REM sleep behaviour disorder in Parkinson's disease: a questionnaire-based study

Risk factors for rapid eye-movement sleep-related behavioral disorders (RBDs): A systematic review and a meta-analysis

OBJECTIVE

The present study aimed to systematically analyze the risk factors for RBD.

METHODS

A systematic review and meta-analysis of case-control studies, cohort studies, and cross-sectional studies derived from the articles published in eight electronic databases before December 1, 2021. The primary outcome was the odds ratio (OR) and 95% confidence interval (95% CI), and heterogeneity was quantified using I². Subgroup analyses and meta-regression were used to explore sources of heterogeneity. Egger's test and sensitivity analysis were performed. The PROSPERO ID number of the present study is CRD42021293942.

RESULTS

We identified 26 studies (44,230 subjects) among 2022 citations, and 13 factors were considered. Male sex (OR = 1.36, 95% CI = 1.13-1.64), smoking (OR = 1.37, 95% CI: 1.26-1.50), depression (OR = 2.06, 95% CI = 1.66-2.56), antidepressant use (OR = 2.36, 95% CI = 1.98-2.82), duration of neuropsychiatric disorders(OR = 1.43, 95% CI = 1.13-1.73), levodopa equivalent daily dose (LEDD, OR = 60.15, 95% CI = 23.95-96.35) and observable motor dysfunction (OR = 2.43, 95% CI = 0.65-4.22) were associated with a higher risk of RBD. Tertiary education and above (OR = 0.58, 95% CI = 0.35-0.96) was associated with a lower RBD risk. Men (OR = 1.40, 95% CI: 1.10-1.78, I² = 0%, P = 0.005) and older individual (OR = 2.73, 95% CI: 1.03-4.43, I² = 60%, P = 0.002) were more likely to have iRBD.

CONCLUSION

Six modifiable risk factors and one protective factor were associated with RBD. Further research is required to understand the mechanisms and to develop preventative strategies.

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.

Clinical manifestations and polysomnography-based analysis in nine cases of probable sporadic Creutzfeldt-Jakob disease

PURPOSE

To summarize the clinical characteristics of patients with sporadic Creutzfeldt-Jakob disease (sCJD), analyze its sleep disorder characteristics using polysomnography (PSG), and compare sleep disturbances with those of fatal familial insomnia (FFI).

PATIENTS AND METHODS

We retrospectively reviewed the sleep disturbances; cerebrospinal fluid (CSF) protein 14-3-3 (CSF-14-3-3 protein); prion protein gene, PRNP; magnetic resonance imaging; and electroencephalogram (EEG) of nine sCJD patients RESULTS: Of the nine sCJD patients, six were positive for CSF-14-3-3 protein. In the eight patients who completed diffusion-weighted imaging, seven showed cortical "ribbons sign" and two showed high signal in the basal ganglia. All nine patients had an EEG, which showed an increase in background slow waves; moreover, four showed typical periodic sharp wave complexes. The codon diversity at position 129, 219 of nine patients were MM, EE. Almost all nine patients had sleep disturbances such as insomnia, hypersomnia, and periodic limb movement disorder (PLMD). Five patients completed PSG, which demonstrated severe sleep structure disorder, prolonged total waking time, significantly reduced sleep efficiency, and absent rapid eye movement in some severe patients.

CONCLUSION

Sleep disturbances are common in sCJD patients, manifested as insomnia, lethargy, and PLMD. The sCJD patients often demonstrate severe sleep structure disorder through PSG, which is similar to patients with FFI.

Current Concepts and Controversies in the Management of REM Sleep Behavior Disorder

Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by dream enactment and the loss of muscle atonia during REM sleep, known as REM sleep without atonia (RSWA). RBD can result in significant injuries, prompting patients to seek medical attention. However, in others, it may present only as non-violent behaviors noted as an incidental finding during polysomnography (PSG). RBD typically occurs in the context of synuclein-based neurodegenerative disorders but can also be seen accompanying brain lesions and be exacerbated by medications, particularly antidepressants. There is also an increasing appreciation regarding isolated or idiopathic RBD (iRBD). Symptomatic treatment of RBD is a priority to prevent injurious complications, with usual choices being melatonin or clonazepam. The discovery that iRBD represents a prodromal stage of incurable synucleinopathies has galvanized the research community into delineating the pathophysiology of RBD and defining biomarkers of neurodegeneration that will facilitate future disease-modifying trials in iRBD. Despite many advances, there has been no progress in available symptomatic or neuroprotective therapies for RBD, with recent negative trials highlighting several challenges that need to be addressed to prepare for definitive therapeutic trials for patients with this disorder. These challenges relate to i) the diagnostic and screening strategies applied to RBD, ii) the limited evidence base for symptomatic therapies, (iii) the existence of possible subtypes of RBD, (iv) the relevance of triggering medications, (v) the absence of objective markers of severity, (vi) the optimal design of disease-modifying trials, and vii) the implications around disclosing the risk of future neurodegeneration in otherwise healthy individuals. Here, we review the current concepts in the therapeutics of RBD as it relates to the above challenges and identify pertinent research questions to be addressed by future work.

[Sleep and wake disorders in epilepsy]

OBJECTIVE

To summarize published data on the prevalence, characteristics and diagnostic criteria of sleep disorders in epilepsy.

MATERIAL AND METHODS

A search of published articles was performed in Medline (Pubmed), Scopus, Web of Science and e-library databases.

RESULTS

Epidemiologic, clinical and diagnostic aspects of excessive daytime sleepiness, obstructive sleep apnea and central apnea, restless leg syndrome and parasomnias related to slow-wave and REM-sleep in patients with epilepsy were analyzed.

CONCLUSIONS

Further studies are needed to gain an insight into the complex associations of sleep disorders in epilepsy to optimize diagnostic and treatment approaches and to improve the quality of life in that patient population.

Clinical, ocular motor, and imaging profile of Niemann-Pick type C heterozygosity

Objective

To characterize subclinical abnormalities in asymptomatic heterozygote NPC1 mutation carriers as markers of neurodegeneration.

Methods

Motor function, cognition, mood, sleep, and smell function were assessed in 20 first-degree heterozygous relatives of patients with Niemann-Pick disease type C (NPC) (13 male, age 52.7 ± 9.9 years). Video-oculography and abdominal ultrasound with volumetry were performed to assess oculomotor function and size of liver and spleen. NPC biomarkers in blood were analyzed. 18F-fluorodesoxyglucose PET was performed (n = 16) to detect patterns of brain hypometabolism.

Results

NPC heterozygotes recapitulated characteristic features of symptomatic NPC disease and demonstrated the oculomotor abnormalities typical of NPC. Hepatosplenomegaly (71%) and increased cholestantriol (33%) and plasma chitotriosidase (17%) levels were present. The patients also showed signs seen in other neurodegenerative diseases, including hyposmia (20%) or pathologic screening for REM sleep behavior disorder (24%). Cognitive function was frequently impaired, especially affecting visuoconstructive function, verbal fluency, and executive function. PET imaging revealed significantly decreased glucose metabolic rates in 50% of participants, affecting cerebellar, anterior cingulate, parieto-occipital, and temporal regions, including 1 with bilateral abnormalities.

Conclusion

NPC heterozygosity, which has a carrier frequency of 1:200 in the general population, is associated with abnormal brain metabolism and functional consequences. Clinically silent heterozygous gene variations in NPC1 may be a risk factor for late-onset neurodegeneration, similar to the concept of heterozygous GBA mutations underlying Parkinson disease.

The Bologna motor and non-motor prospective study on parkinsonism at onset (BoProPark): study design and population

Objective

The Bologna motor and non-motor prospective study on parkinsonism at onset (BoProPark) was designed to prospectively characterize motor and non-motor features in patients with a progressive neurodegenerative disease starting with parkinsonism since early disease stage and to investigate their diagnostic and prognostic role in the differential diagnosis of Parkinson’s disease from atypical parkinsonisms. The aim of this paper is to describe the method and population of the BoProPark study.

Methods

Patients referred to our Department with parkinsonism within 3 years from motor onset were recruited. Secondary causes of parkinsonism were excluded. Each patient underwent a comprehensive evaluation of motor and non-motor symptoms, assessed by means of quantitative, objective instrumental tests in addition to scales and questionnaires. The evaluations were performed at enrolment (T0), after 16 months (T1) and after 5 years (T2). Diagnoses were made according to consensus criteria.

Results

We recruited 150 patients, with mean age 61.5 ± 9.8 years and mean disease duration 20 ± 9 months. H&Y stage was 1 in 47.3% and 2 in 46.7% of cases. Mean UPDRS-III was 17.7 ± 9.2. Fifty-four patients were on dopaminergic treatment with median levodopa equivalent daily dose (LEDD) of 200 mg.

Conclusions

We expect that the prospective nature of the BoProPark study as well as the comprehensive, instrumental evaluation of motor and non-motor symptoms in patients with parkinsonism will provide important new insights for both clinical practice and research. Our data could be used for comparison with other cohorts and shared with national and international collaborators to develop new innovative projects.

Nightmare disorder and REM sleep behavior disorder in inflammatory arthritis: Possibility beyond neurodegeneration

OBJECTIVES

To investigate the prevalence of REM sleep behavior disorder (RBD) in patients with inflammatory arthritis (IA) to ascertain if RBD could be an internal red flag signaling a fluctuating state of inflammation based on the theory of "protoconsciousness".

MATERIALS & METHODS

One hundred and three patients with a confirmed diagnosis of IA were consecutively recruited. The patients underwent general (IA activity, functional status, laboratory tests) and neurological evaluations. A neurologist investigated RBD and REM sleep parasomnias in a semi-structured interview. Sleep quality was assessed with the Pittsburgh Sleep Quality Index, while the risk of obstructive sleep apnea syndrome (OSAS) was evaluated with the Berlin questionnaire. Beck Depression Inventory II and State-Trait Anxiety Inventory investigated depression and anxiety.

RESULTS

Patients had a mean age of 53.7 ± 14.6 years, 65% were women; 57.3% were in a clinically active phase of IA. Two women fulfilled ICSD-3 criteria for RBD appearing 11 years after and 20 years before IA onset respectively. 31 patients scored positive for nightmare disorder (ND), 8 for recurrent isolated sleep paralysis. 65 (63.1%) patients reported poor sleep quality and 25 (24.3%) resulted at high risk for OSAS. 32 (31.0%) patients scored positively for depression or anxiety.

CONCLUSIONS

The prevalence of RBD in patients with IA did not differ from that in the general population, whereas ND presented a 2-fold increased prevalence. Whether RBD can be considered a red flag signaling an internal danger remains an open question, while ND may be a new player in this intriguing relation.

Disturbances of Sleep and Alertness in Parkinson's Disease

PURPOSE OF REVIEW

Parkinson's disease (PD) is the second most common neurodegenerative disorder. Sleep dysfunction is one of the most common non-motor manifestations of PD that has gained significant interest over the past two decades due to its impact on the daily lives of PD patients, poorly understood mechanisms, and limited treatment options. In this review, we discuss the most common sleep disorders in PD and present recent investigations that have broadened our understanding of the epidemiology, clinical manifestations, diagnosis, and treatment of disturbed sleep and alertness in PD.

RESENT FINDINGS

The etiology of impaired sleep-wake cycles in PD is multifactorial. Sleep dysfunction in PD encompasses insomnia, REM sleep behavior disorder, sleep-disordered breathing, restless legs syndrome, and circadian dysregulation. Despite the high prevalence of sleep dysfunction in PD, evidence supporting the efficacy of treatment strategies is limited. We are at the opportune time to advance our understanding of sleep dysfunction in PD, which will hopefully lead to mechanisms-driven interventions for better sleep and allow us to approach sleep as a modifiable therapeutic target for other non-motor and motor manifestations in PD.

High Frequency of Sleep Disorders in Parkinson's Disease and Its Relationship with Quality of Life

OBJECTIVES

To determine the frequency of major sleep disorders in patients with Parkinson's disease (PD), diagnosed according to the third international classification of sleep disorders, and assess the relationship of those disorders with the quality of life.

METHODS

A cross-sectional study was performed involving 88 consecutive patients with PD from outpatient clinic. Participants were subjected to clinical interviews, assessment using standardized scales (Epworth Sleepiness Scale, PD Questionnaire, Pittsburgh sleep quality index (PSQI) and, for individuals with a diagnosis of RLS/WED, International RLS/WED grading scale), and video-polysomnography.

RESULTS

We observed sleep disorders in 96.5% of the participants, with REM-sleep behavior disorder found in 62.5%, obstructive sleep apnea in 62.5%, insomnia in 55.7%, and restless legs syndrome in 28.4%. We observed a correlation between health-related quality of life with the PSQI and the Epworth sleepiness scale.

CONCLUSION

Patients with PD have a high prevalence of sleep disorders. The quality of sleep and excessive daytime sleepiness significantly affect the quality of life in these individuals.

A systematic review of the literature on disorders of sleep and wakefulness in Parkinson's disease from 2005 to 2015

Sleep disorders are among the most common non-motor manifestations in Parkinson's disease (PD) and have a significant negative impact on quality of life. While sleep disorders in PD share most characteristics with those that occur in the general population, there are several considerations specific to this patient population regarding diagnosis, management, and implications. The available research on these disorders is expanding rapidly, but many questions remain unanswered. We thus conducted a systematic review of the literature published from 2005 to 2015 on the following disorders of sleep and wakefulness in PD: REM sleep behavior disorder, insomnia, nocturia, restless legs syndrome and periodic limb movements, sleep disordered breathing, excessive daytime sleepiness, and circadian rhythm disorders. We discuss the epidemiology, etiology, clinical implications, associated features, evaluation measures, and management of these disorders. The influence on sleep of medications used in the treatment of motor and non-motor symptoms of PD is detailed. Additionally, we suggest areas in need of further research.

REM sleep behaviour disorder: not just a bad dream

Rapid eye movement (REM) sleep behaviour disorder (RBD) is a parasomnia characterised by the loss of the normal atonia during the REM stage of sleep, resulting in overt motor behaviours that usually represent the enactment of dreams. Patients will seek medical attention due to sleep-related injuries or unpleasant dream content. Idiopathic RBD which occurs independently of any other disease occurs in up to 2% of the older population. Meanwhile, secondary RBD is very common in association with certain neurodegenerative conditions. RBD can also occur in the context of antidepressant use, obstructive sleep apnoea and narcolepsy. RBD can be diagnosed with a simple screening question followed by confirmation with polysomnography to exclude potential mimics. Treatment for RBD is effective and involves treatment of underlying causes, modification of the sleep environment, and pharmacotherapy with either clonazepam or melatonin. An important finding in the past decade is the recognition that almost all patients with idiopathic RBD will ultimately go on to develop Parkinson disease or dementia with Lewy bodies. This suggests that idiopathic RBD represents a prodromal phase of these conditions. Physicians should be aware of the risk of phenoconversion. They should educate idiopathic RBD patients to recognise the symptoms of these conditions and refer as appropriate for further testing and enrolment into research trials focused on neuroprotective measures.

SLEEP AND CIRCADIAN RHYTHM DISORDERS IN PARKINSON'S DISEASE

Purpose of review

Sleep disorders are among the most challenging non-motor features of Parkinson's disease (PD) and significantly affect quality of life. Research in this field has gained recent interest among clinicians and scientists and is rapidly evolving. This review is dedicated to sleep and circadian dysfunction associated with PD.

Recent findings

Most primary sleep disorders may co-exist with PD; majority of these disorders have unique features when expressed in the PD population.

Summary

We discuss the specific considerations related to the common sleep problems in Parkinson's disease including insomnia, rapid eye movement sleep behavior disorder, restless legs syndrome, sleep disordered breathing, excessive daytime sleepiness and circadian rhythm disorders. Within each of these sleep disorders, we present updated definitions, epidemiology, etiology, diagnosis, clinical implications and management. Furthermore, areas of potential interest for further research are outlined.

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.

Distinct Parameters in the EEG of the PLP α-SYN Mouse Model for Multiple System Atrophy Reinforce Face Validity

Multiple system atrophy (MSA) is a neurodegenerative movement disorder characterized by parkinsonian symptoms and cerebellar symptoms. Sleep disturbances also play a crucial role in MSA. One of the most convincing animal models in MSA research is the PLP α-SYN model, but to date no studies on sleep disturbances in this mouse model, frequently found in MSA patients are available. We identified spectral shifts within the EEG of the model, strikingly resembling results of clinical studies. We also characterized muscle activity during REM sleep, which is one of the key symptoms in REM sleep behavioral disorder. Spectral shifts and REM sleep-linked muscle activity were age dependent, supporting Face Validity of the PLP α-SYN model. We also strongly suggest our findings to be critically evaluated for Predictive Validity in future studies. Currently, research on MSA lacks potential compounds attenuating or curing MSA. Future drugs must prove its potential in animal models, for this our study provides potential biomarkers.

Sexual dimorphism in Parkinson's disease: differences in clinical manifestations, quality of life and psychosocial functioning between males and females

INTRODUCTION

Sex-related differences in clinical manifestations and consequences of Parkinson's disease (PD) have been poorly explored. Better understanding of sexual dimorphism in neurologic diseases such as PD has been announced as a research priority. The aim of our study was to determine independent sex differences in clinical manifestations and subtypes, psychosocial functioning, quality of life (QoL) and its domains between male and female individuals with PD.

PATIENTS AND METHODS

A comprehensive list of demographics, motor symptoms and subtypes, nonmotor features, health-related quality of life (HRQoL), psychosocial functioning and general aspects of daily life was assessed in 157 individuals (108 males and 49 females) with idiopathic PD. In order to control for potential confounding variables, we applied Orthogonal Partial Least Squares - Discriminant Analysis (OPLS-DA) to explore the strength of each feature to discriminate male and female patients with PD.

RESULTS

While no sex difference was found in the total Unified Parkinson's Disease Rating Scale (UPDRS) score and cumulative daily dose of levodopa, females had significantly more severe anxiety (mean difference =2.2 [95% confidence interval, CI: 0.5-4.0], P=0.011), worse nutritional status (23.8 [standard deviation, SD =4.2] vs 25.8 [SD =2.6], P=0.003) and poorer QoL (28.3 [SD =15.7] vs 17.9 [SD =14.2], P<0.001). Based on multivariate discriminant analysis, emotional well-being, bodily discomfort, social support, mobility and communication domains of HRQoL, together with anxiety, depression and psychosocial functioning, were the strongest features with more severe/worse status in females after adjustment for potential statistical confounders.

CONCLUSION

Our study provides a comprehensive understanding of sexual dimorphism in PD. Anxiety, depression, specific domains of HRQoL (mobility, emotional well-being, social support and bodily discomfort) and psychosocial functioning were significantly worse in female individuals with PD. Sexual dimorphism in PD highlights the features that are more likely to be affected in each sex and should be specifically targeted when managing male and female individuals with PD.

Living with Parkinson's disease: A Jordanian perspective

BACKGROUND

Parkinson's disease (PD) has a major impact on mobility, as well as cognition which can consequently impair aspects of individual's lives. Many studies have examined the living experiences of individuals with PD and its impact on their daily lives. None of these studies have explored the life experiences of Jordanian individuals living with PD. Therefore, the purpose of this qualitative study was to describe the daily living experiences and impact on lives of Jordanian individuals with PD.

METHODS

A qualitative phenomenological design was used. Interviews were recorded and transcribed. Transcripts were analysed using thematic analysis.

RESULTS

Experiences of 8 Jordanian individuals with PD who participated in this study can be categorized in the following major themes: (1) challenging perspectives and (2) adaptations. Challenging perspectives included stigma, emotional drainer, and experience of decreased independence and difficulty in occupational performance. Adaptations included embracing early acceptance and intervention, spiritual experience, and family support.

CONCLUSIONS

Study provided a wealth of knowledge related to the effect of PD and its intersection with the Arabic Jordanian culture. Such knowledge should aid healthcare professionals involved with providing services to Jordanian individuals with PD to provide better holistic services.

Gender differences in the adverse events' profile registered in seven observational studies of a wide gender-medicine (MetaGeM) project: the MetaGeM safety analysis

Background

MetaGeM is a wide gender-medicine project comprising post hoc and meta-analyses by gender of clinical outcomes, therapeutic approaches, and safety data from previously conducted observational studies to explore possible gender differences in real-life clinical settings. We report the results of the safety meta-analysis of seven MetaGeM studies, evaluating gender differences in adverse event (AE) incidence and severity.

Methods

Data were collected between February 2002 and July 2013. Male and female patients were compared for the main safety variables, using Student’s t-test, χ² test, or Fisher’s exact test as appropriate. As supportive analysis, a logistic regression model was estimated to evaluate associations between gender and outcome.

Results

In total, 4,870 patients (46% females, 54% males) were included in the analysis; age was higher for females (mean ± standard deviation 61.2±18.3 years) than males (56.3±16.6 years). Overall, 264 AEs were reported (59.1% in males). There were no significant gender differences in the percentage of patients with at least one AE: 3.0% for females versus 3.9% for males, χ² test P>0.05. According to the logistic regression model results, no association between gender and AEs occurrence seems to exist. A statistically significant gender difference in the percentage of drug-related AEs emerged (37.6% in females vs 20.8% in males, χ²P=0.0039). Slightly significantly more AEs in females were addressed with treatment compared with males (78.1% vs 66.7%, χ²P=0.0485). Total serious AEs (SAEs) were 47 (72% in males). The frequency of patients with ≥1 SAE was 0.6% in females versus 1.2% in males (χ² test P=0.0246).

Conclusion

This safety analysis on a large sample of almost 5,000 patients with different diseases and treated with a wide range of different drugs provides a useful overview on possible gender differences in drug tolerability, which may be helpful in more accurately designing future clinical trials from a gender-specific perspective.

The combined effect of REM sleep behavior disorder and hyposmia on cognition and motor phenotype in Parkinson's disease

BACKGROUND

Olfactory dysfunction and REM sleep behavior disorder (RBD) are recognized as pre-motor symptoms of Parkinson's disease (PD). Cognitive dysfunction is observed at a high rate even in the early stages of PD as an important non-motor symptom. PD has been classified in different subtypes and it is unknown if olfactory dysfunction and RBD occur more often in one particular subtype. We investigated the relationship between olfactory impairment, RBD, initial cognitive performance and motor phenotype in PD.

METHOD

Nighty-eight patients with drug-naïve idiopathic PD who visited the Movement Disorders Unit of Korea University Guro Hospital, Seoul, Korea from March 2012 to February 2014 were retrospectively included. Patients were divided into tremor-dominant-type and akinetic-rigid-type PD subgroups using part III of the Unified Parkinson's Disease Rating Scale. Olfaction was assessed by the Cross Cultural Smell Identification Test. RBD was screened using screening questionnaires. Initial cognitive function was assessed with Mini-Mental State Examination.

RESULT

The PD-normosmia group had higher MMSE scores (p=0.008). PD patients who have both RBD and olfactory dysfunction had lower MMSE scores (p=0.013). Presence of both RBD and hyposmia in PD patients was more strongly correlated with poor cognitive dysfunction. PD patients with RBD and/or hyposmia primarily exhibited the akinetic-rigidity phenotype.

CONCLUSION

Olfactory dysfunction and RBD differed according to the motor phenotypes of PD. This suggests that olfactory dysfunction and RBD might relate to prognosis in patients with PD. Patients who have both hyposmia and RBD were more likely to exhibit cognitive dysfunction.

Sex and Gender Differences in Central Nervous System-Related Disorders

There are important sex differences in the brain that seem to arise from biology as well as psychosocial influences. Sex differences in several aspects of human behavior and cognition have been reported. Gonadal sex steroids or genes found on sex chromosomes influence sex differences in neuroanatomy, neurochemistry and neuronal structure, and connectivity. There has been some resistance to accept that sex differences in the human brain exist and have biological relevance; however, a few years ago, it has been recommended by the USA National Institute of Mental Health to incorporate sex as a variable in experimental and clinical neurological and psychiatric studies. We here review the clinical literature on sex differences in pain and neurological and psychiatric diseases, with the aim to further stimulate interest in sexual dimorphisms in the brain and brain diseases, possibly encouraging more research in the field of the implications of sex differences for treating these conditions.

RBD and Neurodegenerative Diseases

Rapid eye movement (REM) sleep behavior disorder (RBD) is a sleep disorder characterized by enacting one's dreams during the REM sleep, with most of the dreams being violent or aggressive, so that patients often come to see the doctor complaining hurting themselves or bed partners during sleep. Prevalence of RBD, based on population, is 0.38-2.01 %, but much higher in patients with neurodegenerative diseases, especially synucleinopathies. RBD may herald the emergence of synucleinopathies by decades, such that it may be used as an effective early marker of neurodegenerative diseases. Pharmaceutical treatment of RBD includes clonazepam, melatonin, pramipexole, and some newly reported medications. In this review, we summarized the clinical and PSG features of RBD, the pathophysiology and the therapy of it, focusing on the correlation between neurodegenerative diseases and RBD, in order to emphasize the significance of RBD as an early marker of neurodegenerative diseases.

Dream Recall Frequencies and Dream Content in Wilson's Disease with and without REM Sleep Behaviour Disorder: A Neurooneirologic Study

Objective. Violent dream content and its acting out during rapid eye movement sleep are considered distinctive for rapid eye movement sleep behaviour disorder (RBD). This study reports first quantitative data on dreaming in a cohort of patients with treated Wilson's disease (WD) and in patients with WD with RBD. Methods. Retrospective questionnaires on different dimensions of dreaming and a prospective two-week home dream diary with self-rating of emotions and blinded, categorical rating of content by an external judge. Results. WD patients showed a significantly lower dream word count and very few other differences in dream characteristics compared to age- and sex-matched healthy controls. Compared to WD patients without RBD, patients with WD and RBD reported significantly higher nightmare frequencies and more dreams with violent or aggressive content retrospectively; their prospectively collected dream reports contained significantly more negative emotions and aggression. Conclusions. The reduction in dream length might reflect specific cognitive deficits in WD. The lack of differences regarding dream content might be explained by the established successful WD treatment. RBD in WD had a strong impact on dreaming. In accordance with the current definition of RBD, violent, aggressive dream content seems to be a characteristic of RBD also in WD.

Rapid Eye Movement Sleep Behavior Disorder in Parkinson's Disease: A Preliminary Study

Objective

Rapid eye movement sleep behavior disorder (RBD) is associated with α-synucleinopathies, such as Parkinson’s disease (PD). We aimed to assess the differences in the clinical characteristics of PD with and without RBD.

Methods

Forty-two patients previously diagnosed with PD were evaluated for clinical history, motor and cognitive functioning using the Unified Parkinson’s Disease Rating Scale (UPDRS) and Mini-Mental State Examination (MMSE), autonomic symptoms, sleep characteristics using the Pittsburg Sleep Quality Index (PSQI), and the presence of RBD using the Korean version of the RBD screening questionnaire (RBDSQ). The prevalence of RBD and the patients’ demographic features were evaluated. The patients were classified into two groups, PD with RBD and PD without RBD, based on the RBDSQ scores. The motor and cognitive functions, as well as other clinical features of the two groups were compared.

Results

A total of 42 PD patients were enrolled. Eighteen patients were classified as PD with RBD. Compared to PD without RBD, PD with RBD showed higher scores of rigidity in the UPDRS subscale. Regarding sleep problems, PD with RBD revealed higher sleep disturbance, lower sleep efficiency, and lower overall sleep quality in the PSQI. There was no difference in cognitive dysfunction between the two groups according to the Korean version of the MMSE.

Conclusions

PD with RBD was associated with poorer sleep and motor symptoms. Therefore, RBD symptoms in PD are possibly poor prognostic markers.

Rotigotine Objectively Improves Sleep in Parkinson's Disease: An Open-Label Pilot Study with Actigraphic Recording

Sleep disturbances represent important predictors of poor quality of life (QoL) in Parkinson's disease (PD). This open-label pilot study aimed to objectively assess, by means of actigraphic recording, effect of rotigotine on sleep in PD patients with self-reported sleep complaints. 15 PD patients underwent one-week actigraphic recording before (T0) and during (T1) rotigotine treatment, which was titrated to the dose subjectively improving motor symptoms (4–8 mg/24 h). Sleep disturbances, daytime sleepiness, cognitive performance, QoL, and depression were also evaluated with questionnaires. Actigraphic recordings showed a significant reduction in nocturnal motor activity and mean duration of wake episodes after sleep onset during rotigotine treatment compared to baseline. In 10 patients presenting objective evidence of poor sleep quality at T0 (sleep efficiency ≤ 85%), rotigotine also significantly improved other sleep parameters and further reduced nocturnal motor activity and mean duration of wake episodes. A significant decrease in number and duration of daytime sleep episodes was also observed at T1. Finally we confirmed that rotigotine significantly improves perceived sleep quality and QoL. Our study showed for the first time that rotigotine is associated with an objective improvement of nocturnal and diurnal sleep disturbances in PD patients with self-reported sleep complaints. This study is registered with AIFA-observational study registry number 12021.

A new view of "dream enactment" in REM sleep behavior disorder

Patients with REM sleep behavior disorder (RBD) exhibit increased muscle tone and exaggerated myoclonic twitching during REM sleep. In addition, violent movements of the limbs, and complex behaviors that can sometimes appear to involve the enactment of dreams, are associated with RBD. These behaviors are widely thought to result from a dysfunction involving atonia-producing neural circuitry in the brainstem, thereby unmasking cortically generated dreams. Here we scrutinize the assumptions that led to this interpretation of RBD. In particular, we challenge the assumption that motor cortex produces twitches during REM sleep, thus calling into question the related assumption that motor cortex is primarily responsible for all of the pathological movements of RBD. Moreover, motor cortex is not even necessary to produce complex behavior; for example, stimulation of some brainstem structures can produce defensive and aggressive behaviors in rats and monkeys that are strikingly similar to those reported in human patients with RBD. Accordingly, we suggest an interpretation of RBD that focuses increased attention on the brainstem as a source of the pathological movements and that considers sensory feedback from moving limbs as an important influence on the content of dream mentation.

Evidence that non-dreamers do dream: a REM sleep behaviour disorder model

To determine whether non-dreamers do not produce dreams or do not recall them, subjects were identified with no dream recall with dreamlike behaviours during rapid eye movement sleep behaviour disorder, which is typically characterised by dream-enacting behaviours congruent with sleep mentation. All consecutive patients with idiopathic rapid eye movement sleep behaviour disorder or rapid eye movement sleep behaviour disorder associated with Parkinson's disease who underwent a video-polysomnography were interviewed regarding the presence or absence of dream recall, retrospectively or upon spontaneous arousals. The patients with no dream recall for at least 10 years, and never-ever recallers were compared with dream recallers with rapid eye movement sleep behaviour disorder regarding their clinical, cognitive and sleep features. Of the 289 patients with rapid eye movement sleep behaviour disorder, eight (2.8%) patients had no dream recall, including four (1.4%) patients who had never ever recalled dreams, and four patients who had no dream recall for 10-56 years. All non-recallers exhibited, daily or almost nightly, several complex, scenic and dreamlike behaviours and speeches, which were also observed during rapid eye movement sleep on video-polysomnography (arguing, fighting and speaking). They did not recall a dream following sudden awakenings from rapid eye movement sleep. These eight non-recallers with rapid eye movement sleep behaviour disorder did not differ in terms of cognition, clinical, treatment or sleep measures from the 17 dreamers with rapid eye movement sleep behaviour disorder matched for age, sex and disease. The scenic dreamlike behaviours reported and observed during rapid eye movement sleep in the rare non-recallers with rapid eye movement sleep behaviour disorder (even in the never-ever recallers) provide strong evidence that non-recallers produce dreams, but do not recall them. Rapid eye movement sleep behaviour disorder provides a new model to evaluate cognitive processing during dreaming and subsequent recall.

Recommendations of the Sleep Study Group of the Italian Dementia Research Association (SINDem) on clinical assessment and management of sleep disorders in individuals with mild cognitive impairment and dementia: a clinical review

Clinical assessment and management of sleep disturbances in patients with mild cognitive impairment and dementia has important clinical and social implications. Poor sleep results in an increased risk of morbidities and mortality in demented patients and is a source of stress for caregivers. Sleep disturbances show high prevalence in mild cognitive impairment and dementia patients and they are often associated one to another in the same patient. A careful clinical evaluation of sleep disorders should be performed routinely in the clinical setting of individuals with cognitive decline. The Sleep Study Group of the Italian Dementia Research Association (SINDem) reviewed evidence from original research articles, meta-analyses and systematic reviews published up to December 2013. The evidence was classified in quality levels (I, II, III) and strength of recommendations (A, B, C, D, E). Where there was a lack of evidence, but clear consensus, good practice points were provided. These recommendations may not be appropriate for all circumstances and should therefore be adopted only after a patient's individual characteristics have been carefully evaluated.

Gender differences on motor and non-motor symptoms of de novo patients with early Parkinson's disease

The affect of gender differences on clinical presentation of Parkinson's disease (PD) remains controversial. De novo PD subjects were recruited from a trial-based multicenter cohort in clinical sites of Chinese Parkinson Study Group. Demographic information, motor and non-motor symptom measurements were performed by face-to-face interview using specific scales. Scores and frequencies of symptoms were compared between male and female patients, and regression models were used to control the effects of age and disease duration. Totally 428 PD patients were enrolled in this study, and 60.3 % of them were male. Total UPDRS scores were not significantly different between male and female (25.02 ± 12.84 vs. 25.24 ± 13.22, adjusted p = 0.984). No significant gender differences were found on scores for four cardinal motor signs, neither on motor subtypes (PIGD 19.0 vs. 15.9 %, adjusted p = 0.303). Female patients more likely had depressive symptoms (38.8 vs. 27.5 %, adjusted p = 0.023; CES-D score 13.78 ± 10.91 vs. 11.23 ± 9.42, adjusted p = 0.015). Male patients had significantly higher scores for MMSE (28.26 ± 2.21 vs. 27.00 ± 3.38, adjusted p = 0.0001), and lower scores for identification (1.39 ± 1.63 vs. 2.01 ± 2.63, adjusted p = 0.002) in ADAS-cog. No significant differences were found for other non-motor symptoms including motivation problems (male 29.8 % vs. female 30.6 %, adjusted p = 0.760), fatigue (62.6 vs. 70.5 %, adjusted p = 0.140), constipation (37.2 vs. 30.1 %, adjusted p = 0.243), and sleep quality (57.6 vs. 61.3 %, adjusted p = 0.357; PSQI score: 5.62 ± 3.31 vs. 6.10 ± 3.53, adjusted p = 0.133). Female might be more depressed and have worse performance on cognition in early untreated PD patients, but gender differences are not apparent on motor and other non-motor symptoms.

REM sleep behaviour disorder is associated with worse quality of life and other non-motor features in early Parkinson's disease

BACKGROUND

Concomitant REM sleep behaviour disorder (RBD) is commonly observed in patients with Parkinson's disease (PD). Although the brainstem structures responsible for the symptoms of RBD correspond to the premotor stages of PD, the association of RBD with motor and non-motor features in early PD remains unclear.

METHODS

The study evaluated 475 patients with PD within 3.5 years of diagnosis for the presence of probable RBD (pRBD) using the REM Sleep Behaviour Disorder Screening Questionnaire (RBDSQ). A neurologist and a trained research nurse carried out evaluation of each participant blinded to the results of the RBDSQ. Standardised rating scales for motor and non-motor features of PD, as well as health-related quality of life measures, were assessed. Multiple linear and logistic regression analyses were used to determine the relationship between pRBD and a variety of outcomes, controlling for confounding factors.

RESULTS

The overall frequency of pRBD was 47.2% (95% CI 42.7% to 51.9%). None of the patients had a previous diagnosis of RBD. Patients with PD and concomitant pRBD did not differ on motor phenotype and scored comparably on the objective motor scales, but reported problems with motor aspects of daily living more frequently. Adjusted for age, sex, disease duration and smoking history, pRBD was associated with greater sleepiness (p=0.001), depression (p=0.001) and cognitive impairment (p=0.006).

CONCLUSIONS

pRBD is common and under-recognised in early PD. It is associated with increased severity and frequency of non-motor features, poorer subjective motor performance and a greater impact on health-related quality of life.

Rapid eye movement sleep behaviour disorder in young- and older-onset Parkinson disease: a questionnaire-based study

BACKGROUND

Rapid eye movement sleep behavior disorder (RBD) is common in Parkinson disease (PD).

OBJECTIVES

To determine the frequency of clinically probable RBD (cpRBD) in young-onset (21 to < or =40 years; YOPD) and older-onset PD (>40 years; OOPD) and characterize its pattern.

METHODS

A total of 156 patients with PD (YOPD-51, OOPD-105) were clinically examined and the presence of RBD was diagnosed using the minimal criteria for diagnosis of RBD (International Classification of Sleep Disorders, ICSD-1). RBD screening questionnaire based on the minimal criteria was used. The bed-partners were also interviewed with Mayo sleep questionnaire. Other scales included Unified Parkinson Disease Rating Scale part III (UPDRS III), Hoehn & Yahr stage, Mini Mental Status Examination, Pittsburgh Sleep Quality Index, Parkinson Disease Sleep Scale, Epworth Sleep Scale, Hamilton Anxiety Rating Scale and Hamilton Depression Rating Scale.

RESULTS

cpRBD was diagnosed in 30 (19.2%) patients, majority being OOPD rather than YOPD (86.7% vs. 13.3%; P=0.01). The frequency of RBD was significantly higher (P=0.016) in OOPD (24.8%) compared to those with YOPD (7.8%). Most often (72.4%) RBD occurred after the onset of parkinsonian symptoms. RBD was independently associated with higher global PSQI scores, total ESS scores and total PDSS scores after adjusting for the effects of age, gender, Hoehn & Yahr stage and duration of illness.

CONCLUSIONS

Patients with RBD were older with later-onset motor symptoms, a more advanced stage, poorer sleep quality, and more frequent daytime sleepiness. Older-onset PD had a higher frequency of RBD than young-onset PD.

A scale for assessing the severity of arousal disorders

BACKGROUND

Arousal disorders may have serious health consequences.

OBJECTIVE

To develop a scale assessing the severity of arousal disorders (Paris Arousal Disorders Severity Scale, PADSS).

SETTING

University hospital.

DESIGN

Controlled study.

PARTICIPANTS

Consecutive patients (older than 15 y), with sleepwalking (SW) and/or sleep terrors (ST), subjects with previous SW/ST, normal controls and patients with rapid eye movement sleep behavior disorder.

INTERVENTION

The self-rated scale listed 17 parasomniac behaviors (PADSS-A), assessed their frequency from never to twice or more per night (PADSS-B) and evaluated the consequences (PADSS-C: disturbed sleep, injuries, fatigue, and psychological consequences). The clinimetric properties and face validity of the scale were tested.

RESULTS

Half of the 73 patients with SW/ST (more men than women) had injured themselves or others, whereas 15% had concomitant sexsomnia and 23% had amnestic eating behaviors. The total PADSS score (range: 0-50) was 19.4 ± 6.3 (range: 8-36) in this group, 11.7 ± 5.9 in 26 subjects with previous SW/ST, 8.8 ± 3.2 in 26 patients with RBD, and 2.0 ± 3.5 in 53 normal controls (P < 0.05). The PADSS demonstrated high sensitivity (83.6%), specificity (87.8%), internal consistency, and test-retest reliability (0.79). The best cutoff for the total score was at 13/14. Exploratory factor analysis revealed two components: wandering and violence/handling. The complexity of behaviors emerging from N3 sleep (scored on videopolysomnography) positively correlated with scores for the PADSS-total, PADSS-A, PADSS-C, and the "violence/handling" factor.

CONCLUSION

This scale had reasonable psychometric properties and could be used for screening and stratifying patients and for evaluating the effects of treatments.

The role of dysfunctional attentional control networks in visual misperceptions in Parkinson's disease

Visual misperceptions and hallucinations represent a problematic symptom of Parkinson's disease. The pathophysiological mechanisms underlying these symptoms remain poorly understood, however, a recent hypothesis has suggested that visual misperceptions and hallucinations may arise from disrupted processing across attentional networks. To test the specific predictions of this hypothesis, 22 patients with Parkinson's disease underwent 3T fMRI while performing the Bistable Percept Paradigm, a task that has previously been shown to identify patients with hallucinations. Subjects are required to study a battery of randomly assigned "monostable" and "bistable" monochromatic images for the presence or absence of a bistable percept. Those patients who scored a high percentage of misperceptions and missed images on the task were less able to activate frontal and parietal hubs of the putative Dorsal Attention Network. Furthermore, poor performance on the task was significantly correlated with the degree of decreased activation in a number of these hubs. At the group level, the difference between processing a bistable versus a monostable cue was associated with increased recruitment of the anterior insula. In addition, those patients with impaired performance on the paradigm displayed decreased resting state functional connectivity between hubs of the Ventral and Dorsal Attention Networks. These same patients had significantly decreased gray matter in the insula bilaterally. In addition, a combined analysis of the separate neuroimaging approaches revealed significant relationships across the impaired networks. These findings are consistent with specific predictions from a recently proposed hypothesis that implicates dysfunction within attentional networks in Parkinsonian hallucinations.

Clinicopathologic correlations in 172 cases of rapid eye movement sleep behavior disorder with or without a coexisting neurologic disorder

OBJECTIVE

To determine the pathologic substrates in patients with rapid eye movement (REM) sleep behavior disorder (RBD) with or without a coexisting neurologic disorder.

METHODS

The clinical and neuropathologic findings were analyzed on all autopsied cases from one of the collaborating sites in North America and Europe, were evaluated from January 1990 to March 2012, and were diagnosed with polysomnogram (PSG)-proven or probable RBD with or without a coexisting neurologic disorder. The clinical and neuropathologic diagnoses were based on published criteria.

RESULTS

172 cases were identified, of whom 143 (83%) were men. The mean±SD age of onset in years for the core features were as follows - RBD, 62±14 (range, 20-93), cognitive impairment (n=147); 69±10 (range, 22-90), parkinsonism (n=151); 68±9 (range, 20-92), and autonomic dysfunction (n=42); 62±12 (range, 23-81). Death age was 75±9 years (range, 24-96). Eighty-two (48%) had RBD confirmed by PSG, 64 (37%) had a classic history of recurrent dream enactment behavior, and 26 (15%) screened positive for RBD by questionnaire. RBD preceded the onset of cognitive impairment, parkinsonism, or autonomic dysfunction in 87 (51%) patients by 10±12 (range, 1-61) years. The primary clinical diagnoses among those with a coexisting neurologic disorder were dementia with Lewy bodies (n=97), Parkinson's disease with or without mild cognitive impairment or dementia (n=32), multiple system atrophy (MSA) (n=19), Alzheimer's disease (AD)(n=9) and other various disorders including secondary narcolepsy (n=2) and neurodegeneration with brain iron accumulation-type 1 (NBAI-1) (n=1). The neuropathologic diagnoses were Lewy body disease (LBD)(n=77, including 1 case with a duplication in the gene encoding α-synuclein), combined LBD and AD (n=59), MSA (n=19), AD (n=6), progressive supranulear palsy (PSP) (n=2), other mixed neurodegenerative pathologies (n=6), NBIA-1/LBD/tauopathy (n=1), and hypothalamic structural lesions (n=2). Among the neurodegenerative disorders associated with RBD (n=170), 160 (94%) were synucleinopathies. The RBD-synucleinopathy association was particularly high when RBD preceded the onset of other neurodegenerative syndrome features.

CONCLUSIONS

In this large series of PSG-confirmed and probable RBD cases that underwent autopsy, the strong association of RBD with the synucleinopathies was further substantiated and a wider spectrum of disorders which can underlie RBD now are more apparent.

Probable rapid eye movement sleep behavior disorder, nocturnal disturbances and quality of life in patients with Parkinson's disease: a case-controlled study using the rapid eye movement sleep behavior disorder screening questionnaire

Background

Increasing evidence provides a clear association between rapid eye movement sleep behavior disorders (RBD) and Parkinson’s disease (PD), but the clinical features that determine the co-morbidity of RBD and PD are not yet fully understood.

Methods

We evaluated the characteristics of nocturnal disturbances and other motor and non-motor features related to RBD in patients with PD and the impact of RBD on their quality of life. Probable RBD (pRBD) was evaluated using the Japanese version of the RBD screening questionnaire (RBDSQ-J).

Results

A significantly higher frequency of pRBD was observed in PD patients than in the controls (RBDSQ-J ≥ 5 or ≥ 6: 29.0% vs. 8.6%; 17.2% vs. 2.2%, respectively). After excluding restless legs syndrome and snorers in the PD patients, the pRBD group (RBDSQ-J≥5) showed higher scores compared with the non-pRBD group on the Parkinson’s disease sleep scale-2 (PDSS-2) total and three-domain scores. Early morning dystonia was more frequent in the pRBD group. The Parkinson’s Disease Questionnaire (PDQ-39) domain scores for cognition and emotional well-being were higher in the patients with pRBD than in the patients without pRBD. There were no differences between these two groups with respect to the clinical subtype, disease severity or motor function. When using a cut-off of RBDSQ-J = 6, a similar trend was observed for the PDSS-2 and PDQ-39 scores. Patients with PD and pRBD had frequent sleep onset insomnia, distressing dreams and hallucinations. The stepwise linear regression analysis showed that the PDSS-2 domain “motor symptoms at night”, particularly the PDSS sub-item 6 “distressing dreams”, was the only predictor of RBDSQ-J in PD.

Conclusion

Our results indicate a significant impact of RBD co-morbidity on night-time disturbances and quality of life in PD, particularly on cognition and emotional well-being. RBDSQ may be a useful tool for not only screening RBD in PD patients but also predicting diffuse and complex clinical PD phenotypes associated with RBD, cognitive impairment and hallucinations.

Gender differences in Parkinson's disease: focus on plasma α-synuclein

Among promising biological markers proposed for Parkinson's disease (PD) and other disorders related to Lewy bodies, plasma alpha-synuclein assay has provided conflicting results mainly owing to the various laboratory assay techniques used and protein forms assayed. In this observational and exploratory cross-sectional study, using an immunoenzymatic technique, we assayed and compared total plasma alpha-synuclein concentrations in 69 patients with PD and 110 age-matched healthy control subjects. Two previously unreported findings concerned gender. First, plasma alpha-synuclein concentrations measured in the more advanced parkinsonian disease stages decreased in men, but not in women. Second, again only in men, plasma alpha-synuclein concentration was associated with cognitive impairments, hallucinations, and sleep disorders. These findings underline the gender-related differences in parkinsonian patients and indicate plasma alpha-synuclein expression as a potential biological marker for PD progression in men.

REM sleep behavior disorder in Parkinson's disease: a questionnaire-based survey

STUDY OBJECTIVES

REM sleep behavior disorder (RBD) is reported in up to 50% of patients with Parkinson's disease (PD). Only a few systematic, large-scale studies have addressed the characteristics of RBD in PD. The aim of the present study is to assess the frequency of RBD in patients with PD and the association with PD characteristics.

METHODS

We sent a questionnaire including items on sleep quality, sleep disorders, and PD characteristics and severity to the members of the national PD patients' organization in Switzerland. To assess and characterize RBD, we used a validated 10-item questionnaire (the RBD screening questionnaire, RBDSQ).

RESULTS

Four hundred seventeen PD patients returned the questionnaire, with RBD scores ≥ 6 in 172 patients. These patients had longer disease duration and lower activity of daily living scores, as well as more frequent nighttime awakenings and hallucinations than PD patients with RBDSQ scores < 6. Age, gender, sleep-wake disorders such as excessive daytime sleepiness, sleep apnea, and insomnia, as well as levodopa equivalent dose did not differ between the 2 groups. Patients with RBDSQ score ≥ 6 were more often treated with antidepressants.

CONCLUSIONS

We confirm a frequent (42.6%) history of RBD in PD. Probable RBD in PD is associated with more advanced disease as suggested by the longer disease duration and higher impairment of daily living. It is also linked to sleep fragmentation with significantly more nighttime awakenings and with hallucinations. Hallucinations might be linked to emotional disinhibition and probably to activation of limbic structures. Both sleep fragmentation and limbic activation might facilitate the occurrence of RBD in PD.

Circadian and sleep disorders in Parkinson's disease

Impaired sleep and alertness, initially recognized by James Parkinson in his famous monograph "An Essay on the Shaking Palsy" in 1817, is one of the most common and disabling nonmotor symptoms of Parkinson's disease (PD). It is only recently, however, that sleep disturbances in PD have received the attention of medical and research community. Dopamine, the major neurotransmitter implicated in the pathogenesis of PD, plays a pivotal role in the regulation of sleep and circadian homeostasis. Sleep dysfunction affects up to 90% of patients with PD, and may precede the onset of the disease by decades. Sleep dysfunction in PD may be categorized into disturbances of overnight sleep and daytime alertness. Etiology of impaired sleep and alertness in PD is multifactorial. Co-existent primary sleep disorders, medication side effects, overnight re-emergence of motor symptoms, and primary neurodegeneration itself, are main causes of sleep disruption and excessive daytime sleepiness among patients with PD. Increasing body of evidence suggests that the circadian system becomes dysregulated in PD, which may lead to poor sleep and alertness. Treatment options are limited and frequently associated with unwanted side effects. Further studies that will examine pathophysiology of sleep dysfunction in PD, and focus on novel treatment approaches are therefore very much needed. In this article we review the role of dopamine in regulation of sleep and alertness and discuss main sleep and circadian disturbances associated with PD.

Clinical correlates of periodic limb movements in sleep in Parkinson's disease

OBJECTIVE

The aim of the current study was to investigate the frequency of periodic limb movements in sleep (PLMS) in Parkinson's disease (PD) and their impact on nocturnal sleep and daytime functioning.

METHODS

Forty-five PD patients (mean age 68.5 ± 8.7 years; 32 males) underwent one night of polysomnography (PSG). Clinical assessment and questionnaires evaluating sleep disturbance and quality of life (QoL) were completed. Patients were divided into two groups based on their PLMS index (PLMSI): PLMSI ≥ 15 (PLMS+) and PLMSI <15 (PLMS-).

RESULTS

There were 26 (57.8%) PD patients in the PLMS+group and 19 (42.2%) patients in the PLMS-group. Subjective assessment revealed an association between PLMS+status and greater PD symptom severity, more subjective sleep disturbance, and decreased QoL. All patients showed poor sleep, and no significant group differences were detected on PSG measures.

CONCLUSION

We observed that PLMS occurred frequently in PD and increased with more severe PD. Although PLMS did not affect objective sleep, it was associated with increased sleep complaints and reduced QoL. Overall, our findings support the association between PLMS and PD as well as the clinical relevance of sleep disturbances in PD.