Higher prevalence of restless legs syndrome/Willis-Ekbom disease in multiple sclerosis patients is related to spinal cord lesions

Initial Cervical Spinal Cord Demyelinating Lesions are not Associated with Restless Legs Syndrome in Patients with Multiple Sclerosis

Purpose

This study aims to determine the prevalence and severity of restless legs syndrome (RLS) in patients with multiple sclerosis (MS) and its association with spinal cord lesions, fatigue, quality of life, and sleep disturbance.

Methods

We recruited 222 consecutive MS patients admitted to MS outpatient clinic. Beck's Depression Inventory (BDI), Fatigue Severity Scale (FSS), Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and MS Quality of Life-54 (MSQoL-54) questionnaire scores of all patients were measured. Initial cervical spinal cord magnetic resonance imaging (MRI) of the patients at first clinical evaluation for diagnosis was reviewed for accompanying demyelinating lesions.

Results

RLS was diagnosed in 53 (23.87%) patients. RLS was associated with poor sleep, worse quality of life, increased fatigue, and depressive mood. The sleep quality index, FSS, and MSQoL-54 physical composite scores significantly correlated with RLS severity (P < 0.001, P = 0.001, P < 0.001, respectively). Of the 200 patients, 127 (63.5%) had spinal cord lesions. 22.83% of the patients with cervical spinal cord lesions had RLS comorbidity. We found no significant difference regarding spinal cord demyelinating lesions between RLS positives and negatives. (P = 0.77). In addition, having multiple spinal cord demyelinating lesions did not differ between the two groups (P = 0.84). Besides, the severity of RLS symptoms did not differ in patients who had a single cervical spinal lesion and those who had multiple lesions (P = 0.35).

Conclusion

We have demonstrated the negative impact of comorbid RLS on fatigue, sleep quality, mood, and quality of life in MS patients. However, initial spinal cord lesions did not correlate with RLS comorbidity. The severity of RLS symptoms is associated with poor sleep and physical health.

The prevalence of restless legs syndrome (RLS) in patients with multiple sclerosis (MS): a systematic review and meta-analysis-an update

INTRODUCTION

The prevalence of restless legs syndrome (RLS) is reported to vary in patients with multiple sclerosis (MS) in studies which are conducted in different populations. The goal of this systematic review and meta-analysis is to update the prevalence of RLS in MS cases.

METHODS

We searched PubMed, Scopus, EMBASE, CINAHL, Web of Science, Google Scholar, and gray literature including references from identified studies and conference abstracts which were published up to June 2021. Data on the total number of participants, first author, country, disease duration, number of controls, mean patient age, male and female numbers, mean EDSS, and number of cases and/or controls with RLS were extracted from the included studies.

RESULTS

The literature search revealed 855 articles; after deleting duplicates, 530 remained. For the meta-analysis, 75 studies were included (Fig. 1). In six articles, the authors did not differentiate between CIS and MS cases when reporting RLS cases. In total, 15,411 MS/CIS patients were evaluated and 4309 had RLS. The pooled prevalence of RLS was 28% (95% CI: 24-33%). The pooled prevalence of RLS in men was 22% (95% CI: 17-26%), and the pooled prevalence of RLS in women was 30% (95% CI: 25-35%). The pooled prevalence of RLS in controls was 8% (95% CI: 6-10%).

CONCLUSION

The results of this systematic review and meta-analysis show that the pooled prevalence of RLS is 28% in MS cases and 8%. The pooled prevalence is higher in women than men (30% vs 22%).

Determination of optimal 25-hydroxyvitamin D cutoff values for the evaluation of restless legs syndrome among pregnant women

STUDY OBJECTIVES

Vitamin D deficiency is associated with restless legs syndrome (RLS). However, a cutoff value for serum 25-hydroxyvitamin D (25[OH]D) level associated with RLS has yet to be clearly determined. We evaluated the association between 25(OH)D and RLS in pregnant women.

METHODS

Data from 203 pregnant women were evaluated using blood samples taken in the third trimester. Liquid chromatography-tandem mass spectrometry and ligand binding assays were used to measure 25(OH)D. RLS was diagnosed based on International Classification of Sleep Disorders, third edition, criteria. The cutoff value for serum 25(OH)D associated with RLS was explored using receiver operating characteristic (ROC) curve and classification and regression tree (CART) analyses.

RESULTS

The results of liquid chromatography-tandem mass spectrometry (x) and ligand binding assays (y) for serum 25(OH)D in the RLS (n = 35, 17.2%) and non-RLS (n = 168) groups showed a relationship of y = -2.65 + 0.08x . The RLS group showed lower serum 25(OH)D and folate levels. ROC curve and CART analyses revealed cutoff values of 10-12.7 ng/mL and 6.6-7.2 ng/mL for 25(OH)D and folate, respectively. Of the 5 women with RLS symptoms persisting at a moderate-to-severe level after delivery, 4 had 25(OH)D levels < 10 ng/mL and all had folate levels < 6 ng/mL.

CONCLUSIONS

Vitamin D and folate deficiency were associated with RLS in pregnant women and may be associated with persistent moderate-to-severe postpartum RLS symptomatology; it is essential to examine associations with RLS while accounting for measurement methods and assay systems.

CITATION

Miyazaki A, Takahashi M, Shuo T, Eto H, Kondo H. Determination of optimal 25-hydroxyvitamin D cutoff values for the evaluation of restless legs syndrome among pregnant women. J Clin Sleep Med. 2023;19(1):73-83.

Restless legs syndrome severity associated with reduced physical function in adults with multiple sclerosis

BACKGROUND

Restless legs syndrome (RLS) is a sleep disorder that occurs in approximately 26 % of adults with multiple sclerosis (MS) and may be associated with reduced physical function.

RESEARCH QUESTION

The present study examined the relationship between RLS symptomology (i.e., overall severity, frequency, and occurrence) and physical function outcomes in adults with MS who had RLS.

METHODS

Participants (N = 22) with MS who had RLS came into the laboratory for a single session wherein a rater performed a brief neurological examination for scoring the Expanded Disability Status Scale (EDSS) and completed a demographics questionnaire, the International Restless Legs Syndrome Study Group Scale (IRLS), and the Restless Legs Syndrome Scale-6 (RLS-6) followed by the Short Physical Performance Battery (SPPB) and the Six-minute Walk Test (6 MW).

RESULTS

Bivariate Spearman's rho correlation analyses indicated total IRLS had a strong, negative association with total distance traveled during the 6 MW (ρ = -0.50) and a moderate association with SPPB scores (ρ = -0.43), but not EDSS scores (ρ = 0.28). RLS severity during the day while active had strong, negative associations with total distance traveled during the 6 MW (ρ = -0.61) and SPPB scores (ρ = -0.52), but not EDSS scores (ρ = 0.13).

SIGNIFICANCE

We observed associations between worse overall RLS severity and RLS severity during the day while active with reduced performance during the 6 MW and lower SPPB scores. The management of RLS may offer an opportunity for mitigating reductions in physical function in adults with MS who have RLS.

Voxel-wise lesion mapping of restless legs syndrome in multiple sclerosis

Objective

Restless legs syndrome (RLS) is known to be associated with multiple sclerosis (MS) and may be caused by MS lesions in specific cerebral brain regions. Applying a voxel-wise lesion analysis, we tried to identify the contribution of cerebral MS lesions to RLS.

Methods

In this retrospective study, we established a cohort of people with MS with documented RLS and controls of people with MS without RLS matched disease severity. Diagnosis of MS and RLS was based on the current guidelines. The MS lesions were analyzed on T2-weighted magnetic resonance imaging scans (1.5 or 3 T). After manual delineation, lesion maps were converted into stereotaxic space. We generated a lesion overlap and performed a Liebermeister test with 4000 permutations to compare the absence or presence of RLS voxel-wise between patients with and without lesions in a given voxel.

Results

Forty of the patients with RLS and MS fulfilled the inclusion criteria. The voxel-wise analysis yielded associations between RLS and MS in the subcortex of the left gyrus precentralis.

Conclusion

Our voxel-wise analysis shows associations in the subcortex of the left gyrus precentralis. Thus, our data suggests that a dysfunction of the efferent motor system due to cerebral lesions may contribute to the pathophysiology of RLS in MS.

Relationship between presence of spinal cord lesion and restless legs syndrome in multiple sclerosis

BACKGROUND

Even though the prevalence of restless leg syndrome in multiple sclerosis (MS) is known to vary between 12.5% and 60%, the underlying pathophysiological mechanism remains unclear.

AIM

This study aims to investigate the relationship between spinal cord lesions and restless leg syndrome in MS.

MATERIALS AND METHODS

In total, 959 persons with MS were enrolled in this study. Demographic and clinical data of persons with MS were recorded by interviewing and medical records. Neurologists blind to the presence of restless leg syndrome evaluated MRI scans for the presence of demyelinating lesions in the brainstem and spinal cord.

RESULTS

The restless leg syndrome was detected in 222 participants (23.15%). Restless leg syndrome was not significantly linked to mean age, body mass index, gender, and MS duration, but persons with MS with restless leg syndrome have a higher disability level (p = 0.044). In addition, no difference in the brainstem and thoracic cord was found between persons with MS with and without restless leg syndrome, while there is a significant relationship between the presence of cervical cord lesion and restless leg syndrome.

CONCLUSION

Higher disability scores and characteristics of lesion patterns in the spinal cord could explain higher rates of restless leg syndrome in persons with MS. Considering the negative effects of restless leg syndrome, the increased awareness and treatment of restless leg syndrome among persons with MS is essential for better managing.

Coexistence of restless legs syndrome and multiple sclerosis aggravates anxiety and depression

BACKGROUND

Among the comorbidities that accompany multiple sclerosis (MS), restless legs syndrome (RLS) is one of the most common. Anxiety and depression are common psychological comorbidities that impact the quality of life of patients with MS (PwMS), as well as patients with RLS.

OBJECTIVE

To investigate the psychiatric burden of MS and RLS coexistence, we conducted a nationwide, multicenter and cross-sectional survey.

METHODS

Participants were assessed by using demographic and clinical parameters along with the Hamilton Anxiety and Hamilton Depression Scales (HAM-A and HAM-D).

RESULTS

Out of the 1,068 participants, 173 (16.2%) were found to have RLS [RLS(+)] and 895 (83.8%) did not [RLS(-)]. The mean scores for HAM-A and HAM-D were significantly higher among RLS(+) subjects than among RLS(-) subjects (p<0.001 for all variables).

CONCLUSIONS

According to our data, the presence of RLS in PwMS may increase the occurrence of both anxiety and depression symptoms. Awareness and treatment of RLS in PwMS could possibly reduce the symptoms of psychiatric comorbidities originating from RLS.

Restless legs syndrome and related factors in people with multiple sclerosis in Turkey

OBJECTIVE

Restless legs syndrome is one of the most reported sleep disorders in multiple sclerosis (MS). The study aims to investigate the possible factors related to the occurrence and severity of restless legs syndrome in persons with MS (pwMS) comparing with healthy controls.

METHODS

This is a case-control study that included 447 pwMS and 57 healthy controls. Demographic and clinical data such as gender, age, duration of education, body mass index, marital status, disease duration, and MS type were recorded. Neurological disability was assessed by the Expanded Disability Status Scale. The Restless Legs Syndrome Rating Scale was used to assess the severity of restless legs syndrome.

RESULTS

The prevalence of restless legs syndrome in pwMS was 133 (29.8%) and 3 (4.9%) in healthy controls (p < 0.001). There was no significant difference between the groups in terms of gender, body mass index, and MS type (p > 0.05). Patients with restless legs syndrome have more advanced age, longer disease duration, and higher Expanded Disability Status Scale scores than patients without restless legs syndrome (p < 0.05). The correlation between restless legs syndrome severity and age, Expanded Disability Status Scale score, disease duration was not statistically significant (p > 0.05).

CONCLUSIONS

This study has shown that the presence of restless legs syndrome is high in persons with MS compared to healthy controls. Advanced age, disease duration, and higher disability level could be related to the increased rate of restless legs syndrome in persons with MS, especially those with high-frequency symptoms.

Restless legs syndrome in people with multiple sclerosis: An updated systematic review and meta-analyses

BACKGROUND

Restless legs syndrome (RLS) is a sensory-motor disorder characterized by an uncomfortable sensation felt in the lower extremity. The aim of this systematic review and meta-analyses was (i) to provide updated information on the prevalence and clinical characteristics of RLS amongst people with multiple sclerosis (PwMS) and (ii) clarify RLS-related factors in PwMS.

METHODS

MEDLINE (PubMed), Scopus, and EMBASE were searched from their inception through April 2021 for the following keywords: 'restless legs syndrome' or 'RLS' and 'multiple sclerosis' or 'MS'. For the analysis of RLS prevalence, we calculated the percentage of RLS sufferers amongst the PwMS and people without MS. The prevalence of RLS was pooled separately for PwMS and healthy controls, regardless of the heterogeneity between studies. The odds ratios (ORs) and 95% CIs were extracted from the data in order to analyze the association between MS and RLS.

RESULTS

Nineteen studies were included in the review (9 case-controlled and 10 cross-sectional).The mean prevalence of RLS in the MS population was 27.5%, ranging from 13.2% to 65.1%, higher than the healthy controls. Based on the case control studies, the pooled RLS prevalence was much higher in PwMS than in healthy controls (OR 4.535, 95% CI 3.043-6.759, p<0.001). The majority of studies found no significant relationship between the presence of RLS in PwMS with disability, disease duration, type of MS, age, or gender.

CONCLUSIONS

Our updated systematic review strengthens the evidence of the increased risk of RLS amongst PwMS. Nevertheless, significant data reporting on characteristics of the MS disease, which increases the risk of suffering from RLS, is still lacking.

Are serum vitamin D, calcium and phosphorous associated with restless leg syndrome? A systematic review and meta-analysis

BACKGROUND

It is hypothesized that vitamin D deficiency, and calcium/phosphate imbalance could be involved in the pathophysiology of restless leg syndrome (RLS). This systematic review and meta-analysis of observational studies were carried out to reach a firm conclusion regarding the possible association between vitamin D, calcium and phosphorous levels with RLS in end-stage renal disease (ESRD) patients, other comorbidities and healthy population.

METHODS

PubMed, Scopus, ISI Web of Science, and Cochrane's library were systematically searched up to June 2020. Quality assessment of the included observational studies was performed using Newcastle-Ottawa Quality Assessment Scale. Statistical analyses were done using STATA 11.2. A P-value <0.05 were considered statistically significant.

RESULTS

A total of 36 studies involving 9590 participants were included in this systematic review and meta-analysis. We found that serum vitamin D level is significantly lower (WMD -3.39 ng/mL; 95% CI, -5.96 to -0.81; P = 0.010; I² = 86.2%) and phosphorous (SMD 0.19; 95% CI, 0.04-0.34; P = 0.011; I² = 83.6%) is significantly higher in RLS individuals compared to the non-RLS individuals. However, the mean difference of serum calcium was not significant in comparison between RLS and control groups (SMD -0.01; 95% CI, -0.19 to 0.18; P = 0.957; I² = 89.2%).

CONCLUSION

Results revealed a significant association between serum vitamin D and phosphorous with RLS. However, further prospective cohort studies and clinical trials are needed for better understanding of the relationship between these variables.

Restless legs syndrome, sleep quality, and perceived cognitive impairment in adults with multiple sclerosis

BACKGROUND

Restless Legs Syndrome (RLS) is a prominent sleep disorder that often worsens sleep quality and perhaps cognitive function in adults with multiple sclerosis (MS). The present study examined the relationships among RLS prevalence and severity, sleep quality, and perceived cognitive impairment in adults with MS.

METHODS

Participants (N=275) completed the Cambridge-Hopkins Restless Legs Syndrome Questionnaire, the International Restless Legs Syndrome Study Group (IRLS) Scale, the Multiple Sclerosis Neuropsychological Screening Questionnaire (MSNQ), the Pittsburgh Sleep Quality Index (PSQI), the Patient Determined Disease Steps (PDDS), and a demographic and clinical characteristics questionnaire.

RESULTS

Persons with MS who had RLS (i.e., MS+RLS; n=74) reported significantly worse perceived cognitive impairment compared with those who did not have RLS (n=201; p=0.015). Bivariate correlation analyses within the MS+RLS group indicated that greater RLS severity was significantly associated with more severe perceived cognitive impairment (r=0.274) and sleep quality (r=0.380), and worse perceived cognitive impairment was significantly associated with worse sleep quality (r=0.438). Linear, step-wise regression analyses indicated that RLS severity significantly predicted perceived cognitive impairment (β=0.274), but the inclusion of sleep quality (β=0.391) accounted for the relationship between RLS severity and perceived cognitive impairment (β=0.126).

CONCLUSIONS

Our results suggest that sleep impairment may be an intermediary factor in the association between RLS severity and cognitive impairment in persons with MS who present with RLS. The diagnosis and treatment of RLS symptoms and other effectors of sleep quality could improve neuropsychological consequences of MS.

A global view of comorbidity in multiple sclerosis: a systematic review with a focus on regional differences, methodology, and clinical implications

Multiple sclerosis (MS) is a chronic autoimmune disorder of the central nervous system which is associated with numerous comorbidities. These include cardiovascular disease, psychiatric and neurologic disturbances, restless leg syndrome, migraine, cancer, autoimmune diseases, and metabolic disorders. Comorbid disease is an important consideration for clinicians treating patients with MS; early presentation of comorbidities can obscure or delay MS diagnosis, as well as significantly impacting the disease course. Improved understanding of comorbidities and their emergence in MS populations is important for improving the quality of life and optimizing treatment for patients. Therefore, we evaluated published studies reporting epidemiologic data on comorbidities and their associated impact on disease progression in patients with MS (PwMS). The prevalence of neurologic, cardiovascular, metabolic, and autoimmune comorbidities was elevated in PwMS in general, and furthermore, this adversely affected a broad range of outcomes. Compared with PwMS, cancer rates in people without MS or the general population were lower, which should prompt further studies into the mechanisms of both diseases. Studies were under-represented in many regions owing to the latitudinal gradient of MS and possible underfunding of studies.

'Is RLS a harbinger and consequence of MS?: Striking results of the 'RELOMS-T' study'

BACKGROUND

Although studies report a high prevalence rate of restless legs syndrome (RLS) among patients with multiple sclerosis (PwMS) ranging from 13.3 to 65.1%, little is known about the causes of this relationship.

METHODS

To ascertain the prevalence, features and impact of RLS among PwMS a nation-wide, multicenter, prospective and a cross-sectional survey, designed to reflect all of the PwMS throughout Turkey, was conducted in 13 centers. Exploring the relationship of the two conditions could possibly contribute to the understanding of the causes of the high and wide-ranging prevalence rates and the pathophysiology of both diseases.

RESULTS

Of the 1068 participants 173 (16,2%) found to have RLS [RLS(+)] and 895 (83,8%) did not [RLS(-)]. Among the RLS(+) 173, all but 8 patients (4,6%) were underdiagnosed in terms of RLS. More than half of the patients with RLS had 'severe' or 'very severe' RLS. The onset of RLS was before or synchronous with the onset of MS in about a half of our patients.

CONCLUSION

We conclude that RLS should be meticulously investigated in PwMS and MS can be a direct cause of RLS at least in part of PwMS. Our data about the timing of the onset of MS and RLS, along with the high prevalence of RLS in PwMS suggest that the pathologic changes in the initial phases of MS can possibly trigger RLS symptoms.

Restless legs syndrome among multiple sclerosis patients in Lebanon

BACKGROUND

Multiple sclerosis (MS) is often associated with fatigue, with an increased prevalence of sleep disorders compared to the general population, notably restless legs syndrome (RLS). The aim of this study was to evaluate the prevalence and severity of RLS as well the co-occurrence of spinal demyelination lesions in patients with MS in Lebanon.

METHODS

In this cross-sectional study, we consulted the MS database of the Lebanese association against Multiple Sclerosis and sent out questionnaires to 300 MS patients to screen then confirm the presence of RLS. The final sample included 28 MS participants with confirmed RLS. We conducted further questionnaires to collect demographic data, screen for comorbidities, gather spinal MRI results, and evaluate the severity of both diseases (using the EDSS and the JHRLSS).

RESULTS

Prevalence of RLS was 15% among MS patients in our study. 46.4% of RLS-affected MS patients had spinal cord demyelination lesions on their MRIs. Participants with MRI lesions had a lower severity score on the JHRLSS (p = 0.088). No association was found between the EDSS results and JHRLSS, demographic data, or comorbidities.

CONCLUSION

Restless legs syndrome is commonly found among patients with multiple sclerosis in Lebanon, is underdiagnosed, and ought to be systematically evaluated for in order to improve the patients' quality of life.

[Frequent neurological diseases associated with the restless legs syndrome]

BACKGROUND

Restless legs syndrome (RLS) is a common neurological disease. Studies have shown that RLS is associated with a variety of medical and neurological disorders.

OBJECTIVES

Using the example of three associated neurological diseases, the significance for everyday therapy decisions is assessed.

MATERIAL AND METHODS

A systematic search was carried out in PubMed for all studies with the keyword "RLS" in combination with polyneuropathies (PNP), Parkinson's disease (PD) and multiple sclerosis (MS) and classified according to the methodology in high, medium or low study quality.

RESULTS

Of 16 studies on RLS and MS, 10 were rated as "high". The high association frequency of RLS in MS between 13.3% and 65.1% (the variability possibly originates from different methods) prevents further statements about the prevalence. Within 30 studies on Parkinson's disease 17 were classified as having a high quality. In patients with Parkinson disease RLS occurs most frequently during therapy and is related to the duration of dopaminergic treatment. In patients with polyneuropathy, only 5 out of 24 studies were classified as being of high quality and an increased RLS prevalence was detected for acquired polyneuropathies with heterogeneous data for hereditary forms.

CONCLUSION

There is an increased prevalence of association with RLS for the diseases discussed. This prevalence is possibly determined by the pathophysiology of these disorders. These diseases are possibly characterized by genetic predispositions as well, which can hopefully be classified more accurately in the future.

Impact, Frequency, and Severity of Restless Legs Syndrome in Patients with Multiple Sclerosis in Argentina

Background

Restless legs syndrome (RLS) frequency, and its association with depression, anxiety, sleep disorders, and fatigue, has not been previously studied in Latin American patients with multiple sclerosis (MS). We aimed to assess RLS frequency in patients with MS living in Argentina and to examine potential associations with depression, anxiety, and sleep disorders.

Methods

A cross-sectional study (n = 427) was conducted using a self-administered questionnaire, including International RLS Study Group criteria, to compare RLS frequency in patients with MS versus controls. The Hospital Anxiety and Depression Scale and the Fatigue Severity Scale were administered to all participants. Insomnia, excessive daytime somnolence, and other risk factors in patients with MS with RLS were analyzed using logistic regression.

Results

We included 189 patients with definite MS and 238 controls. The RLS frequency was 29.1% in patients with MS versus 13.0% in controls (odds ratio [OR] = 2.74, P = .00005). Moreover, clinically significant RLS (csRLS; ie, symptoms present ≥2 days per week) frequency was 19.4% in patients with MS versus 4.2% in controls (OR = 5.37, P < .00001). Longer MS duration and presence of anxiety, depression, insomnia, and smoking cigarettes were all significantly associated with RLS. Multivariate analysis showed that anxiety and fatigue were significantly associated with MS with RLS and MS with csRLS.

Conclusions

Both RLS and csRLS showed strong association with MS, supporting the need to screen for anxiety/depression, sleep quality, and fatigue in this patient population. We believe that identifying the presence and severity of these conditions would contribute to better MS management and treatment.

Systematic review and meta-analysis of observational studies to understand the prevalence of restless legs syndrome in multiple sclerosis: an update

OBJECTIVE

Multiple sclerosis (MS) is related to the demyelination of intracranial nerves at multiple sites, while restless legs syndrome (RLS) appears to be caused by dysfunction of the dopaminergic system. Since RLS prevalence is higher among MS patients than in the general population, we carried out an updated meta-analysis to understand whether the two diseases might be associated.

METHOD

Web of Science, PubMed, Embase, Chinese National Knowledge Infrastructure, Wanfang, and SinoMed databases were searched for observational and case-controlled studies of RLS prevalence in MS. Eligible studies were meta-analyzed using Stata 12.0.

RESULTS

Pooled RLS prevalence among MS patients of various ethnicities was 26%, and prevalence was lower in Asia (20%) than outside Asia (27%). Prevalence was higher among cross-sectional studies (30%) than among case-control studies (23%). RLS prevalence was higher among female than male MS patients (26% vs. 17%), and it was higher among MS patients than among healthy controls (OR 3.96, 95%CI 3.29-4.77, p < 0.001).

CONCLUSION

Our meta-analysis updates the most recent meta-analysis in 2013 and provides perhaps the first reliable pooled estimate of RLS prevalence in MS. The available evidence strongly suggests that RLS risk is higher among MS patients than healthy controls.