Parkinson's disease and sleep/wake disturbances

Efficacy and Safety of Pramipexole Sustained Release versus Immediate Release Formulation for Nocturnal Symptoms in Chinese Patients with Advanced Parkinson's Disease: A Pilot Study

Objective

To explore the efficacy and safety of pramipexole sustained release (SR) versus pramipexole immediate release (IR) in treating nocturnal symptoms in levodopa-treated Chinese patients with advanced Parkinson's disease (PD) and sleep disturbances.

Method

SUSTAIN was an open-label, randomised, active-controlled parallel group exploratory pilot study (NCT03521635). A total of 98 patients were randomly allocated (1 : 1) to either pramipexole SR (n = 49) or pramipexole IR (n = 49) groups. The primary endpoint was a change from baseline in PD Sleep Scale 2^nd version (PDSS-2) total score at 18 weeks. A reduction in score represents improvement. Secondary endpoints included Nocturnal Hypokinesia Questionnaire, Scales for Outcomes in PD Sleep Scale, Early Morning Off (EMO), Epworth Sleepiness Scale, PD Questionnaire-8, and responder rates as measured by PDSS-2 total score (<18), EMO scores (≥1 point change), Clinical Global Impression Improvement scale, and Patient Global Impression-Improvement scale. Other endpoints included motor complications (MDS-UPDRS part IV) score. Adverse events were evaluated for each group.

Results

The mean pramipexole dose for both groups was 1.5 mg/day at week 18, and the mean changes in PDSS-2 total score for pramipexole SR and IR were –13.7 (95% CI –16.0 to –11.4) and –14.4 (–16.8 to –12.0) (difference of 0.7; p=0.688). Change from baseline for both groups achieved the minimal clinical important difference threshold (MCID = –3.44). No significant difference was observed in change from baseline for other measures of sleep-related disturbances or responder rates. For motor complications, a greater improvement in MDS-UPDRS part IV score was observed in pramipexole SR over IR (–3.4 vs –2.3; treatment group difference: –1.1; p=0.036). Both groups had comparable safety profiles.

Conclusion

In Chinese patients with advanced PD and sleep disturbances, pramipexole SR and IR have similar benefits in the treatment of nocturnal symptoms and safety, and an improvement from baseline in nocturnal symptoms was observed regardless of pramipexole formulation.

Inhibition of Orexin/Hypocretin Neurons Ameliorates Elevated Physical Activity and Energy Expenditure in the A53T Mouse Model of Parkinson's Disease

Aside from the classical motor symptoms, Parkinson's disease also has various non-classical symptoms. Interestingly, orexin neurons, involved in the regulation of exploratory locomotion, spontaneous physical activity, and energy expenditure, are affected in Parkinson's. In this study, we hypothesized that Parkinson's-disease-associated pathology affects orexin neurons and therefore impairs functions they regulate. To test this, we used a transgenic animal model of Parkinson's, the A53T mouse. We measured body composition, exploratory locomotion, spontaneous physical activity, and energy expenditure. Further, we assessed alpha-synuclein accumulation, inflammation, and astrogliosis. Finally, we hypothesized that chemogenetic inhibition of orexin neurons would ameliorate observed impairments in the A53T mice. We showed that aging in A53T mice was accompanied by reductions in fat mass and increases in exploratory locomotion, spontaneous physical activity, and energy expenditure. We detected the presence of alpha-synuclein accumulations in orexin neurons, increased astrogliosis, and microglial activation. Moreover, loss of inhibitory pre-synaptic terminals and a reduced number of orexin cells were observed in A53T mice. As hypothesized, this chemogenetic intervention mitigated the behavioral disturbances induced by Parkinson's disease pathology. This study implicates the involvement of orexin in early Parkinson's-disease-associated impairment of hypothalamic-regulated physiological functions and highlights the importance of orexin neurons in Parkinson's disease symptomology.

Risk factors for depression in patients with Parkinson's disease: A nationwide nested case-control study

Objectives

Patients with Parkinson’s disease (PD) have higher prevalence of depression than the general population; however, the risk factors for depression in PD remain uncertain.

Methods/Design

Using the 2000–2010 Taiwan National Health Insurance Research Database, we selected 1767 patients aged ≧ 40 years with new-onset PD during 2000–2009. Among them, 324 patients with a new incidence of depression were enrolled as cases and 972 patients without depression were randomly selected as controls. The groups were frequency-matched at a ratio of 1:3 by age, sex, and index year. Thus, this nested case-control study compared differences between the cases and the controls. Logistic regression models were used to identify risk factors for depression in PD.

Results

Compared with the controls, the odds ratio (OR) of anxiety disorders in the cases was 1.53 (95% confidence interval [95% CI], 1.16–2.02; P = 0.003), after adjusting for the confounding factors of age, sex, index year, geographic region, urban level, monthly income, and other coexisting medical conditions. The OR for sleep disturbances in the cases was 1.49 (95% CI, 1.14–1.96; P = 0.004) compared to the controls, after adjusting these confounding factors. Hence, the risk factors for depression in PD were nonsignificantly associated with physical comorbidities.

Conclusions

In the present study, depression in PD was significantly associated with anxiety disorders and sleep disturbances. Integrated care for early identification and treatment of neuropsychiatric comorbidities is crucial in patients with new-onset PD so as to prevent further PD degeneration.

Prevalence and predictors of mood disturbances in idiopathic REM sleep behaviour disorder

Depression and anxiety are commonly associated with synucleinopathies. Mood disturbances have also been reported in patients with idiopathic REM sleep behaviour disorder (iRBD) and are difficult to treat due to exacerbation of sleep symptoms with standard antidepressants. Despite this, detailed prevalence studies of mood symptomatology and contributors to mood disturbances in iRBD are limited. Mood, sleep, autonomic, cognitive and motor symptoms were assessed in 49 well-characterized patients with iRBD using a variety of clinical scales. Spearman correlations, factor analysis and multiple linear regression were used to uncover associations between mood and non-motor and motor symptoms. The prevalence of significant depression was 17.0% and that of anxiety was 14.6% in the iRBD cohort. Age and disease duration were not correlated with these affective symptoms in iRBD patients. We found depression was significantly predicted by the presence and severity of motor, sleep and cognitive symptoms. Anxiety was predicted by the severity of nocturnal and daytime sleep-related symptoms, cognitive symptoms and autonomic symptoms, with a differential effect depending on the questionnaire used. Depression and anxiety are common in iRBD patients and can be significantly explained by specific sets of non-motor and motor symptoms. These associations provide insight into the underlying pathophysiology and emphasize the importance of a holistic approach to mood disturbance in this population, which may circumvent the reliance on pharmacotherapy that can exacerbate dream enactment behaviour.

A Cleaning Crew: The Pursuit of Autophagy in Parkinson's Disease

Parkinson's disease (PD) is the second-most common neurodegenerative disorder, neuropathologically characterized by the aggregation of misfolded α-synuclein (α-syn) protein, which appears to be central to the onset and progression of PD pathology. Evidence from pioneering studies has highly advocated the existence of impaired autophagy pathways in the brains of PD patients. Autophagy is an evolutionarily conserved, homeostatic mechanism for minimizing abnormal protein aggregates and facilitating organelle turnover. Any aberration in constitutive autophagy activity results in the aggregation of misfolded α-syn, which, in turn, may further inhibit their own degradation-leading to a vicious cycle of neuronal death. Despite the plethora of available literature, there are still lacunas existing in our understanding of the exact cellular interplay between autophagy impairment and α-syn accumulation-mediated neurotoxicity. In this context, clearance of aggregated α-syn via up-regulation of the autophagy-lysosomal pathway could provide a pharmacologically viable approach to the treatment of PD. The present Review highlights the basics of autophagy and detrimental cross-talk between α-syn and chaperone-mediated autophagy, and α-syn and macroautophagy. It also depicts the interaction between α-syn and novel targets, LRRK2 and mTOR, followed by the role of autophagy in PD from a therapeutic perspective. More importantly, it further updates the reader's understanding of various newer therapeutic avenues that may accomplish disease modification via promoting clearance of toxic α-syn through activation of autophagy.

Relationship of Nocturnal Sleep Dysfunction and Pain Subtypes in Parkinson's Disease

Background

Little research has been conducted regarding the relationship between sleep disorders and different pain types in Parkinson's disease (PD).

Objective

To explore the influence of the various pain subtypes experienced by PD patients on sleep.

Methods

Three hundred consecutive PD patients were assessed with the PD Sleep Scale-Version 2 (PDSS-2), King's PD Pain Scale (KPPS), King's PD Pain Questionnaire (KPPQ), Visual Analog Scales for Pain (VAS-Pain), and Hospital Anxiety and Depression Scale.

Results

According to the PDSS-2, 99.3% of our sample suffered from at least one sleep issue. Those who reported experiencing any modality of pain suffered significantly more from sleep disorders than those who did not (all, P < 0.003). The PDSS-2 showed moderate-to-high correlations with the KPPS (r_S = 0.57), KPPQ (0.57), and VAS-Pain (0.35). When PDSS-2 items 10 to 12 (pain-related) were excluded, the correlation values decreased to 0.50, 0.51, and 0.28, respectively, while these items showed moderate-to-high correlations with KPPS (0.56), KPPQ (0.54), and VAS-Pain (0.42). Among the variables analyzed, multiple linear regression models suggested that KPPS and KPPQ were the most relevant predictors of sleep disorders (as per the PDSS-2), although following exclusion of PDSS-2 pain items, depression was the relevant predictor. Depression and anxiety were the most relevant predictors in the analysis involving the VAS-Pain. Regression analysis, considering only the KPPS domains, showed that nocturnal and musculoskeletal pains were the best predictors of overall nocturnal sleep disorder.

Conclusions

Pain showed a moderate association with nocturnal sleep dysfunction in PD. Some pain subtypes had a greater effect on sleep than others.

Absent Audiovisual Integration Elicited by Peripheral Stimuli in Parkinson's Disease

The basal ganglia, which have been shown to be a significant multisensory hub, are disordered in Parkinson's disease (PD). This study was to investigate the audiovisual integration of peripheral stimuli in PD patients with/without sleep disturbances. Thirty-six age-matched normal controls (NC) and 30 PD patients were recruited for an auditory/visual discrimination experiment. The mean response times for each participant were analyzed using repeated measures ANOVA and race model. The results showed that the response to all stimuli was significantly delayed for PD compared to NC (all p < 0.01). The response to audiovisual stimuli was significantly faster than that to unimodal stimuli in both NC and PD (p < 0.001). Additionally, audiovisual integration was absent in PD; however, it did occur in NC. Further analysis showed that there was no significant audiovisual integration in PD with/without cognitive impairment or in PD with/without sleep disturbances. Furthermore, audiovisual facilitation was not associated with Hoehn and Yahr stage, disease duration, or the presence of sleep disturbances (all p > 0.05). The current results showed that audiovisual multisensory integration for peripheral stimuli is absent in PD regardless of sleep disturbances and further suggested the abnormal audiovisual integration might be a potential early manifestation of PD.

Recurrent Sleep Fragmentation Induces Insulin and Neuroprotective Mechanisms in Middle-Aged Flies

Lack of quality sleep increases central nervous system oxidative stress and impairs removal of neurotoxic soluble metabolites from brain parenchyma. During aging poor sleep quality, caused by sleep fragmentation, increases central nervous system cellular stress. Currently, it is not known how organisms offset age-related cytotoxic metabolite increases in order to safeguard neuronal survival. Furthermore, it is not understood how age and sleep fragmentation interact to affect oxidative stress protection pathways. We demonstrate sleep fragmentation increases systems that protect against oxidative damage and neuroprotective endoplasmic reticulum molecular chaperones, as well as neuronal insulin and dopaminergic expression in middle-aged Drosophila males. Interestingly, even after sleep recovery the expression of these genes was still upregulated in middle-aged flies. Finally, sleep fragmentation generates higher levels of reactive oxygen species (ROS) in middle-aged flies and after sleep recovery these levels remain significantly higher than in young flies. The fact that neuroprotective pathways remain upregulated in middle-aged flies beyond sleep fragmentation suggests it might represent a strong stressor for the brain during later life.

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.

Associations between severity of motor function and nonmotor symptoms in Parkinson's disease: a post hoc analysis of the RECOVER Study

BACKGROUND

RECOVER (NCT00474058), a double-blind, placebo-controlled trial in patients with Parkinson's disease (PD) and unsatisfactory early-morning motor symptom control, demonstrated significant improvements with rotigotine in early-morning motor function (Unified Parkinson's Disease Rating Scale [UPDRS] III), and nocturnal sleep disturbances (modified Parkinson's Disease Sleep Scale [PDSS-2]), and improvements in nonmotor symptoms (NMS; Non-Motor Symptom Scale [NMSS]).

METHODS

Post hoc analyses investigated the correlation between motor symptom and NMS severity in PD by evaluating associations between UPDRS III and both NMSS and PDSS-2 scores. Categories were defined for UPDRS III, NMSS, and PDSS-2 total scores; analyses were conducted for the full analysis set (n = 267).

RESULTS

There was a trend toward increasing PDSS-2 and NMSS total and domain scores with increasing UPDRS III category at baseline and end of maintenance (EoM). Pearson correlation coefficients between UPDRS III and both NMSS and PDSS-2 total and domain scores were r = 0.12-0.44 (r(2) = 0.01-0.19) at baseline, r = 0.05-0.38 (r(2) = 0.00-0.14) at EoM, and r = -0.02-0.36 (r(2) = 0.00-0.13) for change from baseline to EoM.

CONCLUSION

There was only a small correlation between severity of early-morning motor symptoms and overall burden of NMS and nocturnal sleep disturbances in RECOVER, suggesting that motor symptoms and NMS originate, at least partly, from distinct pathophysiological pathways.