Practical Evaluation and Management of Insomnia in Parkinson's Disease: A Review

Managing sleep issues in Parkinson's disease: an up-to-date review

INTRODUCTION

In Parkinson's disease (PD), sleep-wake problems are disease-related symptoms that occur throughout the day and have a negative impact on patients' quality of life to an extent that is equal to or greater than that of typical motor symptoms.

AREAS COVERED

Insomnia due to fragmented sleep and excessive daytime sleepiness (EDS) worsen as PD progresses. Nighttime wearing-off and early morning-off should be considered first when fragmented sleep is reported in PD patients. If the main complaint of patients with insomnia is difficulty falling asleep, restless legs syndrome should be differentiated first. Obstructive sleep apnea causes sleep quality deterioration and fragmented sleep. For rapid eye movement sleep behavior disorder (RBD), preventative measures against sleep-related trauma are necessary. RBD has also attracted attention as a PD precursor state and as a disease progression marker that is associated with specific PD clinical subtypes. In PD patients, the sleep-wake phase may advance/delay or become irregular due to circadian dysfunction.

EXPERT OPINION

Importantly, sleep-wake problems are core symptoms related to the pathogenesis and progression of PD, and addressing a wide range of these symptoms will improve patients' quality of life.

Intersection of Sleep Disorders and Parkinson Disease: Unveiling the Bidirectional Relationship

BACKGROUND

Patients with Parkinson's Disease (PD) frequently exhibit non-motor symptoms, particularly sleep disturbances. Sleep disorders in PD patients are intricately linked to the pathogenesis and progression of PD itself, exacerbating neurodegenerative processes and worsening patient quality of life.

OBJECTIVES

This review underscores the significance of sleep disorders in PD, highlighting their prevalence, impact on disease progression, and the bidirectional relationship between sleep disruption and neurodegeneration. It aims to enhance clinician awareness for better diagnosis and management of sleep-related comorbidities in PD.

METHODS

A comprehensive literature search was conducted in PubMed and Scopus using key terms such as "sleep disorders", "Parkinson's disease", "REM sleep behavior disorder", "restless legs syndrome", "insomnia", "obstructive sleep apnea", "excessive daytime sleepiness", "circadian rhythm disorders", "sleep and neurodegeneration".

RESULTS

Sleep disorders are prevalent in PD affecting up to 90% of patients. Conditions such as insomnia, REM sleep behavior disorder, restless legs syndrome, obstructive sleep apnea, excessive daytime sleepiness, and circadian rhythm disorders are commonly reported. These disorders are linked to multifactorial biological mechanisms and are associated with more severe disease phenotypes. Of note, several evidence shows that sleep abnormalities may contribute to neuroinflammation and neurodegeneration, further accelerating the disease course.

CONCLUSIONS

Sleep disturbances are critical non-motor symptoms in PD. Early diagnosis and tailored management of sleep disorders are essential for improving clinical outcomes and potentially offering neuroprotective benefits.

Sleep-Related Disorders in Parkinson's Disease: Mechanisms, Diagnosis, and Therapeutic Approaches

BACKGROUND

Parkinson's Disease (PD) is frequently associated with a spectrum of sleep-related disorders, including insomnia, Excessive Daytime Sleepiness (EDS), REM sleep Behaviour Disorder (RBD), Restless Legs Syndrome (RLS), and Sleep-related Breathing Disorders (SBDs). These disorders significantly impact PD patients' Quality of Life (QoL) and present unique diagnostic and therapeutic challenges.

METHODS

This review has explored the intricate relationship between PD and sleep-related disorders, emphasizing their distinctive features and underlying neurobiological mechanisms. It aimed to consolidate current knowledge to optimize clinical management and improve patient care. The profound impact of these disorders on QoL has been evaluated, along with precise diagnostic methodologies. Additionally, various therapeutic strategies, including pharmacological treatments, nonpharmacological interventions, and device-aided therapies, have been examined.

RESULTS

Sleep-related disorders are prevalent among PD patients. Specifically, RBD exhibits a prevalence of 40-50%, often preceding the onset of motor symptoms, indicating its potential as an early marker of PD. Despite their significant impact on QoL, these non-motor symptoms are frequently under-recognized and inadequately managed in clinical practice. Pharmacological treatments, along with nonpharmacological interventions, like cognitive-behavioral therapy for insomnia and lifestyle modifications, have shown varied efficacy. Device-aided therapies have also demonstrated the potential to improve sleep-related disorders and overall non-motor symptom burden.

CONCLUSION

Effective management of sleep-related disorders in PD calls for personalized, comprehensive, and multimodal therapeutic approaches. This requires the collaborative efforts of neurologists, sleep specialists, psychiatrists, and other healthcare professionals. Future research should focus on the intricate relationship between PD and sleep disorders, aiming to develop innovative treatments and significantly improve patient outcomes.

Reducing Parkinson's disease incidence in patients with insomnia through acupuncture: A cohort study

Background

Parkinson's disease (PD) is a prevalent neurodegenerative condition characterized primarily by motor symptoms, often accompanied by non-motor manifestations such as insomnia. Acupuncture, an increasingly popular alternative therapy, has shown promise in the prevention and alleviation of PD motor symptoms. However, the specific impact of acupuncture on the risk of developing PD in insomnia patients remains uncertain.

Methods

In this retrospective study, we identified and matched 152,585 newly diagnosed insomnia patients from Taiwan's National Health Insurance Research Database (NHIRD) from 2000 to 2010. Using a 1:1 propensity score matching method, we ensured the comparability of two groups: patients who received acupuncture treatment and those who did not. It resulted in a final cohort of 20,112 patients in both the acupuncture and non-acupuncture groups.

Results

Our analysis revealed that insomnia patients who underwent acupuncture treatment exhibited a significantly reduced risk of developing PD. The adjusted hazard ratio (aHR) was 0.44 (95 % confidence interval = 0.39-0.50) compared to those who did not receive acupuncture. Furthermore, the cumulative incidence of PD in the acupuncture group was significantly lower, as evidenced by the log-rank test (p < 0.001).

Conclusion

In conclusion, our study provides evidence suggesting that acupuncture treatment is associated with a decreased risk of PD in patients with insomnia. However, further research is warranted to strengthen the evidence supporting these findings.

Effect of zonisamide on sleep and rapid eye movement sleep behavioral disorders in patients with Parkinson's disease: A randomized control trial

Introduction

Zonisamide is a medication developed in Japan that is effective for motor symptoms and wearing off in Parkinson's disease (PD). Zonisamide has properties that may improve sleep disorders. The aim of this study is to verify the safety and efficacy of zonisamide for sleep disorders and rapid eye movement (REM) sleep behavioral disorders (RBD) using a mobile two-channel electroencephalography /electrooculography recording system in patients with PD.

Methods

The present study is a single-blind randomized placebo-controlled trial. The subjects in the treatment group took zonisamide (25 mg per day) before bedtime. The primary outcome was sleep efficiency. The secondary endpoints were assessed as followed; objective outcomes of TST, WASO, SOL, REM sleep/non-REM sleep ratio, deep sleep (N3) time, ratio of RWA to total REM sleep epochs, and subjective outcomes of the PDSS-2, Pittsburgh sleep questionnaire, and RBDSQ.

Results

Between the zonisamide and placebo groups, no significant differences were found in the primary outcome and secondary outcomes.

Conclusions

The objective and subjective sleep metrics in this clinical trial did not significantly demonstrate zonisamide efficacy for sleep disorder in patients with PD. Although not significant, improvement in WASO and SOL was observed when zonisamide was compared with the placebo.

Cardiovascular dysautonomia and cognitive impairment in Parkinson's disease (Review)

Cognitive impairment is a prevalent non-motor symptom of Parkinson's disease (PD), which can result in significant disability and distress for patients and caregivers. There is a marked variation in the timing, characteristics and rate at which cognitive decline occurs in patients with PD. This decline can vary from normal cognition to mild cognitive impairment and dementia. Cognitive impairment is associated with several pathophysiological mechanisms, including the accumulation of β-amyloid and tau in the brain, oxidative stress and neuroinflammation. Cardiovascular autonomic dysfunctions are commonly observed in patients with PD. These dysfunctions play a role in the progression of cognitive impairment, the incidents of falls and even in mortality. The majority of symptoms of dysautonomia arise from changes in the peripheral autonomic nervous system, including both the sympathetic and parasympathetic nervous systems. Cardiovascular changes, including orthostatic hypotension, supine hypertension and abnormal nocturnal blood pressure (BP), can occur in both the early and advanced stages of PD. These changes tend to increase as the disease advances. The present review aimed to describe the cognitive changes in the setting of cardiovascular dysautonomia and to discuss strategies through which these changes can be modified and managed. It is a multifactorial process usually involving decreased blood flow to the brain, resulting in the development of cerebral ischemic lesions, an increased presence of abnormal white matter signals in the brain, and a potential influence on the process of neurodegeneration in PD. Another possible explanation is this association being independent observations of PD progression. Patients with clinical symptoms of dysautonomia should undergo 24-h ambulatory BP monitoring, as they are frequently subtle and underdiagnosed.

Relationship Between Melatonin Receptor Agonists and Parkinson's Disease

Parkinson's disease affects millions of people worldwide, and without significant progress in disease prevention and treatment, its incidence and prevalence could increase by more than 30% by 2030. Researchers have focused on targeting sleep and the circadian system as a novel treatment strategy for Parkinson's disease. This study investigated the association between melatonin receptor agonists and Parkinson's disease, using the Food and Drug Administration (FDA) Adverse Events Reporting System (FAERS). The target drugs were melatonin receptor agonists including ramelteon, tasimelteon, and agomelatine. Parkinson's disease cases were defined according to the Medical Dictionary for Regulatory Activities (MedDRA) 25.0; Standardized MedDRA Query (SMQ) using both the "narrow" and "broad" preferred terms (PTs) associated with Parkinson's disease. The association between melatonin receptor agonists (ramelteon, tasimelteon, and agomelatine) and Parkinson's disease was evaluated by the reporting odds ratio. Upon analyzing the data from all patients registered in the FAERS, ramelteon (ROR: 0.66, 95% confidence interval [95% CI]: 0.51-0.84) and tasimelteon (ROR: 0.49, 95% CI: 0.38-0.62) showed negative correlations with Parkinson's disease. Conversely, only agomelatine was positively correlated with Parkinson's disease (ROR: 2.63, 95% CI: 2.04-3.40). These results suggest that among the melatonin receptor agonists, ramelteon and tasimelteon are negatively correlated with Parkinson's disease. In contrast, agomelatine was shown to be positively correlated with Parkinson's disease. These results should be used in research to develop drugs for the treatment of Parkinson's disease, fully considering the limitations of the spontaneous reporting system.

Effect of melatonin on insomnia and daytime sleepiness, in patients with obstructive sleep apnea and insomnia (COMISA): A randomized double-blinded placebo-controlled trial

BACKGROUND

COMISA is a common disorder that results in nighttime awakenings ,daytime sleepiness and PAP intolerance. Cognitive behavioral therapy for insomnia is used to improve PAP adherence and no medication has been evaluated in such population yet. Melatonin with its chronobiotic and antioxidant effects may have potential benefits on COMISA consequences at the appropriate dose and time. This study aimed to evaluate the effect of melatonin on sleep quality, daytime sleepiness and PAP Compliance in patients with COMISA.

METHODS

This double-blind placebo trial randomly assigned eligible OSA patients who suffered from insomnia despite using PAP for over a month to receive either melatonin 10 mg or placebo. The primary outcomes were measured by changes in the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS), and Functional Outcomes of Sleep Questionnaire (FOSQ-10) over one month. Adherence to PAP was measured by the results of the PAP device reports on the average length of time and number of nights that the device was used.

RESULTS

Thirty patients were enrolled in the study after randomization. The melatonin arm showed significant improvement in all four primary outcomes compared to the placebo arm. The PSQI score was 3.836±1.839 in the melatonin arm versus 10.522±3.626 in the placebo arm (Pvalue<0.001). The ISI score was 8.476±3.568 in the melatonin arm versus 14.47±4.50 in the placebo arm (Pvalue<0.001). The ESS score was 6.854±4.334 in the melatonin arm versus 13.298±5.119 in the placebo arm (Pvalue<0.001). The FOSQ-10 score was 24.93±5.02 in the melatonin arm versus 19.87±4.24 in the placebo arm (Pvalue= 0.006). Additionally, nighttime consequences such as sleep latency and awakenings showed significant improvement in the melatonin arm. PAP devices results revealed improvement in duration of PAP use overnight.  CONCLUSIONS: Administering melatonin has been shown to improve self-reported sleep quality and PAP adherence in patients with COMISA.

TRIAL REGISTRATION

Registration number IRCT20220105053635N1 was issued by the Iranian Registry of Clinical Trials (IRCT).

Clinical usefulness of dual orexin receptor antagonism beyond insomnia: Neurological and psychiatric comorbidities

Orexin is a neurotransmitter produced by a small group of hypothalamic neurons. Besides its well-known role in the regulation of the sleep-wake cycle, the orexin system was shown to be relevant in several physiological functions including cognition, mood and emotion modulation, and energy homeostasis. Indeed, the implication of orexin neurotransmission in neurological and psychiatric diseases has been hypothesized via a direct effect exerted by the projections of orexin neurons to several brain areas, and via an indirect effect through orexin-mediated modulation of sleep and wake. Along with the growing evidence concerning the use of dual orexin receptor antagonists (DORAs) in the treatment of insomnia, studies assessing their efficacy in insomnia comorbid with psychiatric and neurological diseases have been set in order to investigate the potential impact of DORAs on both sleep-related symptoms and disease-specific manifestations. This narrative review aimed at summarizing the current evidence on the use of DORAs in neurological and psychiatric conditions comorbid with insomnia, also discussing the possible implication of modulating the orexin system for improving the burden of symptoms and the pathological mechanisms of these disorders. Target searches were performed on PubMed/MEDLINE and Scopus databases and ongoing studies registered on Clinicaltrials.gov were reviewed. Despite some contradictory findings, preclinical studies seemingly support the possible beneficial role of orexin antagonism in the management of the most common neurological and psychiatric diseases with sleep-related comorbidities. However, clinical research is still limited and further studies are needed for corroborating these promising preliminary results.

Comparison of sleep characteristics between Parkinson's disease with and without freezing of gait: A systematic review

Parkinson's disease (PD) is a neurodegenerative disorder characterized by a range of motor and non-motor symptoms. Among the motor complaints, freezing of gait (FOG) is a common and disabling phenomenon that episodically hinders patients' ability to produce efficient steps. Concurrently, sleep disorders are prevalent in PD and significantly impact the quality of life of affected individuals. Numerous studies have suggested a bidirectional relationship between FOG and sleep disorders. Therefore, our objective was to systematically review the literature and compare sleep outcomes in PD patients with FOG (PD + FOG) and those without FOG (PD-FOG). By conducting a comprehensive search of the PubMed and Web of Science databases, we identified 20 eligible studies for inclusion in our analysis. Our review revealed that compared to PD-FOG, PD + FOG patients exhibited more severe symptoms of rapid eye movement sleep behavior disorder in nine studies, increased daytime sleepiness in eight studies, decreased sleep quality in four studies, and more frequent and severe sleep disturbances in four studies. These findings indicate that PD + FOG patients generally experience worse sleep quality, higher levels of daytime sleepiness, and more disruptive sleep disturbances compared to those without FOG (PD-FOG). The association between sleep disturbances and FOG highlights the importance of evaluating and monitoring these symptoms in PD patients and open the possibility for future studies to assess the impact of managing sleep disturbances on the severity and occurrence of FOG, and vice versa.

Medical, surgical, and physical treatments for Parkinson's disease

Although dopamine replacement therapy remains a core component of Parkinson's disease treatment, the onset of motor fluctuations and dyskinetic movements might require a range of medical and surgical approaches from a multidisciplinary team, and important new approaches in the delivery of dopamine replacement are becoming available. The more challenging, wide range of non-motor symptoms can also have a major impact on the quality of life of a patient with Parkinson's disease, and requires careful multidisciplinary management using evidence-based knowledge, as well as appropriately tailored strategies according to the individual patient's needs. Disease-modifying therapies are urgently needed to prevent the development of the most disabling refractory symptoms, including gait and balance difficulties, cognitive impairment and dementia, and speech and swallowing impairments. In the third paper in this Series, we present the latest evidence supporting the optimal treatment of Parkinson's disease, and describe an expert approach to many aspects of treatment choice where an evidence base is insufficient.

Neuroprotective effect of Kurarinone against corticosterone-induced cytotoxicity on rat hippocampal neurons by targeting BACE1 to activate P13K-AKT signaling - A potential treatment in insomnia disorder

The hippocampus has been implicated in the pathogenesis of insomnia disorder (ID) and the purpose of this study was to investigate the neuroprotective mechanism of the natural flavone Kurarinone (Kur) on hippocampal neurotoxicity as a potential treatment of ID. The effect of Kur on hippocampal neuronal cell (HNC) viability and apoptosis were assessed by Cell counting kit-8 (CCK-8) assay and flow cytometry, respectively. Then, the effect of Kur on β-site amyloid precursor protein-cleaving enzyme 1 (BACE1), brain-derived neurotrophic factor (BDNF), and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) phosphorylation level were measured by Western blot. Further, SwissTargetPrediction analysis and molecular docking experiments were used to detect a potential target of Kur. Then, the p-chlorophenylalanine (PCPA) model was established in vivo to further study the effect of BACE1 expression on Kur and HNC. As a result, HNC viability was only significantly decreased by 2 μM of Kur. Kur reversed the impacts of corticosterone upon inhibiting viability (0.25-1 μM), PI3K (0.5-1 μM)/AKT phosphorylation, and BDNF (1 μM) level, and enhancing the apoptosis (0.25-1 μM) and BACE1 expression (1 μM) in HNCs. BACE1 was a potential target of Kur. Notably, Kur (150 mg/kg) attenuated PCPA-induced upregulation of BACE1 expression in rat hippocampal tissues as ZRAS (0.8 g/kg). The effects of Kur (1 μM) on corticosterone-treated HNCs were reversed by BACE1 overexpression. Collectively, Kur downregulates BACE1 level to activate PI3K/AKT, thereby attenuating corticosterone-induced toxicity in HNCs, indicating that Kur possibly exerted a neuroprotective effect, which providing a new perspective for the treatment of insomnia disorders.

Parkinson's Disease: A Narrative Review on Potential Molecular Mechanisms of Sleep Disturbances, REM Behavior Disorder, and Melatonin

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. There is a wide range of sleep disturbances in patients with PD, such as insomnia and rapid eye movement (REM) sleep behavior disorder (or REM behavior disorder (RBD)). RBD is a sleep disorder in which a patient acts out his/her dreams and includes abnormal behaviors during the REM phase of sleep. On the other hand, melatonin is the principal hormone that is secreted by the pineal gland and significantly modulates the circadian clock and mood state. Furthermore, melatonin has a wide range of regulatory effects and is a safe treatment for sleep disturbances such as RBD in PD. However, the molecular mechanisms of melatonin involved in the treatment or control of RBD are unknown. In this study, we reviewed the pathophysiology of PD and sleep disturbances, including RBD. We also discussed the potential molecular mechanisms of melatonin involved in its therapeutic effect. It was concluded that disruption of crucial neurotransmitter systems that mediate sleep, including norepinephrine, serotonin, dopamine, and GABA, and important neurotransmitter systems that mediate the REM phase, including acetylcholine, serotonin, and norepinephrine, are significantly involved in the induction of sleep disturbances, including RBD in PD. It was also concluded that accumulation of α-synuclein in sleep-related brain regions can disrupt sleep processes and the circadian rhythm. We suggested that new treatment strategies for sleep disturbances in PD may focus on the modulation of α-synuclein aggregation or expression.

Mediating role of psychological flexibility in the effect of obsessive-compulsive symptoms on sleep quality among nurses during the COVID-19 pandemic

Front-line nurses suffered unprecedented mental distress and severe insomnia during the COVID-19 pandemic. Present study aimed to explore the relationship between obsessive-compulsive symptoms and sleep quality and examine the potential mediating role of psychological flexibility between obsessive-compulsive symptoms and sleep quality. A total of 496 nurses from a Chinese large-scale Class 3 A Comprehensive Hospital were included in an online cross-sectional survey and completed the revised obsessive-compulsive inventory (OCI-R), Multidimensional Psychological Flexibility Inventory (MPFI) and Pittsburgh Sleep Quality Index (PSQI). As predicted, obsessive-compulsive symptoms were negatively associated with psychological flexibility and sleep quality, and psychological flexibility was positively associated with sleep quality. In addition, the relationship between obsessive-compulsive symptoms and sleep quality was partially mediated by psychological flexibility, which can provide some reference for the treatment of the obsessive-compulsive disorder (OCD) and insomnia, and lead to improvements in clinical and psychotherapy planning.

Sleep Disturbances in Neurological Disease: A Target for Intervention

Sleep is a biological function required for neurological and general health, but a significant and under-recognized proportion of the population has disturbed sleep. Here, we briefly overview the biology of sleep, sleep requirements over the lifespan, and common sleep disorders. We then turn our attention to five neurological diseases that significantly contribute to global disease burden and neurology practice makeup: epilepsy, headache, ischemic stroke, Parkinson's disease, and Alzheimer's disease. For each disease, we review evidence that sleep disturbances contribute to disease risk and severity and discuss existing data that addressing sleep disturbances may have disease-modifying effects. We provide recommendations derived from the literature and existing clinical guidelines to facilitate the evaluation and management of sleep disturbances within the context of each neurological disease. Finally, we synthesize identified needs and commonalities into future directions for the field and practical sleep-related recommendations for physicians caring for patients at risk for or currently suffering from neurological disease.

Bidirectional Relationship Between Sleep Disturbances and Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease (AD). Both diseases share common clinical and pathological features: the gradual progression of neurological and psychiatric symptoms caused by neuronal dysfunction and neuronal cell death due to the accumulation of misfolded and neurotoxic proteins. Furthermore, both of them are multifactorial diseases in which both genetic and non-genetic factors contribute to the disease course. Non-genetic factors are of particular interest for the development of preventive and therapeutic approaches for these diseases because they are modifiable; of these, sleep is a particularly intriguing factor. Sleep disturbances are highly prevalent among both patients with AD and PD. To date, research has suggested that sleep disturbances are a consequence as well as a risk factor for the onset and progression of AD, which implies a bidirectional relationship between sleep and AD. Whether such a relationship exists in PD is less certain, albeit highly plausible given the shared pathomechanisms. This review examines the current evidence for the bidirectional relationship between sleep and PD. It includes research in both humans and animal models, followed by a discussion of the current understanding of the mechanisms underlying this relationship. Finally, potential avenues of research toward achieving disease modification to treat or prevent PD are proposed. Although further efforts are crucial for preventing the onset and slowing the progress of PD, it is evident that sleep is a valuable candidate target for future interventions to improve the outcomes of PD patients.

Melatonin Treatment for Sleep Disorders in Parkinson's Disease: A Meta-Analysis and Systematic Review

Objective

The efficacy of melatonin on sleep disorders in Parkinson's disease (PD) is still unclear. The purpose of this study was to investigate the efficacy of melatonin on sleep disorders in PD by summarizing evidence from randomized clinical trials (RCTs).

Methods

PubMed, Cochrane Library, EMBASE, and Web of Science databases were searched for studies published before 20 August 2021. Results were analyzed using Review Manager 5.2 software. We used Trial Sequential Analysis (TSA) software to avoid false-positive results caused by random errors.

Results

We included 7 studies in this systematic review and meta-analysis. The results of the meta-analysis showed that compared with placebo, the subjective sleep quality of patients with PD significantly improved after melatonin treatment (MD = −2.19, 95% CI: −3.53 to −0.86, P = 0.001). In the systematic review, we qualitatively analyzed the efficacy of melatonin on the objective sleep quality of patients with PD, and the results showed that melatonin exerted a positive effect with good safety and tolerability. However, there was no significant improvement in excessive daytime sleepiness assessed by the Epworth Sleepiness Scale (ESS).

Conclusion

We found that melatonin can significantly improve the subjective and objective sleep quality of patients with PD with good safety and tolerability. Melatonin could be considered an effective treatment for insomnia in patients with PD.

Etiologies of insomnia in Parkinson's disease - Lessons from human studies and animal models

Sleep disorders are integral to Parkinson's disease (PD). Insomnia, an inability to maintain stable sleep, affects most patients and is widely rated as one of the most debilitating facets of this disease. PD insomnia is often perceived as a multifactorial entity - a consequence of several of the disease symptoms, comorbidities and therapeutic strategies. Yet, this view evolved against a backdrop of a relative scarcity of works trying to directly dissect the underlying neural correlates and mechanisms in animal models. The last years have seen the emergence of a wealth of new evidence regarding the neural underpinnings of insomnia in PD. Here, we review early and recent reports from patients and animal models evaluating the etiology of PD insomnia. We start by outlining the phenomenology of PD insomnia and continue to analyze the evidence supporting insomnia as emanating from four distinct subdivisions of etiologies - the symptoms and comorbidities of the disease, the medical therapy, the degeneration of non-dopaminergic cell groups and subsequent alterations in circadian rhythms, and the degeneration of dopaminergic neurons in the brainstem and its resulting effect on the basal ganglia. Finally, we review emerging neuromodulation-based therapeutic avenues for PD insomnia.

Zonisamide for the Efficacy of Sleep Abnormality in Parkinson's Disease (ZEAL Study): A Protocol for Randomized Controlled Trials

Background: Sleep disorders are one of the most frequent non-motor symptoms of Parkinson's disease (PD), and the efficacy of dopaminergic agents remains controversial. Clinical randomized control trials for the treatment of sleep disorders in PD are limited. Zonisamide (1,2-benzisoxazole-3-methanesulfonamide) improved motor symptoms and wearing-off in patients with PD. Patients with PD were reported to have dream-enacting behavior that was resolved after treatment with zonisamide. This study aimed to verify the safety and efficacy of zonisamide for sleep disorders and rapid eye movement (REM) sleep behavioral disorders using a mobile two-channel electroencephalography (EEG)/electrooculography (EOG) recording system.

Methods and Analysis: The present study is a randomized placebo-controlled trial to determine the efficacy of zonisamide for sleep disorders in patients with PD. This study was designed to be single-blind, but the subject allocation is randomized by an independent allocation manager via computer-generated block randomization. The subjects in the treatment group took zonisamide (25 mg per day) before bedtime for 28 days. The sleep index is analyzed using a portable EEG/EOG recording system collected on two consecutive nights within 7 days prior to the intervention and reobtained on one night within 2 days after the 28-day administration of zonisamide. The amount of change in sleep efficiency before and after the 28-day administration will be compared between the zonisamide treatment group and placebo group concerning the primary endpoint. As for the secondary endpoint, the change in the ratio of other sleep parameters, including REM sleep without atonia, or sleep architecture will be evaluated.

Ethics and Dissemination: The protocol was approved by the Nara Medical University Certified Review Board (CRB5200002). The trial was notified and registered with the Japan Registry of Clinical Trials (jRCTs051200160). Written informed consent will be obtained from every participant using informed consent approved by the CRB. The results of this trial will be disseminated through peer-reviewed scientific journals.

Insomnia Burden and Future Perspectives

Insomnia is an important but widely ignored health problem in modern society. Despite unequivocal evidence on its large prevalence, health and social impacts, comorbidities, and various pharmacologic and nonpharmacologic (behavioral and device-based) approaches, its effective management is still difficult and often incomplete. This article discusses the role of insomnia in modern societies, newer complicating factors, and its overall social and public health burden. Acute insomnia and sleep difficulties during pandemic and confinement are reviewed. The article also focuses on newer developments accumulating in the field of insomnia and possible future trends.

Insomnia disorder: clinical and research challenges for the 21st century

BACKGROUND AND PURPOSE

Insomnia is a common and debilitating disorder that is frequently associated with important consequences for physical health and well-being.

METHODS

An international expert group considered the current state of knowledge based on the most relevant publications in the previous 5 years, discussed the current challenges in the field of insomnia and identified future priorities.

RESULTS

The association of trajectories of insomnia with subsequent quality of life, health and mortality should be investigated in large populations. Prospective health economics studies by separating the costs driven specifically by insomnia and costs attributable to its long-term effects are needed. Ignoring the heterogeneity of insomnia patients leads to inadequate diagnosis and inefficient treatment. Individualized interventions should be promoted. More data are needed on both the impact of sleep on overnight effects, such as emotion regulation, and the potential compensatory effort to counteract diurnal impairments. Another gap is the definition of neurocognitive deficits in insomnia patients compared to normal subjects after chronic sleep loss. There are also a number of key gaps related to insomnia treatment. Expert guidelines indicate cognitive-behavioural therapy for insomnia as first-line treatment. They neglect, however, the reality of major healthcare providers. The role of combined therapy, cognitive-behavioural therapy for insomnia plus pharmacological treatment, should be evaluated more extensively.

CONCLUSION

Whilst insomnia disorder might affect large proportions of the population, there are a number of significant gaps in the epidemiological/clinical/research studies carried out to date. In particular, the identification of different insomnia phenotypes could allow more cost-effective and efficient therapies.

Pharmacological and Non-pharmacological Treatments of Sleep Disorders in Parkinson's Disease

Sleep disorders are one of the most common non-motor symptoms in Parkinson's disease (PD). It can cause a notable decrease in quality of life and functioning in PD patients, as well as place a huge burden on both patients and caregivers. The most cited sleep disorders in PD included insomnia, restless legs syndrome (RLS), rapid eye movement (REM), sleep behavior disorders (RBD), excessive daytime sleepiness (EDS) and sleep disordered breathing (SDB), which can appear alone or several at the same time. In this review, we listed the recommended pharmacological treatments for common sleep disorders in PD, and discussed the recommended dosages, benefits and side effects of relative drugs. We also discussed non-pharmacological treatments to improve sleep quality, including sleep hygiene education, exercise, deep brain stimulation, cognitive behavior therapy and complementary therapies. We tried to find proper interventions for different types of sleep disorders in PD, while minimizing relative side effects.

Approach to Cognitive Impairment in Parkinson's Disease

Cognitive dysfunction is common in Parkinson's disease (PD) and predicts poor clinical outcomes. It is associated primarily with pathologic involvement of basal forebrain cholinergic and prefrontal dopaminergic systems. Impairments in executive functions, attention, and visuospatial abilities are its hallmark features with eventual involvement of memory and other domains. Subtle symptoms in the premotor and early phases of PD progress to mild cognitive impairment (MCI) which may be present at the time of diagnosis. Eventually, a large majority of PD patients develop dementia with advancing age and longer disease duration, which is usually accompanied by immobility, hallucinations/psychosis, and dysautonomia. Dopaminergic medications and deep brain stimulation help motor dysfunction, but may have potential cognitive side effects. Central acetylcholinesterase inhibitors, and possibly memantine, provide modest and temporary symptomatic relief for dementia, although there is no evidence-based treatment for MCI. There is no proven disease-modifying treatment for cognitive impairment in PD. The symptomatic and disease-modifying role of physical exercise, cognitive training, and neuromodulation on cognitive impairment in PD is under investigation. Multidisciplinary approaches to cognitive impairment with effective treatment of comorbidities, proper rehabilitation, and maintenance of good support systems in addition to pharmaceutical treatment may improve the quality of life of the patients and caregivers.

The Spectrum of Sleep Disorders in Parkinson Disease: A Review

There is increasing interest in the effects of sleep and sleep disturbances on the brain, particularly in relation to aging and neurodegenerative processes. Parkinson disease (PD) is the second most common neurodegenerative disorder, with growing prevalence worldwide. Sleep disorders, including sleep-disordered breathing (SDB), are among the most frequent non-motor manifestations of PD. They can substantially impair quality of life and possibly affect the course of the disease. This article reviews the etiology, implications, and management of sleep disturbances in PD, such as excessive daytime sleepiness, insomnia, restless legs syndrome, rapid eye movement sleep behavior disorder, and SDB. Also briefly explored is the potential role of sleep disorders, including SDB, in the progression of neurodegeneration.

Depressive symptoms effect subjective sleep quality in Chinese patients with Parkinson's disease

OBJECTIVES

The objective of this paper was aimed to estimate the influence of depressive symptoms on subjective sleep quality in Chinese PD patients.

PATIENTS AND METHODS

A sample of 491 PD patients was collected and studied in the present study. Depressive symptoms were assessed using the Hamilton Rating Scale for Depression (HAMD). PD severity was assessed using Hoehn and Yahr (H-Y) staging, and motor symptoms were measured with the Unified PD Rating Scale (UPDRS) part III. The Montreal Cognitive Assessment (MOCA) was used to evaluate the global Cognitive status and PD Sleep Scale (PDSS) was used to quantify sleep quality. Three linear regression models were built to check factors associated with caregiver burden, one for the total sample and two for subgroups stratified by the presence of cognitive disturbance.

RESULTS

In our sample, 29.9% of patients suffer from sleep disturbance. The most frequent depressive symptoms were helplessness (81.5%), depressed mood (57.8%), and general somatic symptoms (55.4%) for entire sample. Patients with cognitive disturbance (n = 274; 55.8% of sample) presented more depressive symptoms than patients without cognitive disturbance. Patients suffer poorer sleep quality when patients experience depression with cognitive disturbance. On linear regression models, the main determinants of subjective quality for the total sample were NMS-depression/anxiety/anhedonia, HAMD-anxiety/somatization, disease severity, age and HAMD-loss of weight. For patients with cognitive disturbance, the significant determinants were NMS-depression/anxiety/anhedonia, HAMD-anxiety/somatization, motor symptoms, HAMD-loss of weight and gender. For patients without cognitive disturbance, the significant determinants were NMS-depression/anxiety/anhedonia, disease severity and HAMD-anxiety/somatization.

CONCLUSION

Depressive symptoms in PD are highly associated with and are determinants of subjective sleep quality, and are more prevalent in patients with cognitive disturbance. Detailed assessment and specific interventions aimed at depression and dementia could alleviate sleep disorder.