Deep brain stimulation improves restless legs syndrome in patients with Parkinson disease

Rethinking clinical trials in restless legs syndrome: A roadmap

The number of large clinical trials of restless legs syndrome (RLS) have decreased in recent years, this coincides with reduced interest in developing and testing novel pharmaceuticals. Therefore, the International Restless Legs Syndrome Study Group (IRLSSG) formed a task force of global experts to examine the causes of these trends and make recommendations to facilitate new clinical trials. In our article, we delve into potential complications linked to the diagnostic definition of RLS, identify subpopulations necessitating more attention, and highlight issues pertaining to endpoints and study frameworks. In particular, we recommend developing alternative scoring methods for more accurate RLS diagnosis, thereby improving clinical trial specificity. Furthermore, enhancing the precision of endpoints will increase study effect sizes and mitigate study costs. Suggestions to achieve this include developing online, real-time sleep diaries with high-frequency sampling of nightly sleep latency and the use of PLMs as surrogate markers. Furthermore, to reduce the placebo response, strategies should be adopted that include placebo run-in periods. As RLS is frequently a chronic condition, priority should be given to long-term studies, using a randomized, placebo-controlled, withdrawal design. Lastly, new populations should be investigated to develop targeted treatments such as mild RLS, pregnancy, hemodialysis, or iron-deficient anemia.

Restless legs syndrome in the dominant Parkinson's side related to subthalamic deep-brain stimulation

BACKGROUND

Restless legs syndrome (RLS) has an increased estimated prevalence in patients with Parkinson's disease (PS). RLS frequently mimics symptoms intrinsic to PD, such as motor restlessness, contributing to making its diagnosis challenging in this population. We report the case of a patient with new-onset RLS following subthalamic deep-brain stimulation (DBS-STN). We assessed symptoms using suggested immobilization test (SIT) with both DBS-STN activated and switched off.

CASE DESCRIPTION

A 59-year-old man with idiopathic PD developed disabling RLS following DBS-STN at age 58, with PD onset at 50 manifesting as left arm tremor. Despite improved motor symptoms during the month following surgery, the patient experienced left leg discomfort at rest, transiently alleviated by movements due to an irrepressible urge to move, and worsened at night. Symptoms had no temporal relationship with oral dopa-therapy and disappeared when DBS-STN was deactivated. A 1 h SIT assessed motor behavior with irrepressible urge to move, as well as sensory symptoms by visual analog scale. After 30 m DBS-STN was switched off followed by the appearance of tremor in the left arm while both motor and sensory symptoms of RLS disappeared in the left leg.

DISCUSSION

The mechanisms of DBS-STN's impact on RLS remain controversial. We hypothesize the DBS-STN to induce in our patient a hyperdopaminergic tone. DBS-induced and DBS-ameliorated RLS represent interesting conditions to further understand the pathophysiology of RLS. Moreover, the present observation suggests that SIT can be a valuable tool to assess RLS in PD patients before and after DBS-STN in future prospective studies.

Deep Brain Stimulation for the Management of Refractory Neurological Disorders: A Comprehensive Review

In recent decades, deep brain stimulation (DBS) has been extensively studied due to its reversibility and significantly fewer side effects. DBS is mainly a symptomatic therapy, but the stimulation of subcortical areas by DBS is believed to affect the cytoarchitecture of the brain, leading to adaptability and neurogenesis. The neurological disorders most commonly studied with DBS were Parkinson's disease, essential tremor, obsessive-compulsive disorder, and major depressive disorder. The most precise approach to evaluating the location of the leads still relies on the stimulus-induced side effects reported by the patients. Moreover, the adequate voltage and DBS current field could correlate with the patient's symptoms. Implantable pulse generators are the main parts of the DBS, and their main characteristics, such as rechargeable capability, magnetic resonance imaging (MRI) safety, and device size, should always be discussed with patients. The safety of MRI will depend on several parameters: the part of the body where the device is implanted, the part of the body scanned, and the MRI-tesla magnetic field. It is worth mentioning that drug-resistant individuals may have different pathophysiological explanations for their resistance to medications, which could affect the efficacy of DBS therapy. Therefore, this could explain the significant difference in the outcomes of studies with DBS in individuals with drug-resistant neurological conditions.

"Unvoluntary" Movement Disorders: Distinguishing between Tics, Akathisia, Restless Legs, and Stereotypies

Tics, stereotypies, akathisia, and restless legs fall at different places on the spectrum of discrete, unwanted and potentially disabling motor routines. Unlike tremor, chorea, myoclonus, or dystonia, this subgroup of abnormal movements is characterized by the subject's variable ability to inhibit or release undesired motor patterns on demand. Though it may be sometimes clinically challenging, it is crucial to distinguish these "unvoluntary" motor behaviors because secondary causes and management approaches differ substantially. To this end, physicians must consider the degree of repetitiveness of the movements, the existence of volitional control, and the association with sensory symptoms, or cognitive-ideational antecedent. This review aims to summarize the current existing knowledge on phenomenology, diagnosis, and treatment of tics, stereotypies, akathisia, and restless leg syndrome.

Sleep-related motor disorders

Sleep-related motor disorders include non-rapid-eye movement (NREM) sleep parasomnias, rapid-eye movement (REM), sleep parasomnias including REM sleep behavior disorder (RBD), isolated motor phenomena in sleep, and periodic limb movement disorder. Restless legs syndrome (RLS) occurs while awake but is closely related to sleep and has a circadian pattern. The pontine sublaterodorsal tegmental nucleus has an important role in aligning motor control with sleep states, and dysfunction in this region can explain motor activities including cataplexy and loss of REM atonia seen in REM sleep behavior disorder. This chapter begins with a review of motor control in sleep. The rest of the chapter summarizes the clinical presentation, epidemiology, differential and treatment of NREM, REM, and isolated sleep-related motor disorders as well as restless legs syndrome.

Optimal Contact Position of Subthalamic Nucleus Deep Brain Stimulation for Reducing Restless Legs Syndrome in Parkinson's Disease Patients: One-Year Follow-Up with 33 Patients

Objectives: To determine the short- and medium-term therapeutic effects of subthalamic nucleus (STN) deep brain stimulation (DBS) on restless legs syndrome (RLS) in patients with Parkinson’s disease (PD) and to study the optimal position of activated contacts for RLS symptoms. Methods: We preoperatively and postoperatively assessed PD Patients with RLS undergoing STN-DBS. Additionally, we recorded the stimulation parameters that induced RLS or relieved RLS symptoms during a follow-up. Finally, we reconstructed the activated contacts’ position that reduced or induced RLS symptoms. Results: 363 PD patients were enrolled. At the 1-year follow-up, we found that the IRLS sum significantly decreased in the RLS group (preoperative 18.758 ± 7.706, postoperative 8.121 ± 7.083, p < 0.05). The results of the CGI score, MOS sleep, and RLS QLQ all showed that the STN-DBS improved RLS symptoms after one year. Furthermore, the activated contacts that relieved RLS were mainly located in the central sensorimotor region of the STN. Activated contacts in the inferior sensorimotor part of the STN or in the substantia nigra might have induced RLS symptoms. Conclusions: STN-DBS improved RLS in patients with PD in one year, which reduced their sleep disorders and increased their quality of life. Furthermore, the central sensorimotor region part of the STN is the optimal stimulation site.

Advances in DBS Technology and Novel Applications: Focus on Movement Disorders

PURPOSE OF REVIEW

Deep brain stimulation (DBS) is an established treatment in several movement disorders, including Parkinson's disease, dystonia, tremor, and Tourette syndrome. In this review, we will review and discuss the most recent findings including but not limited to clinical evidence.

RECENT FINDINGS

New DBS technologies include novel hardware design (electrodes, cables, implanted pulse generators) enabling new stimulation patterns and adaptive DBS which delivers potential stimulation tailored to moment-to-moment changes in the patient's condition. Better understanding of movement disorders pathophysiology and functional anatomy has been pivotal for studying the effects of DBS on the mesencephalic locomotor region, the nucleus basalis of Meynert, the substantia nigra, and the spinal cord. Eventually, neurosurgical practice has improved with more accurate target visualization or combined targeting. A rising research domain emphasizes bridging neuromodulation and neuroprotection. Recent advances in DBS therapy bring more possibilities to effectively treat people with movement disorders. Future research would focus on improving adaptive DBS, leading more clinical trials on novel targets, and exploring neuromodulation effects on neuroprotection.

Basal Ganglia Local Field Potentials as a Potential Biomarker for Sleep Disturbance in Parkinson's Disease

Sleep disturbances, specifically decreases in total sleep time and sleep efficiency as well as increased sleep onset latency and wakefulness after sleep onset, are highly prevalent in patients with Parkinson's disease (PD). Impairment of sleep significantly and adversely impacts several comorbidities in this patient population, including cognition, mood, and quality of life. Sleep disturbances and other non-motor symptoms of PD have come to the fore as the effectiveness of advanced therapies such as deep brain stimulation (DBS) optimally manage the motor symptoms. Although some studies have suggested that DBS provides benefit for sleep disturbances in PD, the mechanisms by which this might occur, as well as the optimal stimulation parameters for treating sleep dysfunction, remain unknown. In patients treated with DBS, electrophysiologic recording from the stimulating electrode, in the form of local field potentials (LFPs), has led to the identification of several findings associated with both motor and non-motor symptoms including sleep. For example, beta frequency (13–30 Hz) oscillations are associated with worsened bradykinesia while awake and decrease during non-rapid eye movement sleep. LFP investigation of sleep has largely focused on the subthalamic nucleus (STN), though corresponding oscillatory activity has been found in the globus pallidus internus (GPi) and thalamus as well. LFPs are increasingly being recognized as a potential biomarker for sleep states in PD, which may allow for closed-loop optimization of DBS parameters to treat sleep disturbances in this population. In this review, we discuss the relationship between LFP oscillations in STN and the sleep architecture of PD patients, current trends in utilizing DBS to treat sleep disturbance, and future directions for research. In particular, we highlight the capability of novel technologies to capture and record LFP data in vivo, while patients continue therapeutic stimulation for motor symptoms. These technological advances may soon allow for real-time adaptive stimulation to treat sleep disturbances.

Thalamic Deep Brain Stimulation May Improve Restless Legs Syndrome in Patients With Essential Tremor

OBJECTIVES

To determine change in restless legs syndrome (RLS) symptoms in essential tremor (ET) patients undergoing bilateral thalamic ventral intermedius (VIM) deep brain stimulation (DBS) surgery.

MATERIALS AND METHODS

We retrospectively reviewed our database of ET patients with RLS who had undergone VIM DBS for tremor from 2012 to 2020. We reviewed the patients with available International Restless Leg Syndrome Study Group RLS scale scores before and after DBS. Percentage of responders, defined as proportion of patients experiencing three or more point improvement of RLS scores post-DBS, was calculated. We performed two-tailed t-test of pre-DBS and post-DBS RLS scores.

RESULTS

We identified 13 patients with ET and RLS who had undergone bilateral VIM DBS, of whom nine (69%) were responders post-DBS. Five of 13 patients (38%) had complete resolution of RLS post-DBS. For all patients, mean pre-DBS RLS score was 15.8 ± 7.9 which improved by 46% post-DBS to a mean of 8.5 ± 8.8 (p = 0.007). Four patients rated their RLS scale one night with the stimulator OFF and another night with the stimulator ON. The mean RLS score with stimulator ON was 15.5 ± 7.6 which improved by 53% to a mean of 6.25 ± 7.8 (p = 0.008), with two having complete resolution of RLS with stimulator ON. Of the nine responders, six preferred to keep their stimulator ON at night due to relief of RLS and better subjective quality of sleep.

CONCLUSIONS

We report for the first time improvement of RLS in patients with ET after bilateral thalamic DBS. Although many ET patients with nonrechargeable DBS systems switch off their stimulator at night to conserve battery life, those with RLS may potentially benefit from keeping their stimulator ON at night to relieve their RLS.

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

Background:

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

Objective:

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

Methods:

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

Results:

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

Conclusion:

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

Sleep disturbance in movement disorders: insights, treatments and challenges

Sleep and circadian rhythm disturbances are central features of many movement disorders, exacerbating motor and non-motor symptoms and impairing quality of life. Understanding these disturbances to sleep is clinically important and may further our understanding of the underlying movement disorder. This review evaluates the current anatomical and neurochemical understanding of normal sleep and the recognised primary sleep disorders. In addition, we undertook a systematic review of the evidence for disruption to sleep across multiple movement disorders. Rapid eye movement sleep behaviour disorder has emerged as the most reliable prodromal biomarker for the alpha synucleinopathies, including Parkinson's disease and multiple system atrophy, often preceding motor symptom onset by several years. Abnormal sleep has also been described for many other movement disorders, but further evidence is needed to determine whether this is a primary or secondary phenotypic component of the underlying condition. Medication used in the treatment of motor symptoms also affects sleep and can aggravate or cause certain sleep disorders. Within the context of movement disorders, there is also some suggestion of a shared underlying mechanism for motor and sleep pathophysiology, with evidence implicating thalamic and brainstem structures and monoaminergic neurotransmission. This review highlights the need for an understanding of normal and abnormal sleep within the movement disorder clinic, an ability to screen for specific causes of poor sleep and to treat sleep disturbance to improve quality of life. Key sleep disorders also act as important biomarkers and have implications in diagnosis, prognosis and the development of future therapies.

The Impact of Subthalamic Deep Brain Stimulation on Restless Legs Syndrome in Parkinson's Disease

INTRODUCTION

The study aimed at evaluating the effect of subthalamic deep brain stimulation (DBS-STN) on restless legs syndrome (RLS) in Parkinson's disease (PD) patients.

MATERIALS AND METHODS

We assessed the presence of RLS before, 6 and 12 months after surgery in 36 patients. Differences between patients with RLS, without RLS, and with remission of RLS in terms of sleep measures (interview and validated questionnaires) and nonmotor symptoms (NMS). Polysomnography (PSG) was performed in 24 patients. Simple and multiple regression models were used to identify potential predictors of RLS outcome after DBS-STN.

RESULTS

Before DBS-STN 14 of the 36 patients (39%) were diagnosed with RLS. DBS-STN resulted in the resolution of RLS in 43% (n = 6) and the emergence of RLS in 2 (9%) patients. During the study, 20 patients remained without RLS and the patients with unremitting RLS (n = 8) experienced alleviation of symptoms. At baseline patients with RLS had higher Non-Motor Symptoms Scale (NMSS) total and sleep domain, Unified Parkinson's Disease Rating Scale (UPDRS) part IV and lower Parkinson's Disease Sleep Scale (PDSS) scores. There were no differences between the groups without and with RLS in terms of PSG recordings.

CONCLUSION

DBS-STN provided relief of symptoms in most of the patients with PD and RLS. We found that RLS was associated with worse subjective sleep quality, more severe NMS, and complications of levodopa therapy. DBS-STN may have direct impact on RLS rather than related indirectly through post-surgery change in medications.

Subthalamic Stimulation Improves Quality of Sleep in Parkinson Disease: A 36-Month Controlled Study

BACKGROUND

Sleep disturbances and neuropsychiatric symptoms are some of the most common nonmotor symptoms in Parkinson's disease (PD). The effect of subthalamic stimulation (STN-DBS) on these symptoms beyond a short-term follow-up is unclear.

OBJECTIVE

To examine 36-month effects of bilateral STN-DBS on quality of sleep, depression, anxiety, and quality of life (QoL) compared to standard-of-care medical therapy (MED) in PD.

METHODS

In this prospective, controlled, observational, propensity score matched, international multicenter study, we assessed sleep disturbances using the PDSleep Scale-1 (PDSS), QoL employing the PDQuestionnaire-8 (PDQ-8), motor disorder with the Scales for Outcomes in PD (SCOPA), anxiety and depression with the Hospital Anxiety and Depression Scale (HADS), and dopaminergic medication requirements (LEDD). Within-group longitudinal outcome changes were tested using Wilcoxon signed-rank and between-group longitudinal differences of change scores with Mann-Whitney U tests. Spearman correlations analyzed the relationships of outcome parameter changes at follow-up.

RESULTS

Propensity score matching applied on 159 patients (STN-DBS n = 75, MED n = 84) resulted in 40 patients in each treatment group. At 36-month follow-up, STN-DBS led to significantly better PDSS and PDQ-8 change scores, which were significantly correlated. We observed no significant effects for HADS and no significant correlations between change scores in PDSS, HADS, and LEDD.

CONCLUSIONS

We report Class IIb evidence of beneficial effects of STN-DBS on quality of sleep at 36-month follow-up, which were associated with QoL improvement independent of depression and dopaminergic medication. Our study highlights the importance of sleep for assessments of DBS outcomes.

DBS in restless legs syndrome: a new therapeutic approach?

OBJECTIVE

Restless legs syndrome (RLS) is a sleep disorder characterized by an urge to move legs or arms, with a typical circadian rhythm. RLS can be treated with pharmacological and non-pharmacological therapies. Nevertheless, in some patients RLS can be refractory to all medical and non-medical treatments. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) has been reported to improve RLS symptoms in Parkinson's disease (PD) patients with RLS. We describe the case of a patient suffering from refractory idiopathic RLS implanted with bilateral GPi DBS.

METHOD

The patient underwent DBS targeting the bilateral GPi. Follow up for three years involved clinical evaluation and polysomnography (PSG).

RESULTS

The patient reported subjective improvement, with reduction in the IRLS score. Furthermore, the polysomnography (PSG) showed an objective improvement of polysomnographic parameters, which remained stable during the follow-up.

CONCLUSION

DBS for RLS can be a new therapeutic approach for severe RLS, but further studies are needed.

A quantitative analysis of the effect of bilateral subthalamic nucleus-deep brain stimulation on subjective and objective sleep parameters in Parkinson's disease

OBJECTIVE

To explore how subjective and objective sleep parameters respond to bilateral subthalamic nucleus-deep brain stimulation (STN-DBS) in patients with Parkinson's disease (PD).

METHODS

Thirty DBS sleep studies were included by searching PubMed, Embase, and the Cochrane Library, and only 21 prospectively designed studies, including 541 patients, were eligible for the main analysis. We evaluated sleep disturbance using 1 objective measurement, polysomnography (PSG), and 4 subjective scales, including PD Sleep Scale (PDSS), Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and restless legs syndrome (RLS). We pooled data using the standard mean difference (SMD). The primary outcome was a change in sleep parameters 6 months postoperatively. Outcomes from <12 months to ≥12 months follow-up were compared in the subgroup analysis. Meta-regression was further conducted.

RESULTS

STN-DBS significantly improved all 4 subjective sleep scales in the 6-month follow-up: ESS (SMD = 0.234), PDSS (SMD = 0.724), PSQI (SMD = 1.374) and RLS (SMD = 1.086), while most PSG parameters remained unchanged, except for shortened rapid eye movement sleep latency (RSL) (SMD = 0.520). In the over-12-month follow-up, improvement persisted in PDSS but not in ESS. Dopamine drug reduction (p = 0.009) and motor improvement (p = 0.036) were correlated with ESS improvement and PDSS improvement, respectively.

CONCLUSIONS

Bilateral STN-DBS continuously improved subjective nocturnal sleep, while its effect on ESS lasted for only 1 year. Medication reduction and motor improvement may contribute to improved daytime sleepiness and better subjective nocturnal sleep, respectively. Except for a shortened RSL, STN-DBS did not change PSG parameters, including sleep efficiency and sleep architecture.

REGISTRATION

Open Science Framework: DOI 10.17605/OSF.IO/3EGRC.

Sleep Issues in Parkinson's Disease and Their Management

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

Improvement of Subthalamic Nucleus Deep Brain Stimulation in Sleeping Symptoms in Parkinson's Disease: A Meta-Analysis

Introduction

The aim of this meta-analysis was to evaluate the effects of STN DBS on sleep quality and restless leg symptoms in individuals with PD.

Methods

We searched the PubMed, Web of Science, EMBASE, CNKI, and WANFANG databases published between 1990 and 2019. The articles included were those that contained both pre- and postsurgery data acquired using International RLS Study Group criteria and the Pittsburgh sleep quality index (PSQI) questionnaire with patients' follow-up of at least three months. All studies that met the quality requirements were included in a meta-analysis performed using STATA 12.0 software.

Results

Of 73 articles identified, 7 studies comprising 82 patients were qualified for the current meta-analysis. After adjusting for heterogeneity in study effect sizes, the random effects meta-analysis indicated that STN DBS improved sleep quality and restless leg symptoms significantly (SMD = −1.111, 95% CI: −1.918∼−0.304, P=0.007). Subgroup analysis showed that different sleep scoring criteria had different effects on the condition of sleeping after surgery.

Conclusions

STN DBS is a powerful method in the management of sleep quality and restless leg symptoms in PD patients, but its long-term effects with larger populations must be thoroughly assessed.

Overview of Sleep and Circadian Rhythm Disorders in Parkinson Disease

Sleep disorders are common among PD patients and affect quality of life. They are often under-recognized and under-treated. Mechanisms of sleep disorders in PD remain relatively poorly understood. Improved awareness of common sleep problems in PD. Tailored treatment and evidence for efficacy are lacking. The purpose of this review is to provide an overview and update on the most common sleep disorders in PD. We review specific features of the most common sleep disorders in PD, including insomnia, excessive daytime sleepiness, sleep-disordered breathing, restless legs syndrome, circadian rhythm disorders and REM sleep behavior disorders.

Association between restless legs syndrome and other movement disorders

OBJECTIVE

This review focuses on the possible association between restless legs syndrome (RLS) and movement disorders, including Parkinson disease (PD), other parkinsonian syndromes, essential tremor, choreic and dystonic syndromes, Tourette syndrome, and heredodegenerative ataxias.

METHODS

Review of PubMed from 1966 to September 2018 and identification of references of interest for the topic. A meta-analysis of eligible studies on the frequency of RLS in patients with PD and controls using Meta-DiSc1.1.1 software and using the PRISMA guidelines was performed.

RESULTS AND CONCLUSIONS

Although there are substantial clinical, neuroimaging, neuropathologic, and genetic differences between RLS and PD, many reports describe a higher than expected prevalence of RLS in patients with PD, when compared with the general population or with matched control groups; several studies have also suggested that RLS could be an early clinical feature of PD. RLS symptoms are frequent in multiple system atrophy, essential tremor, Tourette syndrome, Friedreich ataxia, and spinocerebellar ataxia type 3 as well. Finally, possible genetic links between PD and RLS (the presence of allele 2 of the complex microsatellite repeat Rep1 within the α-synuclein gene promoter) and between Tourette syndrome and RLS (several variants in the BTBD9 gene) have been reported in 2 case-control association studies, although these data, based on preliminary data with small sample sizes, need to be replicated in further studies.

Restless Legs Syndrome in Parkinson's Disease Patients: Clinical Features Including Motor and Nonmotor Symptoms

Background and Purpose

We investigated the frequency and clinical features of restless legs syndrome (RLS) in patients with Parkinson's disease (PD).

Methods

This study included 74 PD patients. RLS was diagnosed in face-to-face assessments of all of the subjects based on diagnostic criteria of the International Restless Legs Syndrome Study Group revised in 2003. We analyzed the clinical features of PD patients with and without RLS and compared the data to idiopathic RLS.

Results

The frequency of RLS in the cohort was 21.6% (n=16). Two (12.5%) of the patients with RLS were not treated with dopaminergic drugs, while 14 (24.1%) of the 58 patients without RLS received treatment with dopaminergic drugs. Anxiety, depression, and quality of life (QoL) were significantly worst in patients with RLS. PD patients with RLS had significantly worse sleep quality (p=0.003) and worse scores on the cardiovascular subscale of the Scales for Outcomes in Parkinson's Disease for Autonomic Symptoms (p=0.031) compared to those without RLS. In the group of PD patients with RLS, RLS preceding PD onset was related to a lower Hoehn and Yahr stage.

Conclusions

We found that the frequency of RLS in the present patients with PD was higher than that in our previous study of a general population of RLS subjects. Compared to the PD patients without RLS, the present PD patients with RLS suffered from worse sleep quality and QoL, depression, anxiety, and autonomic disturbances, especially those with cardiovascular problems.