No increased risk of obstructive sleep apnea in Parkinson's disease

Meta-analysis of the prevalence of obstructive sleep apnea and associated risk factors among Parkinson's disease

Sleep disorders are the most distressing non-motor problems among Parkinson's disease (PD), whereas obstructive sleep apnea (OSA) is a type of sleep disorder that commonly occurs in Parkinson's disease. Therefore, we conducted this meta-analysis to estimate the prevalence of OSA in Parkinson's disease. A comprehensive search in CINAHL, Embase, Ovid MEDLINE, PubMed, Scopus, and Web of Science, following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, was conducted from inception to September 2023 to identify studies on the prevalence of PD patients with OSA. A Comprehensive Meta-Analysis software version 3.0 and R software with random-effects models were used for pooled prevalence and prediction interval analysis. We assessed heterogeneity using I 2 test and Cochran's Q-statistic and study quality with Hoy's risk of bias. Moreover, meta-regression and subgroup analysis identified factors contributing to prevalence. A total of 42 studies with 3342 participants were included. The pooled prevalence of OSA among Parkinson's disease patients was 45% (95% CI: 39-52%). Based on 95% prediction interval, the future prevalence of OSA in PD was expected to vary from 13 to 83%. Moderator analyses showed that male sex, higher BMI, and country geographical area were significantly associated with OSA prevalence, in which South and North America are the top two continents that have a high prevalence of OSA. This study gives a comprehensive overview of the high prevalence of OSA and associated factors in Parkinson's disease, which can be used for planning care and future research.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41105-024-00561-w.

Sleep disorders in Parkinson's disease, an early and multiple problem

In Parkinson's disease (PD), it remains unclear whether sleep disorders including insomnia, REM sleep behavior disorder (RBD), excessive daytime sleepiness (EDS), restless legs syndrome (RLS) and sleep-disordered breathing (SDB), are isolated or combined, interact with each other and are associated with clinical factors. We sought to determine the prevalence and combinations of the main sleep disorders, and their clinical and polysomnographic associations in early stage PD. Sleep disorders were systematically diagnosed after medical interview and video-polysomnography in 162 participants with early stage PD and 58 healthy controls from the baseline of the longitudinal ICEBERG cohort. Demographic, clinical (motor, cognitive, autonomic, psychological and sensory tests), therapeutic and polysomnographic associations of sleep disorders were investigated. Sleep disorders were frequent (71%) and combined in half of the patients. The number of sleep disorders increased with disease duration and dysautonomia. Insomnia was the most common (41%), followed by definite RBD (25%), EDS (25%), and RLS (16%). These disorders were more frequent than in controls whereas SDB was rare, moderate and similar in both groups. In patients, insomnia (mainly difficulties maintaining sleep) was associated with female gender, shorter sleep time and RLS, but not with motor or psychological symptoms. RBD was associated with dysautonomia and advanced age, but not with motor and cognitive measures. EDS was associated with psychiatric and motor symptoms as well as the sedative effects of dopamine agonists but not with other sleep disturbances. Sleep disturbances are frequent and combined in early patients with PD. Their determinants and markers are more organic than psychological.

Setting the clinical context to non-motor symptoms reflected by Park-pain, Park-sleep, and Park-autonomic subtypes of Parkinson's disease

Non-motor symptoms (NMS) of Parkinson's disease (PD) are well described in both clinical practice and the literature, enabling their management and enhancing our understanding of PD. NMS can dominate the clinical pictures and NMS subtypes have recently been proposed, initially based on clinical observations, and later confirmed in data driven analyses of large datasets and in biomarker-based studies. In this chapter, we provide an update on what is known about three common subtypes of NMS in PD. The pain (Park-pain), sleep dysfunction (Park-sleep), and autonomic dysfunction (Park-autonomic), providing an overview of their individual classification, clinical manifestation, pathophysiology, diagnosis, and potential treatments.

Sleep disorders in Lewy body dementia: Mechanisms, clinical relevance, and unanswered questions

In Lewy body dementia (LBD), disturbances of sleep and/or arousal including insomnia, excessive daytime sleepiness, rapid eye movement (REM) sleep behavior disorder, obstructive sleep apnea, and restless leg syndrome are common. These disorders can each exert a significant negative impact on both patient and caregiver quality of life; however, their etiology is poorly understood. Little guidance is available for assessing and managing sleep disorders in LBD, and they remain under-diagnosed and under-treated. This review aims to (1) describe the specific sleep disorders which occur in LBD, considering their putative or potential mechanisms; (2) describe the history and diagnostic process for these disorders in LBD; and (3) summarize current evidence for their management in LBD and consider some of the ongoing and unanswered questions in this field and future research directions.

Stroke in Parkinson's disease: a review of epidemiological studies and potential pathophysiological mechanisms

Parkinson's disease (PD) is the fastest growing neurological disorder and one of the leading neurological causes of disability worldwide following stroke. An overall aging global population, as well as general changes in lifestyle associated with mass industrialization in the last century, may be linked to both increased incidence rates of PD and an increase in cumulative cardiovascular risk. Recent epidemiological studies show an increased risk of stroke, post-stroke complications, and subclinical ischemic insults in PD. PD patients have a host of characteristics that might contribute to increasing the risk of developing ischemic stroke including motor impairment, dysautonomia, and sleep disorders. This increases the urgency to study the interplay between PD and other neurological disorders, and their combined effect on mortality, morbidity, and quality of life. In this review, we provide a comprehensive overview of the studied etiological factors and pathological processes involved in PD, specifically with regard to their relationship to stroke. We hope that this review offers an insight into the relationship between PD and ischemic stroke and motivates further studies in this regard.

Validation of STOP, STOP-BANG, STOP-BAG, STOP-B28, and GOAL screening tools for identification of obstructive sleep apnea in patients with Parkinson disease

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is common in Parkinson disease (PD). Questionnaires can be used as screening tools and have been used as a surrogate definition of OSA in large-scale research. This study aimed to validate the performance of STOP, STOP-BANG, STOP-BAG, STOP-B28, and GOAL and OSA predictors as tools to identify OSA in PD.

METHODS

Data were analyzed from a PD cohort study in which OSA was diagnosed using laboratory polysomnography. We calculated sensitivity and specificity of each questionnaire for OSA using different definitions and performed receiver operating characteristics curve analysis. Linear regression was used to assess adjusted associations between questionnaires and outcomes: Montreal Cognitive Assessment, Epworth Sleepiness Scale, and Movement Disorder Society revision of the Unified Parkinson Disease Rating Scale.

RESULTS

Questionnaire data were available for 68 PD patients (61.8% male, mean age 64.5 [standard deviation 9.9] years, and Hoehn and Yahr score 2.1 [0.8]). OSA (apnea-hypopnea index ≥ 15 events/h) occurred in 69.4% of participants. STOP-B28 ≥ 2 presented a higher sensitivity for OSA than STOP ≥ 2 (0.76 vs 0.65, respectively) and slightly lower specificity (0.65 vs 0.70, respectively). GOAL ≥ 2 had the highest sensitivity but poor specificity. Loud snoring had sensitivity 0.63 and specificity 0.65. STOP and snoring were significantly associated with Montreal Cognitive Assessment, Epworth Sleepiness Scale, and Movement Disorder Society revision of the Unified Parkinson Disease Rating Scale (total, motor, and nonmotor); STOP-BANG, STOP-BAG, and STOP-B28 showed associations with most outcomes, but the GOAL showed none.

CONCLUSIONS

The STOP-B28 followed by STOP and presence of loud snoring alone seem to have the best overall properties to identify PD patients with OSA, whose clinical characteristics differ from the general population with OSA.

CITATION

Gomes T, Benedetti A, Lafontaine A-L, Kimoff RJ Robinson A, Kaminska M. Validation of STOP, STOP-BANG, STOP-BAG, STOP-B28, and GOAL screening tools for identification of obstructive sleep apnea in patients with Parkinson disease. J Clin Sleep Med. 2023;19(1):45-54.

Respiratory Abnormalities in Parkinson's Disease: What Do We Know from Studies in Humans and Animal Models?

Parkinson’s disease (PD) is the second most common progressive neurodegenerative disease characterized by movement disorders due to the progressive loss of dopaminergic neurons in the ventrolateral region of the substantia nigra pars compacta (SNpc). Apart from the cardinal motor symptoms such as rigidity and bradykinesia, non-motor symptoms including those associated with respiratory dysfunction are of increasing interest. Not only can they impair the patients’ quality of life but they also can cause aspiration pneumonia, which is the leading cause of death among PD patients. This narrative review attempts to summarize the existing literature on respiratory impairments reported in human studies, as well as what is newly known from studies in animal models of the disease. Discussed are not only respiratory muscle dysfunction, apnea, and dyspnea, but also altered central respiratory control, responses to hypercapnia and hypoxia, and how they are affected by the pharmacological treatment of PD.

Breathing disorders in neurodegenerative diseases

Neurodegenerative disorders are a diverse group of conditions caused by progressive degeneration of neurons resulting in cognitive, motor, sensory, and autonomic dysfunction, leading to severe disability and death. Pulmonary dysfunction is relatively common in these conditions, may be present early in the disease, and is less well recognized and treated than other symptoms. There are variable disorders of upper and lower airways, central control of ventilation, strength of respiratory muscles, and breathing during sleep which further impact daily activities and quality of life and have the potential to injure vulnerable neurons. Laryngopharyngeal dysfunction affects speech, swallowing, and clearance of secretions, increases the risk of aspiration pneumonia, and can cause stridor and sudden death. In Parkinson's disease, L-Dopa benefits some pulmonary symptoms but there are limited pharmacological treatment options for pulmonary dysfunction. Targeted treatments include strengthening of respiratory muscles, positive airway pressure in sleep and techniques to improve cough efficacy. Well-designed clinical trials are needed to evaluate the long-term benefits of these interventions. Challenges for the future include earlier identification of pulmonary dysfunction in the clinic, institution of the most effective treatments (based on clinical trials that measure long-term meaningful outcomes) and the development of neuroprotective treatment.

Sleep Disorders and Future Diagnosis of Parkinsonism: A Prospective Study Using the Canadian Longitudinal Study on Aging

BACKGROUND

Earlier detection of parkinsonism, specifically during its prodromal stage, may be key to preventing its progression. Previous studies have produced contradictory results on the association between sleep symptoms and prodromal parkinsonism.

OBJECTIVE

We conducted a prospective study within the Canadian Longitudinal Study on Aging (CLSA) to determine whether self-reported symptoms of insomnia, somnolence, apnea, and restless legs syndrome predate the diagnosis of parkinsonism after three years of follow-up.

METHODS

At baseline, amongst other information, participants completed a questionnaire for difficulty initiating or maintaining sleep, daytime somnolence, snoring or stopping breathing during sleep, and symptoms of restless legs syndrome. After 3 years of follow-up, baseline responses from participants who self-reported a new diagnosis of parkinsonism (cases) were compared to those who did not (controls). For each case, 10 controls were individually matched by age, sex, education, BMI, caffeine, smoking, and alcohol. Binary unconditional logistic regression models were used to estimate the association between sleep symptoms and new-onset parkinsonism, adjusting for age, sex, education, BMI, smoking, alcohol, and caffeine.

RESULTS

We identified 58 incident-parkinsonism cases and 580 matched controls (65.5%male, mean age = 69.60, SD = 8.0). Baseline symptoms of sleep-onset insomnia (12.1%vs. 13.0%, Adjusted OR[95%CI] = 0.87[0.32,2.33]), sleep-maintenance insomnia (24.1%vs. 20.2%, AOR = 1.01[0.46,2.20]), daytime somnolence (8.6%vs. 7.4%, AOR = 1.11[0.37,3.39]), obstructive sleep apnea (27.3%vs. 26.2%, AOR = 0.84[0.40,1.79]), and restless leg syndrome (20.6%vs. 9.9%, AOR = 1.34[0.42,4.25]) were similar among those who developed parkinsonism and those who did not.

CONCLUSION

Symptoms of insomnia, somnolence, apnea, and restless legs did not predate a new diagnosis of parkinsonism over 3 years.

Sleep apnea syndrome and subthalamic stimulation in Parkinson's disease

OBJECTIVES

Τhe association between Parkinson's disease (PD) and sleep apnea syndrome (SAS) is not fully elucidated and very few studies reported on SAS outcome after deep brain stimulation (DBS). Here, we compare the clinical profile of PD patients with and without SAS and assess, for the first time, the value of pre-DBS SAS as predictor of post-DBS outcome in PD.

METHODS

Fifty patients were grouped into PD with SAS (PD-SAS+,n = 22) and without (PD-SAS-,n = 28), based on the Apnea-Hypopnea-Index (AHI≥5) in polysomnography. We used novel multivariate statistical models to compare pre-DBS profiles and assess post-DBS motor, non-motor and quality of life (QoL) changes in both groups.

RESULTS

In the entire cohort, 44% of patients had at least mild SAS (AHI≥5), while 22% had at least moderate (AHI≥15). Mean AHI was 11/h (NREM-AHI = 10.2/h and REM-AHI = 13.5/h). The two groups had equal demographics and PD characteristics, and did not differ in respect to unified Parkinson's disease rating scale (UPDRS)-II_OFF, Body-Mass-Index, polysomnographic features, RBD, depression, sleepiness and QoL scores. The PD-SAS+ group had significantly higher scores in UPDRS-III_OFF (41.1 ± 17.7 vs. 30.9 ± 11.7,p < 0.05) compared to PD-SAS- group. The groups did not differ in respect to post-DBS change in UPDRS-II, UPDRS-III, Epworth sleepiness scale, Hamilton depression rating scale and PDQ39 scores. Positive airway pressure therapy had no impact on post-DBS outcome.

CONCLUSIONS

In patients with PD and candidates for DBS, the presence of SAS is associated with increased motor signs, but not with a specific non-motor, QoL or sleep-wake profile. The presence of SAS prior to STN-DBS is not associated with worse outcome after surgery.

Sleep disturbance in movement disorders: insights, treatments and challenges

Sleep and circadian rhythm disturbances are central features of many movement disorders, exacerbating motor and non-motor symptoms and impairing quality of life. Understanding these disturbances to sleep is clinically important and may further our understanding of the underlying movement disorder. This review evaluates the current anatomical and neurochemical understanding of normal sleep and the recognised primary sleep disorders. In addition, we undertook a systematic review of the evidence for disruption to sleep across multiple movement disorders. Rapid eye movement sleep behaviour disorder has emerged as the most reliable prodromal biomarker for the alpha synucleinopathies, including Parkinson's disease and multiple system atrophy, often preceding motor symptom onset by several years. Abnormal sleep has also been described for many other movement disorders, but further evidence is needed to determine whether this is a primary or secondary phenotypic component of the underlying condition. Medication used in the treatment of motor symptoms also affects sleep and can aggravate or cause certain sleep disorders. Within the context of movement disorders, there is also some suggestion of a shared underlying mechanism for motor and sleep pathophysiology, with evidence implicating thalamic and brainstem structures and monoaminergic neurotransmission. This review highlights the need for an understanding of normal and abnormal sleep within the movement disorder clinic, an ability to screen for specific causes of poor sleep and to treat sleep disturbance to improve quality of life. Key sleep disorders also act as important biomarkers and have implications in diagnosis, prognosis and the development of future therapies.

Sleep Disorders in Parkinson Disease

Sleep disorders in Parkinson disease have attracted the attention of clinicians and researchers for decades. Recently, major advances in their clinical characterization, polysomnographic description, pathophysiologic understanding, and treatment took place. Parkinson disease encompasses the whole spectrum of sleep medicine: every category of sleep disorder can be observed in these patients. Video polysomnography frequently is indicated, sometimes followed by multiple sleep latency/maintenance of wakefulness tests. Additional studies may include actigraphy, cardiorespiratory polygraphy, and dim light melatonin assessment. Treatment needs to be specific to the underlying sleep disorder and can include medications and nondrug treatments, for example, behavioral therapy and light therapy.

Sleep Disturbances and Sleep Disordered Breathing Impair Cognitive Performance in Parkinson's Disease

Background

Sleep disturbances and impairment of cognitive function are among the most frequent non-motor symptoms in Parkinson’s disease (PD) with negative implications on quality of life of patients and caregivers. Despite the fact that sleep disturbances are a major issue in PD patients, only limited data are available regarding interactions of sleep disturbances and cognitive performance.

Objective

This post hoc analysis of the RaSPar trial was therefore designed to further elucidate sleep disturbances and their impact on cognition in PD.

Methods

Twenty-six PD patients with sleep disturbances were evaluated thoroughly including assessments of patients’ subjective and objective sleep quality by interview, questionnaires, and polysomnography (PSG). Cognitive performance was assessed by Parkinson Neuropsychometric Dementia Assessment (PANDA) and Test of Attentional Performance (TAP), and associations of sleep and cognitive function were evaluated.

Results

We did not detect differences in cognitive performance between patients with and without rapid eye movement (REM) sleep behavior disorder (RBD). Instead, cognitive impairment, particularly affecting cognitive domains attention, executive function/working memory, and semantic memory, was associated with impaired PSG-measured sleep quality (e.g., sleep efficiency) and sleep disordered breathing (SDB) (Apnea-Hypopnea Index > 5/h). Global cognitive performance was decreased in patients with SDB (PANDA score 23.2 ± 3.5 vs. 26.9 ± 2.2, P = 0.020, unpaired two-sided t-test).

Conclusion

Sleep apnea and other sleep disturbances impair cognitive performance in PD and should be evaluated in routine care, and treatment options such as continuous airway pressure therapy should be considered.

Sleep-Disordered Breathing in REM Sleep Behavior Disorder with or without Parkinson's Disease

REM sleep behavior disorder (RBD) might render patients with Parkinson's disease prone to sleep-disordered breathing. This retrospective polysomonographic study assessed the prevalence of sleep-disordered breathing in 108 consecutive patients with either both Parkinson's disease and RBD (n = 37), Parkinson's disease without RBD (n = 21), or isolated RBD (n = 50). Across all patients, 25% had at least moderate sleep-related breathing disorder, without significant differences between groups. Following multivariable analysis, RBD influenced sleep-related breathing parameters modestly but not significantly, whereas body mass index had a prominent impact. Further studies with larger patient cohorts are needed, and confounders like body mass index must adequately be controlled for.

Obstructive Sleep Apnea in Neurodegenerative Disorders: Current Evidence in Support of Benefit from Sleep Apnea Treatment

Obstructive sleep apnea (OSA) is a prevalent disorder characterized by recurrent upper airway obstruction during sleep resulting in intermittent hypoxemia and sleep fragmentation. Research has recently increasingly focused on the impact of OSA on the brain's structure and function, in particular as this relates to neurodegenerative diseases. This article reviews the links between OSA and neurodegenerative disease, focusing on Parkinson's disease, including proposed pathogenic mechanisms and current knowledge on the effects of treatment.

Sleep in Parkinson's disease

Sleep disturbances are common in Parkinson's disease and comprise the entire spectrum of sleep disorders. On the one hand regulation of sleep and wakefulness is affected in Parkinson's disease, leading to the development of disorders, such as insomnia and daytime sleepiness. While on the other hand control of motor activity during sleep is impaired, with subsequent manifestation of parasomnias (mainly REM sleep behavior disorders, but also, albeit more rarely, sleepwalking, and overlap parasomnia). Restless legs syndrome has been reported to be frequent in patients with Parkinson's disease, although there is no consensus on whether it is more frequent in Parkinson's disease than in the general population. The same is true for sleep-related breathing disorders. Regarding the diagnosis of sleep disorders in patients with Parkinson's disease, one of the main challenges is correctly identifying excessive daytime sleepiness as there are many potential confounding factors, for example it is necessary to distinguish sleep-related breathing disorders from medication effects, and to distinguish restless legs syndrome from the concomitant presence of potential mimics specific to Parkinson's disease, such as akathisia, nocturnal leg cramps, nocturnal hypokinesia, early morning dystonia, etc. The correct diagnosis of REM sleep behavior disorder is also not always easy, and video-polysomnography should be performed in order to exclude mimic-like movements at the end of sleep apneas or violent periodic leg movements of sleep. These aspects and specific considerations about diagnosis and treatment of sleep disorders in patients with Parkinson's disease will be reviewed.

New awakenings: current understanding of sleep dysfunction and its treatment in Parkinson's disease

The non-motor features of Parkinson’s disease (PD) are increasingly being recognised. This review deals with the spectrum of sleep disorders associated with PD, which have a multifactorial aetiology and can significantly have an impact on the quality of life of patients and their carers. Some sleep disorders represent a prodromal phase of PD, with REM sleep behaviour disorder (RBD) being of particular interest in this regard, whereas others become more common as the disease advances. Understanding the pathophysiology of these sleep disturbances will hopefully lead to new treatment opportunities in the future. The recent discovery of the glymphatic system for removal of waste products from the brain has also raised the possibility that sleep disruption may cause or accelerate the underlying disease process.

Overview of Sleep and Circadian Rhythm Disorders in Parkinson Disease

Sleep disorders are common among PD patients and affect quality of life. They are often under-recognized and under-treated. Mechanisms of sleep disorders in PD remain relatively poorly understood. Improved awareness of common sleep problems in PD. Tailored treatment and evidence for efficacy are lacking. The purpose of this review is to provide an overview and update on the most common sleep disorders in PD. We review specific features of the most common sleep disorders in PD, including insomnia, excessive daytime sleepiness, sleep-disordered breathing, restless legs syndrome, circadian rhythm disorders and REM sleep behavior disorders.

Obstructive sleep apnea and Parkinson's disease: characteristics and associated factors

ABSTRACT Obstructive sleep apnea (OSA) occurs in up to 66% of Parkinson's disease (PD) patients, higher than in the general population. Although it is more prevalent, the relationship between OSA and PD remains controversial, with some studies confirming and others denying the relationship of OSA with some risk factors and symptoms in patients with PD. Objective: To determine the factors associated with OSA in PD patients com DP. Methods: A cross-sectional study was performed with 88 consecutive patients with PD from the outpatient clinic. Participants underwent clinical interviews with neurologists and a psychiatrist, assessment using standardized scales (Epworth Sleepiness Scale, Parkinson's Disease Questionnaire, Pittsburgh Sleep Quality Index and, for individuals with a diagnosis of restless legs syndrome/Willis-Ekbom disease, the International Restless Legs Syndrome Rating Scale), and video-polysomnography. Results: Individuals with PD and OSA were older and had less insomnia than those with PD without OSA. Regarding the polysomnographic variables, we observed a lower percentage of stage N3 sleep, a higher arousal index, and a higher oxygen desaturation index in those individuals with OSA, relative to those without OSA. In the multivariate analysis, only the percentage of stage N3 sleep and the oxygen desaturation index were significantly different. Besides this, most of the PD patients with OSA had a correlation with sleeping in the supine position (58% of OSA individuals). Conclusion: The PD patients showed a high prevalence of OSA, with the supine position exerting a significant influence on the OSA in these patients, and some factors that are associated with OSA in the general population did not seem to have a greater impact on PD patients.

Parkinson's disease: Diagnosis and appreciation of comorbidities

Parkinson's disease (PD) is a complex neuropsychiatric disorder that manifests with a variety of motor and nonmotor symptoms. Its incidence increases with age. It is important for clinicians to be able to distinguish symptoms of aging and other comorbidities from those of PD. The diagnosis of PD has traditionally been rendered using strict criteria that mainly rely on the cardinal motor symptoms of rest tremor, rigidity, and bradykinesia. However, newer diagnostic criteria proposed by the Movement Disorders Society for diagnosis of PD collectively reflect a greater appreciation for the nonmotor symptoms. The treatment of PD remains symptomatic and the most noticeable improvements have been documented in the motor symptoms. Levodopa remains the gold standard for therapy, however there are now many other potential medical and surgical treatment strategies. Nonmotor symptoms have been shown to affect quality of life more than the motor symptoms. There is ongoing research into symptomatic and disease modifying treatments. Given the multisystem involvement in PD, an interdisciplinary patient-centered approach is recommended by most experts. This chapter addresses first the diagnostic approach and the many geriatric considerations. This is followed by a review of the nonmotor symptoms. Finally, a summary of current treatment strategies in PD is presented along with potential treatment complications.

Comorbid Sleep Disturbances in Neurologic Disorders

PURPOSE OF REVIEW

This article provides a review of disturbances of sleep comorbid with common neurologic disorders.

RECENT FINDINGS

A wide variety of neurologic disorders are frequently complicated by comorbid sleep disturbances. In many cases, a bidirectional relationship appears to occur between sleep function and the neurologic disease, such that treatment of comorbid sleep disturbances may improve the symptoms of the neurologic disease.

SUMMARY

Neurologic disorders are often associated with abnormalities of sleep. Sleep influences the severity of both epilepsy and headache, and treatment of comorbid sleep disorders may improve seizure and headache frequency. Alzheimer disease is characterized by circadian phase delay and poor nighttime sleep and is strongly associated with obstructive sleep apnea. Parkinson disease is associated with several sleep disorders, including insomnia, restless legs syndrome, rapid eye movement (REM) sleep behavior disorder, daytime hypersomnia, and sleep-disordered breathing. Hypoventilation in amyotrophic lateral sclerosis and other neuromuscular disorders often presents initially with sleep problems, and treatment with noninvasive ventilation improves survival and quality of life.

An overview of sleep and circadian dysfunction in Parkinson's disease

Sleep and circadian alterations are amongst the very first symptoms experienced in Parkinson's disease, and sleep alterations are present in the majority of patients with overt clinical manifestation of Parkinson's disease. However, the magnitude of sleep and circadian dysfunction in Parkinson's disease, and its influence on the pathophysiology of Parkinson's disease remains often unclear and a matter of debate. In particular, the confounding influences of dopaminergic therapy on sleep and circadian dysfunction are a major challenge, and need to be more carefully addressed in clinical studies. The scope of this narrative review is to summarise the current knowledge around both sleep and circadian alterations in Parkinson's disease. We provide an overview on the frequency of excessive daytime sleepiness, insomnia, restless legs, obstructive apnea and nocturia in Parkinson's disease, as well as addressing sleep structure, rapid eye movement sleep behaviour disorder and circadian features in Parkinson's disease. Sleep and circadian disorders have been linked to pathological conditions that are often co-morbid in Parkinson's disease, including cognitive decline, memory impairment and neurodegeneration. Therefore, targeting sleep and circadian alterations could be one of the earliest and most promising opportunities to slow disease progression. We hope that this review will contribute to advance the discussion and inform new research efforts to progress our knowledge in this field.

Sleep-wake disturbances in the premotor and early stage of Parkinson's disease

PURPOSE OF REVIEW

Review of recent literature pertaining to frequency, associations, mechanisms, and overall significance of sleep--wake disturbances (SWD) in the premotor and early phase of Parkinson's disease.

RECENT FINDINGS

SWD are frequent in Parkinson's disease and their prevalence increases with disease progression. Recent studies confirm previous findings that SWD can appear as initial manifestation of Parkinson's disease even decades before motor signs appear and highlight their clinical associations in these early stages. More intriguingly, new evidence underpins their role as risk factors, predictors, or even as driving force for the neurodegenerative process. As our understanding of sleep--wake neurobiology increases, new hypotheses emerge concerning the pathophysiology of SWD in early Parkinson's disease stages involving dopaminergic and nondopaminergic mechanisms.

SUMMARY

SWD are predictors for the development of parkinsonian syndromes including Parkinson's disease. This may offer the opportunity of developing new preventive strategies and interventions at an early stage of this neurodegenerative disease.

Ventilatory Dysfunction in Parkinson's Disease

In contrast to some other neurodegenerative diseases, little is known about ventilatory dysfunction in Parkinson’s disease (PD). To assess the spectrum of ventilation disorders in PD, we searched for and reviewed studies of dyspnea, lung volumes, respiratory muscle function, sleep breathing disorders and the response to hypoxemia in PD. Among the studies, we identified some limitations: (i) small study populations (mainly composed of patients with advanced PD), (ii) the absence of long-term follow-up and (iii) the absence of functional evaluations under “off-drug” conditions. Although there are many reports of abnormal spirometry data in PD (mainly related to impairment of the inspiratory muscles), little is known about hypoventilation in PD. We conclude that ventilatory dysfunction in PD has been poorly studied and little is known about its frequency and clinical relevance. Hence, there is a need to characterize the different phenotypes of ventilation disorders in PD, study their relationships with disease progression and assess their prognostic value.

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.

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 influence of sleep disordered breathing in REM sleep behavior disorder

OBJECTIVES/BACKGROUND

Because both REM sleep behavior disorder (RBD) and Obstructive Sleep Apnea (OSA) can present with similar symptoms, it is important to understand the influence of OSA in the clinical manifestations of RBD and whether RBD modulates OSA severity. Our objectives were to compare: 1. the intensity of non-motor symptoms between RBD patients with (RBD-OSA) and without OSA (RBD-non-OSA), and 2. polysomnographic features between RBD-OSA and OSA without RBD (OSA-non-RBD) patients.

METHODS

32 RBD cases were divided in two groups according to the presence of moderate to severe OSA [Apnea Hypopnea Index (AIH) > 14] (RBD-OSA vs. RBD-non-OSA). Non-motor symptoms were assessed with Montreal Cognitive Assessment Scale, SCOPA-Sleep and the Non-Motor Symptom Scale (NMSS) for Parkinson's disease. RBD-OSA patients were compared to 20 OSA-non-RBD patients matched for age, AHI and gender.

RESULTS

Compared to RBD-non-OSA (n = 22) patients, RBD-OSA patients (n = 10) showed significantly higher scores in SCOPA-Sleep Daytime and NMSS Attention/Memory, Gastrointestinal and Urinary domains, as well as higher sleep fragmentation, more oxygen desaturation and higher AIH in NREM sleep. RBD-OSA patients presented with less O₂ desaturation, snoring, and BMI when compared to OSA-non-RBD patients.

DISCUSSION

Our data suggests that OSA contributes to hypersomnolence, gastro-intestinal, memory, and urinary complaints in RBD patients. RBD patients seem to have a milder OSA phenotype (possible reflecting a protective role conferred by the maintenance of muscle tone during REM sleep) and to be less prone to obesity and snoring than non-RBD patients.

Multifactorial sleep disturbance in Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder, ranking only behind Alzheimer's disease and affecting 2% of the population over the age of 65. Pathophysiologically, PD is characterized by selective degeneration of the dopaminergic neurons of the substantia nigra pars compacta (SNpc) and striatal dopamine depletion. Patients may also exhibit mild-to-severe degeneration of other central and peripheral nervous tissues. The most dramatic symptoms of the disease are profound dopamine-responsive motor disturbances, including bradykinesia, akinesia, rigidity, resting tremor, and postural instability. PD patients commonly present with debilitating non-motor symptoms, including cognitive impairment, autonomic nervous system dysfunction, and sleep disturbance. Of these, sleep disturbance is the most consistently reported, and likely represents a disorder integrative of PD-related motor impairment, autonomic nervous system dysfunction, iatrogenic insult, and central neurodegeneration. The pathophysiology of PD may also indirectly disrupt sleep by increasing susceptibility to sleep disorders, including sleep disordered breathing, periodic limb movements, and REM behavior disorder. In this review, we will discuss these systems representing a multifactorial etiology in PD sleep disturbance.

Reduced cognitive function in patients with Parkinson disease and obstructive sleep apnea

OBJECTIVE

To assess the association between obstructive sleep apnea (OSA) and nonmotor symptoms (NMS), including cognitive dysfunction, in patients with Parkinson disease (PD).

METHODS

Patients with idiopathic PD, recruited from a movement disorder clinic, underwent overnight polysomnography. OSA was defined as an apnea-hypopnea index (AHI) ≥15/h. PD severity was assessed using the Hoehn & Yahr (H&Y) scale and the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS). NMS were assessed using the Montreal Cognitive Assessment (MoCA), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale, Apathy Scale, Beck Depression Inventory, Hospital Depression and Anxiety Scale, and PD sleep Scale.

RESULTS

Sixty-seven patients (61.2% male), mean age 64.4 (SD 9.9) years and motor MDS-UPDRS 21.9 (12.6) using levodopa equivalent dose (LED) 752.4 (714.6) mg/d, were studied. OSA occurred in 47 patients (61.6%, mean AHI 27.1/h, SD 20.2/h), and NMS in 57 patients (85%). ESS and MoCA were associated with the AHI (ESS β = 0.0670, p = 0.031; MoCA β = -0.0520, p = 0.043, adjusted for age, sex, body mass index, LED, and H&Y). ESS was associated with respiratory arousals (β = 0.1015, p = 0.011) and intermittent hypoxemia (β = 0.1470, p = 0.006). MoCA was negatively associated with respiratory arousals (β = -0.0596, p = 0.049) but not intermittent hypoxemia.

CONCLUSIONS

OSA is associated with sleepiness and cognitive dysfunction in PD, suggesting that OSA may be a reversible contributor to these NMS. Further studies will be required to evaluate whether OSA treatment can improve excessive sleepiness and cognitive dysfunction in PD.

Management of sleep disorders in Parkinson's disease and multiple system atrophy

Parkinson's disease (PD) and multiple system atrophy (MSA) are disorders associated with α synuclein-related neurodegeneration. Nonmotor symptoms are common hallmarks of these disorders, and disturbances of the sleep-wake cycle are among the most common nonmotor symptoms. It is only recently that sleep disturbances have received the attention of the medical and research community. Significant progress has been made in understanding the pathophysiology of sleep and wake disruption in alphasynucleinopathies during the past few decades. Despite these advancements, treatment options are limited and frequently associated with problematic side effects. Further studies that center on the development of novel treatment approaches are very much needed. In this article, the author discusses the current state of the management of disturbed sleep and alertness in PD and MSA. © 2017 International Parkinson and Movement Disorder Society.

Sleep apnoea and the neurologist

There is increasing awareness and interest in the complex and extensive inter-relationships between sleep disorders and neurological disorders. This review focuses on the clinical interactions between obstructive sleep apnoea and stroke, headaches, epilepsy, cognition and idiopathic Parkinson's disease. We highlight to the neurologist the importance of taking a sleep history and considering the diagnosis and treatment of obstructive sleep apnoea.

Diagnosis of Obstructive Sleep Apnea in Parkinson's Disease Patients: Is Unattended Portable Monitoring a Suitable Tool?

Purpose. Obstructive sleep apnea (OSA) is frequent in Parkinson's disease (PD) and may contribute to nonmotor symptoms. Polysomnography (PSG) is the gold standard for OSA diagnosis. Unattended portable monitoring (PM) may improve access to diagnosis but has not been studied in PD. We assessed feasibility and diagnostic accuracy in PD. Methods. Selected PD patients without known OSA underwent home PM and laboratory PSG. The quality of PM signals (n = 28) was compared with matched controls. PM accuracy was calculated compared with PSG for standard apnea hypopnea index (AHI) thresholds. Results. Technical failure rate was 27.0% and airflow signal quality was lower than in controls. Sensitivity of PM was 84.0%, 36.4%, and 50.0% for AHI cut-offs of 5/h, 15/h, and 30/h, respectively, using the same cut-offs on PM. Specificity was 66.7%, 83.3%, and 100%, respectively. PM underestimated the AHI with a mean bias of 12.4/h. Discrepancy between PM and PSG was greater in those with more motor dysfunction. Conclusion. PM was adequate to “rule in” moderate or severe OSA in PD patients, but the failure rate was relatively high and signal quality poorer than in controls. PM overall underestimated the severity of OSA in PD patients, especially those with greater motor dysfunction.

The Interaction between Obstructive Sleep Apnea and Parkinson's Disease: Possible Mechanisms and Implications for Cognitive Function

Parkinson's disease (PD) is a relentlessly progressive neurodegenerative disorder associated with hallmark motor and nonmotor symptoms (NMS) such as sleep disturbances and cognitive dysfunction. While dopaminergic treatments have improved the motor aspects of PD, progression remains inevitable. Research has recently increasingly focused on strategies to modify disease progression and on nonmotor manifestations of PD, given their impact on patients' quality of life. Obstructive sleep apnea (OSA) is a treatable sleep disorder, common in the general population, associated with excessive daytime sleepiness and neurocognitive deficits. Neuroimaging has demonstrated structural and functional changes in OSA patients; in animal models, OSA causes brain inflammation and oxidative injury, including in key areas involved in PD pathophysiology such as locus coeruleus. The prevalence of OSA in PD has been variable in studies to date, and potential consequences and interrelationship between the two disorders have not been well studied. There is however emerging evidence that OSA is associated with increased NMS in PD, particularly cognitive dysfunction. This review focuses on the possible interrelationship between OSA and PD. Mechanisms promoting OSA in PD will be reviewed, as well as mechanisms whereby OSA can affect the neurodegenerative process in PD.

A Polysomnographic Study of Parkinson's Disease Sleep Architecture

Sleep disturbance is a common nonmotor phenomenon in Parkinson's disease (PD) affecting patient's quality of life. In this study, we examined the association between clinical characteristics with sleep disorders and sleep architecture patterns in a PD cohort. Patients underwent a standardized polysomnography study (PSG) in their “on medication” state. We observed that male gender and disease duration were independently associated with obstructive sleep apnea (OSA). Only lower levodopa equivalent dose (LED) was associated with periodic limb movement disorders (PLMD). REM sleep behavior disorder (RBD) was more common among older patients, with higher MDS-UPDRS III scores, and LED. None of the investigated variables were associated with the awakenings/arousals (A/A). Sleep efficiency was predicted by amantadine usage and age, while sleep stage 1 was predicted by dopamine agonists and Hoehn & Yahr severity. The use of MAO-B inhibitors and MDS-UPDRS part III were predictors of sleep stages 2 and 3. Age was the only predictor of REM sleep stage and gender for total sleep time. We conclude that sleep disorders and architecture are poorly predictable by clinical PD characteristics and other disease related factors must also be contributing to these sleep disturbances.

Parkinson's disease and sleep/wake disturbances

Sleep disturbances are a common non-motor feature in patients with Parkinson's disease (PD). Early diagnosis and appropriate management are imperative for enhancing patient quality of life. Sleep disturbances can be caused by multiple factors in addition to age-related changes in sleep, such as nocturnal motor symptoms (rigidity, resting tremor, akinesia, tardive dyskinesia, and the "wearing off" phenomenon), non-motor symptoms (pain, hallucination, and psychosis), nocturia, and medication. Disease-related pathology involving the brainstem and changes in the neurotransmitter systems (norepinephrine, serotonin, and acetylcholine) responsible for regulating sleep structure and the sleep/wake cycle play a role in emerging excessive daytime sleepiness and sleep disturbances. Additionally, screening for sleep apnea syndrome, rapid eye movement sleep behavior disorder, and restless legs syndrome is clinically important. Questionnaire-based assessment utilizing the PD Sleep Scale-2 is useful for screening PD-related nocturnal symptoms. In this review, we focus on the current understanding and management of sleep disturbances in PD.

Development of the National Healthy Sleep Awareness Project Sleep Health Surveillance Questions

OBJECTIVES

For the first time ever, as emphasized by inclusion in the Healthy People 2020 goals, sleep health is an emphasis of national health aims. The National Healthy Sleep Awareness Project (NHSAP) was tasked to propose questions for inclusion in the next Behavioral Risk Factor Surveillance System (BRFSS), a survey that includes a number of questions that target behaviors thought to impact health, as a means to measure community sleep health. The total number of questions could not exceed five, and had to include an assessment of the risk for obstructive sleep apnea (OSA).

METHODS

An appointed workgroup met via teleconference and face-to-face venues to develop an inventory of published survey questions being used to identify sleep health, to develop a framework on which to analyze the strengths and weaknesses of current survey questions concerning sleep, and to develop recommendations for sleep health and disease surveillance questions going forward.

RESULTS

The recommendation was to focus on certain existing BRFSS questions pertaining to sleep duration, quality, satisfaction, daytime alertness, and to add to these other BRFSS existing questions to make a modified STOP-BANG questionnaire (minus the N for neck circumference) to assess for risk of OSA.

CONCLUSIONS

Sleep health is an important dimension of health that has previously received less attention in national health surveys. We believe that 5 questions recommended for the upcoming BRFSS question banks will assist as important measures of sleep health, and may help to evaluate the effectiveness of interventions to improve sleep health in our nation.

Obstructive sleep apnea and risk of Parkinson's disease: a population-based cohort study

Sleep disorders could be associated with neurodegenerative diseases. This study aimed to determine the risk of Parkinson's disease in patients with obstructive sleep apnea. The incident cases of newly diagnosed obstructive sleep apnea were identified between 2000 and 2009 from the medical claims database of National Health Institute of Taiwan. The risk of Parkinson's disease onset at least 1 year after the diagnosis of obstructive sleep apnea was measured during and up to 11 years of period, compared to that of age- and gender-matched controls estimated in the same period. A total of 5864 patients with newly diagnosed obstructive sleep apnea and 23,269 subjects without obstructive sleep apnea were identified for data analysis. The study reported that the incidence of Parkinson's disease in the obstructive sleep apnea cohort was approximately two times higher than that in the control cohort (2.57 versus 1.32 per 1000 person-years), with an adjusted hazard ratio of 1.84. Furthermore, the risk of Parkinson's disease was particularly greater for the obstructive sleep apnea with insomnia subgroup (adjusted hazard ratio = 1.97, 95% confidence interval = 1.44-2.69) than for the control cohort. The sex-age-specific analysis further discovered that the most elevated risk of Parkinson's disease onset was noted in female obstructive sleep apnea patients aged 50-69 years (adjusted hazard ratio = 2.82). This population-based study indicated that patients with obstructive sleep apnea, especially those who suffered from insomnia, are at an increased risk of Parkinson's disease onset.

Obstructive sleep apnea and neurodegenerative diseases: A bidirectional relation

Sleep disorders are common during the clinical course of the main neurodegenerative diseases. Among these disorders, obstructive sleep apnea has been extensively studied in the last decade and recent knowledge regarding its relationship with the neurodegenerative process points a bidirectional relationship. Neurodegenerative diseases can lead to functional changes in the respiratory system that facilitate the emergence of apnea. On the other hand, obstructive sleep apnea itself can lead to acceleration of neuronal death due to intermittent hypoxia. Considering that obstructive sleep apnea is a potentially treatable condition, its early identification and intervention could have a positive impact on the management of patients with neurodegenerative diseases.