Sleep Disturbances and Sleep Disordered Breathing Impair Cognitive Performance in 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.

Prevalence and clinical aspects of obstructive sleep apnea in Parkinson disease: A meta-analysis

BACKGROUND AND PURPOSE

Obstructive sleep apnea (OSA) frequently occurs in Parkinson Disease (PD), probably caused by upper airway dysfunctions or shared pathogenetic mechanisms. OSA may precede PD diagnosis or worsen throughout its course, but its relationship with clinical features and dopaminergic medication remains unclear. This meta-analysis aimed to provide a reliable estimate of OSA prevalence in the PD population (PD-OSA) and to clarify its clinical associated factors to help clinicians in understanding the underlying pathophysiological mechanisms.

METHODS

A systematic literature search was performed up to April 2023 using the PubMed, Scopus, and PsycINFO databases. Articles were included if they provided data on PD patients with and without OSA. Pooled prevalence for PD-OSA was calculated using the proportions of PD participants diagnosed with OSA. Demographic and clinical features associated with PD-OSA were explored by comparing PD patients with and without OSA.

RESULTS

Seventeen studies were included in the meta-analysis. Pooled OSA prevalence was 45% of a total sample of 1448 PD patients and was associated with older age, male sex, higher body mass index (BMI), more severe motor disturbances and periodic limb movements, reduced risk of rapid eye movement sleep behavior disorder, intake of dopamine agonists, and worse excessive daytime sleepiness. No relationship emerged with cognitive functioning and neuropsychiatric manifestations.

CONCLUSIONS

OSA affects nearly half of PD patients as a secondary outcome of predisposing factors such as older age and higher BMI in addition to PD-related motor impairment. Future studies should focus on determining the impact of both clinical features and dopaminergic medication on the development of PD-OSA.

Correlation and underlying brain mechanisms between rapid eye movement sleep behavior disorder and executive functions in Parkinson's disease: an fNIRS study

Purpose

Rapid eye movement sleep behavior disorder (RBD) affects 30%-40% of patients with Parkinson's disease (PD) and has been linked to a higher risk of cognitive impairment, especially executive dysfunction. The aim of this study was to investigate the brain activation patterns in PD patients with RBD (PD-RBD+) compared to those without RBD (PD-RBD-) and healthy controls (HCs), and to analyze the correlation between changes in cerebral cortex activity and the severity of RBD.

Methods

We recruited 50 PD patients, including 30 PD-RBD+, 20 PD-RBD-, and 20 HCs. We used functional near infrared spectroscopy during a verbal fluency task (VFT-fNIRS) and clinical neuropsychological assessment to explore the correlation between PD-RBD+ and executive function and changes in neural activity.

Results

The VFT-fNIRS analysis revealed a significant reduction in activation among PD-RBD+ patients across multiple channels when compared to both the PD-RBD- and HC groups. Specifically, PD-RBD+ patients exhibited diminished activation in the bilateral dorsolateral prefrontal cortex (DLPFC) and the right ventrolateral prefrontal cortex (VLPFC) relative to their PD-RBD- counterparts. Furthermore, compared to the HC group, PD-RBD+ patients displayed reduced activation specifically in the right DLPFC. Significantly, a noteworthy negative correlation was identified between the average change in oxygenated hemoglobin concentration (ΔHbO2) in the right DLPFC of PD-RBD+ patients and the severity of their RBD.

Conclusion

Our study offers compelling evidence that RBD exacerbates cognitive impairment in PD, manifested as executive dysfunction, primarily attributed to reduced prefrontal activation. These aberrations in brain activation may potentially correlate with the severity of RBD.

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 disturbance and health-related quality of life in Parkinson's disease: A clear correlation between health-related quality of life and subjective sleep quality

INTRODUCTION

Comorbid insomnia and poor sleep quality in Parkinson's disease (PD) are associated with a poor health-related quality of life (HRQoL). However, the relationship between HRQoL and sleep measures obtained using polysomnography (PSG) remains unclear. We aimed to examine the association between various sleep measures and HRQoL in PD patients.

METHODS

We retrospectively included patients with PD who underwent PSG and responded to self-administered questionnaires including the Pittsburgh Sleep Quality Index (PSQI) and Medical Outcomes Study 36-Item Short-Form Health Survey.

RESULTS

The patients' (n = 120) mean age was 67.06 (SD = 8.77) years, and their mean Hoehn and Yahr stage was 2.25 (SD = 0.78). A higher PSQI score (worse subjective sleep quality) was correlated in PSG with shorter sleep latency, less N1 sleep, and more N2 sleep. Multiple regression analysis showed that the total PSQI score correlated with both physical and mental HRQoL (p < 0.001 in both cases). However, neither type of HRQoL studied correlated with objective sleep measures, including indicators of sleep architecture, sleep-disordered breathing, and sleep related movement disorders.

CONCLUSION

Despite the association between subjective sleep quality and HRQoL, the associations between objective measures and HRQoL were negligible. Objective sleep fragmentation may not be perceived as a sleep disturbance in patients with PD, and therefore may not adversely affect their subjective health, given the paradoxical correlation between PSQI score and sleep architecture.

Progressive Prefrontal Cortex Dysfunction in Parkinson's Disease With Probable REM Sleep Behavior Disorder: A 3-Year Longitudinal Study

This study aimed to explore the disrupted prefrontal cortex activity specific to patients with Parkinson's disease (PD) with rapid eye movement sleep behavior disorder (RBD) compared with those without and to further examine the associations between these alterations and neuropsychological measurements. Ninety-six patients with early PD underwent both structural and functional MRI, and also neuropsychological assessments in the Parkinson's Progression Markers Initiative (PPMI) database. Of these, 46 patients who completed 1- and 3-year fMRI follow-up examinations were categorized as PD with probable RBD (PD-pRBD+) and without (PD-pRBD−). The left dorsolateral prefrontal cortex (DLPFC) seed-to-voxel functional connectivity analysis was conducted to evaluate the progressive neural alterations specific to PD-pRBD+ compared with PD-pRBD− over time. Furthermore, relationships between these alterations and neuropsychological performance were examined. Compared with patients with PD-pRBD−, patients with PD-pRBD+ initially exhibited connectivity deficits between the left DLPFC and the medial frontopolar cortex. Moreover, these patients further exhibited disrupted DLPFC connectivity in the lateral frontopolar cortex at the 3-year follow-up evaluation. Correlation analysis revealed that connectivity between the left DLPFC and frontopolar cortex was positively related to executive function in PD-pRBD+ after adjusting for nuisance variables. Progressive prefrontal cortex dysfunction associated with RBD in early PD may provide an effective subtype-specific biomarker of neurodegenerative progression, which may shed light on the neuropathological mechanisms underlying the clinical heterogeneity of this disease.

Obesity-related kidney disease: Beyond hypertension and insulin-resistance

Chronic kidney disease (CKD) causes considerable morbidity, mortality, and health expenditures worldwide. Obesity is a significant risk factor for CKD development, partially explained by the high prevalence of diabetes mellitus and hypertension in obese patients. However, adipocytes also possess potent endocrine functions, secreting a myriad of cytokines and adipokines that contribute to insulin resistance and induce a chronic low-grade inflammatory state thereby damaging the kidney. CKD development itself is associated with various metabolic alterations that exacerbate adipose tissue dysfunction and insulin resistance. This adipose-renal axis is a major focus of current research, given the rising incidence of CKD and obesity. Cellular senescence is a biologic hallmark of aging, and age is another significant risk factor for obesity and CKD. An elevated senescent cell burden in adipose tissue predicts renal dysfunction in animal models, and senotherapies may alleviate these phenotypes. In this review, we discuss the direct mechanisms by which adipose tissue contributes to CKD development, emphasizing the potential clinical importance of such pathways in augmenting the care of CKD.

Management of Sleep Disturbances in Parkinson's Disease

Parkinson's disease (PD) is defined by its motor symptoms rigidity, tremor, and akinesia. However, non-motor symptoms, particularly autonomic disorders and sleep disturbances, occur frequently in PD causing equivalent or even greater discomfort than motor symptoms effectively decreasing quality of life in patients and caregivers. Most common sleep disturbances in PD are insomnia, sleep disordered breathing, excessive daytime sleepiness, REM sleep behavior disorder, and sleep-related movement disorders such as restless legs syndrome. Despite their high prevalence, therapeutic options in the in- and outpatient setting are limited, partly due to lack of scientific evidence. The importance of sleep disturbances in neurodegenerative diseases has been further emphasized by recent evidence indicating a bidirectional relationship between neurodegeneration and sleep. A more profound insight into the underlying pathophysiological mechanisms intertwining sleep and neurodegeneration might lead to unique and individually tailored disease modifying or even neuroprotective therapeutic options in the long run. Therefore, current evidence concerning the management of sleep disturbances in PD will be discussed with the aim of providing a substantiated scaffolding for clinical decisions in long-term PD therapy.

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

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

Sleep Disorders and Cognitive Dysfunctions in Parkinson's Disease: A Meta-Analytic Study

A relationship between sleep disorders and cognitive dysfunctions was reported in Parkinson's Disease (PD), however, some studies did not confirm the link. A meta-analytic study was performed to investigate the relationship between sleep disorders and cognitive dysfunctions, and to clarify the evolution of cognitive status in PD patients with sleep disorders.The systematic literature search was performed up to November 2020 using PubMed, Scopus, and PsycINFO databases. We included studies published in peer-reviewed journals in English providing results about neuropsychological comparison between patients with or without sleep disorders. Meta-analysis on cross-sectional data included 54 studies for REM Sleep Behavior Disorder (RBD), 22 for Excessive Daytime Sleepiness (EDS), 7 for Obstructive Sleep Apnea (OSA), 13 for Restless Legs Syndrome (RLS), and 5 for insomnia, the meta-analysis on longitudinal data included 7 studies.RBD was related to deficits of global cognitive functioning, memory, executive functions, attention/working memory, language, and visuospatial abilities. EDS was associated with deficits of global cognitive functioning and attention and working memory abilities, whereas RLS and OSA were related to global cognitive dysfunction. Moreover, we revealed that PD patients with RBD and those with EDS performed worse than PD patients without sleep disorders at follow-up rather than baseline evaluation. Our results suggest that sleep disorders are associated with cognitive deficits supporting indirectly that these, especially the REM Sleep Behavior Disorder, reflect abnormalities of frontal networks and posterior cortical areas. Sleep disorders in patients with PD seem to also increase the risk for long-term cognitive decline.