD transforming synucleinopathies.

Non-motor symptoms are associated with REM sleep behavior disorder in Parkinson's disease: a systematic review and meta-analysis

OBJECTIVE

Parkinson's disease (PD) is usually accompanied by rapid eye movement sleep behavior disorder (RBD). A systematic review has concluded that motor manifestations are associated with RBD in PD patients, but whether the same is true of non-motor symptoms is unclear.

METHODS

A systematic review and meta-analysis was conducted by searching studies related to PD and RBD in PubMed, Web of Science, Embase, and Cochrane databases. Data were pooled where appropriate and used to calculate odds ratios (ORs), mean differences (MDs), or standardized mean differences (SMDs) with 95% confidence intervals (CI). Heterogeneity was assessed using the I² statistic.

RESULTS

PD patients with RBD were more likely to be male (OR 1.26, 95% CI 1.14-1.40) and older (MD 1.70 years, 95% CI 1.24-2.16) than those of patients without RBD. Patients with RBD were at a higher risk of non-motor symptoms such as constipation (OR 1.94, 95% CI 1.57-2.38), hallucination (OR 2.62, 95% CI 2.01-3.41), depression (SMD 0.39, 95% CI 0.25-0.53), and cognitive impairment (SMD - 0.29, 95% CI - 0.42 to - 0.17) based on standardized questionnaire scores. Similarly, PD patients with RBD suffered more severe motor symptoms and required higher doses of levodopa therapy.

CONCLUSIONS

The available evidence suggests that PD patients with RBD suffer severer non-motor and motor symptoms than those without RBD. A potential explanation is that PD patients with RBD present more diffuse neurodegeneration.

Efficacy of yokukansan compared with clonazepam for rapid eye movement sleep behaviour disorder: a preliminary retrospective study

AIM

Rapid eye movement sleep behaviour disorder (RBD) is characterized by abnormal behaviours accordant with nightmares during rapid eye movement sleep and is considered a prodromal marker of dementia with Lewy body. Most common in the elderly population, RBD is generally treated with clonazepam (CZP), a long-term acting benzodiazepine antiepileptic. As such, alternative drugs for RBD are urgently needed to minimize the adverse effects peculiar to benzodiazepines. The efficacy of yokukansan (YKS), a traditional Japanese herbal medicine, on RBD was initially reported by Shinno et al. in 2008. However, no study has compared YKS with CZP. Therefore, this study aimed to clarify the possibility of using YKS as an alternative to CZP.

METHODS

This was a retrospective cohort study conducted at Jikei University Affiliated Hospital. The subjects were selected from 36 outpatients who had been diagnosed with RBD based on the International Classification of Sleep Disorders, third edition. Of the 23 who met the inclusion criteria but not the exclusion criteria, 11 were treated with YKS monotherapy, and 12 were treated with CZP monotherapy. The primary outcome was the total score on the Japanese version of the Rapid Eye Movement Sleep Behaviour Disorder Questionnaire (RBDQ-JP), and the secondary outcomes were the scores from the eight-item Short-Form Health Survey and factors 1 and 2 of the RBDQ-JP.

RESULTS

The mean total RBDQ-JP score significantly improved from 52.5 to 21.7 (P = 0.002) after treatment with YKS (mean dosage: 3.0 g/day), which was similar to the change after CZP treatment (from 43.8 to 21.3). On RBDQ-JP factor 1 (dream content), the mean score on five of six items significantly improved after treatment with YKS. There was no significant change in Short-Form Health Survey scores after treatment with either drug. Potassium concentrations were within the normal range in patients treated with YKS.

CONCLUSIONS

The present results suggest that a small amount of YKS may be an alternative to CZP for RBD, without remarkable adverse events. Further study is needed to prospectively clarify the efficacy and safety of YKS in more detail.

Sleep in Parkinson's disease: A systematic review and meta-analysis of polysomnographic findings

Polysomnographic studies have been conducted to explore sleep changes in Parkinson's disease (PD), but the relationships between sleep disturbances and PD are imperfectly understood. We conducted a systematic review of the literature exploring polysomnographic differences between PD patients and controls in EMBASE, MEDLINE, All EBM databases, CINAHL, and PsycIFNO. 67 studies were identified for systematic review, 63 of which were used for meta-analysis. Meta-analyses revealed significant reductions in total sleep time, sleep efficiency, N2 percentage, slow wave sleep, rapid eye movement sleep (REM) percentage, and increases in wake time after sleep onset, N1 percentage, REM latency, apnea hypopnea index, and periodic limb movement index in PD patients compared with controls. There were no remarkable differences in sleep continuity or sleep architecture between PD patients with and without REM sleep behavior disorder (RBD). Our study suggests that PD patients have poor sleep quality and quantity. Sex, age, disease duration, presence of RBD, medication status, cognitive impairment, and adaptation night are factors that contributed to heterogeneity between studies.

The sleeping brain in Parkinson's disease: A focus on REM sleep behaviour disorder and related parasomnias for practicing neurologists

Sleep disorders are identified as common non-motor symptoms of Parkinson's disease (PD) and recently this recognition has been expanded to include parasomnias, encompassing not only REM sleep behaviour disorder (RBD), but also other non-REM forms. RBD, a prototypical parasomnia in PD, exists even in the prodromal stage of the disease, and is characterized by the presence of dream enactment behaviours occurring alongside a loss of normal skeletal muscle atonia during REM sleep. In contrast, non-REM parasomnias are more frequently observed in the late stage PD. However, the development of these disorders often overlaps and it is not uncommon for PD patients to meet the criteria for more than one type of parasomnias, thus making a clinical distinction challenging for practicing neurologists who are not sleep specialists. Indeed, clinical recognition of the predominant form of parasomnia does not just depend on video-polysomnography, but also on an individual physician's clinical acumen in delineating pertinent clinical history to determine the most likely diagnosis and proceed accordingly. In this review article, we highlight the various forms of parasomnias that have been reported in PD, including, but not limited to, RBD, with a focus on clinical symptomatology and implications for clinical practice. In addition, we review the differences in PD-related parasomnias compared to those seen in general populations. With advances in sleep research and better technology for ambulatory home monitoring, it is likely that many unanswered questions on PD-related parasomnias will soon be resolved resulting in better management of this nocturnal challenge in PD.

Non-Motor Correlates of Smoking Habits in de Novo Parkinson's Disease

BACKGROUND

Parkinson's disease (PD) subjects are less likely to ever smoke and are more prone to quit smoking, as compared to controls. Therefore, smoking habits can be considered part of the non-motor phenotype, preceding the onset of motor PD by several years.

OBJECTIVE

To explore non-motor symptom (NMS) correlates of smoking habits in de novo PD.

METHODS

This cross-sectional study included 281 newly diagnosed, drug-naïve PD subjects, recruited in Naples (Italy) and in Kassel (Germany). All subjects completed the NMS Questionnaire (NMSQ), and were investigated for smoking status (never, current and former smokers) and intensity (pack-years).

RESULTS

140 PD subjects never smoked, 20 currently smoked, and 121 had quit smoking before PD diagnosis. NMSQ total score did not associate with smoking status, but with smoking intensity (p = 0.028; coefficient = 0.088). A multinomial logistic regression stepwise model presenting never smoking as reference, selected as NMSQ correlates of current smoking: sex difficulties (p = 0.002; OR = 5.254), daytime sleepiness (p = 0.046; OR = 0.085), insomnia (p = 0.025; OR = 0.135), and vivid dreams (p = 0.040; OR = 3.110); and of former smoking: swallowing (p = 0.013; OR = 0.311), nausea (p = 0.027; OR = 7.157), unexplained pains (p = 0.002; OR = 3.409), forgetfulness (p = 0.005; OR = 2.592), sex interest (p = 0.007; OR = 0.221), sex difficulties (p = 0.038; OR = 4.215), and daytime sleepiness (p = 0.05; OR = 0.372). An ordinal logistic regression stepwise model selected as NMSQ correlates of smoking intensity: nocturnal restlessness (p = 0.027; coefficient = 0.974), and leg swelling (p = 0.004; coefficient = 1.305).

CONCLUSIONS

Certain NMSs are associated with different smoking status and intensity, suggesting a variety of adaptive mechanisms to cigarette smoking.

Caring burden of REM sleep behavior disorder - spouses' health and marital relationship

OBJECTIVES

Idiopathic REM sleep behavior disorder (iRBD) is noxious due to the high prevalence of sleep-related injuries to patients and their bed-partners. In this study, we aimed to investigate the impact of patients' RBD symptoms on their spouses, in terms of the quality of sleep, and physical, mental and marital aspects.

METHOD

A cross-sectional study comparing spouses of iRBD patients to the spouses of the age-and-sex-matched OSAS patients.

RESULTS

40 iRBD patients and their spouses (patients' age 66.6 ± 9.1, male 90%; spouses' age 62.9 ± 7.5), and 35 OSAS patients and their spouses (patients' age 67.8 ± 8.7 years old, male 80%; spouses' age 64.1 ± 9.1) were recruited. Almost all iRBD spouses (90%) reported disturbances by the nocturnal RBD behavioral symptoms of their bedpartners. About two-thirds (62.5%, N = 25) of the iRBD spouses reported a history of being injured during sleep. Spouses of both iRBD and OSAS patients reported a comparably high prevalence of insomnia, anxiety and depressive symptoms. Spouses of iRBD patients, however, reported more impaired quality of life and marital relationship. Nearly two-thirds of RBD couples continued co-sleeping, despite the risk of sleep-related injuries and nocturnal disturbances.

CONCLUSIONS

Both iRBD and OSAS spouses exhibited a high prevalence of insomnia and mood problems. In particular, iRBD significantly and negatively affect the spouses' quality of life and the marital relationship. Optimization of iRBD treatment, proper diagnosis, and management of sleep and mental health aspects of spouses may help to lessen the caring burden.

Dopaminergic system and dream recall: An MRI study in Parkinson's disease patients

We investigated the role of the dopamine system [i.e., subcortical-medial prefrontal cortex (mPFC) network] in dreaming, by studying patients with Parkinson's Disease (PD) as a model of altered dopaminergic transmission. Subcortical volumes and cortical thickness were extracted by 3T-MR images of 27 PD patients and 27 age-matched controls, who were asked to fill out a dream diary upon morning awakening for one week. PD patients do not substantially differ from healthy controls with respect to the sleep, dream, and neuroanatomical measures. Multivariate correlational analyses in PD patients show that dopamine agonist dosage is associated to qualitatively impoverished dreams, as expressed by lower bizarreness and lower emotional load values. Visual vividness (VV) of their dream reports positively correlates with volumes of both the amygdalae and with thickness of the left mPFC. Emotional load also positively correlates with hippocampal volume. Beside the replication of our previous finding on the role of subcortical nuclei in dreaming experience of healthy subjects, this represents the first evidence of a specific role of the amygdala-mPFC dopaminergic network system in dream recall. The association in PD patients between higher dopamine agonist dosages and impoverished dream reports, however, and the significant correlations between VV and mesolimbic regions, however, provide an empirical support to the hypothesis that a dopamine network plays a key role in dream generation. The causal relation is however precluded by the intrinsic limitation of assuming the dopamine agonist dosage as a measure of the hypodopaminergic state in PD. Periodicals, Inc.