REM Sleep Behavior Disorder and REM Sleep Without Atonia are More Frequent in Advanced versus Early Parkinson's Disease

Sleep and sleep disorders in people with Parkinson's disease

Sleep disorders are common in people with Parkinson's disease. These disorders, which increase in frequency throughout the course of the neurodegenerative disease and impair quality of life, include insomnia, excessive daytime sleepiness, circadian disorders, obstructive sleep apnoea, restless legs syndrome, and rapid eye movement (REM) sleep behaviour disorder. The causes of these sleep disorders are complex and multifactorial, including the degeneration of the neural structures that modulate sleep, the detrimental effect of some medications on sleep, the parkinsonian symptoms that interfere with mobility and comfort in bed, and comorbidities that disrupt sleep quality and quantity. The clinical evaluation of sleep disorders include both subjective (eg, questionnaires or diaries) and objective (eg, actigraphy or video polysomnography) assessments. The management of patients with Parkinson's disease and a sleep disorder is challenging and should be individualised. Treatment can include education aiming at changes in behaviour (ie, sleep hygiene), cognitive behavioural therapy, continuous dopaminergic stimulation at night, and specific medications. REM sleep behaviour disorder can occur several years before the onset of parkinsonism, suggesting that the implementation of trials of neuroprotective therapies should focus on people with this sleep disorder.

REM sleep and neurodegeneration

Several brainstem, subcortical and cortical areas are involved in the generation of rapid eye movement (REM) sleep. The alteration of these structures as a result of a neurodegenerative process may therefore lead to REM sleep anomalies. REM sleep behaviour disorder is associated with nightmares, dream-enacting behaviours and increased electromyographic activity in REM sleep. Its isolated form is a harbinger of synucleinopathies such as Parkinson's disease or dementia with Lewy bodies, and neuroprotective interventions are advocated. This link might also be present in patients taking antidepressants, with post-traumatic stress disorder, or with a history of repeated traumatic head injury. REM sleep likely contributes to normal memory processes. Its alteration has also been proposed to be part of the neuropathological changes occurring in Alzheimer's disease.

Pervasive and diffuse muscle activity during REM sleep and non-REM sleep characterises multiple system atrophy in comparison with Parkinson's disease

Multiple system atrophy (MSA) and Parkinson's disease (PD) may share overlapping features particularly at early disease stage, including sleep alterations, but have profoundly different prognoses. Certain sleep phenomena and disorders of motor control are more prevalent in multiple system atrophy, such as REM sleep behaviour disorder (RBD). We quantitatively tested whether pervasive muscle activity during sleep occurs in subjects with multiple system atrophy versus Parkinson's disease. Laboratory polysomnographic studies were performed in 50 consecutive subjects with Parkinson's disease and 26 age- and gender-matched subjects with multiple system atrophy at <5 years from disease onset. The distributions of normalised electromyographic activity of submentalis, wrist extensor, and tibialis anterior muscles in different wake-sleep states during the night were analysed. Subjects with multiple system atrophy had significantly higher activity of submentalis, wrist extensor, and tibialis anterior muscles than subjects with Parkinson's disease during non-REM sleep, including separately in stages N1, N2, and N3, and during REM sleep, but not during nocturnal wakefulness. The activity of wrist extensor and tibialis anterior muscles during non-REM sleep and the activity of tibialis anterior muscles during REM sleep were also significantly higher in subjects with multiple system atrophy and RBD than in subjects with Parkinson's disease and RBD. In conclusion, with respect to Parkinson's disease, multiple system atrophy is characterised by a pervasive and diffuse muscle overactivity that involves axial and limb muscles and occurs not only during REM sleep, but also during non-REM sleep and between subjects with comorbid RBD.

Automatic analysis of muscular activity in the flexor digitorum superficialis muscles: a fast screening method for rapid eye movement sleep without atonia

STUDY OBJECTIVES

To identify a fast and reliable method for rapid eye movement (REM) sleep without atonia (RWA) quantification.

METHODS

We analyzed 36 video-polysomnographies (v-PSGs) of isolated REM sleep behavior disorder (iRBD) patients and 35 controls' v-PSGs. Patients diagnosed with RBD had: i) RWA, quantified with a reference method, i.e. automatic and artifact-corrected 3-s Sleep Innsbruck Barcelona (SINBAR) index in REM sleep periods (RSPs, i.e. manually selected portions of REM sleep); and ii) v-PSG-documented RBD behaviors. We quantified RWA with other (semi)-automated methods requiring less human intervention than the reference one: the indices proposed by the SINBAR group (the 3-s and 30-s phasic flexor digitorum superficialis (FDS), phasic/"any"/tonic mentalis), and the REM atonia, short and long muscle activity indices (in mentalis/submentalis/FDS muscles). They were calculated in whole REM sleep (i.e. REM sleep scored following international guidelines), in RSPs, with and without manual artifact correction. Area under curves (AUC) discriminating iRBD from controls were computed. Using published cut-offs, the indices' sensitivity and specificity for iRBD identification were calculated. Apnea-hypopnea index in REM sleep (AHIREM) was considered in the analyses.

RESULTS

RWA indices from FDS muscles alone had the highest AUCs and all of them had 100% sensitivity. Without manual RSP selection and artifact correction, the "30-s phasic FDS" and the "FDS long muscle activity" had the highest specificity (85%) with AHIREM < 15/h. RWA indices were less reliable when AHIREM≥15/h.

CONCLUSIONS

If AHIREM<15/h, FDS muscular activity in whole REM sleep and without artifact correction is fast and reliable to rule out RWA.

Searching for Biomarkers in the Blood of Patients at Risk of Developing Parkinson's Disease at the Prodromal Stage

Parkinson's disease (PD) is diagnosed many years after its onset, under a significant degradation of the nigrostriatal dopaminergic system, responsible for the regulation of motor function. This explains the low effectiveness of the treatment of patients. Therefore, one of the highest priorities in neurology is the development of the early (preclinical) diagnosis of PD. The aim of this study was to search for changes in the blood of patients at risk of developing PD, which are considered potential diagnostic biomarkers. Out of 1835 patients, 26 patients were included in the risk group and 20 patients in the control group. The primary criteria for inclusion in a risk group were the impairment of sleep behavior disorder and sense of smell, and the secondary criteria were neurological and mental disorders. In patients at risk and in controls, the composition of plasma and the expression of genes of interest in lymphocytes were assessed by 27 indicators. The main changes that we found in plasma include a decrease in the concentrations of l-3,4-dihydroxyphenylalanine (L-DOPA) and urates, as well as the expressions of some types of microRNA, and an increase in the total oxidative status. In turn, in the lymphocytes of patients at risk, an increase in the expression of the DA D3 receptor gene and the lymphocyte activation gene 3 (LAG3), as well as a decrease in the expression of the Protein deglycase DJ-1 gene (PARK7), were observed. The blood changes we found in patients at risk are considered candidates for diagnostic biomarkers at the prodromal stage of PD.

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.

Analysis of sleep, daytime sleepiness, and autonomic function in multiple system atrophy and Parkinson disease: a prospective study

STUDY OBJECTIVES

Sleep disorders, daytime sleepiness, and autonomic dysfunction are commonly reported among patients with multiple system atrophy and Parkinson disease (PD). We aimed to assess sleep and autonomic function in these patients to evaluate the relationships between sleep disorders, excessive daytime sleepiness, and autonomic function.

METHODS

Twenty patients with multiple system atrophy (n = 7) and PD (n = 13) underwent clinical assessment including questionnaires for autonomic function and sleep. Cardiovascular autonomic function tests and 2-night video-polysomnography were followed by administration of the Multiple Sleep Latency Test. Rapid eye movement sleep without atonia was quantified in the chin, flexor digitorum superficialis, tibial anterior, and sternocleidomastoid muscles.

RESULTS

Rapid eye movement sleep behavior disorder was associated with orthostatic hypotension (P = .017) and constipation (P = .019) in PD. Patients with orthostatic hypotension had higher rapid eye movement sleep without atonia indices than those without orthostatic hypotension (P < .001). The Sleep Innsbruck Barcelona rapid eye movement sleep without atonia index ("any" chin and/or flexor digitorum superficialis) correlated with systolic/diastolic blood pressure fall upon tilt-table examination in patients with multiple system atrophy (P < .05) and with gastrointestinal (P = .010), urinary (P = .022), and total Scales for Outcomes in Parkinson's Disease-Autonomic Dysfunction scores (P = .006) in all patients. Patients with a pathological deep breathing ratio showed higher Sleep Innsbruck Barcelona indices (P = .031). Objective daytime sleepiness was exclusively present in PD (P = .034) and correlated with levodopa-equivalent dosage (P = .031).

CONCLUSIONS

The relationship of autonomic dysfunction with rapid eye movement sleep without atonia in PD and multiple system atrophy is accounted for by shared brainstem neuropathology and likely identifies patients in a more advanced stage of disease. Excessive daytime sleepiness is found exclusively in PD and may be secondary to levodopa treatment and not related to α-synuclein disease.

CITATION

Eckhardt C, Fanciulli A, Högl B, et al. Analysis of sleep, daytime sleepiness, and autonomic function and multiple system atrophy and Parkinson disease: a prospective study. J Clin Sleep Med. 2023;19(1):63-71.

Overnight Distribution of REM Sleep Features in People with Parkinson's Disease (PD) and Non-PD Controls

BACKGROUND

Rapid eye movement (REM) sleep behavior disorder (RBD) is a leading predictor of Parkinson's disease (PD). Diagnosis is performed in the sleep laboratory by detecting pathological REM sleep without atonia (RSWA). The evidence on the overnight distribution of RSWA% is conflicting.

OBJECTIVE

To investigate the temporal distribution of the number of ocular movements per REM sleep minute (REM density), and RSWA% in people with PD and non-PD controls.

METHODS

All participants underwent a single overnight evaluation in a sleep laboratory. Clinical evaluation was performed on a separate day. REM density and RSWA% were compared between PD and controls both across four sleep periods and individual REM cycles.

RESULTS

A total of 51 participants with recorded RSWA in polysomnography laboratory were included, 28 with PD aged 64±9 years with a disease duration of 3.3±2.9 years, and 23 controls aged 55±8 years. People with PD had lower REM density and higher RSWA% compared to controls. As expected, REM density was higher towards the morning. In contrast, RSWA% was equally distributed across the night, for both PD and controls.

CONCLUSIONS

PD pathology affects REM sleep features, but not the overnight distribution of those features. While REM density increased towards the end of the night, RSWA% was equally distributed across the night for both PD and controls. Our findings have clinical implications for diagnosing RBD, as quantification of RSWA% in any sleep cycle is sufficient for reliably evaluating total RSWA% and reduced REM density may be a marker of PD.

Predictors of anxiety in Parkinson's disease: results from a 3-year longitudinal cohort study

INTRODUCTION

Anxiety symptoms are the most common neuropsychiatric manifestation of Parkinson's disease (PD), contributing to decreased quality of life. Few longitudinal studies in PD samples have examined correlates of anxiety symptoms over time. Understanding predictor variables may help to identify novel targets for reducing anxiety in PD. The aim of this study was to identify predictors of anxiety symptoms over 3 years in a clinic-based PD cohort.

METHODS

Our cohort included patients with PD at an academic medical center in the Southeastern United States (n = 105). Visits included assessment of motor, psychiatric, and cognitive features, including neuropsychological testing. For our multivariate model, we selected 11 predictor variables with the most existing evidence or theoretical support for an association with anxiety symptoms in PD. Multivariate linear mixed model regression was performed to determine which variables were significantly associated with anxiety symptoms over time.

RESULTS

Over half of participants (57%) met the screening threshold for an anxiety disorder at some point during the study. Independent predictors of anxiety symptoms over time included symptoms of REM sleep behavior disorder (RBD) and dysautonomia.

DISCUSSION

In this PD sample, RBD and dysautonomia symptoms were significantly associated with anxiety symptoms over time. Each of these relationships has been reported in one of two prior longitudinal studies. Unlike prior studies, cognitive impairment was not a significant predictor of anxiety symptoms in our sample. Future research should confirm the direction and mechanisms underlying these relationships, including the potential for anxiety symptom reduction through treatment for RBD and dysautonomia.

Long-term effects of intrajejunal levodopa infusion on sleep in people with advanced Parkinson's disease

Background

Sleep disturbances are commonly encountered in people with advanced Parkinson's disease (PD). In these stages, levodopa-carbidopa intestinal gel (LCIG) is recommended for improving motor symptoms, some non-motor dysfunctions, and quality of life in these patients. This study aimed to assess the effects of LCIG on sleep in PD in a longitudinal study.

Study design

An open-label observational study in patients with advanced PD undergoing LCIG treatment was carried out.

Measures and outcomes

In total, 10 consecutive advanced people with PD were evaluated at the baseline and after 6 months and 1 year, respectively, of LCIG infusion. Sleep parameters were assessed with several validated scales. We assessed the evolution of sleep parameters under LCIG infusion over time and the effects on sleep quality.

Results

Significant improvement following LCIG was observed in PSQI total score (p = 0.007), SCOPA-SLEEP total score (p = 0.008), SCOPA-NS subscale (p = 0.007), and AIS total score (p = 0.001) at 6 months and 1 year, compared to the baseline. The PSQI total score at 6 months correlated significantly with the Parkinson's Disease Sleep Scale, version 2 (PDSS-2) "disturbed sleep" item at 6 months (p = 0.28; R = 0.688), while the PSQI total score at 12 months significantly correlated with the PDSS-2 total score at 1 year (p = 0.025, R = 0.697) and with the AIS total score at 1 year (p = 0.015, R = 0.739).

Conclusion

LCIG infusion demonstrated beneficial effects on sleep parameters and sleep quality, which were constant over time for up to 12 months.

Striatal-Inoculation of α-Synuclein Preformed Fibrils Aggravated the Phenotypes of REM Sleep without Atonia in A53T BAC-SNCA Transgenic Mice

Accumulation of α-synuclein (α-syn) is the pathological hallmark of α-synucleinopathy. Rapid eye movement (REM) sleep behavior disorder (RBD) is a pivotal manifestation of α-synucleinopathy including Parkinson's disease (PD). RBD is clinically confirmed by REM sleep without atonia (RWA) in polysomnography. To accurately characterize RWA preceding RBD and their underlying α-syn pathology, we inoculated α-syn preformed fibrils (PFFs) into the striatum of A53T human α-syn BAC transgenic (A53T BAC-SNCA Tg) mice which exhibit RBD-like phenotypes with RWA. RWA phenotypes were aggravated by PFFs-inoculation in A53T BAC-SNCA Tg mice at 1 month after inoculation, in which prominent α-syn pathology in the pedunculopontine nucleus (PPN) was observed. The intensity of RWA phenotype could be dependent on the severity of the underlying α-syn pathology.

Basal ganglia engagement during REM sleep movements in Parkinson's disease

To elucidate the role of the basal ganglia during REM sleep movements in Parkinson's disease (PD) we recorded pallidal neural activity from four PD patients. Unlike desynchronization commonly observed during wakeful movements, beta oscillations (13-35 Hz) synchronized during REM sleep movements; furthermore, high-frequency oscillations (150-350 Hz) synchronized during movement irrespective of sleep-wake states. Our results demonstrate differential engagement of the basal ganglia during REM sleep and awake movements.

Evolution patterns of probable REM sleep behavior disorder predicts Parkinson's disease progression

The course of REM sleep behavior disorder (RBD) variates in the early stage of Parkinson's disease. We aimed to delineate the association between the evolution pattern of probable RBD (pRBD) and the progression of Parkinson's disease (PD). 281 de novo PD patients from the Parkinson's Progression Markers Initiative database were included. Patients were followed up for a mean of 6.8 years and were classified into different groups according to the evolution patterns of pRBD. Disease progression was compared among groups using survival analysis, where the endpoint was defined as progression to Hoehn-Yahr stage 3 or higher for motor progression and progression to mild cognitive impairment for cognitive decline. At the 4th year of follow-up, four types of pRBD evolution patterns were identified: (1) non-RBD-stable (55.5%): patients persistently free of pRBD; (2) late-RBD (12.1%): patients developed pRBD during follow-up; (3) RBD-stable (24.9%): patients showed persistent pRBD, and (4) RBD-reversion (7.5%): patients showed pRBD at baseline which disappeared during follow-up. The RBD-reversion type showed the fastest motor progression while the RBD-stable type showed the fastest cognitive decline. At baseline, the RBD-reversion type showed the most severe gray matter atrophy in the middle frontal gyrus, while the RBD-stable type showed gray matter atrophy mainly in the para-hippocampal gyrus. Four types of early pRBD evolution patterns featured different brain lesions and predicted different courses of motor and cognitive decline in PD.

Longitudinal Studies of Sleep Disturbances in Parkinson's Disease

PURPOSE OF REVIEW

Sleep disorders are among the most common non-motor symptoms in Parkinson's disease (PD). Recent longitudinal studies of sleep in PD have utilized validated sleep questionnaires and video-polysomnography performed over multiple time points. This review summarizes existing longitudinal studies focusing on the prevalence, associations, and changes of sleep disorders in PD over time, as well as the methodologies used in these studies.

RECENT FINDINGS

Fifty-three longitudinal studies of sleep in PD were identified: excessive daytime sleepiness, insomnia, obstructive sleep apnea, rapid eye movement sleep behavior disorder (RBD), restless legs syndrome, and shift work disorder were studied in addition to other studies that had focused on either multiple sleep disorders or broadly on sleep disorders as a whole. The prevalence of sleep disorders increases over time and are associated particularly with non-motor features of disease. RBD is now considered an established prodromal feature of PD, but other sleep disorders do not clearly increase risk of subsequent PD. Further work is necessary to determine if treatment of sleep disorders in PD alters disease symptom and their progression or reduces PD risk. Longitudinal studies of sleep in PD have demonstrated a high prevalence of sleep disorders that are associated with non-motor features of PD which can increase over time. More work is necessary to determine if treatment of sleep disorders can alter the course of PD.

Progression in Parkinson's Disease: Variation in Motor and Non-motor Symptoms Severity and Predictors of Decline in Cognition, Motor Function, Disability, and Health-Related Quality of Life as Assessed by Two Different Methods

Background

Parkinson's disease (PD) is multi-symptom disease with variable progression.

Objectives

We performed a longitudinal study to address the evolution of motor symptoms (MS) and non-motor symptoms (NMS), predictors of motor-, cognitive-, disability-, and health-related quality of life (HRQL) status and the relative usefullness of a battery of separate NMS scales (BSS) versus the Non-Motor Symptom Scale (NMSS).

Methods

Seventy-two patients were assessed at baseline and 4 years later with the NMSS and BSS. We assessed the following outcomes: cognition (Montreal Cognitive Assessment scale [MoCA]), disability (Unified Parkinson's Disease Rating Scale Part II [UPDRS II], Schwab and England [S&E]), motor dysfunction (Unified Parkinson's Disease Rating Scale Part III [UPDRS III], Hoehn and Yahr [HY]), and HRQL (EuroQol [EQ] EQ-vertical visual analogue scale [VAS] and EQ-Index). Statistical analysis included a comparison between scales scores at both time points and multivariate regression analysis to calculate the impact of each baseline symptom in outcomes. NMSS and BSS were introduced in separate models.

Results

NMSS Domain 4: perception/hallucinations, Parkinson's Psychosis Questionnaire, Apathy Scale, NMSS Domain 7: urinary, S&E, UPDRS II, HY, and MoCA scores worsened significantly. Dementia increased to a 4-year prevalence of 39.8%. In the multivariate model using BSS, cognitive state variation was significantly predicted by baseline HY, EQ-Index, and S&E. Using the NMSS, MoCA change was significantly associated with NMSS Domain 4: perceptions/hallucination score, cognitive status with UPDRS III score, HRQL with NMSS Domain 4: perception/hallucinations score, and S&E.

Conclusion

Our study suggests that NMS progress heterogeneously, BSS approach being more sensitive to change than NMSS. The multivariate analysis has shown that S&E and NMSS Domain 4: perception/hallucinations scores are the stronger predictors of HRQL and cognitive dysfunction variation, favoring NMSS over the BSS approach.

Asymmetric Dopaminergic Dysfunction in Brain-First versus Body-First Parkinson's Disease Subtypes

BACKGROUND

We have hypothesized that Parkinson's disease (PD) comprises two subtypes. Brain-first, where pathogenic α-synuclein initially forms unilaterally in one hemisphere leading to asymmetric nigrostriatal degeneration, and body-first with initial enteric pathology, which spreads through overlapping vagal innervation leading to more symmetric brainstem involvement and hence more symmetric nigrostriatal degeneration. Isolated REM sleep behaviour disorder has been identified as a strong marker of the body-first type.

OBJECTIVE

To analyse striatal asymmetry in [18F]FDOPA PET and [123I]FP-CIT DaT SPECT data from iRBD patients, de novo PD patients with RBD (PD +RBD) and de novo PD patients without RBD (PD - RBD). These groups were defined as prodromal body-first, de novo body-first, and de novo brain-first, respectively.

METHODS

We included [18F]FDOPA PET scans from 21 iRBD patients, 11 de novo PD +RBD, 22 de novo PD - RBD, and 18 controls subjects. Also, [123I]FP-CIT DaT SPECT data from iRBD and de novo PD patients with unknown RBD status from the PPPMI dataset was analysed. Lowest putamen specific binding ratio and putamen asymmetry index (AI) was defined.

RESULTS

Nigrostriatal degeneration was significantly more symmetric in patients with RBD versus patients without RBD or with unknown RBD status in both FDOPA (p = 0.001) and DaT SPECT (p = 0.001) datasets.

CONCLUSION

iRBD subjects and de novo PD +RBD patients present with significantly more symmetric nigrostriatal dopaminergic degeneration compared to de novo PD - RBD patients. The results support the hypothesis that body-first PD is characterized by more symmetric distribution most likely due to more symmetric propagation of pathogenic α-synuclein compared to brain-first PD.