Diurnal effects of motor activity and fatigue in Parkinson's disease

Effects of MicroRNAs and Long Non-coding RNAs on Beneficial Action of Exercise on Cognition in Degenerative Diseases: A Review

Recent research has exposed a growing body of proof underscoring the importance of microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) in maintaining the physical composition of neurons and influencing cognitive functioning in both standard and atypical circumstances. Extensive research has been conducted on the possible application of miRNAs and lncRNAs as biomarkers for various diseases, with a particular focus on brain disorders, as they possess remarkable durability in cell-free surroundings and can endure repeated freezing and thawing processes. It is intriguing to note that miRNAs and lncRNAs have the ability to function through paracrine mechanisms, thereby playing a role in communication between different organs. Recent research has proposed that the improvement of cognitive abilities through physical exercise in mentally healthy individuals is a valuable method for uncovering potential connections between miRNAs, or microRNAs, and lncRNAs, and human cognitive function. The process of cross-correlating data from disease models and patients with existing data will be crucial in identifying essential miRNAs and lncRNAs, which can potentially act as biomarkers or drug targets in the treatment of cognitive disorders. By combining this method with additional research in animal models, we can determine the function of these molecules and their potential impact on therapy. This article discusses the latest research about the primary miRNAs, lncRNAs, and their exosomes that are affected by physical activity in terms of human cognitive function.

Circadian rhythms in the blood-brain barrier: impact on neurological disorders and stress responses

Circadian disruption has become more prevalent in society due to the increase in shift work, sleep disruption, blue light exposure, and travel via different time zones. The circadian rhythm is a timed transcription-translation feedback loop with positive regulators, BMAL1 and CLOCK, that interact with negative regulators, CRY and PER, to regulate both the central and peripheral clocks. This review highlights the functions of the circadian rhythm, specifically in the blood-brain barrier (BBB), during both healthy and pathological states. The BBB is a highly selective dynamic interface composed of CNS endothelial cells, astrocytes, pericytes, neurons, and microglia that form the neurovascular unit (NVU). Circadian rhythms modulate BBB integrity through regulating oscillations of tight junction proteins, assisting in functions of the NVU, and modulating transporter functions. Circadian disruptions within the BBB have been observed in stress responses and several neurological disorders, including brain metastasis, epilepsy, Alzheimer's disease, and Parkinson's disease. Further understanding of these interactions may facilitate the development of improved treatment options and preventative measures.

How Does Chronobiology Contribute to the Development of Diseases in Later Life

An increasingly older population is one of the major social and medical challenges we currently face. Between 2010 and 2050, it is estimated that the proportion of adults over 65 years of age will double from 8% to 16% of the global population. A major concern associated with aging is the changes in health that can lead to various diseases such as cancer and neurogenerative diseases, which are major burdens on individuals and societies. Thus, it is imperative to better understand changes in sleep and circadian rhythms that accompany aging to improve the health of an older population and target diseases associated with aging. Circadian rhythms play a role in most physiological processes and can contribute to age-related diseases. Interestingly, there is a relationship between circadian rhythms and aging. For example, many older adults have a shift in chronotype, which is an individual's natural inclination to sleep certain times of the day. As adults age, most people tend to go to sleep earlier while also waking up earlier. Numerous studies also suggest that disrupted circadian rhythms may be indicative of developing age-related diseases, like neurodegenerative disorders and cancer. Better understanding the relationship between circadian rhythms and aging may allow us to improve current treatments or develop novel ones that target diseases commonly associated with aging.

Why do 'OFF' periods still occur during continuous drug delivery in Parkinson's disease?

Continuous drug delivery (CDD) is used in moderately advanced and late-stage Parkinson’s disease (PD) to control motor and non-motor fluctuations (‘OFF’ periods). Transdermal rotigotine is indicated for early fluctuations, while subcutaneous apomorphine infusion and levodopa-carbidopa intestinal gel are utilised in advanced PD. All three strategies are considered examples of continuous dopaminergic stimulation achieved through CDD. A central premise of the CDD is to achieve stable control of the parkinsonian motor and non-motor states and avoid emergence of ‘OFF’ periods. However, data suggest that despite their efficacy in reducing the number and duration of ‘OFF’ periods, these strategies still do not prevent ‘OFF’ periods in the middle to late stages of PD, thus contradicting the widely held concepts of continuous drug delivery and continuous dopaminergic stimulation. Why these emergent ‘OFF’ periods still occur is unknown. In this review, we analyse the potential reasons for their persistence. The contribution of drug- and device-related involvement, and the problems related to site-specific drug delivery are analysed. We propose that changes in dopaminergic and non-dopaminergic mechanisms in the basal ganglia might render these persistent ‘OFF’ periods unresponsive to dopaminergic therapy delivered via CDD.

Perception of Physical Demand, Mental Demand, and Performance: A Comparison of Two Voice Interventions for Parkinson's Disease

PURPOSE

The purpose of the study was to examine the effect of two voice intervention approaches for hypophonia secondary to Parkinson's disease (PD) on self-reported measures of physical demand, mental demand, and vocal performance.

METHOD

Thirty-four persons with hypophonia secondary to PD were assigned to one of three groups: Lee Silverman Voice Treatment (LSVT) LOUD (n = 12), SpeechVive (n = 12), and nontreatment clinical control (n = 10). The LSVT LOUD and the SpeechVive participants received 8 weeks of voice intervention following the standardized protocol previously described for each approach. To confirm the effectiveness of each voice intervention, sound pressure level (dB SPL) data were analyzed for the experimental and control participants for a monologue sample obtained pretreatment, midtreatment, and posttreatment. During the voice intervention period, the LSVT LOUD and the SpeechVive participants were instructed to complete a modified version of the National Aeronautics and Space Administration Task Load Index rating scale to indicate the mental and physical demand required to complete the intervention activities, and to indicate how well they performed in completing the assigned vocal tasks.

RESULTS

The LSVT LOUD and the SpeechVive participants demonstrated a significant posttreatment increase in SPL (dB), in comparison to the clinical controls, thus confirming a positive intervention effect. The LSVT LOUD participants reported significantly higher ratings of physical and mental demand over the course of treatment, in comparison to the SpeechVive participants.

CONCLUSION

Consideration of the mental and physical demand associated with two voice intervention approaches, commonly used for PD, may help to foster improved therapeutic compliance and treatment outcomes.

Exploring the management approaches of cytokines including viral infection and neuroinflammation for neurological disorders

Considerable evidence supports that cytokines are important mediators of pathophysiologic processes within the central nervous system (CNS). Numerous studies have documented the increased production of various cytokines in the human CNS in various neurological and neuropsychiatric disorders. Deciphering cytokine actions in the intact CNS has important implications for our understanding of the pathogenesis and treatment of these disorders. The purpose of this study is to discuss the recent research on treating cytokine storm and amyloids, including stroke, Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's condition, Multi-sclerosis (MS), Amyotrophic Lateral Sclerosis (ALS). Neuroinflammation observed in neurological disorders has a pivotal role in exacerbating Aβ burden and tau hyperphosphorylation, suggesting that stimulating cytokines in response to an undesirable external response could be a checkpoint for treating neurological disorders. Furthermore, the pro-inflammatory cytokines help our immune system through a neuroprotective mechanism in clearing viral infection by recruiting mononuclear cells. This study reveals that cytokine applications may play a vital role in providing novel regulation and methods for the therapeutic approach to neurological disorders and the causes of the deregulation, which is responsible for neuroinflammation and viral infection. However, it needs to be further investigated to clarify better the mechanisms of cytokine release in response to various stimuli, which could be the central point for treating neurological disorders.

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.

Mammalian circadian networks mediated by the suprachiasmatic nucleus

The brain has a complex structure composed of hundreds of regions, forming networks to cooperate body functions. Therefore, understanding how various brain regions communicate with each other and with peripheral organs is important to understand human physiology. The suprachiasmatic nucleus (SCN) in the brain is the circadian pacemaker. The SCN receives photic information from the environment and conveys this to other parts of the brain and body to synchronize all circadian clocks. The circadian clock is an endogenous oscillator that generates daily rhythms in metabolism and physiology in almost all cells via a conserved transcriptional-translational negative feedback loop. So, the information flow from the environment to the SCN to other tissues synchronizes locally distributed circadian clocks to maintain homeostasis. Thus, understanding the circadian networks and how they adjust to environmental changes will better understand human physiology. This review will focus on circadian networks mediated by the SCN to understand how the environment, brain, and peripheral tissues form networks for cooperation.

Expression levels of specific microRNAs are increased after exercise and are associated with cognitive improvement in Parkinson's disease

There is a consensus regarding the efficacy of physical exercise in maintaining or improving human health; however, there are few studies examining the effect of physical exercise on the expression levels of microRNAs (miRNA/miRs) in Parkinson's disease (PD). The aim of the present study was to investigate the effects of an interval training program on a cycle ergometer on the expression levels of miR‑106a‑5p, miR‑103a‑3p and miR‑29a‑3p in serum samples from men with PD. This was a quasi‑experimental study with pre‑ and post‑testing and with a non‑equivalent group design. The participants were selected based on the eligibility criteria and subsequently classified into two groups: Experimental group and control group. The evaluations were performed at the beginning of the study (week 0) and after 8 weeks of the intervention program (week 9). The interval training program was performed on a cycle ergometer for 30 min, three times a week during an 8‑week period. The expression levels of miR‑106a‑5p, miR‑103a‑3p and miR‑29a‑3p in the experimental group were increased after physical exercise and were associated with cognitive improvement in men with PD. However, further studies are required to clarify the potential use of these circulating miRNAs as markers of adaptation to physical exercise. Collectively, the present results indicated that these three miRNAs may be associated with the exercise response and cognitive improvement in men with PD.

How Time Rules: Diurnal Motor Patterns in de novo Parkinson’s Disease

Background: Several small-scale studies have shown that motor performance in Parkinson’s disease (PD) fluctuates throughout the day. Studies specifically focusing on de novo patients are, however, lacking. Objective: To evaluate the effect of clock time on motor performance in de novo drug-naïve patients with PD. Methods: We retrieved MDS-UPDRS III scores for 421 de novo PD patients from the PPMI cohort and stratified them into three groups based on time of assessment: group 1) 7:00–10:00; group 2) 10:00–13:00, and group 3) 13:00–18:00. Groups were compared using Kruskal-Wallis test and results corrected for multiple testing. In addition, we obtained 27 wearable sensor reports, objectively capturing bradykinesia scores in a home setting over a 6-day continuous period, in 12 drug-naïve patients from the Parkinson’s Kinetigraph Registry held at King’s College Hospital London. Time spent in severe bradykinesia scores were broken down into five daytime (06:00–21:00) three-hourly epochs and scores compared using the Friedman test. Results: There were no group differences in demographic or other clinical variables for the cross-sectional analysis. MDS-UPDRS III total scores worsened significantly during the course of the day (median 18 (group 1); 20 (group 2); and 23 (group 3); p = 0.001). In the longitudinal wearable sensor cohort, diurnal variations were present in percentage of time spent in severe bradykinesia (p < 0.001) with the lowest percentage during the 09:00–12:00 epoch (69.56±16.68%), when most patients are awake and start daily activity, and the highest percentage during the 18:00–21:00 epoch (73.58±16.35%). Conclusion: This exploratory study shows the existence of a diurnal pattern of motor function in patients with de novo PD. The results obtained were corroborated by objective measurements in a small longitudinal cohort confirming a similar diurnal motor score variation.

Gait speed in clinical and daily living assessments in Parkinson's disease patients: performance versus capacity

Gait speed often referred as the sixth vital sign is the most powerful biomarker of mobility. While a clinical setting allows the estimation of gait speed under controlled conditions that present functional capacity, gait speed in real-life conditions provides the actual performance of the patient. The goal of this study was to investigate objectively under what conditions during daily activities, patients perform as well as or better than in the clinic. To this end, we recruited 27 Parkinson's disease (PD) patients and measured their gait speed by inertial measurement units through several walking tests in the clinic as well as their daily activities at home. By fitting a bimodal Gaussian model to their gait speed distribution, we found that on average, patients had similar modes in the clinic and during daily activities. Furthermore, we observed that the number of medication doses taken throughout the day had a moderate correlation with the difference between clinic and home. Performing a cycle-by-cycle analysis on gait speed during the home assessment, overall only about 3% of the strides had equal or greater gait speeds than the patients' capacity in the clinic. These strides were during long walking bouts (>1 min) and happened before noon, around 26 min after medication intake, reaching their maximum occurrence probability 3 h after Levodopa intake. These results open the possibility of better control of medication intake in PD by considering both functional capacity and continuous monitoring of gait speed during real-life conditions.

A tablet- and mobile-based application for remote diagnosis and analysis of movement disorder symptoms

One significant hindrance to effective diagnosis of movement disorders (MDs) and analysis of their progression is the requirement for patients to conduct tests in the presence of a clinician. Here is presented a pilot study for diagnosis of essential tremor (ET), the world's most common MD, through analysis of a tablet- or mobile-based drawing task that may be selected at will, with the spiral- and line-drawing tasks of the Fahn-Tolosa-Marin tremor rating scale serving as our task in this work. This system replaces the need for pen-and-paper drawing tests while permitting advanced quantitative analysis of drawing smoothness, pressure applied, and other measures. Data is securely recorded and stored in the cloud, from which all analysis was conducted remotely. This will enable longitudinal analysis of patient disease progression without the need for excessive clinical visits. Several features were extracted and recursive feature elimination applied to rank the features' individual contribution to our classifier. Maximum cross-validated classification accuracy on a preliminary sample set was 98.3%. Future work will involve collecting healthy subject data from an age-controlled population and extending this diagnostic application to additional conditions, as well as incorporating regression-based symptom severity analysis. This highly promising new technology has the potential to substantially alleviate the demands placed on both clinicians and patients by bringing MD treatment more into line with the era of personalized medicine.

Fatigue in Parkinson's Disease Associates with Lower Ambulatory Diastolic Blood Pressure

BACKGROUND/OBJECTIVE

Fatigue is a common debilitating symptom in Parkinson's disease (PD) of unclear etiology. Hypotension and blood pressure variability are common in PD though their relationship to other non-motor symptoms is less well understood.

METHODS

We conducted a cross-sectional study to explore differences in 24-hour ambulatory blood pressure measurements in PD subjects (n = 35) with and without fatigue. Subjects underwent hourly systolic (SBP) and diastolic (DBP) blood pressure testing in their home environment. The presence of fatigue was assessed using the Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part 1. We compared blood pressure measurements in fatigued vs. non-fatigued PD subjects, assessed over 4 epochs: overnight, morning, midday, and evening.

RESULTS

PD subjects with symptoms of fatigue demonstrated lower mean DBP, compared to those without fatigue (67.8±4.8 mmHg vs. 75.6±9.4 t = 2.57, p = 0.014). These intergroup differences were most notable in the morning. The two groups did not differ in scoring on the Survey of Autonomic Symptoms or on an office-based blood assessment of SBP or DBP performed on the day of 24-hour monitor initiation.

CONCLUSIONS

Fatigue in PD may be a clinical manifestation of low-grade systemic hypotension.

Therapeutic implications of circadian clocks in neurodegenerative diseases

Circadian clocks, endogenous oscillators generating daily biological rhythms, have important roles in the nervous system to control diverse cellular processes-not only in the suprachiasmatic nucleus (SCN), where the master clocks reside to synchronize all circadian clocks in the body but also in other non-SCN areas. Accumulating evidence has shown relationships between circadian abnormalities (e.g., sleep disturbances and abnormal rest-activity rhythms) and disease progressions in various neurodegenerative diseases, including Alzheimer's (AD) and Parkinson's (PD) disease. Although circadian abnormalities were frequently considered as consequences of disease onsets, recent studies suggest altered circadian clocks as risk factors to develop neurodegenerative diseases via altered production or clearance rates of toxic metabolites like amyloid β. In this review, we will summarize circadian clock-related pathologies in the most common neurodegenerative diseases in the central nervous system, AD and PD. Then, we will introduce the current clinical trials to rescue circadian abnormalities in AD and PD patients. Finally, a discussion about how to improve targeting circadian clocks to increase treatment efficiencies and specificities will be followed. This discussion will provide insight into circadian clocks as potential therapeutic targets to attenuate onsets and progressions of neurodegenerative diseases.

Circadian Rhythm Abnormalities in Parkinson's Disease from Humans to Flies and Back

Clinical and research studies have suggested a link between Parkinson’s disease (PD) and alterations in the circadian clock. Drosophila melanogaster may represent a useful model to study the relationship between the circadian clock and PD. Apart from the conservation of many genes, cellular mechanisms, signaling pathways, and neuronal processes, Drosophila shows an organized central nervous system and well-characterized complex behavioral phenotypes. In fact, Drosophila has been successfully used in the dissection of the circadian system and as a model for neurodegenerative disorders, including PD. Here, we describe the fly circadian and dopaminergic systems and report recent studies which indicate the presence of circadian abnormalities in some fly PD genetic models. We discuss the use of Drosophila to investigate whether, in adults, the disruption of the circadian system might be causative of brain neurodegeneration. We also consider approaches using Drosophila, which might provide new information on the link between PD and the circadian clock. As a corollary, since PD develops its symptomatology over a large part of the organism’s lifespan and given the relatively short lifespan of fruit flies, we suggest that genetic models of PD could be used to perform lifelong screens for drug-modulators of general and/or circadian-related PD traits.

Fatigue in Parkinson's disease: A systematic review and meta-analysis

We conducted a systematic review and meta-analysis aimed at establishing robust prevalence estimates and identifying clinical correlates of fatigue in PD. From 2,459 titles and abstracts, we selected 44 relevant studies (n = 7427 patients). Overall, the meta-analysis showed a prevalence of fatigue of 50% in PD. This prevalence estimate, however, was significantly moderated by study heterogeneity in measurement scales and cut-off thresholds. In contrast, demographic features, disease severity, cognitive impairment, and depression did not moderate prevalence estimates. Moreover, fatigue prevalence did not differ between de novo and treated PD patients. Compared to nonfatigued patients, fatigued patients had sligthly higher age (1.44 years), disease duration (0.93 years), l-dopa equivalent daily dose (50.89 units), UPDRS-III (4.99 points), and H & Y (0.33 points), as well as risk of comorbid depression (risk ratio = 1.89) and had a little lower MMSE score (-0.66 points). Fatigue was moderately associated with apathy (Hedges' g = 0.55), anxiety (Hedges' g = 0.67), daytime somnolence (Hedges' g = 0.43), sleep disturbances (Hedges' g = 0.66), and poorer quality of life (Hedges' g = 1.23). Our analyses suggest that fatigue is a frequent, independent nonmotor symptom in PD appearing early and persisting throughout the disease course, and that establishing uniform diagnostic criteria for PD-related fatigue is critical. In addition, several nonmotor symptoms appear to be associated with fatigue and negatively impact quality of life. Pharmacological and nonpharmacological interventions targeting fatigue and associated symptoms may improve quality of life in patients with PD. © 2018 International Parkinson and Movement Disorder Society.

Does fatigue in Parkinson's disease correlate with autonomic nervous system dysfunction?

BACKGROUND

Despite its negative impact on quality of life, fatigue in Parkinson's disease (PD) remains an under-recognized issue and the underlying pathology is undetermined.

OBJECTIVE

To contribute at understanding the pathogenesis of fatigue in a naturalistic cohort of cognitively intact PD patients.

METHODS

In a Caucasian population of PD patients (n = 27), we evaluated to what extent fatigue (quantified as PFS-16 score) is associated with PD duration and with autonomic dysfunction, studied by both MIBG scintigraphy and autonomic nervous system testing. The latter included the head-up tilt test, Valsalva maneuver, deep breathing, and handgrip tests.

RESULTS

PFS-16 score correlated with disease duration (R = 0.57, p = 0.002). Fatigue showed a clear correlation with deep breathing test (R = - 0.53, p = 0.004) but not with the MIBG H/M ratios.

CONCLUSIONS

Our data are consistent with a multifactorial pathogenesis of fatigue and with effects of dopamine depletion in PD-related fatigue; on the other hand, our findings do not support a role for sympathetic denervation in PD-related fatigue.

Multidimensional Circadian Monitoring by Wearable Biosensors in Parkinson's Disease

Parkinson's disease (PD) is associated with several non-motor symptoms that may precede the diagnosis and constitute a major source of frailty in this population. The digital era in health care has open up new prospects to move forward from the qualitative and subjective scoring for PD with the use of new wearable biosensors that enable frequent quantitative, reliable, repeatable, and multidimensional measurements to be made with minimal discomfort and inconvenience for patients. A cross-sectional study was conducted to test a wrist-worn device combined with machine-learning processing to detect circadian rhythms of sleep, motor, and autonomic disruption, which can be suitable for the objective and non-invasive evaluation of PD patients. Wrist skin temperature, motor acceleration, time in movement, hand position, light exposure, and sleep rhythms were continuously measured in 12 PD patients and 12 age-matched healthy controls for seven consecutive days using an ambulatory circadian monitoring device (ACM). Our study demonstrates that a multichannel ACM device collects reliable and complementary information from motor (acceleration and time in movement) and common non-motor (sleep and skin temperature rhythms) features frequently disrupted in PD. Acceleration during the daytime (as indicative of motor impairment), time in movement during sleep (representative of fragmented sleep) and their ratio (A/T) are the best indexes to objectively characterize the most common symptoms of PD, allowing for a reliable and easy scoring method to evaluate patients. Chronodisruption score, measured by the integrative algorithm known as the circadian function index is directly linked to a low A/T score. Our work attempts to implement innovative technologies based on wearable, multisensor, objective, and easy-to-use devices, to quantify PD circadian rhythms in huge populations over extended periods of time, while controlling at the same time exposure to exogenous circadian synchronizers.

Fatigue in Parkinson's disease: concepts and clinical approach

Parkinson's disease (PD) is a progressive neurological disorder characterized by a large number of motor and non-motor features. Fatigue is one of the most common and most disabling symptoms among patients with PD, and it has a significant impact on their quality of life. Although fatigue has been recognized for a long time, its pathophysiology remains poorly understood, and there is no evidence to support any therapeutic approach in PD patients. Expert consensus on case definition and diagnostic criteria for PD-related fatigue have been recently published, and although they still need to be adequately validated, they provide a great step forward in the study of fatigue. The goal of this article is to provide relevant information for the identification and management of patients with fatigue.

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

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

CLOCK 3111T/C Variant Correlates with Motor Fluctuation and Sleep Disorders in Chinese Patients with Parkinson's Disease

Background

The clock genes controlling biological rhythm play an important role in the pathophysiology of aging. The purpose of this study was to determine whether there is an association between a variant of the circadian locomotor output cycles kaput (CLOCK) gene and circadian dysfunction of Parkinson's disease (PD).

Methods

Six hundred and forty-six cases of Parkinson's disease from consecutive outpatients and inpatients ward from our hospital were included in this study. Kompetitive allele-specific PCR was used to determine the frequency distribution of genotypes and alleles. The examinations for the PD group were assessed in person in order to evaluate motor symptoms, cognitive function, sleep, and depression, including the Unified Parkinson's Disease Rating Scale (UPDRS), Mini-Mental State Examination (MMSE), Pittsburgh Sleep Quality Index (PSQI), and 17-item Hamilton Rating Scale for Depression (HAMD-17).

Results

Motor fluctuation (P < 0.001) and sleep disorders (P=0.007) were significantly different between the two groups. These correlations persisted after adjusting for confounding risk factors by further binary logistic regression analysis, suggesting that the CLOCK 3111T/C variant was associated with motor fluctuation (OR = 1.080, P < 0.001) and a subjective sleep disorder (OR = 1.130, P=0.037).

Conclusion

The CLOCK 3111T/C variant can be an independent risk factor for motor fluctuation and sleep disorder in Parkinson's disease.

Sleep and Neurodegeneration: A Critical Appraisal

Sleep abnormalities are clearly recognized as a distinct clinical symptom of concern in neurodegenerative disorders. Appropriate management of sleep-related symptoms has a positive impact on quality of life in patients with neurodegenerative disorders. This review provides an overview of mechanisms that are currently being considered that tie sleep with neurodegeneration. It appraises the literature regarding specific sleep changes seen in common neurodegenerative diseases, with a focus on Alzheimer disease and synucleinopathies (ie, Parkinson disease, dementia with Lewy bodies, multiple system atrophy), that have been better studied. Sleep changes may also serve as markers to identify patients in the preclinical stage of some neurodegenerative disorders. A hypothetical model is postulated founded on the conjecture that specific sleep abnormalities, when noted to increase in severity beyond that expected for age, could be a surrogate marker reflecting pathophysiological processes related to neurodegenerative disorders. This provides a clinical strategy for screening patients in the preclinical stages of neurodegenerative disorders to enable therapeutic trials to establish the efficacy of neuroprotective agents to prevent or delay the development of symptoms and functional decline. It is unclear if sleep disturbance directly impacts neurodegenerative processes or is a secondary outcome of neurodegeneration; this is an active area of research. The clinical importance of recognizing and managing sleep changes in neurodegenerative disorders is beyond doubt.

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.

Serotonergic dysfunctions and abnormal iron metabolism: Relevant to mental fatigue of Parkinson disease

Fatigue is a very common non-motor symptom in Parkinson disease (PD) patients. It included physical fatigue and mental fatigue. The potential mechanisms of mental fatigue involving serotonergic dysfunction and abnormal iron metabolism are still unknown. Therefore, we evaluated the fatigue symptoms, classified PD patients into fatigue group and non-fatigue group, and detected the levels of serotonin, iron and related proteins in CSF and serum. In CSF, 5-HT level is significantly decreased and the levels of iron and transferrin are dramatically increased in fatigue group. In fatigue group, mental fatigue score is negatively correlated with 5-HT level in CSF, and positively correlated with the scores of depression and excessive daytime sleepiness, and disease duration, also, mental fatigue is positively correlated with the levels of iron and transferrin in CSF. Transferrin level is negatively correlated with 5-HT level in CSF. In serum, the levels of 5-HT and transferrin are markedly decreased in fatigue group; mental fatigue score exhibits a negative correlation with 5-HT level. Thus serotonin dysfunction in both central and peripheral systems may be correlated with mental fatigue through abnormal iron metabolism. Depression, excessive daytime sleepiness and disease duration were the risk factors for mental fatigue of PD.

A New Perspective for Parkinson's Disease: Circadian Rhythm

Circadian rhythm is manifested by the behavioral and physiological changes from day to night, which is controlled by the pacemaker and its regulator. The former is located at the suprachiasmatic nuclei (SCN) in the anterior hypothalamus, while the latter is composed of clock genes present in all tissues. Circadian desynchronization influences normal patterns of day-night rhythms such as sleep and alertness cycles, rest and activity cycles. Parkinson's disease (PD) exhibits diurnal fluctuations. Circadian dysfunction has been observed in PD patients and animal models, which may result in negative consequences to the homeostasis and even exacerbate the disease progression. Therefore, circadian therapies, including light stimulation, physical activity, dietary and social schedules, may be helpful for PD patients. However, the cellular and molecular mechanisms that underlie the circadian dysfunction in PD remain elusive. Further research on circadian patterns is needed. This article summarizes the existing research on the circadian rhythms in PD, focusing on the clinical symptom variations, molecular changes, as well as the available treatment options.

Alterations of the circadian system in Parkinson's disease patients

Alterations of circadian rhythms are among the most debilitating non-motor symptoms in Parkinson's Disease (PD). Although a growing awareness towards these symptoms has occurred during the last decade, their underlying neuropathophysiology remains poorly understood and consequently no effective therapeutic strategies are available to alleviate these problems. Recent studies have investigated multiple circadian rhythms at different stages of PD. The advances made have allowed an accurate evaluation of the affected underlying pathways and mechanisms. Here I dissect, over disease progression, the relative causal contribution to health impairments in PD patients of dysfunctions in the different components of the neural network governing circadian rhythms. A deeper understanding of these mechanisms will provide not only a greater understanding of disease neuropathology, but also hold the promise for effective therapies. © 2016 International Parkinson and Movement Disorder Society.

Main determinants of physical activity levels in individuals with Parkinson’s disease

ABSTRACT This study analyzed the relationship between patient characteristics, factors associated with Parkinson’s disease (PD), and physical activity level of individuals affected by the disease. Forty-six volunteers with mild-to-moderate idiopathic PD were assessed using sections II/III of the Unified Parkinson’s Disease Rating Scale and their motor functions were classified according to the modified Hoehn and Yahr (HY) scale. Data such as age, disease duration, the Human Activity Profile (HAP), the Fatigue Severity Scale were collected. Lower limb bradykinesia and clinical subtypes of PD were defined. Two models that explained 76% of the variance of the HAP were used. The first comprised age, ability to perform activities of daily living (ADL), and the HY scale; the second comprised age, ability to perform ADL, and lower limb bradykinesia. Possible modifiable factors such as the ability to perform ADL and lower limb bradykinesia were identified as predictors of physical activity level of individuals with PD.

Circadian system - A novel diagnostic and therapeutic target in Parkinson's disease?

The circadian system regulates biological rhythmicity in the human body. The role of the circadian system in neurological disorders is a theme that is attracting an increasing amount of interest from the scientific community. This has arisen, in part, from emerging evidence that disorders such as Parkinson's disease (PD) are multifactorial with many features exhibiting diurnal fluctuations, thereby suggestive of circadian involvement. Although the importance of fluctuating motor and nonmotor manifestations in PD have been well acknowledged, the role of the circadian system has received little attention until recently. It is proposed that intervening with circadian function provides a novel research avenue down which new strategies for improving symptomatic treatment and slowing of the progressive degenerative process can be approached to lessen the burden of PD. In this article we review the literature describing existing circadian research in PD and its experimental models.

Risk Factors of Fatigue in Idiopathic Parkinson's Disease in a Polish Population

Introduction. Fatigue syndrome is one of the nonmotor symptoms in Parkinson's disease (PD). The aim of the study was assessment of prevalence of fatigue syndrome in PD and answering the question what are the independent risk factors connected with intensity of fatigue in PD. Methods. 114 patients with idiopathic PD (mean age 62.2 + 10.8 years) were enrolled. The fatigue was assessed according to the Fatigue Severity Scale (FSS). We analyzed associations between fatigue and sex, age, education, duration and severity of the disease, everyday activity, intensity of the main symptoms, treatment, presence of dyskinesias and fluctuations, depression and excessive sleep during the day, and presence of pain and nycturia. Results. The fatigue syndrome was detected in 57.9% of patients. The score in the FSS was 1 to 7 points, 4.3 average. Greater fatigue intensity correlated with higher total daily levodopa equivalent dose. Patients with moderate depression had significantly greater fatigue. Conclusions. Fatigue syndrome affects 57.9% of patients with PD. Use of higher LED and presence of moderate depression are independent risk factors of greater intensity of fatigue.

Consequences of Circadian Disruption on Neurologic Health

Circadian rhythms have a major role in physiology and behavior. Circadian disruption has negative consequences for physiologic homeostasis at molecular, cellular, organ-system, and whole-organism levels. The onset of many cerebrovascular insults shows circadian temporal trends. Impaired sleep-wake cycle, the most robust output rhythms of the circadian system, is significantly affected by neurodegenerative disorders, may precede them by decades, and may also affect their progression. Emerging evidence suggests that circadian disruption may be a risk factor for these neurologic disorders. This article discusses the implications of circadian rhythms in brain disorders, with an emphasis on cerebrovascular and neurodegenerative disorders.

High rates of fatigue and sleep disturbances in dystonia

BACKGROUND

Nonmotor symptoms in dystonia are increasingly recognized to impair the quality of life. The primary objective of this study was to determine the prevalence of fatigue and sleep disturbances in dystonia and to ascertain their impact on quality of life using standardized questionnaires.

METHODS

Dystonia patients presenting to a Botulinum toxin clinic were prospectively administered Fatigue Severity Scale (FSS), Multidimensional Fatigue Inventory (MFI), Epworth Sleepiness Scale (ESS) and Parkinson's Disease Sleep Scale (PDSS) for assessment of fatigue and sleep disturbances. Health-related Quality of life (HRQOL) was determined using MOS SF-36 scale and depressive symptoms were assessed using the Beck Depression Inventory II.

RESULTS

Ninety-one patients with dystonia participated (66 women, 25 men, mean age 60 ± 17 years). Nine subjects had generalized dystonia, 18 segmental dystonia and 64 had focal dystonia. Moderate to severe fatigue was present in 43% of the cohort (FSS), excessive daytime somnolence in 27% (ESS) and other sleep disturbances in 26% (PDSS). FSS and MFI scores correlated significantly with HRQOL even when controlled for depression and sleep disturbances. Excessive daytime somnolence and nocturnal sleep disturbances correlated significantly with the HRQOL; however, these effects were not seen for daytime somnolence when controlled for depression. Psychometric testing found adequate reliabilities and convergent validities for both fatigue and sleep scales.

CONCLUSION

Fatigue and sleep disturbances revealed high prevalence rates in this large, first of its dystonia study. They negatively impacted the quality of life even when controlled for comorbid depression.

Levels and Patterns of Physical Activity and Sedentary Behavior in Elderly People With Mild to Moderate Parkinson Disease

BACKGROUND

Decreased movement ability, one of the hallmarks of Parkinson disease (PD), may lead to inadequate physical activity (PA) and excessive time spent in sedentary behaviors-2 factors associated with an elevated risk for lifestyle-related diseases, poor management of PD, and premature death. To identify the extent to which people with PD are physically active, a comprehensive characterization of PA in this population is needed.

OBJECTIVE

The study objective was to describe levels and patterns of PA and sedentary behaviors in elderly people with PD.

DESIGN

This cross-sectional study involved a free-living setting and 53 men and 42 women (mean age=73.4 years) with mild to moderate idiopathic PD.

METHODS

Time spent in PA and sedentary behaviors was assessed for 1 week with accelerometers.

RESULTS

Mean daily step counts were 4,765; participants spent 589 minutes in sedentary behaviors, 141 minutes in low-intensity activities, 30 minutes in moderate-intensity lifestyle activities, and 16 minutes in moderate- to vigorous-intensity ambulatory activities. No differences were found between weekdays and weekend days. Patterns were characterized by a rise in total PA in the morning, peaking between 10 am and 3 pm, and a gradual decline toward the late evening. The proportion achieving 150 minutes of moderate- to vigorous-intensity PA per week was 27%, and 16% achieved 7,000 or more steps per day.

LIMITATIONS

Nonrandomized selection of participants may limit the generalizability of the results.

CONCLUSIONS

Physical activity levels were generally low, in terms of both total volume and intensity, with only minor variations over the course of a day or between days. These results emphasize the need to develop strategies to increase PA and reduce time spent in sedentary behaviors in elderly people with mild to moderate PD.

Comparison of strength training, aerobic training, and additional physical therapy as supplementary treatments for Parkinson's disease: pilot study

Introduction

Physical rehabilitation is commonly used in patients with Parkinson’s disease (PD) to improve their health and alleviate the symptoms.

Objective

We compared the effects of three programs, strength training (ST), aerobic training (AT), and physiotherapy, on motor symptoms, functional capacity, and electroencephalographic (EEG) activity in PD patients.

Methods

Twenty-two patients were recruited and randomized into three groups: AT (70% of maximum heart rate), ST (80% of one repetition maximum), and physiotherapy (in groups). Subjects participated in their respective interventions twice a week for 12 weeks. The assessments included measures of disease symptoms (Unified Parkinson’s Disease Rating Scale [UPDRS]), functional capacity (Senior Fitness Test), and EEG before and after 12 weeks of intervention.

Results

The PD motor symptoms (UPDRS-III) in the group of patients who performed ST and AT improved by 27.5% (effect size [ES]=1.25, confidence interval [CI]=−0.11, 2.25) and 35% (ES=1.34, CI=−0.16, 2.58), respectively, in contrast to the physiotherapy group, which showed a 2.9% improvement (ES=0.07, CI=−0.85, 0.99). Furthermore, the functional capacity of all three groups improved after the intervention. The mean frequency of the EEG analysis mainly showed the effect of the interventions on the groups (F=11.50, P=0.0001).

Conclusion

ST and AT in patients with PD are associated with improved outcomes in disease symptoms and functional capacity.

Loss of dopamine disrupts circadian rhythms in a mouse model of Parkinson's disease

Although a wide range of physiological functions regulated by dopamine (DA) display circadian variations, the role of DA in the generation and/or modulation of these rhythms is unknown. In Parkinson's disease (PD) patients, in addition to the classical motor symptoms, disturbances of the pattern of daily rest/wake cycles are common non-motor symptoms. We investigated daily and circadian rhythms of rest/activity behaviors in a transgenic MitoPark mouse model with selective inactivation of mitochondrial transcription factor A (Tfam) resulting in a slow and progressive degeneration of DA neurons in midbrain structures. Correlated with this, MitoPark mice show a gradual reduction in locomotor activity beginning at about 20weeks of age. In a light-dark cycle, MitoPark mice exhibit a daily pattern of rest/activity rhythms that shows an age-dependent decline in both the amplitude and the stability of the rhythm, coupled with an increased fragmentation of day/night activities. When the circadian system is challenged by exposure to constant darkness or constant light conditions, control littermates retain a robust free-running circadian locomotor rhythm, whereas in MitoPark mice, locomotor rhythms are severely disturbed or completely abolished. Re-exposure to a light/dark cycle completely restores daily locomotor rhythms. MitoPark mice and control littermates express similar masking behaviors under a 1h light/1h dark regime, suggesting that the maintenance of a daily pattern of rest/activity in arrhythmic MitoPark mice can be attributed to the acute inhibitory and stimulatory effects of light and darkness. These results imply that, in addition to the classical motor abnormalities observed in PD, the loss of the midbrain DA neurons leads to impairments of the circadian control of rest/activity rhythms.

Ambulatory activity in incident Parkinson's: more than meets the eye?

Physical activity is important for people with Parkinson's disease (PD) to improve disease-specific impairment and ameliorate secondary consequences related to deconditioning. Activity may also have a neuroprotective role if instigated early. Ambulatory activity has not been examined in incident PD. Eighty-nine newly diagnosed PD cases [mean (SD) age 67.3 (9.9) years] and 97 controls [mean (SD) 69.2 (7.7) years] wore an activity monitor (activPAL™) for 7 days. Volume, pattern and variability outcomes were compared. Accumulation of activity (α) was classified as short (< 30 s), medium (30 s-2 min) and long (> 2 min) bouts of walking. Associations between sustained walking (> 2 min) and motor, cognitive and affective characteristics were identified. Activity outcomes were considered with respect to global health recommendations. Total steps (volume), accumulation of bout length (α), and variability (S2w) outcomes were significantly different (all P < 0.001). PD participants (including Hoehn & Yahr (H&Y) stage I) accumulated significantly less time in long bouts (> 2 min) of walking compared with controls, due to performing fewer long bouts, rather than a reduction in time spent in walking per bout. For PD and controls there were weak but significant correlations for a range of characteristics and sustained walking. Fewer people with PD achieved the recommended 30 min of walking per day comprised of bouts > 10 min (P = 0.02) and bouts > 2 min (P < 0.001). People with PD were significantly less active than controls, with an inability to sustain levels of walking, and with differences apparent very early on in the disease process. A focus on increasing general ambulatory activity and exercise from the outset is recommended.

Quality of life in Parkinson's disease

In this review report, current possibilities of evaluation of quality of life in Parkinson's disease have been critically presented. Health Related Quality of Life (-HRQoL) comprises a wide spectrum of consequences of the disease. Measurement of quality of life has become increasingly relevant as an outcome parameter, especially in long-term trials. Most of the available QoL instruments depend on patient self-reports. The data can be collected by written questionnaires. There are universal questionnaires of QoL--for many diseases and the specific ones--specially created for one disease. Among universal questionnaires, the Sickness Impact Profile (SIP) and the Short-Form Health Status Survey (SF-36) are the most popular in Parkinson's disease. As for specific questionnaires: the Parkinson`s Disease Questionnaire (PDQ-39) and the Parkinson's Disease Quality of Life Questionnaire (PDQL) have been described.

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.

The possible clinical predictors of fatigue in Parkinson's disease: a study of 135 patients as part of international nonmotor scale validation project

Fatigue is a common yet poorly understood and underresearched nonmotor symptom in Parkinson's disease. Although fatigue is recognized to significantly affect health-related quality of life, it remains underrecognised and empirically treated. In this paper, the prevalence of fatigue as measured by a validated visual analogue scale and the Parkinson's disease nonmotor symptoms scale (PDNMSS) was correlated with other motor and nonmotor comorbidities. In a cohort of patients from a range of disease stages, occurrence of fatigue correlated closely with more advanced Parkinson's disease, as well as with depression, anxiety, and sleep disorders, hinting at a common underlying basis.

Physical inactivity in Parkinson's disease

Patients with Parkinson’s disease (PD) are likely to become physically inactive, because of their motor, mental, and emotional symptoms. However, specific studies on physical activity in PD are scarce, and results are conflicting. Here, we quantified daily physical activities in a large cohort of PD patients and another large cohort of matched controls. Moreover, we investigated the influence of disease-related factors on daily physical activities in PD patients. Daily physical activity data of PD patients (n = 699) were collected in the ParkinsonNet trial and of controls (n = 1,959) in the Longitudinal Aging Study Amsterdam (LASA); data were determined using the LAPAQ, a validated physical activity questionnaire. In addition, variables that may affect daily physical activities in PD were recorded, including motor symptoms, depression, disability in daily life, and comorbidity. Patients were physically less active; a reduction of 29% compared to controls (95% CI, 10–44%). Multivariate regression analyses demonstrated that greater disease severity, gait impairment, and greater disability in daily living were associated with less daily physical activity in PD (R² = 24%). In this large study, we show that PD patients are about one-third less active compared to controls. While disease severity, gait, and disability in daily living predicted part of the inactivity, a portion of the variance remained unexplained, suggesting that additional determinants may also affect daily physical activities in PD. Because physical inactivity has many adverse consequences, work is needed to develop safe and enjoyable exercise programs for patients with PD.

Fatigue in spinocerebellar ataxia: patient self-assessment of an early and disabling symptom

OBJECTIVE

To identify the prevalence and severity of fatigue and predicting factors for severe fatigue in autosomal dominant spinocerebellar ataxia (SCA).

METHODS

We studied a cross-section of 123 patients with SCA. Six functional scales were used in a self-assessment: the Fatigue Severity Scale (FSS); the Beck Depression Inventory (BDI); the Rotterdam Handicap Scale (RHS); the Short Form-36 health survey, distinguishing a norm-based physical and mental component score (Nb-PCS and Nb-MCS); the Pittsburgh Sleep Quality Index (PSQI); and the Epworth Sleepiness Scale (ESS). A subset of 58 patients was clinically evaluated, measuring severity of ataxia with the Scale for the Assessment and Rating of Ataxia and cognitive functioning with the Mini-Mental State Examination.

RESULTS

Severe fatigue (FSS ≥5) was present in 69% of patients and FSS value correlated with the scores on RHS, Nb-PCS, Nb-MCS, BDI, PSQI, and ESS. There was no relation with disease duration, gender, or medication use. Multivariate analysis revealed that Nb-PCS and BDI were the best independent predictors for severe fatigue. Interestingly, the presence of visual symptoms was related to FSS value in the clinically evaluated subgroup.

CONCLUSION

Fatigue is a severe and disabling symptom in adult patients with SCA, even early in the course of disease. Physical functioning and depression are the strongest predictors of fatigue. In treatment strategies, all treatable factors for fatigue should be addressed, especially depression, visual symptoms, and sleeping disorders.

The pattern of habitual sedentary behavior is different in advanced Parkinson's disease

Physical behavior changes in Parkinson's disease (PD), however, objective evidence of this is lacking. This study explored methods to objectively quantify sedentary behavior (SB) in advanced PD with the aim of identifying changes that could impact on the burden of disease. We compared the SB of 17 PD (UPDRS III 29.1 ± 5.5; disease duration 12.5 ± 6.4; H&Y (3 & 4) and 17 aged and gender matched healthy subjects. SB was measured objectively over a 7 day period using the activPAL accelerometer. SB was defined as sitting or lying and described in terms of the volume and pattern of SB. Comparison between PD and controls showed that whilst there was no difference in the volume of sedentary time (P = 0.15), there was a significant difference in distribution (P < 0.01) and pattern of accumulation of sedentary time (P < 0.01). Bouts of SB in people with PD tend to last longer than that of controls, whilst the total time spent inactive is the same for the two groups. These results suggest that PD leads to a change in the pattern of SB but not the volume. This may be interpreted as a strategy to conserve energy to maximize function. Studying the pattern of SB appears promising and has the potential to help us to understand the impact of PD and the consequences of changes in SB on the burden of disease.

Imaging non-motor aspects of Parkinson's disease

In this chapter the imaging changes associated with non-motor aspects of Parkinson's disease (PD) are reviewed. The relationship between reduced monoaminergic and cholinergic function and cognitive difficulties, depression, fatigue, sleep disorders, and dysautonomia is discussed and the relevance of Alzheimer pathology to PD dementia debated. Finally the discordance between the development of functional changes in PD and Braak staging is highlighted.