Diagnosis and treatment of restless legs syndrome in progressive supranuclear palsy

Prevalence and clinical profile of patients with restless legs syndrome in Parkinson's disease: A meta-analysis

INTRODUCTION

Restless legs syndrome (RLS) is a sensorimotor disorder of sleep/wake regulation characterized by an urge to move the legs accompanied by a wide range of sensory symptoms, mainly affecting the lower limbs. An increased incidence of RLS has been demonstrated in Parkinson's disease (PD) and has been associated with severe motor and non-motor manifestations. We aimed to provide a reliable estimate of RLS prevalence and the clinical features associated with its occurrence in PD (PD-RLS).

METHODS

We performed a systematic literature search up to January 2024 using PubMed, Scopus, and PsycINFO databases. Articles were included if they provided data on PD patients with or without RLS, and these proportions were used to estimate the prevalence of PD-RLS. Clinical profile associated with PD-RLS was explored by comparing the clinical characteristics of PD patients with and without RLS.

RESULTS

Forty-six studies were included in the meta-analysis. Pooled RLS prevalence was 20 % of a total sample of 6990 PD patients and was associated with female sex, mixed motor phenotype, worse motor disturbances and functional disability, and a wide range of non-motor symptoms such as sleep disorders, cognitive and autonomic dysfunctions, and more severe neuropsychiatric manifestations. Sensitivity analyses indicated significant associations of PD-RLS with variables related to dopaminergic therapy. No association was found with serum ferritin, serum iron and hemoglobin levels.

CONCLUSIONS

The prevalence of PD-RLS exceeds that reported in the general population, suggesting the existence of a relationship between the two disorders. Dopaminergic treatment seems to play an ambivalent role relieving, worsening or "mimicking" RLS manifestations. However, the clinical profile of PD-RLS patients, characterized by a greater severity of non-motor symptoms, also suggests that neurotransmitter systems other than the dopaminergic one are involved in PD-RLS etiology.

Luxembourg Parkinson's study -comprehensive baseline analysis of Parkinson's disease and atypical parkinsonism

Background

Deep phenotyping of Parkinson's disease (PD) is essential to investigate this fastest-growing neurodegenerative disorder. Since 2015, over 800 individuals with PD and atypical parkinsonism along with more than 800 control subjects have been recruited in the frame of the observational, monocentric, nation-wide, longitudinal-prospective Luxembourg Parkinson's study.

Objective

To profile the baseline dataset and to explore risk factors, comorbidities and clinical profiles associated with PD, atypical parkinsonism and controls.

Methods

Epidemiological and clinical characteristics of all 1,648 participants divided in disease and control groups were investigated. Then, a cross-sectional group comparison was performed between the three largest groups: PD, progressive supranuclear palsy (PSP) and controls. Subsequently, multiple linear and logistic regression models were fitted adjusting for confounders.

Results

The mean (SD) age at onset (AAO) of PD was 62.3 (11.8) years with 15% early onset (AAO < 50 years), mean disease duration 4.90 (5.16) years, male sex 66.5% and mean MDS-UPDRS III 35.2 (16.3). For PSP, the respective values were: 67.6 (8.2) years, all PSP with AAO > 50 years, 2.80 (2.62) years, 62.7% and 53.3 (19.5). The highest frequency of hyposmia was detected in PD followed by PSP and controls (72.9%; 53.2%; 14.7%), challenging the use of hyposmia as discriminating feature in PD vs. PSP. Alcohol abstinence was significantly higher in PD than controls (17.6 vs. 12.9%, p = 0.003).

Conclusion

Luxembourg Parkinson's study constitutes a valuable resource to strengthen the understanding of complex traits in the aforementioned neurodegenerative disorders. It corroborated several previously observed clinical profiles, and provided insight on frequency of hyposmia in PSP and dietary habits, such as alcohol abstinence in PD.Clinical trial registration: clinicaltrials.gov, NCT05266872.

Circadian disruption and sleep disorders in neurodegeneration

Disruptions of circadian rhythms and sleep cycles are common among neurodegenerative diseases and can occur at multiple levels. Accumulating evidence reveals a bidirectional relationship between disruptions of circadian rhythms and sleep cycles and neurodegenerative diseases. Circadian disruption and sleep disorders aggravate neurodegeneration and neurodegenerative diseases can in turn disrupt circadian rhythms and sleep. Importantly, circadian disruption and various sleep disorders can increase the risk of neurodegenerative diseases. Thus, harnessing the circadian biology findings from preclinical and translational research in neurodegenerative diseases is of importance for reducing risk of neurodegeneration and improving symptoms and quality of life of individuals with neurodegenerative disorders via approaches that normalize circadian in the context of precision medicine. In this review, we discuss the implications of circadian disruption and sleep disorders in neurodegenerative diseases by summarizing evidence from both human and animal studies, focusing on the bidirectional links of sleep and circadian rhythms with prevalent forms of neurodegeneration. These findings provide valuable insights into the pathogenesis of neurodegenerative diseases and suggest a promising role of circadian-based interventions.

Long-term treatment with rotigotine in drug-naïve PSP patients

Progressive supranuclear palsy (PSP) is a severe neurodegenerative disease still lacking of alleviating treatments for either cognitive or motor disturbances. Aimed at widening the spectrum of therapeutic options, here, we describe efficacy and safety of a long-term treatment with Rotigotine, a non-ergolinic dopamine agonist, in PSP. Seven PSP drug-naïve patients, presenting with Richardson's syndrome, received up to 6 mg/24 h transdermal patch for 42 weeks as unique therapy. Adverse effects were recorded; efficacy was measured by comparing baseline and final treatment scores of Montreal Cognitive Assessment (MoCA), Unified Parkinson Disease Rating Scale part3, and PSP rating scale (PSP-RS). At the end of our observation, no significant adverse events occurred; the cognitive item of PSP-RS was improved and MoCA score was similar at baseline. Contrariwise, motor disturbances worsened according to disease progression. Our observation thus suggests that long-term treatment with low doses of rotigotine is well tolerated and may support cognitive functions of PSP patients.

A Review of Treatment Options for Progressive Supranuclear Palsy

Progressive supranuclear palsy (PSP) is an atypical parkinsonian condition characterized by a symmetric akinetic-rigid syndrome, early falls, supranuclear gaze palsy, and a frontotemporal behavioral syndrome. The typical phenotype is termed Richardson's syndrome, but numerous other phenotypes have been described. The pathophysiology of PSP is not fully understood, but dysfunction of the tau protein seems to play a central role. Despite exciting new knowledge on the pathophysiology of PSP, there is still no highly effective symptomatic or disease-modifying treatment. We review the evidence on pharmacotherapy and experimental therapies in PSP and provide levels of recommendation for the off-label use of commonly used drugs in this disorder.