Is autonomic nervous system involved in restless legs syndrome during wakefulness?

Compromised Dynamic Cerebral Autoregulation in Patients with Restless Legs Syndrome

Background

Restless legs syndrome (RLS) is a prevalent sensorimotor nervous system disorder in patients accompanied with insomnia, blood pressure fluctuation, and sympathetic dysfunction. These symptoms may disrupt cerebral hemodynamics. Dynamic cerebral autoregulation (dCA) describes the temporary response of cerebrovascular system to abrupt fluctuations in blood pressure, which keep cerebral blood flow stable and serve as a marker of cerebrovascular system ability.

Objective

This research aimed to assess dCA in RLS patients.

Methods

In this study, RLS patients were recruited and subsequently classified into four groups (mild, moderate, severe, and very severe) based on the International RLS Rating Scale (IRLS). Healthy controls matched for age and sex were enrolled. All participants were evaluated dCA by assessing phase difference (PD). A portion of patients with RLS was reassessed for dCA after one month of medication therapy (pramipexole [0.125 mg/day] and gabapentin [300 mg/day]).

Results

There were altogether 120 patients with RLS and 30 controls completed the polysomnography and dCA assessment. PD was lower in the moderate, severe, and very severe RLS groups than that in the controls and mild RLS groups. Periodic limb movement index (PLMI), arousal index, and IRLS all showed a linear correlation with PD in RLS patients. Additionally, PD increased in RLS patients after therapy.

Conclusion

The dCA was compromised in moderate, severe, and very severe RLS patients and was negatively correlated with the IRLS, arousal index, and PLMI. After 1 month of therapy, dCA improved in RLS patients.

Comparative assessment of choroidal thickness and choroidal vascularity index in patients with restless legs syndrome

BACKGROUND

Increased sympathetic activity has been emphasized in the pathophysiology of restless legs syndrome (RLS). This study aims to evaluate the choroidal thickness (CT) and choroidal vascularity index (CVI) values of individuals with RLS.

METHODS

A total of 60 volunteers, 30 individuals with RLS and 30 healthy individuals, were included in the study. The central macular thickness, subfoveal CT, and the CTs 1000 μm away from the fovea in the temporal and nasal regions were measured by optical coherence tomography. Total choroidal area (TCA), luminal area (LA) and stromal area (SA) were calculated using the binarization method. CVI was calculated as the ratio of lumen area to total choroidal area (LA/TCA).

RESULTS

There was no significant difference between the participants in terms of age, gender, spherical equivalent, intraocular pressure, and axial length (p>0.05). The mean LA/SA was 1.56%±0.05 in RLS group and 1.99%±0.28 in the control group. The mean CVI was 0.64%±0.02% in RLS group and 0.66%±0.03 in the control group. There was no significant difference between the groups in terms of CT, TCA and LA values. There were significant differences between the groups in SA, LA/SA and CVI values (p = 0.017, p<0.001, and p = 0.004, respectively).

CONCLUSION

SA values were significantly higher in RLS group than in control group. The LA/SA and CVI values were significantly lower in RLS group than in control group. These findings suggests that there is vascular narrowing due to sympathetic overactivity in RLS patients.

Noninvasive Vagus Nerve Stimulation: A New Therapeutic Approach for Pharmacoresistant Restless Legs Syndrome

AIMS

This work aimed to study the effect of noninvasive vagus nerve stimulation on severe restless legs syndrome (RLS) resistant to pharmacotherapy.

MATERIALS AND METHODS

Patients with severe pharmacoresistant RLS were recruited from a tertiary care sleep center. Intervention was one-hour weekly sessions of transauricular vagus nerve stimulation (tVNS) in the left cymba concha, for eight weeks. The primary outcome measure was the score on the International Restless Legs Rating Scale (IRLS); secondary outcome measures were quality of life (Restless Legs Syndrome Quality of Life scale [RLSQOL]), mood disorders using the Hospital Anxiety and Depression scale subscale for depression (HADD) and Hospital Anxiety and Depression scale subscale for anxiety (HADA), and objective sleep latency, sleep duration, efficiency, and leg movement time measured by actigraphy.

RESULTS

Fifteen patients, 53% male, aged mean 62.7 ± 12.3 years with severe RLS, reduced quality of life, and symptoms of anxiety and depression, were included. The IRLS improved from baseline to session eight: IRLS 31.9 ± 2.9 vs 24.6 ± 5.9 p = 0.0003. Of these participants, 27% (4/15) had a total response with a decrease below an IRLS score of 20; 40% (6/15) a partial response with an improvement in the IRLS > 5 but an IRLS above 20; and 33% (5/15) were nonresponders. After tVNS, quality of life improved (RLSQOL 49.3 ± 18.1 vs 80.0 ± 19.6 p = 0.0005), as did anxiety (HADA 8.9 ± 5.4 vs 6.2 ± 5.0 p = 0.001) and depression (HADD 5.2 ± 4.5 vs 4.0 ± 4.0 p = 0.01). No significant change was found in actigraphic outcome measures.

CONCLUSIONS

In this pilot study, tVNS improved the symptoms of RLS in 66% of participants (10/15) with severe pharmacoresistant RLS, with concomitant improvements in quality of life and mood. Randomized controlled trials evaluating therapeutic efficacy of tVNS in RLS are needed to confirm these promising findings.

Autonomic Dysfunction in Sleep Disorders: From Neurobiological Basis to Potential Therapeutic Approaches

Sleep disorder has been portrayed as merely a common dissatisfaction with sleep quality and quantity. However, sleep disorder is actually a medical condition characterized by inconsistent sleep patterns that interfere with emotional dynamics, cognitive functioning, and even physical performance. This is consistent with sleep abnormalities being more common in patients with autonomic dysfunction than in the general population. The autonomic nervous system coordinates various visceral functions ranging from respiration to neuroendocrine secretion in order to maintain homeostasis of the body. Because the cell population and efferent signals involved in autonomic regulation are spatially adjacent to those that regulate the sleep-wake system, sleep architecture and autonomic coordination exert effects on each other, suggesting the presence of a bidirectional relationship in addition to shared pathology. The primary goal of this review is to highlight the bidirectional and shared relationship between sleep and autonomic regulation. It also introduces the effects of autonomic dysfunction on insomnia, breathing disorders, central disorders of hypersomnolence, parasomnias, and movement disorders. This information will assist clinicians in determining how neuromodulation can have the greatest therapeutic effects in patients with sleep disorders.

Screening autonomic functions in patients with restless legs syndrome: A case-control study in a tertiary care hospital

PURPOSE

The clinical importance of autonomic involvement in patients with restless legs syndrome (RLS) remains unclear. To our knowledge, no study has explored the relationship between autonomic dysfunction and disease-related variables in patients with RLS. Therefore, this study aimed 1) to determine the presence of autonomic symptoms in drug-naïve patients with RLS in comparison with healthy controls using Scales for Outcomes in Parkinson's disease-Autonomic (SCOPA-AUT) questionnaire and 2) to evaluate the possible associations of autonomic dysfunction with clinical factors in RLS.

METHODS

A total of 70 drug-naïve patients with RLS and 85 healthy volunteers were enrolled. The SCOPA-AUT questionnaire and Epworth Sleepiness Scale (ESS) scores were used to determine autonomic functions and sleep propensity, respectively. Moreover, the International Restless Legs Syndrome Study Group rating scale was used to evaluate disease severity in the patient group.

RESULTS

Compared with the control group, the RLS group had significantly higher subscale scores (gastrointestinal, urinary, cardiovascular, thermoregulatory, pupillomotor, and sexual [women]) and total scores of the SCOPA-AUT questionnaire (p < 0.05). In the patient group, there was a significant correlation between the total scores and subscale scores (gastrointestinal, cardiovascular, and thermoregulatory subscales) of the SCOPA-AUT questionnaire and disease severity. Moreover, ESS was positively correlated with the total scores and subscale scores (urinary, cardiovascular, and pupillomotor) of the SCOPA-AUT questionnaire.

CONCLUSION

Disease severity and daytime sleepiness may be related to autonomic dysfunction in RLS. Further studies focusing on autonomic functions in RLS are required to improve management strategies and clinical outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT04906486; May 28, 2021.

Heart rate variability during sleep in children and adolescents with restless sleep disorder: a comparison with restless legs syndrome and normal controls

STUDY OBJECTIVES

Restless sleep disorder (RSD) has recently been characterized clinically and polysomnographically in children and differentiated from restless legs syndrome (RLS). Heart rate variability is a reliable method to quantify autonomic changes during sleep. The aim of this study was to characterize heart rate variability in children with RSD, RLS, and individuals without these disorders, with the hypothesis that children with RSD have a shift toward sympathetic predominance during sleep.

METHODS

We analyzed polysomnographic recordings from 32 children who fulfilled RSD diagnostic criteria (19 boys and 13 girls), 32 children with RLS (20 boys and 12 girls), and 33 individuals without disorders (17 boys and 16 girls). Four electrocardiographic epochs were chosen, 1 for each stage, and were analyzed for automatic detection of R waves. Time domain and frequency domain heart rate variability parameters were obtained and analyzed.

RESULTS

In terms of time domain, only the standard deviation of the average interval between successive R waves during stage N3 was slightly but significantly higher in patients with RSD than in patients with RLS. In terms of frequency domain, in patients with RSD, the very-low-frequency and low-frequency bands were increased (vs patients with RLS and individuals without disorders, respectively), whereas low-frequency/high-frequency ratio tended to be increased in both patients with RSD and with RLS. In rapid eye movement sleep, low-frequency/high-frequency ratio was increased in both patients with RSD and with RLS. The low-frequency/high-frequency ratio increased in patients with RLS during quiet wakefulness preceding sleep.

CONCLUSIONS

Children with RSD have increased sympathetic activation during sleep, particularly N3 and rapid eye movement sleep, compared with individuals without disorders but, as expected, not during wakefulness. Differently, children with RLS have sympathetic activation during relaxed wakefulness preceding sleep and during sleep.

Reduced sympatho-vagal responses to orthostatic stress in drug-naïve idiopathic restless legs syndrome

STUDY OBJECTIVES

Restless legs syndrome (RLS) is known to be a risk factor for cardiovascular disease. However, there are no electrophysiological biomarkers to assess this risk. This study aimed to evaluate heart rate variability (HRV) and cardiovascular reflexes in the supine and standing positions during wakefulness in patients with RLS.

METHODS

Fourteen drug-naïve patients with RLS (12 women and 2 men, mean age, 42.14 ± 7.81 years) and 10 healthy control patients underwent tests for blood pressure, heart rate when in the supine and standing positions, and deep breathing and handgrip tests in controlled laboratory conditions. Data on 5-minute R-R intervals at each position were collected and analyzed for HRV.

RESULTS

Expected cardiovascular reflexes were within the normal range and were similar between the 2 groups. In HRV analysis, the normalized unit of the low-frequency component and the low-frequency/high-frequency ratio during standing were lower in patients with RLS than in the control patients. The low-frequency/high-frequency ratio responses during the change from the supine to the standing position were significantly reduced in patients with RLS (mean ± standard deviation, 2.94 ± 3.11; control patients: 7.51 ± 5.58; P = .042.) On Spearman rank correlation, questionnaires related to sleep problems were associated with the parameters of HRV.

CONCLUSIONS

Patients with RLS showed reduced sympatho-vagal responses during the change from the supine to the upright position during wakefulness, and RLS-related sleep disturbance was a contributing factor for autonomic nervous system dysfunction. This case-control study showed a difference in HRV response to position change in a considerably small group of patients with RLS. The relevance of this finding is uncertain, but it may be worthy of further investigation in longitudinal studies on RLS and cardiovascular disease.

Restless legs syndrome is increased in postural orthostatic tachycardia syndrome

STUDY OBJECTIVES

Postural orthostatic tachycardia syndrome (POTS) and restless legs syndrome (RLS) are both characterized by sleep disturbance along with autoimmune/inflammatory features and autonomic dysfunction. However, to our knowledge, there has been no direct study looking at the prevalence of RLS in patients with POTS patients compared with healthy participants (controls).

METHODS

Ninety-six physician-diagnosed patients with POTS (89 female and 7 male) and 130 controls (99 female and 31 male) were administered the Cambridge Hopkins questionnaire. Participants who were diagnosed with probable or definite RLS on the Cambridge Hopkins questionnaire were then contacted to determine the severity of RLS with the International Restless Legs Scale.

RESULTS

More patients with POTS (15 of 96; 15.6%) than controls (6 of 130; 4.6%) were diagnosed with probable or definite RLS on the Cambridge Hopkins questionnaire (P = .0048). A sensitivity analysis with only female respondents yielded similar results. RLS severity was in the moderate range (12.23 ± 9.22).

CONCLUSIONS

There is a higher prevalence of RLS in patients with POTS patients compared with controls. This association may have to do with shared increased inflammatory/autoimmune load and autonomic dysfunction.

Systematic assessment of autonomic symptoms in restless legs syndrome

OBJECTIVES

To compare the clinical features of autonomic dysfunction using the SCOPA-AUT questionnaire in untreated patients with restless legs syndrome (RLS) with controls, to identify factors associated with more severe autonomic symptoms, and to assess the effect of medication in patients.

METHODS

The SCOPA-AUT questionnaire that evaluates cardiovascular, gastrointestinal, urinary, thermoregulatory, pupillomotor, and sexual dysfunctions was completed by 409 consecutive untreated patients with RLS (54.1 ± 14.5 y.o; 265 women) and 331 controls (59.0 ± 17.0; 161 women). Clinical and polysomnographic data were assessed in all patients. A subgroup of 57 patients were evaluated a second time after treatment (mostly dopaminergic agonist) after an interval of 0.88 ± 1.42 year.

RESULTS

Compared to controls, untreated patients with RLS were younger, more often women, obese, with increased cardiovascular diseases (CVD). The SCOPA-AUT total score was higher in patients than controls in unadjusted and adjusted models. Patients had more autonomic symptoms in all subdomains of the scale (except for sexual dysfunction in men). These results were confirmed in a subgroup of 259 cases and age-sex-matched controls. Female gender, obesity, RLS severity, diabetes mellitus, CVD, sleepiness, insomnia and depressive symptoms but neither periodic legs movements during sleep (PLMS) nor objective sleep parameters were associated with high scores. Despite RLS and PLMS improvement, medication did not change total and subdomain scores.

CONCLUSIONS

Patients with RLS have frequent and large spectrum of autonomic symptoms, without effect of PLMS, sleep fragmentation and medication. These results suggest a global autonomic dysfunction in RLS that should be assessed more systematically in severe patients.

Effect of electroacupuncture on restless legs syndrome (RLS) in hemodialysis patients: A protocol for systematic review and meta-analysis

BACKGROUND

Restless legs syndrome (RLS) is frequent in dialysis patients and occurs predominantly in its most severe forms. The aim of the present study was to evaluate the effects of electroacupuncture (EA) in hemodialysis patients with RLS by heart rate variability (HRV) monitor.

METHODS

One hundred twelve subjects who were hemodialysis patients with RLS will be divided into 2 groups: experimental and control. Each subject will receive the treatment relevant to their group 2 times a week for 4 weeks. After 4 weeks of treatment the subject will enter a 2-week washout period, after which the subjects will switch groups. Measurements will include HRV recordings, International Restless Legs Syndrome Rating Scale (IRLSRS) and Insomnia Severity Index (ISI).

RESULT

The results of this study will systematically evaluate the effectiveness and safety of electoracupuncture intervention for hemodialysis patients with RLS.

DISCUSSION

This study is the first investigation to analyze the relationship between EA and the change of HRV by an objective monitor. If the findings of the current trial are positive, this study will also help support an effective, safe and cheap approach to clinical treatment of this challenging disorder, help foster improved understanding the relationship between autonomic nervous system and RLS, and ultimately contribute to elucidate the mechanisms of EA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04356794; registration date: April 22, 2020.

Restless legs syndrome is associated with mast cell activation syndrome

STUDY OBJECTIVES

Mast cell activation syndrome (MCAS) is an inflammatory and allergic disorder. We determined the prevalence of restless legs syndrome (RLS) in MCAS because each common syndrome may be inflammatory in nature and associated with dysautonomia.

METHODS

Individuals with MCAS were evaluated for RLS by two standard questionnaires. Prevalence comparisons included spouse control patients and two prevalence publications. MCAS diagnosis required mast cell (MC) symptoms in ≥ 2 organs plus ≥ 1 elevated MC mediators, improvement with MC therapy, and/or increased intestinal MC density. Clinical variables were studied.

RESULTS

There were 174 patients with MCAS (146 female, 28 male, mean age 44.8 years) and 85 spouse control patients (12 female, 73 male, mean age 50.9 years). Patients with MCAS as a whole had a higher prevalence of RLS (40.8%) than spouse control (12.9%) (P < .0001) Male patients with MCAS had a higher prevalence of RLS (32.1%) than male controls (12.3%, odds ratio [OR] 3.4, confidence interval [CI] 1.2-9.7, P = .025), American men (8.4%, OR 5.2, CI 2.2-12.0, P < .001), and French men (5.8%, OR 7.7, CI 3.4-17.1, P < .001). Female patients with MCAS also had a higher prevalence of RLS (42.5%) than female controls (16.7%) but this did not reach statistical significance perhaps because of the sample size of the female controls. However, female patients with MCAS had a statistically higher prevalence of RLS than American women (10.0%, OR 6.7, CI 4.5-9.7, P < .0001) and French women (10.8%, OR 6.1, CI 4.4-8.6, P < .0001).

CONCLUSIONS

RLS appears to be associated with MCAS. Effects of mast cell mediators, inflammation, immune mechanisms, dysautonomia, or hypoxia may theoretically activate RLS in MCAS.

Blood pressure profile and endothelial function in restless legs syndrome

Restless legs syndrome (RLS) is frequently comorbid with hypertension and cardiovascular diseases; however this relationship and underlying mechanisms remain controversial. After clinical evaluation, 84 drug-free patients with primary RLS (53 women; mean age 55.1 ± 12.3 years) and 76 controls (47 women; mean age 52.2 ± 15.3 years) underwent 24-hour ambulatory blood pressure (BP) and polysomnographic monitoring, and peripheral arterial tonometry to assess endothelial function for 61 patients and 69 controls. Hypertension was diagnosed in 11.9% of patients with RLS based on office measurement, and in 46.4% on the 24 h recording, with nighttime hypertension, two times more frequent than daytime hypertension. Periodic limb movement during sleep (PLMS), markers of sleep fragmentation, and systolic and mean BP non-dipping profile were more frequent among patients. BP non-dipping status was associated with older age, later RLS onset and diagnosis, RLS severity and higher sleep fragmentation. The mean 24-hour, daytime and nighttime BP values, the frequency of hypertension and the endothelial function were comparable between groups. However, both systolic and diastolic BP trajectories over a 24-hour period differed between groups. In conclusion, patients with RLS exhibit a 24-hour BP deregulation with increased frequency of systolic non-dipping profiles that could worsen the risk for CVD morbidity and mortality.

Determinants of Nocturnal Cardiovascular Variability and Heart Rate Arousal Response in Restless Legs Syndrome (RLS)/Periodic Limb Movements (PLMS)

Recent studies have suggested that restless legs syndrome is associated with an increased prevalence of cardiovascular diseases mediated by sympathetic activation occurring during periodic limb movements. The aim of this study was to establish which factors affect the degree of sympathetic activation during the basal condition and during periodic limb movements that may contribute to increased vascular risk. Fifty untreated restless legs syndrome patients aged 62.6 ± 11.1 y, free of cardiovascular diseases, were examined. Heart rate variability was calculated during wakefulness and all sleep stages, during periods with and without periodic limb movements. Heart rate changes before and after periodic limb movement onset were analyzed to assess the arousal response to periodic limb movements. Both analyses took into account the effects of age, gender, periodic limb movement duration, periodic limb movement index, periodic limb movement interval and periodicity, and magnitude of muscular activity (electromyogram power). Compared to periods without periodic limb movements, a significant increase in sympathetic activity occurred in periods with periodic limb movements, independent of age, sex and periodic limb movement characteristics. Data obtained from the cardiac arousal response to periodic limb movements showed that electromyogram power is the factor affecting sympathetic tonus. These results suggest that other factors, such as electromyogram power and individual susceptibility, should be considered in the assessment of the vascular risk related to restless legs syndrome.

Neurological Sleep Disorders and Blood Pressure: Current Evidence

Hypertension is a major determinant of cardiovascular morbidity and mortality and is highly prevalent in the general population. While the relationship between sleep apnea and increased blood pressure has been well documented, less recognized is emerging evidence linking sleep-related movement disorders such as restless legs syndrome/periodic limb movements of sleep and sleep-related bruxism with blood pressure (BP) dysregulation and hypertension. There is also recent literature linking narcolepsy-cataplexy with elevated BP and altered pressor responses, and there are data suggesting abnormal BP control in rapid eye movement sleep behavior disorder. It is thought that neural circulatory mechanisms, sympathetic activation in particular, comprise the predominant mediator underlying elevated BP in these neurological sleep disorders. There is very limited evidence that treating these sleep disorders may be beneficial in lowering BP primarily because this question has received very little attention. In this review, we discuss the potential pathophysiologic mechanisms underlying elevated BP in restless legs syndrome/periodic limb movements of sleep, sleep-related bruxism, narcolepsy-cataplexy, and rapid eye movement sleep behavior disorder. We also examine the relationship between these sleep disorders and elevated BP and the impact of treatment of these conditions on BP control. Last, we discuss gaps in the literature evaluating the associations between these sleep disorders and elevated BP and identify areas for further research.

Restless legs syndrome, periodic limb movements during sleep and cardiovascular risk

Multiple mechanisms may modulate an association between restless legs syndrome/Willis-Ekbom disease (RLS/WED) and cardiovascular disease (CVD), including chronic sleep deprivation, intermittent, periodic limb movements in sleep (PLMS)-related autonomic fluctuations and possible autonomic dysfunction intrinsically associated with RLS per se. The purpose of this paper is to review the existing RLS/WED literature focusing on the pathophysiologic evidence for possible associations between RLS/WED and PLMS with CVD and events (CVE). Specific intrinsic dysautonomic aspects of the disease, which may contribute to generating CVD, are separately discussed. The association between RLS/WED and both CV risk factors and CVD still remains elusive. Although several shared pathophysiological causes could explain these possible relationships, the emerging body of literature focusing on these disorders remains controversial. Not only longitudinal population-based studies and meta-analyses, but also more animal models and therapeutic interventions are needed in order to build a sufficiently robust body of evidence on this topic.

Restless legs syndrome is associated with arterial stiffness and clinical outcome in stroke patients

OBJECTIVE

Restless legs syndrome (RLS) has been associated with vascular diseases, including cerebrovascular and cardiovascular diseases. Among the various mechanisms in RLS, peripheral vascular endothelial dysfunction in patients with RLS has recently been proposed as a vascular pathophysiology of RLS. This study investigated arterial stiffness related to RLS in acute ischemic stroke patients and its influence on stroke outcome.

METHODS

RLS in patients with acute ischemic stroke was assessed based on the four essential criteria of the International Restless Legs Syndrome Study Group described in 2003. The patients' clinical and laboratory characteristics, arterial stiffness, small vessel disease occurrence, and burden on brain MRI were recorded. Stroke severity was determined using the National Institute of Health Stroke Scale (NIHSS), and clinical outcomes were determined using the modified Rankin Scale.

RESULTS

Of 296 patients with acute ischemic stroke, 16 (5.4%) were diagnosed with restless legs syndrome. Logistic regression analysis showed that a 1 m/s increase in brachial arterial pulse wave velocity was associated with the diagnosis of RLS (odds ratio, 1.092; 95% confidence interval, 1.019-1.170, p = 0.012). Diagnosis of RLS in patients with acute ischemic stroke was associated with poor clinical outcome three months after stroke (modified Rankin Scale 3-6) (odds ratio, 4.263; 95% confidence interval, 1.229-14.792, p = 0.022) along with initial NIHSS score.

CONCLUSION

RLS in patients with acute ischemic stroke is associated with increased arterial stiffness and poor clinical outcomes.

Ocular morphological changes in patients with restless legs syndrome analyzed by optical coherence tomography

BACKGROUND

Two leading hypotheses for restless legs syndrome (RLS) pathophysiology are dopaminergic dysfunction and sympathetic overactivity. Ocular changes occur with both dopaminergic and sympathetic pathologies, and thus may provide unique insights into the pathophysiology of RLS.

METHODS

Thirty-five patients with RLS and 35 healthy individuals were enrolled in the study. Peripapillary retinal nerve fiber layer (RNFL), macular, and choroidal thicknesses were measured by optical coherence tomography (OCT).

RESULTS

There were no statistically significant differences between the two groups regarding RNFL and macular thicknesses. The subfoveal, temporal and nasal choroidal thicknesses were significantly thinner in patients with RLS compared with normal subjects (p < 0.05).

CONCLUSION

Thinning of the choroid is linked to sympathetic overactivity. Our results provide further evidence for sympathetic overactivity in the pathogenesis of RLS.

Clinical and radiological characteristics of restless legs syndrome following acute lacunar infarction

BACKGROUND

Recent studies have suggested that cerebral ischemic infarction may contribute to the development of restless legs syndrome (RLS). This study analyzed the clinical and radiological profiles of RLS with onset after acute lacunar infarction.

METHODS

In this retrospective study we enrolled 244 consecutive patients with acute lacunar infarction between January 2012 and June 2014. RLS was identified and evaluated based on the International RLS Rating Scale (IRLS-RS). Individual sleep quality was assessed using the Epworth Sleepiness Scale (ESS). Psychological state was also assessed using the Hamilton Depression Scale (HDS) and the Hamilton Anxiety Scale (HAS).

RESULTS

The incidence of RLS in patients with lacunar infarction was 5.33%. Our participant group consisted of nine males and four females. Three patients had symptoms in bilateral limbs, and 10 patients had symptoms only contralateral to the cerebral infarction. The infarctions were localized to the pons, centrum semiovale, thalamus, putamen, medulla, and occipital lobe. Contralateral paralysis was found in 13 patients, and contralateral sensory deficit in seven patients. The average IRLS-RS, ESS, HDS, HAS scores were 19.07 ± 8.70, 4.69 ± 5.82, 4.38 ± 4.68, and 3.85 ± 4.76, respectively. Nine patients had diabetes mellitus. After administration of dopaminergic drugs, patients' RLS significantly improved.

CONCLUSIONS

The incidence of RLS after acute lacunar infarction was 5.33%. Pons, centrum semiovale, and basal ganglia were the common locations of responsible lesions. Compared to idiopathic RLS, symptoms of RLS after acute lacunar infarction appeared more unilateral and more likely involved the arm. Moreover, diabetes mellitus may be a risk factor for RLS in stroke patients.

Restless legs syndrome in Parkinson's disease and increased cardiovascular risk

ABSTRACT Restless legs syndrome (RLS) is a disorder commonly found in patients with Parkinson's disease, with descriptions for both conditions impairing dopaminergic transmission in central nervous system. Previous studies in varied populations indicate an association between the presence of RLS and increased cardiovascular risk and, so far, there are no consistent studies of this association in Parkinson's disease. Objective: To analyze the influence of RLS on cardiovascular risk in patients with Parkinson's disease. Methods: We reviewed the medical records of 202 patients diagnosed with Parkinson's disease and verified the presence of RLS, cardiovascular comorbidities, blood pressure measurements, lipid profiles and Framingham Risk Scores. Results: Statistically significant higher values of total cholesterol were found for the RLS group (mean 216.6 mg/dL), as well as for LDL cholesterol (mean 145 mg/dL). No statistical difference was found among the other factors. Conclusion: Patients with Parkinson's disease and RLS have a higher prevalence of dyslipidemia than patients without RLS, suggesting a correlation between restless legs and hyperlipidemia. It is questioned whether the dopaminergic substrate is the main factor in the genesis of the syndrome, as even with the use of dopaminergic agonists by both groups, it was possible to observe differences between groups. The hypothesis of the real interference of the syndrome treatment as a protective factor for cardiovascular risk was generated.

Heart rate variability testing: could it change spending for rheumatoid arthritis patients in the United States? An exploratory economic analysis

BACKGROUND

Autonomic nervous system (ANS) testing with heart rate variability (HRV) has been shown in early research to predict 52-week outcomes in rheumatoid arthritis (RA). HRV testing could be combined with putative ANS biologic pathways to improve treatment response for RA patients. This study explored potential costs and health outcomes of introducing HRV testing into RA treatment, without and with ANS optimization.

METHODS

A decision tree exploratory economic model compared HRV testing to standard care in moderate-to-severe biologic-eligible patients over a 10-year time horizon. HRV data was derived from an observational study of RA patients (n = 33). Patients were stratified into treatment groups based on HRV test scores indicating "low probability of response" and "moderate to high probability of response". This study explored adding ANS optimization based on HRV score followed by clinically-appropriate treatment. Costs and quality-adjusted life-years (QALYs) for the US population were estimated.

RESULTS

HRV testing in biologic-eligible patients decreased non-effective biologic use, reducing US healthcare costs by $34.6 billion over 10 years with QALYs unchanged. When combined with ANS optimization in biologic-eligible patients, HRV testing could increase costs by $3.6 billion over 10 years but save over 350,000 QALYs. Among all RA patients, HRV testing with ANS optimization could save over $8 billion and over 100,000 QALYs over 10 years, depending on the positive predictive value (PPV) of the HRV test.

CONCLUSIONS

The potential economic impact of introducing HRV testing and ANS optimization into RA treatment appears substantial and cost-effective based on the exploratory analysis. Additional rigorous studies are warranted in larger patient samples to better inform decision-making.

Patients with primary restless legs syndrome have higher prevalence of autonomic dysfunction and irritable bowel syndrome

INTRODUCTION

Given the limited data on autonomic dysfunction in patients with primary restless legs syndrome (pRLS), we compared autonomic dysfunction and presence of irritable bowel syndrome (IBS) between patients with pRLS and control patients.

METHODS

Consecutive adult drug-naïve patients with pRLS, and age- and gender-matched healthy control patients were enrolled in this study. Diagnoses, based on validated self-reported questionnaires, were made using the following guidelines: Rome III classification system for functional gastrointestinal disorders for IBS; Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) for the presence of anxiety and depression, respectively; Pittsburgh Sleep Quality Index (PSQI) for severity of sleep disturbances; and Scales for Outcomes in Parkinson's disease-Autonomic (SCOPA-AUT) for autonomic dysfunction.

RESULTS

There were 88 patients with pRLS (18 male, 70 female) and 128 control patients (40 men, 88 women). The mean age of the pRLS patients and control patients was 50.3 ± 9.3 years and 49.7 ± 8.2 years, respectively. Overall, 41 (46.6%) of the patients with pRLS and 16 (12.5%) of the control patients had IBS. Among patients with pRLS, IBS was significantly more common and the total autonomic SCOPA-AUT scores were higher than those found among control patients. Among pRLS patients with IBS, total autonomic SCOPA-AUT, PSQI, BAI and BDI scores were significantly higher than among pRLS patients without IBS. The presence of IBS did not affect the severity of restless legs syndrome.

CONCLUSION

The presence of autonomic nervous system impairment in patients with pRLS and the strong link between IBS and pRLS merit further, more extensive investigation.

Heart rate variability in restless legs syndrome and periodic limb movements of Sleep

INTRODUCTION

The relationship between the autonomic nervous system and restless legs syndrome (RLS) and periodic limb movements of sleep (PLMS) consists of varied and somewhat conflicting reports. In order to further elucidate these complexities, a retrospective analysis of polysomnography (PSG) records and clinical data was performed.

METHODS

Records from 233 adult subjects were randomly selected and organized into one of four groups ("non-RLS/PLMS" [n=61], "RLS" [n=60], "PLMS" [n=58], and "RLS/PLMS" [n=54]). Heart rate variability (HRV) analysis was based on 5-minute samples of 2-lead electrocardiogram data isolated from PSG recordings during wakefulness and NREM sleep, and included mean RR interval (labeled "NN") and standard deviation of the RR intervals (labeled "SDNN"), and HRV power, very low frequency (VLF), low frequency (LF), and high frequency (HF) spectral bands.

RESULTS

A significant reduction in the VLF band in the PLMS group as compared to the non-RLS/PLMS group (542±674 vs. 969±1025 ms², p=0.038) was found in wakefulness. Statistically significant differences were seen in the PLMS group as compared to the non-RLS/PLMS group with a reduction in SDNN (p=0.001) and the HF (p=0.001) band, and an increase in HRV power (p=0.001), and the VLF (p=0.005) and LF (p=0.001) bands in NREM sleep.

CONCLUSIONS

The PLMS group exhibited reduced basal sympathetic activity in wakefulness, but basal sympathetic predominance during NREM sleep, distinguishing this group from the RLS and RLS/PLMS groups.

MEIS1 variant as a determinant of autonomic imbalance in Restless Legs Syndrome

Restless Legs Syndrome (RLS) is a genetically complex neurological disorder in which overlapping genetic risk factors may contribute to the diversity and heterogeneity of the symptoms. The main goal of the study was to investigate, through analysis of heart rate variability (HRV), whether in RLS patients the MEIS1 polymorphism at risk influences the sympathovagal regulation in different sleep stages. Sixty-four RLS patients with periodic leg movement index above 15 per hour, and 38 controls underwent one night of video-polysomnographic recording. HRV in the frequency- and time- domains was analyzed during nighttime sleep. All RLS patients were genotyped, and homozygotes for rs2300478 in the MEIS1 locus were used for further analysis. Comparison of the sympathovagal pattern of RLS patients to control subjects did not show significant differences after adjustments for confounding factors in frequency-domain analyses, but showed an increased variability during N2 and N3 stages in time-domain analyses in RLS patients. Sorting of RLS patients according to MEIS1 polymorphism reconfirmed the association between MEIS1 and PLMS, and showed a significant increased sympathovagal balance during N3 stage in those homozygotes for the risk allele. RLS patients should be considered differently depending on MEIS1 genotype, some being potentially at risk for cardiovascular disorders.

Restless legs syndrome and cardiovascular disease: a research roadmap

In this paper, we first critically appraise the epidemiologic literature examining the association of restless legs syndrome (RLS) with cardiovascular disease (CVD) and then consider whether lessons learned from the study of cardiovascular consequences of other sleep disorders might inform a research agenda to examine the potential mechanisms of cardiovascular morbidity of RLS. Cross-sectional and longitudinal studies are both mixed as to whether there is a meaningful association of RLS and CVD. On the other hand, numerous cross-sectional and longitudinal observational studies have shown a strong association of obstructive sleep apnea (OSA) with CVD risk. Each of the potential mediating mechanisms in OSA may also be assessed in RLS, including 1) neural mechanisms such as increased central sympathetic outflow, impaired baroreflex function, diminished heart rate and blood pressure variability, and increased chemoreflex sensitivity, 2) metabolic mechanisms such as glucose intolerance and reduced insulin sensitivity/diabetes as a result of sleep disturbance in RLS, 3) oxidative stress, 4) systemic or vascular inflammatory mechanisms, and 5) vascular mechanisms including impaired endothelial functioning, increased aortic stiffness, hypothalamic-pituitary axis activation or renin-angiotensin-aldosterone activation. Three known characteristics of RLS may contribute to these specific mechanisms of increased cardiovascular risk: 1) periodic limb movements of sleep, which are associated with large increases in heart rate and blood pressure, 2) sleep fragmentation and sleep deprivation, which are known to produce adverse consequences for neural, metabolic, oxidative, inflammatory, and vascular systems, and 3) iron deficiency, which is an emerging risk for cardiovascular disease. Future research priorities include additional epidemiologic studies which characterize multiple CVD risk factors, case-control studies which examine known markers of cardiovascular risk, and small clinical trials which assess the effects of RLS treatment on intermediate physiological markers such as sympathetic activity or baroreflex control, measures of vascular stiffness and reactivity, or measures of insulin sensitivity and glucose tolerance.

Restless Legs Syndrome: Current Concepts about Disease Pathophysiology

Background

In the past few decades, much has been learned about the pathophysiology of restless legs syndrome (RLS). Investigators have studied neuropathology, imaging, electrophysiology, and genetics of RLS, identifying brain regions and biological systems affected in RLS. This manuscript will review RLS pathophysiology literature, examining the RLS state through consideration of the neuroanatomy, then the biological, organ, and genetic systems.

Methods

Pubmed (1966 to April 2016) was searched for the term “restless legs syndrome” cross-referenced with “pathophysiology,” “pathogenesis,” “pathology,” or “imaging.” English language papers were reviewed. Studies that focused on RLS in relation to another disease were not reviewed.

Results

Although there are no gross structural brain abnormalities in RLS, widespread brain areas are activated, including the pre- and post-central gyri, cingulate cortex, thalamus, and cerebellum. Pathologically, the most consistent finding is striatal iron deficiency in RLS patients. A host of other biological systems are also altered in RLS, including the dopaminergic, oxygen-sensing, opioid, glutamatergic, and serotonergic systems. Polymorphisms in genes including BTBD9 and MEIS1 are associated with RLS.

Discussion

RLS is a neurologic sensorimotor disorder that involves pathology, most notably iron deficiency, in motor and sensory brain areas. Brain areas not subserving movement or sensation such as the cingulate cortex and cerebellum are also involved. Other biological systems including the dopaminergic, oxygen-sensing, opioid, glutamatergic, and serotonergic systems are involved. Further research is needed to determine which of these anatomic locations or biological systems are affected primarily, and which are affected in a secondary response.

Tilt table test today - state of the art

A tilt table test (TTT) is an inexpensive, noninvasive tool for the differential diagnosis of syncope and orthostatic intolerance and has good diagnostic yield. The autonomic system malfunction which underlines the reflex syncope is manifested as either hypotension or bradycardia, while an orthostatic challenge is applied. The timing of the response to the orthostatic challenge, as well as the predominant component of the response help to differentiate between various forms of neurocardiogenic syncope, orthostatic hypotension and non-cardiovascular conditions (e.g., pseudosyncope). Medications, such as isoproterenol and nitrates, may increase TTT sensitivity. Sublingual nitrates are easiest to administer without the need of venous access. TTT can be combined with carotid sinus massage to evaluate carotid sinus hypersensitivity, which may not be present in supine position. TTT is not useful to access the response to treatment. Recently, implantable loop recorders (ILR) have been used to document cardioinhibitory reflex syncope, because pacemakers are beneficial in many of these patients, especially those over 45 years of age. The stepwise use of both TTT and ILR is a promising approach in these patients. Recently, TTT has been used for indications other than syncope, such as assessment of autonomic function in Parkinson's disease and its differentiation from multiple system atrophy.

Impact of Restless Legs Syndrome on Cardiovascular Autonomic Control

STUDY OBJECTIVES

To examine whether patients with restless legs syndrome demonstrate specific alterations in cardiovascular autonomic control.

METHODS

Patients with moderate-severe restless legs syndrome (n = 20, 80% female) and controls (n = 20) matched for age, sex, body mass index, and free of hypertension and cardiovascular disease were enrolled. We assessed cardiovagal baroreflex gain via the modified Oxford technique, sympathetically mediated vascular responses to isometric exercise to fatigue, bradycardiac response to Valsalva maneuver, and respiratory sinus arrhythmia during paced breathing. Standard electrocardiography, beat-by-beat arterial pressure, respiration, and popliteal blood flow velocity were recorded continuously.

RESULTS

Resting blood pressure and heart rate were similar between groups. However, baroreflex gain averaged 14.3 ± 1.4 msec/mm Hg in restless legs syndrome and was lower than in controls (22.6 ± 3.5 msec/mm Hg, P = 0.04). Hemodynamic responses to isometric exercise were similar between groups, though participants with restless legs syndrome had lower leg blood flow (P < 0.001), with greater leg vascular resistance (P < 0.0001), before and during isometric exercise. Respiratory sinus arrhythmia and Valsalva ratios were similar between groups. Neither baroreflex gain nor vascular resistance was correlated with sleep duration, sleep quality, or symptom duration.

CONCLUSION

Patients with restless legs syndrome demonstrate compromised cardiovagal control, specific to the arterial baroreflex, with greater peripheral vascular resistance, potentially due to heightened sympathetic outflow. These autonomic alterations may directly relate to the higher prevalence of cardiovascular disease in restless legs syndrome.

Restless Legs Symptoms and Pregnancy and Neonatal Outcomes

PURPOSE

Restless legs syndrome (RLS) is a commonly occurring neurologic disorder that affects up to one third of women during pregnancy. RLS has been associated with increased sympathetic tone in the nonpregnant population. We examined whether a RLS surrogate is associated with a higher prevalence of pregnancy and neonatal outcomes.

METHODS

Data were analyzed from a cross-sectional survey of 1000 women interviewed soon after delivery by using an RLS surrogate question. Women were asked how frequently (0 = none, 1 = rarely [<1 time/week], 2 = sometimes [1-2 times/week], 3 = frequently [3-4 times/week], and 4 = always [5-7 times/week]) they had "experienced jumpy or jerky leg movements" in the last 3 months of pregnancy. Clinical charts were reviewed to obtain relevant demographic and clinical data, including the presence of gestational hypertensive disorders and neonatal outcomes at birth. Subjects who "always" experienced RLS were compared with subjects experiencing symptoms less frequently or not at all with respect to prevalence of gestational hypertensive disorder.

FINDINGS

The mean ([SD]) age, prepregnancy body mass index (BMI), and BMI at delivery were 29.0 (6.1) years, 26.1 (6.2) kg/m(2), and 32.0 (6.3) kg/m(2), respectively. The overall prevalence of the RLS surrogate (jumpy or jerky leg movements) was 35.5% with the following distribution on a Likert scale: score 1 = 6.4%; score 2 = 10.2%; score 3 = 8.1%; and score 4 = 10.8%. Chronic hypertension was present in 2.1%, pregnancy-induced hypertension in 9.5%, and preeclampsia in 4.5% of respondents. Subjects who reported "always" having sensations of jumpy or jerky legs were more likely to have gestational hypertensive disorders compared with those who reported less frequent occurrence of the symptoms. Adjusted odds ratios were 3.74 (95% CI, 1.31-10.72; P = 0.014) for chronic hypertension; 1.26 (95% CI, 0.65-2.46; P = 0.487) for pregnancy-induced hypertension; and 2.15 (95% CI, 0.97-4.75; P = 0.060) for preeclampsia. There was a significant association between leg movement score and neonatal birth weight (coefficient, -149.5 g [95% CI, -276.9 to -22.5]; P = 0.005) and gestational age at birth (-0.7 week [95% CI, -1.1 to -0.2]; P = 0.021) that persisted after adjusting for preeclampsia, diabetes, and smoking.

IMPLICATIONS

A higher frequency of jumpy or jerky leg symptoms, a proxy for RLS during pregnancy, was associated with a higher likelihood of gestational hypertensive disorders and neonatal outcomes such as gestational age at birth and birth weight. These findings may affect RLS treatment decisions during pregnancy.

Impaired vascular endothelial function in patients with restless legs syndrome: a new aspect of the vascular pathophysiology

BACKGROUND

Restless legs syndrome (RLS) is a common sleep disorder in which patients feel unpleasant leg sensations and the urge to move their legs during rest, particularly at night. Leg movement improves these symptoms. Although several studies have demonstrated an association between cardiovascular disease and RLS, the mechanisms underlying this relationship remain unclear. Recent studies have shown changes in the peripheral microvasculature, including altered blood flow and capillary tortuosity, and peripheral hypoxia. Vascular endothelial dysfunction can be assessed noninvasively with ultrasound measurements of brachial artery flow-mediated dilatation (FMD). Therefore, this study investigated FMD in RLS patients to determine the involvement of microvascular alterations in this disorder.

METHODS

The study enrolled 25 drug-naïve RLS patients and 25 sex- and age-matched controls and compared the FMD values of the two groups. RLS was diagnosed according to the criteria of the International Restless Legs Syndrome Study Group.

RESULTS

FMD was significantly lower in the RLS patients (6.6 ± 1.2%) compared to the controls (8.4 ± 1.8%; p<0.05) and the RLS patients showed a weak, negative correlation between RLS severity and FMD (r=-0.419, p=0.04). Multivariate linear regression analysis revealed that RLS (B=-1.87, 95% confidence interval [CI] -2.72 to -1.02; p<0.001) and age (B=-0.06; 95% CI -0.12 to -0.02; p<0.001) were significantly and inversely correlated with FMD.

CONCLUSIONS

This study demonstrated that RLS patients have poorer vascular endothelial function than normal healthy subjects and provides further evidence supporting the involvement of peripheral systems in the generation of RLS.

Autonomic Function Tests and MIBG in Parkinson's Disease: Correlation to Disease Duration and Motor Symptoms

AIMS

Disorders of the autonomic nervous system (ANS) have a variable degree of clinical relevance in patients with Parkinson's disease (PD). Here, we assessed whether subclinical autonomic dysfunction, as evaluated by a complete battery of autonomic function tests (AFTs), correlates with PD progression.

METHODS

A series of 27 consecutive patients with PD underwent extensive ANS investigations including the head-up tilt test (HUTT), Valsalva maneuver, deep-breathing test, and handgrip test (HG); further, they performed 123I-meta-iodobenzylguanidine (MIBG) scintigraphy.

RESULTS

Seven of the 27 patients showed orthostatic hypotension (OH) at HUTT and pathological responses to the deep-breathing and HG test and Valsalva maneuver. The majority of the remaining 20 patients with PD showed pathological responses to deep-breathing (n = 13) and/or HG (n = 11). Only 3 of 27 suffered relevant OH. MIBG uptake of myocardium was decreased in 19 patients with PD (H/M ratio 1.3 ± 0.2). Prolonged clinical observation (>3 years), persistent response to levodopa, and MIBG repetition allowed us to exclude negative MIBG as attributable to atypical Parkinsonism. MIBG uptake did not correlate with OH and other AFTs. Both HG test response and MIBG did correlate with the Unified Parkinson's Disease Rating Scale (UPDRS) motor score and disease duration. A positive correlation emerged between diastolic blood pressure (DBP) response to HG test and MIBG and with systolic blood pressure (SBP) response at tilt test.

CONCLUSIONS

Our investigation suggests that ANS impairment affects the majority of patients with PD, even those PD patients showing negative MIBG, irrespective of clinical neurovegetative symptoms. The strict correlation that has been revealed with disease progression supports the routine utilization of AFTs as a reliable and inexpensive tool for monitoring peripheral sympathetic dysfunction in PD and optimizing therapy.