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

Orexin and Sleep Disturbances in Alpha-Synucleinopathies: a Systematic Review

PURPOSE OF REVIEW

Sleep disturbances are amongst most frequent non-motor symptoms of Parkinson's Disease (PD), and they are similarly frequently reported in other alpha-syncleinopathies, such as Dementia with Lewy Bodies (DLB) and Multiple System Atrophy (MSA). More recently, the orexin system has been implicated in control of arousal based on salient environmental set points, and its dysregulation in sleep issues in alpha-synucleinopathies suggested by the findings from the translational animal models. However, its role in the patients with alpha-synucleinopathies remains unclear. We thus set to systematically review, and to critically assess, contemporary evidence on the association of the orexinergic system and sleep disturbances in alpha-synucleinopathies. In this systematic review, studies investigating orexin and sleep in alpha-synucleinopathies (Rapid Eye Movement (REM) Behaviour Disorder (RBD), Parkinson's Disease (PD), Dementia with Lewy Bodies (DLB), Multiple System Atrophy (MSA)) were identified using electronic database searches of PubMed, Web of Science and PsychINFO using MeSH terms, keywords, and title words such as "Alpha-synucleinopathies" AND "Orexin" AND "Sleep Disturbances".

RECENT FINDINGS

17 studies were included in this systemic review, of which 2 studies on RBD, 10 on PD, 4 on DLB, and 1 on MSA patients. Taken together, RBD and PD studies suggest a potential adaptive increase in orexin levels in early stages of the neurodegenerative process, with reduced levels more often reported for later, more advanced stages of illness. To date, no differences in orexin levels were demonstrated between MSA patients and healthy controls. There is a dearth of studies on the role of orexin levels in alpha-synucleinopathies. Moreover, significant methodologic limitations in the current body of work, including use of non-standardised research protocols and lack of prospective, multi-centre studies, disallow for any finite conclusion in regards to underlying pathomechanisms. Nonetheless, a picture of a complex, multifaceted relationship between the dysregulation of the orexinergic pathway and sleep disturbances in alpha-synucleinopathies is emerging. Hence, future studies disentangling orexinergic pathomechanisms of alpha-syncleinopathies are urgently needed to obtain a more comprehensive account of the role of orexinergic pathway in alpha-synucleinopathies. Pharmacological manipulations of orexins may have multiple therapeutic applications in treatment strategies, disease diagnosis, and might be effective for treating both motor and non-motor symptoms.

Objective sleep enhancement in Parkinson's disease: A sham-controlled trial of low-frequency repetitive transcranial magnetic stimulation over the right dorsolateral prefrontal cortex

INTRODUCTION

Parkinson's disease (PD) is often accompanied by sleep disturbances, impacting patients' quality of life. While repetitive transcranial magnetic stimulation (rTMS) shows promise in improving self-reported sleep quality, its effects on objective sleep architecture in PD remain understudied. Sleep disturbances, including rapid eye movement (REM) and slow-wave sleep disturbances, correlate with cognitive decline and motor symptoms. This study investigated the effect of low-frequency rTMS targeting the right dorsolateral prefrontal cortex (DLPFC) modifying objective sleep architecture and explored symptom improvement mechanisms in PD patients.

METHODS

In this randomized, double-blind, sham-controlled trial, 67 PD patients received 10 consecutive days of 1-Hz rTMS over the right DLPFC. Polysomnography assessed sleep microstructure, while electroencephalogram recordings evaluated power spectral density and sleep spindle activity. Clinical scales measured sleep quality, motor symptoms, and cognition at baseline, post-treatment, and 3 months post-rTMS.

RESULTS

The rTMS group exhibited improvements in sleep quality, motor symptoms, and cognition post-treatment, persisting at the 3-month follow-up. There was a notable increase in the REM sleep proportion post-rTMS. The rTMS group exhibited elevated low-frequency (0.5-2 Hz) slow-wave electroencephalogram spectral density during non-REM sleep. Cognitive enhancement correlated with increased lower delta power, while motor symptom progression correlated with spindle frequency and slow-wave sleep percentage changes.

CONCLUSION

Low-frequency rTMS targeting the right DLPFC holds promise for improving clinical symptoms and modulating sleep architecture in PD. These findings suggest a link between symptom improvement and sleep structure enhancement, highlighting the need for further investigation into the therapeutic potential of rTMS in PD management.

Does glial lipid dysregulation alter sleep in Alzheimer's and Parkinson's disease?

In this opinion article, we discuss potential connections between sleep disturbances observed in Alzheimer's disease (AD) and Parkinson's disease (PD) and the dysregulation of lipids in the brain. Research using Drosophila has highlighted the role of glial-mediated lipid metabolism in sleep and diurnal rhythms. Relevant to AD, the formation of lipid droplets in glia, which occurs in response to elevated neuronal reactive oxygen species (ROS), is required for sleep. In disease models, this process is disrupted, arguing a connection to sleep dysregulation. Relevant to PD, the degradation of neuronally synthesized glucosylceramides by glia requires glucocerebrosidase (GBA, a PD-associated risk factor) and this regulates sleep. Loss of GBA in glia causes an accumulation of glucosylceramides and neurodegeneration. Overall, research primarily using Drosophila has highlighted how dysregulation of glial lipid metabolism may underlie sleep disturbances in neurodegenerative diseases.

Disrupted sleep-wake regulation in the MCI-Park mouse model of Parkinson's disease

Disrupted sleep has a profound adverse impact on lives of Parkinson's disease (PD) patients and their caregivers. Sleep disturbances are exceedingly common in PD, with substantial heterogeneity in type, timing, and severity. Among the most common sleep-related symptoms reported by PD patients are insomnia, excessive daytime sleepiness, and sleep fragmentation, characterized by interruptions and decreased continuity of sleep. Alterations in brain wave activity, as measured on the electroencephalogram (EEG), also occur in PD, with changes in the pattern and relative contributions of different frequency bands of the EEG spectrum to overall EEG activity in different vigilance states consistently observed. The mechanisms underlying these PD-associated sleep-wake abnormalities are poorly understood, and they are ineffectively treated by conventional PD therapies. To help fill this gap in knowledge, a new progressive model of PD - the MCI-Park mouse - was studied. Near the transition to the parkinsonian state, these mice exhibited significantly altered sleep-wake regulation, including increased wakefulness, decreased non-rapid eye movement (NREM) sleep, increased sleep fragmentation, reduced rapid eye movement (REM) sleep, and altered EEG activity patterns. These sleep-wake abnormalities resemble those identified in PD patients. Thus, this model may help elucidate the circuit mechanisms underlying sleep disruption in PD and identify targets for novel therapeutic approaches.

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.

Fine-tuning the circadian system with light treatment for Parkinson's disease: an in-depth, critical review

Late in the twentieth century, interest intensified regarding the involvement of the circadian system in the aetiology and treatment of Parkinson's disease (PD). It has been envisaged that this approach might provide relief beyond the limited benefits and severe side effects achieved by dopamine (DA) replacement. In the first clinical article, published in 1996, polychromatic light was used to shift the circadian clock as it is considered to be the most powerful zeitgeber (time keeper) that can be implemented to realign circadian phase. Since that time, 11 additional articles have implemented light treatment (LT) in various forms as an adjuvant to DA replacement. In spite of the growing interest in this area, the systematic exploration of LT in PD has been stymied by several methodological factors. Such factors include time of LT presentation, duration of studies undertaken, frequency of light employed, dose of light prescribed and relevance of experimental design to the prolonged course of the illness. On this basis, it is the purpose of this review to provide an in-depth examination of these papers, and the underlying preclinical work, to provide critique, thereby giving direction for future studies in therapeutic applications of LT for PD. Consideration of this collective work may serve to carve a path for future research and thereby improve the lives of those suffering from this debilitating disorder.

The Park Sleep subtype in Parkinson's disease: from concept to clinic

INTRODUCTION

The heterogeneity of Parkinson's disease (PD) is evident from descriptions of non-motor (NMS) subtypes and Park Sleep, originally identified by Sauerbier et al. 2016, is one such clinical subtype associated with the predominant clinical presentation of sleep dysfunctions including excessive daytime sleepiness (EDS), along with insomnia.

AREAS COVERED

A literature search was conducted using the PubMed, Medline, Embase, and Web of Science databases, accessed between 1 February 2023 and 28 March 2023. In this review, we describe the clinical subtype of Park Sleep and related 'tests' ranging from polysomnography to investigational neuromelanin MRI brain scans and some tissue-based biological markers.

EXPERT OPINION

Cholinergic, noradrenergic, and serotonergic systems are dominantly affected in PD. Park Sleep subtype is hypothesized to be associated primarily with serotonergic deficit, clinically manifesting as somnolence and narcoleptic events (sleep attacks), with or without rapid eye movement behavior disorder (RBD). In clinic, Park Sleep recognition may drive lifestyle changes (e.g. driving) along with therapy adjustments as Park Sleep patients may be sensitive to dopamine D3 active agonists, such as ropinirole and pramipexole. Specific dashboard scores based personalized management options need to be implemented and include pharmacological, non-pharmacological, and lifestyle linked advice.

Clinical Evaluation of the Sleepy and Sleepless Patient

OBJECTIVE

This article addresses the approach to the evaluation of patients who present to a neurologist with excessive daytime sleepiness or difficulty sleeping.

LATEST DEVELOPMENTS

Greater emphasis on the importance of sleep reflects the growing scientific understanding that sleep is critical to overall health and well-being. Consumer sleep technologies, which measure parameters related to sleep, may provide insight into an individual's sleep-related symptoms and tendencies and have a role in patient-centered sleep evaluation when used within an appropriate clinical context.

ESSENTIAL POINTS

A thorough review of a patient's history and physical examination findings are important components of the assessment and management of their sleep-related symptoms. An understanding of how the clinical context relates to the categorization of sleep disorders can impact a patient's symptoms, comorbid neurologic disorders, and overall well-being. Many neurologic conditions are strongly associated with sleep disturbance, risk factors for the development of a sleep disorder, or both. Therefore, it is critical for neurologists to be familiar and comfortable with taking a focused sleep history. Modalities such as in-laboratory polysomnography, home sleep apnea testing, multiple sleep latency testing, and actigraphy, as well as contextualized and prudent use of data obtained from consumer sleep technologies, can be helpful in appropriately selected patients. Mindful integration of these objective data facilitates the diagnosis and management of sleep disorders.

Evaluation of consensus sleep stage scoring of dysregulated sleep in Parkinson's disease

OBJECTIVE

Sleep dysregulation in Parkinson's disease (PD) has been hypothesized to occur, in part, from dysfunction in the basal ganglia-cortical circuit. Assessment of this relationship requires accurate sleep stage determination, a known challenge in this clinical population. Our objective was to optimize the consensus on the sleep staging process and reduce interrater variability in a cohort of advanced PD subjects.

METHODS

Fifteen PD subjects were enrolled from three sites in a clinical trial that involved recordings from subthalamic nucleus (STN) deep brain stimulation (DBS) leads (NCT04620551). Video polysomnography (vPSG) data for a total of 45 nights were analyzed. Four experienced scorers independently scored data on initial review. Epochs with less than 75% consensus were flagged for secondary review. In secondary review of discordant epochs, two of the original scorers re-assessed epochs, from which the final consensus stage was derived.

RESULTS

Sleep stage classification agreement averaged 83.10% across all sleep stages on initial scoring (IS), and on secondary consensus scoring (CS) review, agreement reached 96.58%. Greatest disagreement was noted in determination of awake epochs (33.6% of discordant epochs) and non-rapid-eye-movement stage 2 (N2) epochs (31.8% of discordant epochs). Scoring discrepancy was resolved with direct measurement of cortical frequency and amplitudes, physiologic context of the epoch, and video review.

CONCLUSION

Our method of multi-level initial and then secondary consensus review scoring resulted in consensus scoring agreement superior to conventional standards. This work features a custom-engineered vPSG software and review platform for integration of consensus sleep stage scoring in a multi-site clinical trial.

Role of astrocytes in sleep deprivation: accomplices, resisters, or bystanders?

Sleep plays an essential role in all studied animals with a nervous system. However, sleep deprivation leads to various pathological changes and neurobehavioral problems. Astrocytes are the most abundant cells in the brain and are involved in various important functions, including neurotransmitter and ion homeostasis, synaptic and neuronal modulation, and blood-brain barrier maintenance; furthermore, they are associated with numerous neurodegenerative diseases, pain, and mood disorders. Moreover, astrocytes are increasingly being recognized as vital contributors to the regulation of sleep-wake cycles, both locally and in specific neural circuits. In this review, we begin by describing the role of astrocytes in regulating sleep and circadian rhythms, focusing on: (i) neuronal activity; (ii) metabolism; (iii) the glymphatic system; (iv) neuroinflammation; and (v) astrocyte-microglia cross-talk. Moreover, we review the role of astrocytes in sleep deprivation comorbidities and sleep deprivation-related brain disorders. Finally, we discuss potential interventions targeting astrocytes to prevent or treat sleep deprivation-related brain disorders. Pursuing these questions would pave the way for a deeper understanding of the cellular and neural mechanisms underlying sleep deprivation-comorbid brain disorders.

Glymphatic System and Mitochondrial Dysfunction as Two Crucial Players in Pathophysiology of Neurodegenerative Disorders

Neurodegenerative diseases are a complex problem affecting millions of people around the world. The pathogenesis is not fully understood, but it is known that both insufficiency of the glymphatic system and mitochondrial disorders affect the development of pathology. It appears that these are not just two independent factors that coexist in the processes of neurodegeneration, but that they often interact and drive each other. Bioenergetics disturbances are potentially associated with the accumulation of protein aggregates and impaired glymphatic clearance. Furthermore, sleep disorders characteristic of neurodegeneration may impair the work of both the glymphatic system and the activity of mitochondria. Melatonin may be one of the elements linking sleep disorders with the function of these systems. Moreover, noteworthy in this context is the process of neuroinflammation inextricably linked to mitochondria and its impact not only on neurons, but also on glia cells involved in glymphatic clearance. This review only presents possible direct and indirect connections between the glymphatic system and mitochondria in the process of neurodegeneration. Clarifying the connection between these two areas in relation to neurodegeneration could lead to the development of new multidirectional therapies, which, due to the complexity of pathogenesis, seems to be worth considering.

Chronodisruption and Loss of Melatonin Rhythm, Associated with Alterations in Daily Motor Activity and Mitochondrial Dynamics in Parkinsonian Zebrafish, Are Corrected by Melatonin Treatment

Beyond sleep/wake, clock genes regulate the daily rhythms of melatonin production, motor activity, innate immunity, and mitochondrial dynamics, among others. All these rhythms are affected in Parkinson's disease (PD), suggesting that chronodisruption may be an early stage of the disease. The aim of this study was to evaluate the connection between clock genes and these rhythms in PD, and whether melatonin administration reestablished the normal clock function. Parkinsonism was induced with 600 μM MPTP (N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) in 24-120 h post fertilization (hpf) zebrafish embryos and melatonin was administered at a dose of 1 μM. Day-night melatonin rhythm disappeared in MPTP-treated embryos, which showed an advance in the activity phase in parallel with changes in the rhythm of clock genes. An alteration in the fission-to-fusion mitochondrial dynamics was also detected in parkinsonian embryos, increasing the former and leading to apoptosis. Melatonin administration to MPTP-treated embryos fully restored the circadian system, including the rhythms of clock genes, motor activity, melatonin rhythm, and mitochondrial dynamics, and decreasing apoptosis. Because clock-controlled rhythms such as sleep/wake alterations are early events in PD, the data here reported may point to chronodisruption as one initial pathophysiological event of the disease.

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.

Association between visual impairment and sleep duration in college students: A study conducted in UAE and Lebanon

Objective: To examine whether self-reported sleep duration and visual impairment were associated among College students. Participants: Students (n = 1002, age 17-35 years) from Lebanon and the United Arab Emirates. Methods: Students were asked to complete a validated questionnaire between October 2018 and May 2019. The questions were related to sociodemographics, lifestyle characteristics, visual impairment status, sleeping pattern, mobile-phone use and chronic conditions. Results: 18.3% of the respondents reported to suffer from visual impairment. Among them, 72.7% were females (p < .001), 65% admitted to frequently use mobile phones before sleeping (p < .001), 54.6% reported to sleep less than 7 h (p = .008) and 71.6% reported to suffer from sleep disturbances (p = .05). Visual impairment was associated with poor sleep quality (p < .001), mobile phone use before sleeping (p < .01) and daily stress (p < .05). Conclusion: Visual impairment in college students is associated with short sleep duration, mobile phone use before sleeping and stress level.

Co-administration of Nanowired DL-3-n-Butylphthalide (DL-NBP) Together with Mesenchymal Stem Cells, Monoclonal Antibodies to Alpha Synuclein and TDP-43 (TAR DNA-Binding Protein 43) Enhance Superior Neuroprotection in Parkinson's Disease Following Concussive Head Injury

dl-3-n-butylphthalide (dl-NBP) is one of the potent antioxidant compounds that induces profound neuroprotection in stroke and traumatic brain injury. Our previous studies show that dl-NBP reduces brain pathology in Parkinson's disease (PD) following its nanowired delivery together with mesenchymal stem cells (MSCs) exacerbated by concussive head injury (CHI). CHI alone elevates alpha synuclein (ASNC) in brain or cerebrospinal fluid (CSF) associated with elevated TAR DNA-binding protein 43 (TDP-43). TDP-43 protein is also responsible for the pathologies of PD. Thus, it is likely that exacerbation of brain pathology in PD following brain injury may be thwarted using nanowired delivery of monoclonal antibodies (mAb) to ASNC and/or TDP-43. In this review, the co-administration of dl-NBP with MSCs and mAb to ASNC and/or TDP-43 using nanowired delivery in PD and CHI-induced brain pathology is discussed based on our own investigations. Our observations show that co-administration of TiO2 nanowired dl-NBP with MSCs and mAb to ASNC with TDP-43 induced superior neuroprotection in CHI induced exacerbation of brain pathology in PD, not reported earlier.

Parkinson’s disease detection based on multi-pattern analysis and multi-scale convolutional neural networks

Parkinson’s disease (PD) is a complex neurodegenerative disease. At present, the early diagnosis of PD is still extremely challenging, and there is still a lack of consensus on the brain characterization of PD, and a more efficient and robust PD detection method is urgently needed. In order to further explore the features of PD based on brain activity and achieve effective detection of PD patients (including OFF and ON medications), in this study, a multi-pattern analysis based on brain activation and brain functional connectivity was performed on the brain functional activity of PD patients, and a novel PD detection model based on multi-scale convolutional neural network (MCNN) was proposed. Based on the analysis of power spectral density (PSD) and phase-locked value (PLV) features of multiple frequency bands of two independent resting-state electroencephalography (EEG) datasets, we found that there were significant differences in PSD and PLV between HCs and PD patients (including OFF and ON medications), especially in the β and γ bands, which were very effective for PD detection. Moreover, the combined use of brain activation represented by PSD and functional connectivity patterns represented by PLV can effectively improve the performance of PD detection. Furthermore, our proposed MCNN model shows great potential for automatic PD detection, with cross-validation accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve all above 99%. Our study may help to further understand the characteristics of PD and provide new ideas for future PD diagnosis based on spontaneous EEG activity.

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.

Elevation of Plasma Homocysteine and Minor Hallucinations in Parkinson’s Disease: A Cross-Sectional Study

Purpose

Minor hallucinations (MHs) are the most common psychotic phenomena in Parkinson's disease (PD), and it has important clinical and prognostic implications in PD. Plasma homocysteine (Hcy) has been reported to predict the outcome of PD; whether or not Hcy is associated with MH is not known. We aim to investigate the Hcy level and related factors in patients with PD and MH.

Methods

We conducted a cross-sectional study and included 99 patients with PD, 34 with MH, and 65 without any hallucinations. The clinical and demographic data of the patients with and without hallucinations were compared. Hcy-related clinical factors were also analyzed.

Results

The plasma Hcy level was higher in MH patients than in patients without hallucinations, and the result was more pronounced in male patients than in female patients. Differences were also observed when the groups were divided on the basis of levodopa equivalent daily dose and disease duration. The high Hcy concentration was correlated with some symptoms in patients with MH, including motor dysfunction and nonmotor symptoms, such as symptoms of the gastrointestinal tract, angiocarpy, sleep/fatigue, and poor visuospatial/executive function.

Conclusions

Results indicated a higher plasma Hcy concentration in MH patients than in their counterparts and revealed that Hcy is associated with certain motor and nonmotor symptoms in patients with MH. Hcy may be a marker of MH and have important therapeutic implications in PD.

Delayed Recovery After Deep Brain Stimulation Surgery for Parkinson's Disease Under General Anesthesia-Cases Report

Objective

Parkinson's disease (PD) is a neurodegenerative syndrome, and deep-brain stimulation (DBS) is an effective therapy for carefully screened patients with PD. However, delayed recovery after anesthesia, which occurs after taking prolonged general anesthesia for such patients, has been reported less frequently in literature. This report explores the possible causes of postoperative awakening delay in patients undergoing DBS surgery due to general anesthesia and provides a reference for anesthesia management of similar operations in the future.

Case Presentation

Three patients with PD elective underwent DBS surgery. The first patients demonstrated walking disability, gait deficits, unstable posture, limb stiffness, and imbalance. The second demonstrated left limb static tremor, stiffness, and bradykinesia. The third demonstrated bradykinesia, rigidity, walking deficits, and decreased facial expression. These included two males and one female with a mean patient age of 60.7 ± 6.7year, weight of 63.7 ± 11 kg, the height of 163.3 ± 7.6 cm, and preoperative American Society of Anesthesiology rating of 2.3 ± 0.6. The preoperative Glasgow Coma Scale mean score was 15. All patients completed the operation under general anesthesia (the mean anesthesia time was 5.3 ± 1.1 h). The mean operation time was 252 ± 60 min. The mean bleeding volume was 50 ml, and the urine volume was 867 ± 569 ml. However, all the patients showed unconsciousness after 95 ± 22 min after stopping the anesthetic, and the respiratory function was in good condition, but they could not cooperate with anesthesiologists and had no response to the anesthesiologist's instructions. The mean hospital stay was 17 ± 7 days. All patients were discharged uneventfully. The average number of days patients followed up postoperatively was 171 ± 28.5 days. Motor and speech were improved significantly postoperatively in three patients compared with preoperatively. Taking anti-Parkinson medication was markedly reduced. There were no complications during postoperative follow-up.

Conclusions

To prevent delayed recovery occurring after DBS surgery in Parkinson's disease, it is recommended to take scalp nerve block + general anesthesia to complete the procedure while avoiding general anesthesia.

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.

Sleep and circadian rhythms in Parkinson's disease and preclinical models

The use of animals as models of human physiology is, and has been for many years, an indispensable tool for understanding the mechanisms of human disease. In Parkinson's disease, various mouse models form the cornerstone of these investigations. Early models were developed to reflect the traditional histological features and motor symptoms of Parkinson's disease. However, it is important that models accurately encompass important facets of the disease to allow for comprehensive mechanistic understanding and translational significance. Circadian rhythm and sleep issues are tightly correlated to Parkinson's disease, and often arise prior to the presentation of typical motor deficits. It is essential that models used to understand Parkinson's disease reflect these dysfunctions in circadian rhythms and sleep, both to facilitate investigations into mechanistic interplay between sleep and disease, and to assist in the development of circadian rhythm-facing therapeutic treatments. This review describes the extent to which various genetically- and neurotoxically-induced murine models of Parkinson's reflect the sleep and circadian abnormalities of Parkinson's disease observed in the clinic.

Association Between Sleep Duration and Parkinson's Disease Varied Across Related Orphan Receptor A rs2028122 Genotypes

Background

The purpose of the study was to examine the association of long and short sleep duration with risk of Parkinson's disease (PD) across RORA rs2028122 genotypes.

Methods

In the present prospective study with a large sized UK Biobank cohort, we performed multivariate logistic regression analyses, generalized additive model, interaction terms, stratification analysis, and mediation analysis to evaluate the association of long and short sleep duration with risk of PD across RORA rs2028122 genotypes.

Results

The GG genotype [1.16 (1.01, 1.33)], a short sleep duration [1.23 (1.10, 1.37)], and a long sleep duration [1.19 (1.03, 1.37)] were identified as the independent risk factors for PD. Sleep duration exhibited a curvilinear U-shaped correlation with the risk of PD; first, the risk of PD gradually decreased as the length of sleep increase, but then, the risk began to increase as the length of sleep increase. Among habitual long sleepers, AG carriers had a higher risk of PD compared with AA carriers [1.67 (1.09, 2.55)]. Among AG carriers, both habitual short [1.28 (1.09, 1.50)] and long [1.38 (1.13, 1.69)] sleepers increased the risk of PD compared with habitual normal sleepers. Among GG carriers, habitual short sleepers have a higher risk of PD [1.26 (1.06, 1.50)] compared with habitual normal sleepers. A mediation model suggested that the rs2028122 genotype partially mediated the causal pathway of sleep duration leading to the development of PD on a positive effect.

Conclusion

Our study demonstrated that the association between sleep duration and PD risk varied across different RORA rs2028122 genotypes. Our findings could help individuals to identify their potential risk profile and take timely actions to prevent the PD.

ENIGMA-Sleep: Challenges, opportunities, and the road map

Neuroimaging and genetics studies have advanced our understanding of the neurobiology of sleep and its disorders. However, individual studies usually have limitations to identifying consistent and reproducible effects, including modest sample sizes, heterogeneous clinical characteristics and varied methodologies. These issues call for a large-scale multi-centre effort in sleep research, in order to increase the number of samples, and harmonize the methods of data collection, preprocessing and analysis using pre-registered well-established protocols. The Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) consortium provides a powerful collaborative framework for combining datasets across individual sites. Recently, we have launched the ENIGMA-Sleep working group with the collaboration of several institutes from 15 countries to perform large-scale worldwide neuroimaging and genetics studies for better understanding the neurobiology of impaired sleep quality in population-based healthy individuals, the neural consequences of sleep deprivation, pathophysiology of sleep disorders, as well as neural correlates of sleep disturbances across various neuropsychiatric disorders. In this introductory review, we describe the details of our currently available datasets and our ongoing projects in the ENIGMA-Sleep group, and discuss both the potential challenges and opportunities of a collaborative initiative in sleep medicine.

What have we really learned from functional connectivity in clinical populations?

Functional connectivity (FC), or the statistical interdependence of blood-oxygen dependent level (BOLD) signals between brain regions using fMRI, has emerged as a widely used tool for probing functional abnormalities in clinical populations due to the promise of the approach across conceptual, technical, and practical levels. With an already vast and steadily accumulating neuroimaging literature on neurodevelopmental, psychiatric, and neurological diseases and disorders in which FC is a primary measure, we aim here to provide a high-level synthesis of major concepts that have arisen from FC findings in a manner that cuts across different clinical conditions and sheds light on overarching principles. We highlight that FC has allowed us to discover the ubiquity of intrinsic functional networks across virtually all brains and clarify typical patterns of neurodevelopment over the lifespan. This understanding of typical FC maturation with age has provided important benchmarks against which to evaluate divergent maturation in early life and degeneration in late life. This in turn has led to the important insight that many clinical conditions are associated with complex, distributed, network-level changes in the brain, as opposed to solely focal abnormalities. We further emphasize the important role that FC studies have played in supporting a dimensional approach to studying transdiagnostic clinical symptoms and in enhancing the multimodal characterization and prediction of the trajectory of symptom progression across conditions. We highlight the unprecedented opportunity offered by FC to probe functional abnormalities in clinical conditions where brain function could not be easily studied otherwise, such as in disorders of consciousness. Lastly, we suggest high priority areas for future research and acknowledge critical barriers associated with the use of FC methods, particularly those related to artifact removal, data denoising and feasibility in clinical contexts.

The Impact of Deep Brain Stimulation on Sleep in Parkinson's Disease: An update

Background:

Parkinson’s disease (PD) can have a significant impact on sleep. Deep brain stimulation (DBS) is an effective treatment for motor features of PD, but less is understood about the impact DBS may have on sleep architecture and various sleep issues commonly seen in PD.

Objective:

To review the impact of DBS on various sleep issues in PD.

Methods:

We reviewed the literature regarding the impact of DBS on sleep patterns, nocturnal motor and non-motor symptoms, and sleep disorders in PD.

Results:

Objective sleep measures on polysomnography (PSG), including sleep latency and wake after sleep onset improve after subthalamic nucleus (STN) and globus pallidus interna (GPi) DBS. Subjective sleep measures, nocturnal motor symptoms, and some non-motor symptoms (nocturia) also may improve. Current evidence suggests STN DBS has no impact on Rapid Eye Movement Behavior Disorder (RBD), while STN DBS may improve symptoms of Restless Legs Syndrome (RLS). There are no studies that have evaluated the impact of GPi DBS on RBD, while it is unclear if GPi has an effect on RLS in PD.

Conclusion:

DBS therapy at either site appears to improve objective and subjective sleep parameters in patients with PD. Most likely, the improvement of motor and some non-motor nocturnal symptoms leads to an increase in total sleep time by up to an hour, as well as reduction of sleep fragmentation. DBS most likely has no impact on RBD, while there is evidence that STN DBS appears to help reduce RLS severity. Further studies are needed.

The Neurophysiology of Sleep in Parkinson's Disease

Sleep disturbances are among the most common nonmotor complications of Parkinson's disease (PD), can present in prodromal stages, and progress with advancing disease. In addition to being a symptom of neurodegeneration, sleep disturbances may also contribute to disease progression. Currently, limited options exist to modulate sleep disturbances in PD. Studying the neurophysiological changes that affect sleep in PD at the cortical and subcortical level may yield new insights into mechanisms for reversal of sleep disruption. In this article, we review cortical and subcortical recording studies of sleep in PD with a particular focus on dissecting reported electrophysiological changes. These studies show that slow-wave sleep and rapid eye movement sleep are both notably disrupted in PD. We further explore the impact of these electrophysiological changes and discuss the potential for targeting sleep via stimulation therapy to modify PD-related motor and nonmotor symptoms. © 2021 International Parkinson and Movement Disorder Society.

Sleep in Neurologic Disorders

Sleep is a complex brain state with fundamental relevance for cognitive functions, synaptic plasticity, brain resilience, and autonomic balance. Sleep pathologies may interfere with cerebral circuit organization, leading to negative consequences and favoring the development of neurologic disorders. Conversely, the latter can interfere with sleep functions. Accordingly, assessment of sleep quality is always recommended in the diagnosis of patients with neurologic disorders and during neurorehabilitation programs. This review investigates the complex interplay between sleep and brain pathologies, focusing on diseases in which the association with sleep disturbances is commonly overlooked and whereby major benefits may derive from their proper management.

Marine Natural Products: Promising Candidates in the Modulation of Gut-Brain Axis towards Neuroprotection

In recent decades, several neuroprotective agents have been provided in combating neuronal dysfunctions; however, no effective treatment has been found towards the complete eradication of neurodegenerative diseases. From the pathophysiological point of view, growing studies are indicating a bidirectional relationship between gut and brain termed gut-brain axis in the context of health/disease. Revealing the gut-brain axis has survived new hopes in the prevention, management, and treatment of neurodegenerative diseases. Accordingly, introducing novel alternative therapies in regulating the gut-brain axis seems to be an emerging concept to pave the road in fighting neurodegenerative diseases. Growing studies have developed marine-derived natural products as hopeful candidates in a simultaneous targeting of gut-brain dysregulated mediators towards neuroprotection. Of marine natural products, carotenoids (e.g., fucoxanthin, and astaxanthin), phytosterols (e.g., fucosterol), polysaccharides (e.g., fucoidan, chitosan, alginate, and laminarin), macrolactins (e.g., macrolactin A), diterpenes (e.g., lobocrasol, excavatolide B, and crassumol E) and sesquiterpenes (e.g., zonarol) have shown to be promising candidates in modulating gut-brain axis. The aforementioned marine natural products are potential regulators of inflammatory, apoptotic, and oxidative stress mediators towards a bidirectional regulation of the gut-brain axis. The present study aims at describing the gut-brain axis, the importance of gut microbiota in neurological diseases, as well as the modulatory role of marine natural products towards neuroprotection.

The CBP KIX domain regulates long-term memory and circadian activity

Background

CREB-dependent transcription necessary for long-term memory is driven by interactions with CREB-binding protein (CBP), a multi-domain protein that binds numerous transcription factors potentially affecting expression of thousands of genes. Identifying specific domain functions for multi-domain proteins is essential to understand processes such as cognitive function and circadian clocks. We investigated the function of the CBP KIX domain in hippocampal memory and gene expression using CBP^KIX/KIX mice with mutations that prevent phospho-CREB (Ser133) binding.

Results

We found that CBP^KIX/KIX mice were impaired in long-term memory, but not learning acquisition or short-term memory for the Morris water maze. Using an unbiased analysis of gene expression in the dorsal hippocampus after training in the Morris water maze or contextual fear conditioning, we discovered dysregulation of CREB, CLOCK, and BMAL1 target genes and downregulation of circadian genes in CBP^KIX/KIX mice. Given our finding that the CBP KIX domain was important for transcription of circadian genes, we profiled circadian activity and phase resetting in CBP^KIX/KIX mice. CBP^KIX/KIX mice exhibited delayed activity peaks after light offset and longer free-running periods in constant dark. Interestingly, CBP^KIX/KIX mice displayed phase delays and advances in response to photic stimulation comparable to wildtype littermates. Thus, this work delineates site-specific regulation of the circadian clock by a multi-domain protein.

Conclusions

These studies provide insight into the significance of the CBP KIX domain by defining targets of CBP transcriptional co-activation in memory and the role of the CBP KIX domain in vivo on circadian rhythms.

Graphical abstract

Sleep Issues in Parkinson's Disease and Their Management

Parkinson's disease (PD) is an alpha-synucleinopathy that leads to prominent motor symptoms including tremor, bradykinesia, and postural instability. Nonmotor symptoms including autonomic, neurocognitive, psychiatric symptoms, and sleep disturbances are also seen frequently in PD. The impact of PD on sleep is related to motor and nonmotor symptoms, in addition to the disruption of the pathways regulating sleep by central nervous system pathology. Rapid eye movement sleep behavior disorder is a parasomnia that can lead to self-injury and/or injury to partners at night. Restless legs syndrome is a subjective sensation of discomfort and urge to move the legs prior to falling asleep and can lead to insomnia and reduced sleep quality. Excessive daytime sleepiness is common in PD and exerts a negative impact on quality of life in addition to increasing the risk of falls. Obstructive sleep apnea is a breathing disorder during sleep that can cause frequent awakenings and excessive daytime sleepiness. Circadian rhythm dysfunction can lead to an advanced or delayed onset of sleep in patients and create disruption of normal sleep and wake times. All of these disorders are common in PD and can significantly reduce sleep quantity, sleep quality, or quality of life for patients and caretakers. Treatment approaches for each of these disorders are distinct and should be individualized to the patient. We review the literature regarding these common sleep issues encountered in PD and their treatment options.

Sleep, caregiver burden, and life satisfaction in Parkinson's disease caregivers: a multinational investigation

PURPOSE

The primary aim of this study was to examine the pattern of associations among PD patient and caregiver sleep problems, caregiver burden, and caregiver life satisfaction. A secondary aim was to assess whether the pattern of associations differed between Mexican and U.S. caregivers.

MATERIALS AND METHODS

Analyses were performed on data obtained from 253 caregivers (M age = 59.92). A composite score was produced for caregiver and patient sleep problems. The Zarit Burden Interview and Satisfaction with Life Scale measured caregiver burden and life satisfaction, respectively. A structural equation model with an invariance design was developed to examine and compare the pattern of associations.

RESULTS

The model was generally invariant across U.S. and Mexican caregivers. Three significant indirect effects were found: caregiver sleep problems were negatively associated with life satisfaction via caregiver burden (p = 0.003); PD patient sleep problems were positively related to caregiver burden via caregiver sleep problems (p = 0.005) and life satisfaction via caregiver burden and caregiver sleep problems (p = 0.002).

CONCLUSIONS

PD patient sleep problems were associated with caregiver sleep problems, leading to increased burden in caregivers and poorer life satisfaction. The findings highlight a potential opportunity for empirically supported sleep interventions.Implications for rehabilitationParkinson's disease is a progressive neurological condition that impacts patient and caregiver quality of life.Patient sleep problems contribute to greater caregiver burden, sleep problems, and reduced life satisfaction.The findings suggest patient and caregiver sleep may be a worthwhile target for intervention in order to reduce risk of caregiver burden and improve life satisfaction.

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.

Nonmotor Symptoms Affect Sleep Quality in Early-Stage Parkinson's Disease Patients With or Without Cognitive Dysfunction

Purpose: Parkinson's disease (PD) patients frequently present with sleep disorders. This study was designed to assess the impact of nonmotor symptoms (NMSs) on sleep quality in early-stage PD patients with and without cognitive dysfunction. Materials and Methods: A sample of 389 early-stage PD patients (modified Hoehn and Yahr score ≤ 2.5, duration ≤ 5 years) was recruited for the present study. The Non-Motor Symptoms Questionnaire (NMS-Quest) was used to screen for global NMSs. Depressive symptoms were assessed using the Hamilton Rating Scale for Depression (HAMD). PD motor symptoms were measured with the Unified PD Rating Scale (UPDRS), part III. The Montreal Cognitive Assessment (MoCA) was used to evaluate global cognitive status, and the PD Sleep Scale (PDSS) was used to quantify sleep quality. Polysomnography (PSG) was used for objective assessment of sleep. Results: In our sample, approximately one-quarter of the PD patients suffered from sleep disturbances (23.7%). Our results also confirmed the high prevalence of cognitive dysfunction in patients with PD (39.8%). In patients with cognitive dysfunction, higher percentage of sleep disorders (34.8 vs. 16.2%, P < 0.01) was observed. They also with lower PDSS score, sleep efficiency (SE) and longer sleep lantency (SL) and wake after sleep onset (WASO) (All P < 0.05). In total, the patients who suffered from NMSs, such as depressive symptoms, anxiety symptoms, urinary tract symptoms and hallucinations/delusions, had poorer sleep quality. Better cognition may predict better sleep quality. In patients with cognitive dysfunction, the NMS-Hallucinations/delusions score was the most important risk factor for sleep disorders. In patients without cognitive dysfunction, NMSs such as anxiety and cognition and medication were related to sleep disorder. Conclusions: NMSs in early-stage PD are highly associated with and are determinants of subjective sleep quality. Future studies should focus on elucidating the pathophysiology of these symptoms.

The Promise and Challenges of Developing miRNA-Based Therapeutics for Parkinson's Disease

MicroRNAs (miRNAs) are small double-stranded RNAs that exert a fine-tuning sequence-specific regulation of cell transcriptome. While one unique miRNA regulates hundreds of mRNAs, each mRNA molecule is commonly regulated by various miRNAs that bind to complementary sequences at 3’-untranslated regions for triggering the mechanism of RNA interference. Unfortunately, dysregulated miRNAs play critical roles in many disorders, including Parkinson’s disease (PD), the second most prevalent neurodegenerative disease in the world. Treatment of this slowly, progressive, and yet incurable pathology challenges neurologists. In addition to L-DOPA that restores dopaminergic transmission and ameliorate motor signs (i.e., bradykinesia, rigidity, tremors), patients commonly receive medication for mood disorders and autonomic dysfunctions. However, the effectiveness of L-DOPA declines over time, and the L-DOPA-induced dyskinesias commonly appear and become highly disabling. The discovery of more effective therapies capable of slowing disease progression –a neuroprotective agent–remains a critical need in PD. The present review focus on miRNAs as promising drug targets for PD, examining their role in underlying mechanisms of the disease, the strategies for controlling aberrant expressions, and, finally, the current technologies for translating these small molecules from bench to clinics.

Deep Phenotyping of Parkinson's Disease

Phenotype is the set of observable traits of an organism or condition. While advances in genetics, imaging, and molecular biology have improved our understanding of the underlying biology of Parkinson's disease (PD), clinical phenotyping of PD still relies primarily on history and physical examination. These subjective, episodic, categorical assessments are valuable for diagnosis and care but have left gaps in our understanding of the PD phenotype. Sensors can provide objective, continuous, real-world data about the PD clinical phenotype, increase our knowledge of its pathology, enhance evaluation of therapies, and ultimately, improve patient care. In this paper, we explore the concept of deep phenotyping-the comprehensive assessment of a condition using multiple clinical, biological, genetic, imaging, and sensor-based tools-for PD. We discuss the rationale for, outline current approaches to, identify benefits and limitations of, and consider future directions for deep clinical phenotyping.

Protocol: Using N-of-1 tests to identify responders to melatonin for sleep disturbance in Parkinson's disease

BACKGROUND

40% of Parkinson's Disease (PD) sufferers experience insomnia, impacting health and quality of life for patients and family members, especially carers. There is little evidence that current treatments are effective.

OBJECTIVES

To determine the effectiveness of melatonin in reducing insomnia in 44 individuals with PD using N-of-1 trials. To aggregate group data to arrive at population estimates of effectiveness (measured by improvements in PDSS-2) and safety (measured by adverse events) of melatonin in improving insomnia in PD. To assess the feasibility of offering N-of-1 trials for insomnia in PD.

METHODOLOGY

Participants will receive either immediate-release melatonin or placebo in random order in 3 paired two-week treatment periods (12 weeks total). Based on their response in a two-week run-in period on 3 mg daily, they will trial either 3 mg or 6 mg. Patients will keep daily sleep diaries and wear a MotionWatch throughout. After the trial patients will discuss their individual report with their doctor, which provides direct feedback about effectiveness and safety of melatonin for them.

STATISTICAL METHODS

We will analyse N-of-1 tests 1) individually: effects of melatonin on PDSS-2 and safety will be reported; and 2) aggregated across individual N-of-1 studies, combined using a Bayesian multilevel random effects model, which will account for repeated measures on individuals over time, and will return posterior estimates of overall treatment effect, and effect in each individual.

CLINICAL TRIAL REGISTRATION NUMBER

ACTRN12617001103358.

Sleep modulating agents

Sleep and wake are two fundamental states of human existence. Conditions such as insomnia and hypersomnia can have profound negative effects on human health. Many pharmacological interventions impacting sleep and wake are available or are under development. This brief digest surveys early approaches to sleep modulation and highlights recent developments in sleep modulating agents.

Update on obstructive sleep apnea for neuro-ophthalmology

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA) is increasing in prevalence. The intermittent hypoxia of OSA has wide-ranging effects on a patient's general health outcomes. However, gold-standard investigations and treatment are expensive and a significant burden on patients. Therefore, OSA research remains focused on improving the means of diagnosing and treating OSA, in high-risk-associated conditions. This review is to provide an update on the advances in the field of OSA.

RECENT FINDINGS

There has been recent debate about the best practice for diagnosis and treatment of OSA. Further work has been done on conditions associated with OSA including hypertension, atherosclerosis, various types of dementia and intracranial aneurysms. Inflammatory and vascular risk factors associated with OSA increase stroke risk and alter outcomes for recovery. OSA should definitely be considered in patients presenting with nonarteritic anterior ischemic optic neuropathy, and perhaps those with intracranial hypertension.

SUMMARY

Newer home-based sleep-apnea testing can be implemented via physician clinics, with oversight by a certified sleep physician. Although continuous positive airway pressure (CPAP) is the gold-standard, management should include diet and exercise. It is important to test for, and treat OSA in patients with a range of neurological diseases. However, further studies into the long-term impact of CPAP on health outcomes are still needed.

Manganese-Enhanced Magnetic Resonance Imaging: Overview and Central Nervous System Applications With a Focus on Neurodegeneration

Manganese-enhanced magnetic resonance imaging (MEMRI) rose to prominence in the 1990s as a sensitive approach to high contrast imaging. Following the discovery of manganese conductance through calcium-permeable channels, MEMRI applications expanded to include functional imaging in the central nervous system (CNS) and other body systems. MEMRI has since been employed in the investigation of physiology in many animal models and in humans. Here, we review historical perspectives that follow the evolution of applied MRI research into MEMRI with particular focus on its potential toxicity. Furthermore, we discuss the more current in vivo investigative uses of MEMRI in CNS investigations and the brief but decorated clinical usage of chelated manganese compound mangafodipir in humans.

[Diagnosis and comorbidities of Circadian Rhythm Sleep Disorders]

Circadian rhythm sleep disorders (CRSD) result from a disturbed endogenous clock (intrinsic CRSD) or from a misalignment between the biological clock and an imposed environment (extrinsic CRSD). Among intrinsic CRSD, one distinguishes the delayed sleep-wake phase disorder, the advanced sleep-wake phase disorder, the irregular sleep-wake rhythm disorder and the non-24-hour sleep-wake rhythm disorder. Shift work disorder, jet lag disorder and circadian sleep-wake disorder not otherwise specified are extrinsic CRSD. Prevalences of the different CRSD remain largely unknown. Some CRSD are particularly frequent such as sleep delayed phase syndrome in adolescents. Overall, CRSD are probably under-diagnosed. CRSD generate insomnia and excessive daytime somnolence. A biological clock dysfunction has to be evoked in case of insomnia or sleepiness. Furthermore, as CRSD can overlap with other sleep disorders, their diagnosis and treatment are essential. CRSD cause significant mental, physical or socio-professional sufferings. They are frequently associated with comorbidities, mainly neurodevelopmental, psychiatric and neurodegenerative disorders. Regarding neurodevelopmental comorbidities, therapy using a chronobiological approach is complementary to the usual clinical care. It helps to limit the significant impact of CRSD on quality of live, daytime functioning, social interactions and neurocognitive difficulties in the children. In psychiatry, sleep disorders and circadian rhythms sleep-wake disorders are a factor of vulnerability, of suicidal risk, of relapse and pharmacoresistance. Thus, diagnosis of CRSD associated with a psychiatric disorder is of major importance. Treatment using a chronobiological approach reinforcing the entrainment of the sleep-wake cycle is complementary to usual treatments. Sleep disorders and circadian sleep-wake rhythm disorders can be a preclinical sign of Alzheimer's and Parkinson's disease. In the elderly, a beginning neurodegenerative disorder can be associated with a CRSD and complaints of sleepiness, nocturnal awakenings and/or irregular sleep-wake cycles. Patients affected by neurogenerative disorders are particularly vulnerable for having CRSD. Data from different studies suggest that CRSD participate in pathophysiology of Alzheimer's disease. Even though treatment of CRSD associated with neurodegenerative disorders is entirely part of the treatment strategy, it remains uncertain to which extend this treatment may impact disease progression.