The frequency and nature of sleep disorders in a community-based population of patients with Parkinson’s disease

GBA-AAV mitigates sleep disruptions and motor deficits in mice with REM sleep behavior disorder

Sleep disturbances, including rapid eye movement sleep behavior disorder (RBD), excessive daytime sleepiness, and insomnia, are common non-motor manifestations of Parkinson's disease (PD). Little is known about the underlying mechanisms, partly due to the inability of current rodent models to adequately mimic the human PD sleep phenotype. Clinically, increasing studies have reported that variants of the glucocerebrosidase gene (GBA) increase the risk of PD. Here, we developed a mouse model characterized by sleep-wakefulness by injecting α-synuclein preformed fibronectin (PFF) into the sublaterodorsal tegmental nucleus (SLD) of GBA L444P mutant mice and investigated the role of the GBA L444P variant in the transition from rapid eye movement sleep behavior disorder to PD. Initially, we analyzed spectral correlates of REM and NREM sleep in GBA L444P mutant mice. Importantly, EEG power spectral analysis revealed that GBA L444P mutation mice exhibited reduced delta power during non-rapid eye movement (NREM) sleep and increased theta power (8.2-10 Hz) in active rapid eye movement (REM) sleep phases. Our study revealed that GBA L444P-mutant mice, after receiving PFF injections, exhibited increased sleep fragmentation, significant motor and cognitive dysfunctions, and loss of dopaminergic neurons in the substantia nigra. Furthermore, the over-expression of GBA-AAV partially improved these sleep disturbances and motor and cognitive impairments. In conclusion, we present the initial evidence that the GBA L444P mutant mouse serves as an essential tool in understanding the complex sleep disturbances associated with PD. This model further provides insights into potential therapeutic approaches, particularly concerning α-synuclein accumulation and its subsequent pathological consequences.

OFF-times before, during, and after nighttime sleep periods in Parkinson's disease patients with motor fluctuations and the effects of opicapone: A post hoc analysis of diary data from BIPARK-1 and -2

INTRODUCTION

In BIPARK-1 and BIPARK-2, addition of once-daily opicapone to levodopa/carbidopa significantly reduced daily "OFF"-time relative to placebo in adults with Parkinson's disease (PD) and motor fluctuations. Diary data from these studies were pooled and analyzed post hoc to characterize "OFF"-times around nighttime sleep and to explore the effects of opicapone 50 mg.

METHODS

"OFF" before sleep (OBS), "OFF during the nighttime sleep period" (ODNSP), early morning "OFF" (EMO), and duration of nighttime sleep and awake periods were analyzed descriptively at baseline. Mean changes from baseline to Week 14/15 (end of double-blind treatment) were analyzed using two-sided t-tests in participants with data for both visits.

RESULTS

At baseline, 88.3 % (454/514) of participants reported having OBS (34.0 %), ODNSP (17.1 %), or EMO (79.6 %). Those with ODNSP had substantially shorter mean duration of uninterrupted sleep (4.4 h) than the overall pooled population (7.1 h). At Week 14/15, mean decrease from baseline in ODNSP duration was significantly greater with opicapone than with placebo (-0.9 vs. -0.4 h, P < 0.05). In participants with ODNSP at baseline, the decrease in total time spent awake during the night-time sleep period was significantly greater with opicapone than with placebo (-1.0 vs. -0.4 h, P < 0.05), as was the reduction in percent time spent awake during the night-time sleep period (-12.8 % vs. -4.5 %, P < 0.05).

CONCLUSION

"OFF"-times around nighttime sleep were common in BIPARK-1 and BIPARK-2. Opicapone may improve sleep by decreasing the amount of time spent awake during the night in patients with PD who have night-time sleep period "OFF" episodes.

Predicting neurodegeneration from sleep related biofluid changes

Sleep-wake disturbances are common in neurodegenerative diseases and may occur years before the clinical diagnosis, potentially either representing an early stage of the disease itself or acting as a pathophysiological driver. Therefore, discovering biomarkers that identify individuals with sleep-wake disturbances who are at risk of developing neurodegenerative diseases will allow early diagnosis and intervention. Given the association between sleep and neurodegeneration, the most frequently analyzed fluid biomarkers in people with sleep-wake disturbances to date include those directly associated with neurodegeneration itself, such as neurofilament light chain, phosphorylated tau, amyloid-beta and alpha-synuclein. Abnormalities in these biomarkers in patients with sleep-wake disturbances are considered as evidence of an underlying neurodegenerative process. Levels of hormonal sleep-related biomarkers such as melatonin, cortisol and orexin are often abnormal in patients with clinical neurodegenerative diseases, but their relationships with the more standard neurodegenerative biomarkers remain unclear. Similarly, it is unclear whether other chronobiological/circadian biomarkers, such as disrupted clock gene expression, are causal factors or a consequence of neurodegeneration. Current data would suggest that a combination of fluid biomarkers may identify sleep-wake disturbances that are most predictive for the risk of developing neurodegenerative disease with more optimal sensitivity and specificity.

Validation of the Arabic version of Parkinson's Disease Sleep Scale-Revised Version (PDSS-2)

OBJECTIVES

Parkinson's disease sleep scale (PDSS) was recommended by the Movement Disorder Society task force for screening and grading the severity of sleep problems in Parkinson's disease (PD). This work aimed to examine the validity and reliability of an Arabic version of PDSS-2.

METHODS

This cross-sectional study was carried out on 133 patients fulfilling diagnostic criteria for PD. The patients were clinically assessed using the following scales: Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), modified Hoehn and Yahr Scale (H&Y), non-motor symptoms scale (NMSS), Beck Depression Inventory (BDI), and Pittsburgh Sleep Quality Index (PSQI). PDSS-2 scale was translated according to approved translation standards into Arabic and back-translated into English. Patients were asked to respond based on their experience in the last week.

RESULTS

The mean PDSS2 score for the included PD patients was 17±10. Cronbach's α coefficient value was 0.89, indicating good internal consistency. Most items showed high item-total correlation; the lowest was 0.375, considered higher than the conventional cut-off of 0.3. Test-retest reliability showed good agreement (ICC: 0.848). The exploratory factor analysis showed that items had been loaded over four factors. Total PDSS-2 score was positively correlated to age, disease duration, modified H&Y scale, MDS-UPDRS, NMSS, BDI, and global PSQI score. A cut-off point of 13 could differentiate poor sleepers from good sleepers with 91% sensitivity and 70% specificity (AUC 0.893, P<0.001).

CONCLUSION

The Arabic version of PDSS-2 has appropriate validity and can be reliably used for assessing sleep-related problems in Arabic-speaking patients with PD.

Correlation of matrix metalloproteinase 3 and matrix metalloproteinase 9 levels with non-motor symptoms in patients with Parkinson’s disease

Objective

Matrix metalloproteinases (MMPs) are essential for tissue formation, neuronal network remodeling, and blood–brain barrier integrity. MMPs have been widely studied in acute brain diseases. However, the relationship with Parkinson’s disease (PD) remains unclear. The purpose of this study was to evaluate the serum MMP3 and MMP9 levels of PD patients and analyze their correlation with non-motor symptoms.

Methods

In this cross-sectional study, we recruited 73 patients with idiopathic PD and 64 healthy volunteers. Serum MMP3 and MMP9 levels were measured by enzyme-linked immunosorbent assay (ELISA). Patients with PD were assessed for non-motor symptoms using the Non-motor Symptoms Scale (NMSS) and Parkinson’s disease sleep scale (PDSS) and Mini Mental State Examination (MMSE).

Results

Serum MMP3 levels were significantly decreased in PD patients, predominantly those with early-stage PD, compared with controls [12.56 (9.30, 17.44) vs. 15.37 (11.33, 24.41) ng/ml; P = 0.004], and the serum MMP9 levels of PD patients were significantly higher than those of healthy controls [522 (419, 729) vs. 329 (229, 473) ng/ml; P < 0.001]. MMP3 levels were positively correlated with the NMSS total score (r = 0.271, P = 0.020) and the single-item scores for item six, assessing the gastrointestinal tract (r = 0.333, P = 0.004), and there was an inverse correlation between serum MMP3 levels and PDSS score (r = –0.246, P = 0.036); meanwhile, MMP9 levels were positively correlated with the NMSS total score (r = 0.234, P = 0.047), and higher serum MMP9 levels were detected in the cognitive dysfunction subgroup than in the cognitively intact subgroup [658 (504, 877) vs. 502 (397, 608) ng/ml, P = 0.008].

Conclusion

The serum MMP3 level of PD patients (especially early-stage patients) was significantly lower than that of the healthy control group, and the MMP9 level was significantly higher than that of the healthy control group. MMP3 and MMP9 levels correlate with sleep disturbance and cognitive function in PD patients, respectively.

[Visual hallucinations in Parkinson's disease]

Visual hallucinations have a negative effect on the course of Parkinson's disease (PD), being a source of stress for the patients themselves and caregivers. The article discusses the basic theories and pathogenetic mechanisms of the development of visual hallucinations in PD consisting of the following components: impairment of the visual information received from the retina with subsequent disruption of its processing in the central parts of the visual system; lack of suppression of internally generated images through the ponto-geniculo-occipital system; the invasion of REM sleep patterns in wakefulness; decreased ability of the brain stem structures to implement appropriate information filtering as well as excessive drug-induced activation of the mesolimbic system. Particular attention is paid to visual impairment and changes in the transmission of information along the retino-hypothalamic tract. In this connection, dysfunction in the «retina - hypothalamus» system can also be considered as one of the factors that determines the time and rhythm of occurrence or exacerbation of visual hallucinations in PD. Attracting attention to this aspect opens new therapeutic possibilities where the circadian system can be positioned as a target of additional exposure in the treatment of visual hallucinations in PD.

Melatonin as a Chronobiotic and Cytoprotective Agent in Parkinson's Disease

This article discusses the role that melatonin may have in the prevention and treatment of Parkinson’s disease (PD). In parkinsonian patients circulating melatonin levels are consistently disrupted and the potential therapeutic value of melatonin on sleep disorders in PD was examined in a limited number of clinical studies using 2–5 mg/day melatonin at bedtime. The low levels of melatonin MT1 and MT2 receptor density in substantia nigra and amygdala found in PD patients supported the hypothesis that the altered sleep/wake cycle seen in PD could be due to a disrupted melatonergic system. Motor symptomatology is seen in PD patients when about 75% of the dopaminergic cells in the substantia nigra pars compacta region degenerate. Nevertheless, symptoms like rapid eye movement (REM) sleep behavior disorder (RBD), hyposmia or depression may precede the onset of motor symptoms in PD for years and are index of worse prognosis. Indeed, RBD patients may evolve to an α-synucleinopathy within 10 years of RBD onset. Daily bedtime administration of 3–12 mg of melatonin has been demonstrated effective in RDB treatment and may halt neurodegeneration to PD. In studies on animal models of PD melatonin was effective to curtail symptomatology in doses that allometrically projected to humans were in the 40–100 mg/day range, rarely employed clinically. Therefore, double-blind, placebo-controlled clinical studies are urgently needed in this respect.

Distinctive Evidence Involved in the Role of Endocannabinoid Signalling in Parkinson's Disease: A Perspective on Associated Therapeutic Interventions

Current pharmacotherapy of Parkinson's disease (PD) is symptomatic and palliative, with levodopa/carbidopa therapy remaining the prime treatment, and nevertheless, being unable to modulate the progression of the neurodegeneration. No available treatment for PD can enhance the patient's life-quality by regressing this diseased state. Various studies have encouraged the enrichment of treatment possibilities by discovering the association of the effects of the endocannabinoid system (ECS) in PD. These reviews delineate the reported evidence from the literature on the neuromodulatory role of the endocannabinoid system and expression of cannabinoid receptors in symptomatology, cause, and treatment of PD progression, wherein cannabinoid (CB) signalling experiences alterations of biphasic pattern during PD progression. Published papers to date were searched via MEDLINE, PubMed, etc., using specific key words in the topic of our manuscript. Endocannabinoids regulate the basal ganglia neuronal circuit pathways, synaptic plasticity, and motor functions via communication with dopaminergic, glutamatergic, and GABAergic signalling systems bidirectionally in PD. Further, gripping preclinical and clinical studies demonstrate the context regarding the cannabinoid compounds, which is supported by various evidence (neuroprotection, suppression of excitotoxicity, oxidative stress, glial activation, and additional benefits) provided by cannabinoid-like compounds (much research addresses the direct regulation of cannabinoids with dopamine transmission and other signalling pathways in PD). More data related to endocannabinoids efficacy, safety, and pharmacokinetic profiles need to be explored, providing better insights into their potential to ameliorate or even regress PD.

Molecular Crosstalk Between Circadian Rhythmicity and the Development of Neurodegenerative Disorders

Neurodegenerative disorders have been shown to exhibit substantial interconnectedness with circadian rhythmicity. Alzheimer's patients exhibit high degradation of the suprachiasmatic nucleus (SCN), the central endogenous circadian timekeeper, and Parkinson's patients have highly disrupted peripheral clock gene expression. Disrupted sleep patterns are highly evident in patients with neurodegenerative diseases; fragmented sleep has been shown to affect tau-protein accumulation in Alzheimer's patients, and rapid eye movement (REM) behavioral disorder is observed in a significant amount of Parkinson's patients. Although numerous studies exist analyzing the mechanisms of neurodegeneration and circadian rhythm function independently, molecular mechanisms establishing specific links between the two must be explored further. Thus, in this review, we explore the possible intersecting molecular mechanisms between circadian rhythm and neurodegeneration, with a particular focus on Parkinson's disease. We provide evidence for potential influences of E3 ligase and poly adenosine diphosphate (ADP-ribose) polymerase 1 (PARP1) activity on neurodegenerative pathology. The cellular stress and subsequent DNA damage signaling imposed by hyperactivity of these multiple molecular systems in addition to aberrant circadian rhythmicity lead to extensive protein aggregation such as α-synuclein pre-formed fibrils (α-Syn PFFs), suggesting a specific molecular pathway linking circadian rhythmicity, PARP1/E3 ligase activity, and Parkinson's disease.

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.

Mastering nocturnal jigsaws in Parkinson's disease: a dusk-to-dawn review of night-time symptoms

Finding out about night-time symptoms from Parkinson's disease (PD) patients can be a challenge as many patients and their carers cannot recall many symptoms that occur during the night, resulting in an under-recognition or a large variability of responses from clinical interviews and scales. Moreover, technology-based assessments for most night-time symptoms are still not universally available for use in a patient's home environment. Therefore, most physicians rely on their clinical acumen to capture these night-time symptoms based on pieces of patients' history, bedpartner's reports, clinical features, associated symptoms or conditions. To capture more night-time symptoms, the authors identified common nocturnal symptoms based on how they manifest from dusk to dawn with selected features relevant to PD. While some symptoms occur in healthy individuals, in PD patients, they may impact differently. The authors intend this narrative review to provide a practical guide on how these common night-time symptoms manifest and highlight pertinent issues by focusing on prevalence, clinical symptomatology, and specific relationships to PD. It is also important to recognise that PD-specific sleep disturbances increase with advancing disease with additional contributions from ageing, comorbidities, and medication side effects. However, the relative contribution of each factor to individual symptom may be different in individual patient, necessitating clinical expertise for individual interpretation. While there are debatable issues in certain areas, they underlie the complexity of night-time symptoms. Understanding night-time symptoms in PD is like re-arranging jigsaw pieces of clinical information to create, but never complete, a picture for physicians to instigate appropriate management.

The Parkinson's Disease Sleep Scale-2 (PDSS-2): Validation of the Spanish Version and Its Relationship With a Roommate-Based Version

Background

Because of the prevalence and impact of sleep disorders in Parkinson's disease (PD), valid instruments for their evaluation and monitoring are necessary. However, some nocturnal sleep disorders may go unnoticed by patients themselves.

Objectives

To validate a pan-Spanish version of the Parkinson's Disease Sleep Scale Version 2 (PDSS-2) and to test the relationships between the PDSS-2 and a PDSS-2 roommate version.

Methods

PD patients (n = 399) from seven Spanish-speaking countries were included. In addition to the tested PDSS-2 scales, valid measures for sleep disorders and both motor and nonmotor manifestations were applied. Acceptability, dimensionality, reliability, precision, and construct validity were explored, as well as discrepancies and agreement between the PDSS-2 and the roommate version.

Results

PDSS-2 showed negligible floor and ceiling effects. Four factors (57% of the variance) were identified. Reliability parameters were satisfactory: alpha = 0.84; item homogeneity coefficient = 0.27; corrected item total correlation = 0.28 to 0.61; and test-retest reliability (average kappa = 0.70; intraclass correlation coefficient [ICC] = 0.83). The standard error of measurement was 5.84, and correlations with other scales assessing nocturnal sleep were high (r_S = 0.62-0.56). In comparison to the patient-based total score, the by proxy total score showed no significant difference, high correlation (r_S = 0.70), and acceptable agreement (ICC = 0.69), but there were discrepancies in two or more points in 18% of item scores.

Conclusions

The Spanish version of the PDSS-2 has shown satisfactory clinimetric attributes. Acceptability and precision data are presented for the first time. The PDSS-2 roommate version could be useful to complement the patient-based evaluation, but additional studies are needed.

Clinical Profile of Chinese Long-Term Parkinson's Disease Survivors With 10 Years of Disease Duration and Beyond

Background

Parkinson’s disease (PD) patients with 10 years or more survival (PD-10) are not well characterized. The aim of this study was to evaluate the main issues facing PD-10 patients and identify factors that independently contributed to quality of life (QoL).

Methods

A group of 121 PD-10 patients recruited from outpatient clinics participated in this cross-sectional study. Data on demographic and clinical factors were collected. Multiple linear regression analyses were conducted to identify determinants of poor QoL.

Results

The entire PD-10 patients had disease duration ranging from 10 to 23 years, with 84.2% of the total cohort skewed to between 10 and 15 years’ duration. The PD-10 patients had great frequency of left-sided onset, increased motor and non-motor symptoms as well as inferior QoL. The more advanced stage of disease in PD-10 patients was associated with motor phenotype, freezing of gait, higher UPDRS sub-scores and levodopa equivalent dose, less balanced confidence, fatigue, anxiety, depression, reduced quality of life and worse Timed Up & Go performance. Self-reported mood symptoms, decreased balance confidence and reduced daily activities were the three factors most closely associated with poorer QoL, but excessive daytime sleepiness and long disease duration additionally contributed to the explanatory power.

Conclusions

This is the first report to investigate the clinical characteristics of Chinese PD-10 patients. Our study may elucidate an important clue for understanding PD-10 patients in clinical practice and identifying patients with PD at risk for reduced QoL.

A systematic review of the literature on disorders of sleep and wakefulness in Parkinson's disease from 2005 to 2015

Sleep disorders are among the most common non-motor manifestations in Parkinson's disease (PD) and have a significant negative impact on quality of life. While sleep disorders in PD share most characteristics with those that occur in the general population, there are several considerations specific to this patient population regarding diagnosis, management, and implications. The available research on these disorders is expanding rapidly, but many questions remain unanswered. We thus conducted a systematic review of the literature published from 2005 to 2015 on the following disorders of sleep and wakefulness in PD: REM sleep behavior disorder, insomnia, nocturia, restless legs syndrome and periodic limb movements, sleep disordered breathing, excessive daytime sleepiness, and circadian rhythm disorders. We discuss the epidemiology, etiology, clinical implications, associated features, evaluation measures, and management of these disorders. The influence on sleep of medications used in the treatment of motor and non-motor symptoms of PD is detailed. Additionally, we suggest areas in need of further research.

Rotigotine transdermal patch and sleep in Parkinson's disease: where are we now?

A wide range of sleep dysfunction complicates Parkinson’s disease during its course from prodromal to palliative stage. It is now increasingly acknowledged that sleep disturbances are thus integral to the disease and pose a significant burden impacting on quality of life of patients. Sleep fragmentation, restless legs syndrome, nocturia, and nocturnal pain are regarded as one of the main components of night-time sleep dysfunction with possible secondary impact on cognition and well-being. The role of dopaminergic therapies, particularly using a continuous drug delivery strategy in managing some of these sleep issues, have been reported but the overall concept remains unclear. This review provides an overview of several aspects of night-time sleep dysfunction in Parkinson’s disease and describes all available published open-label and blinded studies that investigated the use of rotigotine transdermal patch targeting sleep. Blinded studies have suggested beneficial effects of rotigotine transdermal patch on maintenance insomnia and restless legs syndrome in Parkinson’s disease patients. Open-label studies support these observations and also suggest beneficial effects on nocturia and nocturnal pain.

Toll-Like Receptor 2 Is a Regulator of Circadian Active and Inactive State Consolidation in C57BL/6 Mice

Regulatory systems required to maintain behavioral arousal remain incompletely understood. We describe a previously unappreciated role that toll-like receptor 2 (Tlr2, a membrane bound pattern recognition receptor that recognizes specific bacterial, viral, and fungal peptides), contributes toward regulation of behavioral arousal. In 4–4.5 month old mice with constitutive loss of Tlr2 function (Tlr2^−/− mice), we note a marked consolidation in the circadian pattern of both active and inactive states. Specifically, Tlr2^−/− mice demonstrated significantly fewer but longer duration active states during the circadian dark cycle, and significantly fewer but longer duration inactive states during the circadian light cycle. Tlr2^−/− mice also consumed less food and water, and moved less during the circadian light cycle. Analysis of circadian rhythms further suggested that Tlr2^−/− mice demonstrated less day-to-day variability in feeding, drinking, and movement behaviors. Reevaluation of this same mouse cohort at age 8–8.5 months revealed a clear blunting of these differences. However, Tlr2^−/− mice were still noted to have fewer short-duration active states during the circadian dark cycle, and continued to demonstrate significantly less day-to-day variability in feeding, drinking, and movement behaviors. These results suggest that Tlr2 function may have a role in promoting transitions between active and inactive states. Prior studies have demonstrated that Tlr2 regulates sickness behaviors including hypophagia, hyperthermia, and decreased activity. Our work suggests that Tlr2 function also evokes behavioral fragmentation, another aspect of sickness behavior and a clinically significant problem of older adults.

Circadian Dysregulation in Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder that affects over one million individuals in the US alone. PD is characterized by a plethora of motor and non-motor manifestations, resulting from a progressive degeneration of dopaminergic neurons and disbalance of several other neurotransmitters. A growing body of evidence points to significant alterations of the circadian system in PD. This is not surprising given the pivotal role that dopamine plays in circadian regulation as well as the role of circadian influences in dopamine metabolism. In this review we present basic and clinical investigations that examined the function of the circadian system in PD.

Marijuana Compounds: A Nonconventional Approach to Parkinson's Disease Therapy

Parkinson's disease (PD), a neurodegenerative disorder, is the second most common neurological illness in United States. Neurologically, it is characterized by the selective degeneration of a unique population of cells, the nigrostriatal dopamine neurons. The current treatment is symptomatic and mainly involves replacement of dopamine deficiency. This therapy improves only motor symptoms of Parkinson's disease and is associated with a number of adverse effects including dyskinesia. Therefore, there is unmet need for more comprehensive approach in the management of PD. Cannabis and related compounds have created significant research interest as a promising therapy in neurodegenerative and movement disorders. In this review we examine the potential benefits of medical marijuana and related compounds in the treatment of both motor and nonmotor symptoms as well as in slowing the progression of the disease. The potential for cannabis to enhance the quality of life of Parkinson's patients is explored.

A Polysomnographic Study of Parkinson's Disease Sleep Architecture

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

Excessive daytime sleepiness and unintended sleep episodes associated with Parkinson's disease

This article looks at the issues of excessive daytime sleepiness and unintended sleep episodes in patients with Parkinson's disease (PD) and explores the reasons why patients might suffer from these symptoms, and what steps could be taken to manage them. During the last decade, understanding of sleep/wake regulation has increased. Several brainstem nuclei and their communication pathways in the ascending arousing system through the hypothalamus and thalamus to the cortex play key roles in sleep disorders. Insomnia is the most common sleep disorder in PD patients, and excessive daytime sleepiness is also common. Excessive daytime sleepiness affects up to 50% of PD patients and a growing body of research has established this sleep disturbance as a marker of preclinical and premotor PD. It is a frequent and highly persistent feature in PD, with multifactorial underlying pathophysiology. Both age and disease-related disturbances of sleep-wake regulation contribute to hypersomnia in PD. Treatment with dopamine agonists also contribute to excessive daytime sleepiness. Effective management of sleep disturbances and excessive daytime sleepiness can greatly improve the quality of life for patients with PD.

Transdermal Rotigotine Improves Sleep Fragmentation in Parkinson's Disease: Results of the Multicenter, Prospective SLEEP-FRAM Study

Sleep disturbances occur frequently in patients with Parkinson's disease (PD). The aim of this study was to investigate the effects of rotigotine on sleep fluctuations in a sample of PD patients with self-reported complaints of nocturnal awakenings. This prospective, open-label, observational, and multicenter study enrolled consecutive outpatients with PD and administered rotigotine (mean dose 8.9 mg/day) for 3 months. The primary endpoint was the change from baseline in sleep fragmentation, assessed using the sleep maintenance subscale score of the Parkinson's Disease Sleep Scale (PDSS). The newly designed Parkinson's Disease Sleep Fragmentation Questionnaire (PD-SFQ) was used to measure other sleep parameters. A total of 62 patients were enrolled (mean age 70.2 years; 66% male). At 3 months, rotigotine significantly improved sleep fragmentation from baseline on the PDSS-2 sleep maintenance subscale (from 3.4 ± 0.9 to 1.9 ± 1.4; P < 0.0001). Rotigotine also significantly improved nocturnal motor symptoms (P < 0.0001), restless legs-like symptoms (P < 0.005), and nocturia (P = 0.004). Rotigotine significantly improved self-reported complaints of sleep fragmentation in PD patients and could be a useful treatment to improve this specific sleep problem in PD. However, these results are based on a small and clinically heterogeneous sample so they must be taken cautiously.

'The clocks that time us'--circadian rhythms in neurodegenerative disorders

Circadian rhythms are physiological and behavioural cycles generated by an endogenous biological clock, the suprachiasmatic nucleus. The circadian system influences the majority of physiological processes, including sleep-wake homeostasis. Impaired sleep and alertness are common symptoms of neurodegenerative disorders, and circadian dysfunction might exacerbate the disease process. The pathophysiology of sleep-wake disturbances in these disorders remains largely unknown, and is presumably multifactorial. Circadian rhythm dysfunction is often observed in patients with Alzheimer disease, in whom it has a major impact on quality of life and represents one of the most important factors leading to institutionalization of patients. Similarly, sleep and circadian problems represent common nonmotor features of Parkinson disease and Huntington disease. Clinical studies and experiments in animal models of neurodegenerative disorders have revealed the progressive nature of circadian dysfunction throughout the course of neurodegeneration, and suggest strategies for the restoration of circadian rhythmicity involving behavioural and pharmacological interventions that target the sleep-wake cycle. In this Review, we discuss the role of the circadian system in the regulation of the sleep-wake cycle, and outline the implications of disrupted circadian timekeeping in neurodegenerative diseases.

Tremor and clinical fluctuation are related to sleep disorders in Chinese patients with Parkinson's disease

Objective

To study the relationship between sleep disturbances and symptoms in patients with Parkinson’s disease (PD).

Methods

The Parkinson’s Disease Sleep Scale-Chinese Version (PDSS-CV) was used to evaluate the sleep disturbances of PD patients in a cross sectional study. The Unified Parkinson’s Disease Rating Scale (UPDRS) parts II-IV, and the Hoehn & Yahr (H&Y) stage were used to determine the level of motor function in PD and the severity of PD. The Spearman correlation and a multiple regression analysis were used to identify the relationship between sleep disturbances and symptoms of PD. The quantities derived from the UPDRS and the H&Y stage and disease duration were compared between groups of patients either with or without sleep disturbances identified by the PDSS. This study was conducted from December 2011 to March 2012 at the First Affiliated Hospital of Sun Yat-sen University, in Guangzhou.

Results

A total of 136 PD patients were included in this study. The overall total PDSS score in PD patients was 107.58 ± 23.35 points (range: 30–146). There were significant differences in the disease duration, the H&Y stage, and the UPDRS section subscores between groups of patients either with or without sleep disturbances (Kruskal-Wallis Test, p <0.05). There were significant negative correlations between PDSS scores and the UPDRS subscores, the H&Y stage and the disease duration (Spearman correlation, p < 0.05). The multiple regression analysis indicated that sleep disturbances identified by the PDSS were only associated with daily life activity, tremor intensity and clinical fluctuation (R² = 0.22, F(3,132) = 12.4, p < 0.001). The correlations were also significant when the contribution of the other two factors was excluded using partial correlations.

Conclusions

The level of daily life activity and the occurrences of tremor and clinical fluctuation are likely to be important factors that lead to PD patients’ sleep disturbances. This study may elucidate an important clue for the relationship between sleep disturbances and PD symptoms.

Sleep dysfunction and its management in Parkinson's disease

OPINION STATEMENT

Sleep disorders are among the most common non-motor symptoms in Parkinson's Disease (PD). In some cases, symptoms can precede a diagnosis of PD by many years, but otherwise they are commonly encountered during the clinical care of patients. Unfortunately, sleep problems are under-recognized and subsequently inadequately addressed. In our experience, when properly addressed, physicians and patients are quickly aware of the often-debilitating nature of sleep dysfunction. This does not mean that solutions are easily attainable. Sleep in PD is held in a delicate balance, influenced by the disease process, medications, co-morbid symptoms, and a variety of other factors. For this reason, management of sleep in PD often requires an inter-disciplinary approach. Physicians should have an intimate knowledge of the many sleep problems apparent in PD, as well as appreciate the challenge presented by diverse therapeutic options that can both ameliorate and aggravate symptoms.

Analysis of clinical evaluation of response to treatment of Parkinson's disease with integrated Chinese and Western medicine therapy

OBJECTIVE

To analyze the clinical evaluation of Parkinson's disease (PD) patients receiving integrated Chinese and Western medicine therapy.

METHODS

One hundred and twenty patients were enrolled and randomly allocated to a control group or treatment group. Patients in the two groups received placebo and Bushen Huoxue Granule (, BHG), respectively. Both groups received baseline levodopa and benserazide (Madopar). The effects of treatment were assessed monthly during the 9-month treatment. Means of evaluation included Unified PD Rating Scale (UPDRS) scores (II and III), sleep scale score, 10 m turn back test (getting up time, 10 m×2 times, and turning time), timing motor test (TMT)-left and TMT-right, which were treated as the dependent variables; and age, sex, duration of PD, Hoehn and Yahr (H-Y) stage and Madopar dosage of admitted PD patients were as the independent variables. Multiple linear regression was used to analyze these factors.

RESULTS

H-Y stage significantly affected UPDRS II score, UPDRS III score, and getting up time (P<0.01). Madopar dosage and H-Y stage significantly affected the 10 m×2 times (P<0.05 or <0.01). Madopar dosage significantly affected the sleep scale score (P<0.05). There were also significant correlations between age and TMT-left or TMT-right (P<0.01), and duration of PD and TMT-right (P<0.05).

CONCLUSIONS

The six assessed means of clinical evaluation (including UPDRS II and UPDRS III scores, sleep scale score, getting up time, 10 m×2 times, and turning time) are sensitive indexes in all PD patients. H-Y stage and Madopar dosage are the major factors influencing means of clinical assessment of PD treatment.

Circadian melatonin rhythm and excessive daytime sleepiness in Parkinson disease

IMPORTANCE

Diurnal fluctuations of motor and nonmotor symptoms and a high prevalence of sleep-wake disturbances in Parkinson disease (PD) suggest a role of the circadian system in the modulation of these symptoms. However, surprisingly little is known regarding circadian function in PD and whether circadian dysfunction is involved in the development of sleep-wake disturbances in PD.

OBJECTIVE

To determine the relationship between the timing and amplitude of the 24-hour melatonin rhythm, a marker of endogenous circadian rhythmicity, with self-reported sleep quality, the severity of daytime sleepiness, and disease metrics.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional study from January 1, 2009, through December 31, 2012, of 20 patients with PD receiving stable dopaminergic therapy and 15 age-matched control participants. Both groups underwent blood sampling for the measurement of serum melatonin levels at 30-minute intervals for 24 hours under modified constant routine conditions at the Parkinson's Disease and Movement Disorders Center of Northwestern University.

INTERVENTIONS

Twenty-four hour monitoring of serum melatonin secretion.

MAIN OUTCOMES AND MEASURES

Clinical and demographic data, self-reported measures of sleep quality (Pittsburgh Sleep Quality Index) and daytime sleepiness (Epworth Sleepiness Scale), and circadian markers of the melatonin rhythm, including the amplitude, area under the curve (AUC), and phase of the 24-hour rhythm.

RESULTS

Patients with PD had blunted circadian rhythms of melatonin secretion compared with controls; the amplitude of the melatonin rhythm and the 24-hour AUC for circulating melatonin levels were significantly lower in PD patients (P < .001). Markers of the circadian phase were not significantly different between the 2 groups. Compared with PD patients without excessive daytime sleepiness, patients with excessive daytime sleepiness (Epworth Sleepiness Scale score ≥10) had a significantly lower amplitude of the melatonin rhythm and 24-hour melatonin AUC (P = .001). Disease duration, Unified Parkinson's Disease Rating Scale scores, levodopa equivalent dose, and global Pittsburgh Sleep Quality Index score in the PD group were not significantly related to measures of the melatonin circadian rhythm.

CONCLUSIONS AND RELEVANCE

Circadian dysfunction may underlie excessive sleepiness in PD. The nature of this association needs to be explored further in longitudinal studies. Approaches aimed to strengthen circadian function, such as timed exposure to bright light and exercise, might serve as complementary therapies for the nonmotor manifestations of PD.

Circadian and sleep disorders in Parkinson's disease

Impaired sleep and alertness, initially recognized by James Parkinson in his famous monograph "An Essay on the Shaking Palsy" in 1817, is one of the most common and disabling nonmotor symptoms of Parkinson's disease (PD). It is only recently, however, that sleep disturbances in PD have received the attention of medical and research community. Dopamine, the major neurotransmitter implicated in the pathogenesis of PD, plays a pivotal role in the regulation of sleep and circadian homeostasis. Sleep dysfunction affects up to 90% of patients with PD, and may precede the onset of the disease by decades. Sleep dysfunction in PD may be categorized into disturbances of overnight sleep and daytime alertness. Etiology of impaired sleep and alertness in PD is multifactorial. Co-existent primary sleep disorders, medication side effects, overnight re-emergence of motor symptoms, and primary neurodegeneration itself, are main causes of sleep disruption and excessive daytime sleepiness among patients with PD. Increasing body of evidence suggests that the circadian system becomes dysregulated in PD, which may lead to poor sleep and alertness. Treatment options are limited and frequently associated with unwanted side effects. Further studies that will examine pathophysiology of sleep dysfunction in PD, and focus on novel treatment approaches are therefore very much needed. In this article we review the role of dopamine in regulation of sleep and alertness and discuss main sleep and circadian disturbances associated with PD.

Roles of endoplasmic reticulum and energetic stress in disturbed sleep

Sleep disturbances are contributing factors to health risk for several diseases including hypertension, diabetes, obesity, depression, and stroke. On a molecular level, sleep disturbances that incur sleep loss and sleep fragmentation result in cellular stress, inflammation, and an impaired immune system. It has been hypothesized that sleep deprivation or prolonged waking leads to increased energy demand and thus energetic stress. Sleep loss and sleep fragmentation are also known to lead to cellular stress specifically endoplasmic reticulum (ER) stress. This review will summarize the current knowledge of the roles of ER and energetic stress during sleep loss and fragmentation that are characteristics of many sleep disturbances. Sleep research pertinent to these specific pathways will be discussed.

Cellular stress/the unfolded protein response: relevance to sleep and sleep disorders

Recent transcript profiling and microarray studies are beginning to unveil some of the mysteries of sleep. One of the most important clues has been the identification of the endoplasmic reticulum (ER) resident chaperone, immunoglobulin binding protein (BiP), that increases with sleep deprivation in all species studied. BiP, an ER resident chaperone, is the key cellular marker and master regulator of a signaling pathway called the ER stress response or unfolded protein response. The ER stress response occurs in 3 phases. It is healthy, protective and adaptive when the ER stress is moderate. Failure of the adaptive response leads to the activation of an inflammatory response. When the ER stress burden is great and prolonged, executioner pathways are activated. Collectively this work provides new evidence that modest sleep deprivation induces cellular stress that activates an adaptive response. Aging tilts the response to sleep deprivation from one that is adaptive and protective to one that is maladaptive. Understanding the pathways activated by sleep loss and the mechanisms by which they occur will allow the development of therapies to protect the brain during prolonged wakefulness and specifically in sleep disorders including those associated with aging.