Blood pressure profile and endothelial function in restless legs syndrome

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.

Restless legs syndrome: From clinic to personalized medicine

Restless legs syndrome (RLS) is a common neurological sensorimotor disorder that impairs sleep, mood and quality of life. RLS is defined by an urge to move the legs at rest that increases in the evening and at night, and is frequently associated with metabolic and cardiovascular diseases. Symptoms frequency, age at RLS onset, severity, familial history and consequences of RLS vary widely between patients. A genetic susceptibility, iron deficiency, dopamine deregulation, and possible hypo-adenosinergic state may play a role in the pathophysiology of RLS. Polysomnographic recordings found often periodic leg movements during sleep and wakefulness in patients with RLS. RLS can be classified as primary or comorbid with major diseases: iron deficiency, renal, neurological, rheumatological and lung diseases. First-line treatments are low-dose dopamine agonists, and alpha-2-delta ligands depending on the clinical context, and second/third line opiates for pharmacoresistant forms of RLS. Augmentation syndrome is a serious complication of dopamine agonists and should be prevented by using the recommended low dose. Despite an increase in knowledge, RLS is still underdiagnosed, poorly recognized, resulting in substantial individual health burden and socioeconomic coast, and education is urgently needed to increase awareness of this disabling disorder.

Polysomnographic features of idiopathic restless legs syndrome: a systematic review and meta-analysis of 13 sleep parameters and 23 leg movement parameters

STUDY OBJECTIVES

This study aims to explore the polysomnographically measured sleep and leg movement differences between idiopathic restless legs syndrome (RLS) patients and healthy controls.

METHODS

An electronic literature search was conducted in EMBASE, MEDLINE, all EBM databases, CINAHL, and PsycINFO. Only observational case-control studies were included in the meta-analysis. The differences in 13 sleep parameters and 23 leg movement parameters between RLS patients and healthy controls were explored.

RESULTS

Thirty-eight studies were identified for systematic review, 31 of which were used for meta-analysis. Meta-analyses revealed significant reductions in total sleep time, sleep efficiency, stage N2 and rapid eye movement (REM) sleep percentages, and increases in wake time after sleep onset, stage shifts per hour, stage N1 percentage, REM latency, arousal index, and apnea-hypopnea index. Some leg movement parameters, such as periodic limb movement during sleep (PLMS) index, PLMS sequence duration, number of PLMS sequence, and periodicity index, were higher in RLS patients compared with healthy controls. Further, our meta-analysis revealed a higher PLMS index during non-REM sleep compared with that during REM sleep.

CONCLUSIONS

RLS patients manifest a lightening of sleep, increased sleep fragmentation, and greater sleep-related breathing disruption and limb movements during sleep relative to healthy normal individuals. The distributions of PLMS during a night's sleep may provide more information to clarify the specific characteristics of leg movements in RLS. PLMS in RLS are concentrated in non-REM sleep. The periodicity index may be a more sensitive and specific marker of RLS than the PLMS index.

CITATION

Zhang H, Zhang Y, Ren R, et al. Polysomnographic features of idiopathic restless legs syndrome: a systematic review and meta-analysis of 13 sleep parameters and 23 leg movement parameters. J Clin Sleep Med. 2022;18(11):2561-2575.

Polysomnographic nighttime features of Restless Legs Syndrome: A systematic review and meta-analysis

Background

Restless Legs Syndrome (RLS) is a common sleep disorder. Polysomnographic (PSG) studies have been used to explore the night sleep characteristics of RLS, but their relationship with RLS has not been fully analyzed and researched.

Methods

We searched the Cochrane Library electronic literature, PubMed, and EMBASE databases to identify research literature comparing the differences in polysomnography between patients with RLS and healthy controls (HCs).

Results

This review identified 26 studies for meta-analysis. Our research found that the rapid eye movement sleep (REM)%, sleep efficiency (SE)%, total sleep time (TST) min, and N2 were significantly decreased in patients with RLS compared with HCs, while sleep latency (SL) min, stage shifts (SS), awakenings number (AWN), wake time after sleep onset (WASO) min, N1%, rapid eye movement sleep latency (REML), and arousal index (AI) were significantly increased. Additionally, there was no significant difference among N3%, slow wave sleep (SWS)%, and apnea-hypopnea index (AHI).

Conclusion

Our findings demonstrated that architecture and sleep continuity had been disturbed in patients with RLS, which further illustrates the changes in sleep structure in patients with RLS. In addition, further attention to the underlying pathophysiological mechanisms of RLS and its association with neurodegenerative diseases is needed in future studies.

A pilot study to understand the relationship between cortical arousals and leg movements during sleep

Leg movements during sleep occur in patients with sleep pathology and healthy individuals. Some (but not all) leg movements during sleep are related to cortical arousals which occur without conscious awareness but have a significant effect of sleep fragmentation. Detecting leg movements during sleep that are associated with cortical arousals can provide unique insight into the nature and quality of sleep. In this study, a novel leg movement monitor that uses a unique capacitive displacement sensor and 6-axis inertial measurement unit, is used in conjunction with polysomnography to understand the relationship between leg movement and electroencephalogram (EEG) defined cortical arousals. In an approach that we call neuro-extremity analysis, directed connectivity metrics are used to interrogate causal linkages between EEG and leg movements measured by the leg movement sensors. The capacitive displacement measures were more closely related to EEG-defined cortical arousals than inertial measurements. Second, the neuro-extremity analysis reveals a temporally evolving connectivity pattern that is consistent with a model of cortical arousals in which brainstem dysfunction leads to near-instantaneous leg movements and a delayed, filtered signal to the cortex leading to the cortical arousal during sleep.

RestEaze: An Emerging Technology to Characterize Leg Movements During Sleep

Several sleep disorders are characterized by periodic leg movements during sleep including Restless Leg Syndrome, and can indicate disrupted sleep in otherwise healthy individuals. Current technologies to measure periodic leg movements during sleep are limited. Polysomnography and some home sleep tests use surface electromyography to measure electrical activity from the anterior tibilias muscle. Actigraphy uses 3-axis accelerometers to measure movement of the ankle. Electromyography misses periodic leg movements that involve other leg muscles and is obtrusive because of the wires needed to carry the signal. Actigraphy based devices require large amplitude movements of the ankle to detect leg movements (missing the significant number of more subtle leg movements) and can be worn in multiple configurations precluding precision measurement. These limitations have contributed to their lack of adoption as a standard of care for several sleep disorders. In this study, we develop the RestEaze sleep assessment tool as an ankle-worn wearable device that combines capacitive sensors and a 6-axis inertial measurement unit to precisely measure periodic leg movements during sleep. This unique combination of sensors and the form-factor of the device addresses current limitations of periodic leg movements during sleep measurement techniques. Pilot data collected shows high correlation with polysomnography across a heterogeneous participant sample and high usability ratings. RestEaze shows promise in providing ecologically valid, longitudinal measures of leg movements that will be useful for clinicians, researchers, and patients to better understand sleep.

Restless legs syndrome

Restless legs syndrome (RLS) is a common sensorimotor disorder characterized by an urge to move that appears during rest or is exacerbated by rest, that occurs in the evening or night and that disappears during movement or is improved by movement. Symptoms vary considerably in age at onset, frequency and severity, with severe forms affecting sleep, quality of life and mood. Patients with RLS often display periodic leg movements during sleep or resting wakefulness. RLS is considered to be a complex condition in which predisposing genetic factors, environmental factors and comorbidities contribute to the expression of the disorder. RLS occurs alone or with comorbidities, for example, iron deficiency and kidney disease, but also with cardiovascular diseases, diabetes mellitus and neurological, rheumatological and respiratory disorders. The pathophysiology is still unclear, with the involvement of brain iron deficiency, dysfunction in the dopaminergic and nociceptive systems and altered adenosine and glutamatergic pathways as hypotheses being investigated. RLS is poorly recognized by physicians and it is accordingly often incorrectly diagnosed and managed. Treatment guidelines recommend initiation of therapy with low doses of dopamine agonists or α₂δ ligands in severe forms. Although dopaminergic treatment is initially highly effective, its long-term use can result in a serious worsening of symptoms known as augmentation. Other treatments include opioids and iron preparations.

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.

Effects of insomnia and restless legs syndrome on sleep arterial blood pressure: A systematic review and meta-analysis

Hypertension and blunted blood pressure (BP) dipping during nighttime sleep are associated with increased cardiovascular risk. Chronic insomnia and restless legs syndrome (RLS) may affect the 24-h BP profile. We systematically reviewed the association of insomnia and RLS with BP values during nighttime sleep and the relative BP dipping pattern. We searched relevant articles in any language with selection criteria including enrolment of subjects with insomnia or RLS and with obstructive sleep apnea comorbidity assessment. Of the 872 studies originally retrieved, seven were selected. Four studies enrolled subjects with insomnia. One study relied on sleep diaries to classify nighttime sleep BP, whereas three relied only on clock time. At meta-analysis, subjects with insomnia displayed an attenuated dipping of systolic BP (-2.00%; 95% confidence interval (CI): -3.61 - -0.39%) and diastolic BP (-1.58%; 95% CI: -2.66 ̶ -0.49%) during nighttime sleep compared to controls. Three studies enrolled subjects with RLS. One study relied on polysomnography to classify nighttime sleep BP, whereas two relied only on clock time. Subjects with RLS showed increases in nighttime sleep systolic BP (5.61 mm Hg, 95% CI 0.13̶-11.09 mm Hg) compared to controls. In conclusion, the limited available data suggest that insomnia and RLS are both associated with altered BP control during nighttime sleep. There is need for more clinical studies to confirm these findings, specifically focusing on measurements of BP during objectively defined sleep, on causal roles of leg movements during sleep and alterations in sleep architecture, and on implications for cardiovascular risk. PROSPERO ACKNOWLEDGEMENT OF NUMBER: CRD42020217947.

Cardiovascular disorders in narcolepsy: Review of associations and determinants

Narcolepsy type 1 (NT1) is a lifelong disorder of sleep-wake dysregulation defined by clinical symptoms, neurophysiological findings, and low hypocretin levels. Besides a role in sleep, hypocretins are also involved in regulation of heart rate and blood pressure. This literature review examines data on the autonomic effects of hypocretin deficiency and evidence about how narcolepsy is associated with multiple cardiovascular risk factors and comorbidities, including cardiovascular disease. An important impact in NT1 is lack of nocturnal blood pressure dipping, which has been associated with mortality in the general population. Hypertension is also prevalent in NT1. Furthermore, disrupted nighttime sleep and excessive daytime sleepiness, which are characteristic of narcolepsy, may increase cardiovascular risk. Patients with narcolepsy also often present with other comorbidities (eg, obesity, diabetes, depression, other sleep disorders) that may contribute to increased cardiovascular risk. Management of multimorbidity in patients with narcolepsy should include regular assessment of cardiovascular health (including ambulatory blood pressure monitoring), mitigation of cardiovascular risk factors (eg, cessation of smoking and other lifestyle changes, sleep hygiene, and pharmacotherapy), and prescription of a regimen of narcolepsy medications that balances symptomatic benefits with cardiovascular safety.

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.

Increased Blood Pressure Dipping in Restless Legs Syndrome With Rotigotine: A Randomized Trial

OBJECTIVE

The objective of this study was to assess the rotigotine effect on the nocturnal blood pressure (BP) dip by 24-hour ambulatory BP monitoring and on endothelial function in patients with restless legs syndrome (RLS) compared with placebo.

METHODS

In this double-blind, placebo-controlled trial, 76 adult patients with moderate to severe RLS and periodic legs movements in sleep index ≥10/hour were randomized to rotigotine at optimal dose of 3 mg per day or placebo for 6 weeks. A total of 6 patients had a major protocol deviation. Polysomnography, ambulatory BP monitoring, and endothelial function were assessed at baseline and end point. The primary outcome was the between-group difference in the percentage of BP nondipper profiles at end point. The main secondary outcomes were the mean BP dip, periodic legs movements in sleep index, and endothelial function.

RESULTS

Of the 70 patients (age, 59.4 ± 11.40; 43 women) randomized to rotigotine (n = 34) and placebo (n = 36), 66 (33 rotigotine, 33 placebo) completed the study. The percentage of BP nondippers at end point was higher in the placebo than in the rotigotine group (systolic BP, 72.22% vs 47.06%; diastolic BP, 47.22% vs 20.59%; P < 0.05). Mean BP dip at end point was higher in the rotigotine than in the placebo group (systolic BP, 11.24 ± 6.15 vs 6.12 ± 7.98; diastolic BP, 15.12 ± 7.09 vs 9.36 ± 10.23; P < 0.05). Endothelial function was comparable between the groups. No significant safety concerns were reported with similar incidences of adverse events between groups.

CONCLUSION

Rotigotine increased the percentage of BP dipper profiles and the BP dip in patients with RLS. Future studies should assess whether this change is associated with a reduction in the long-term cardiovascular risk in RLS. © 2020 International Parkinson and Movement Disorder Society.

Restless Legs Syndrome across the Lifespan: Symptoms, Pathophysiology, Management and Daily Life Impact of the Different Patterns of Disease Presentation

Restless legs syndrome is a common but still underdiagnosed neurologic disorder, characterized by peculiar symptoms typically occurring in the evening and at night, and resulting in sleep disruption and daily functioning impairment. This disease can affect subjects of all age ranges and of both sexes, manifesting itself with a broad spectrum of severity and deserving special attention in certain patient categories, in order to achieve a correct diagnosis and an effective treatment. The diagnosis of restless legs syndrome can be challenging in some patients, especially children and elderly people, and an effective treatment might be far from being easy to achieve after some years of drug therapy, notably when dopaminergic agents are used. Moreover, the pathophysiology of this disorder offers an interesting example of interaction between genetics and the environment, considering strong iron metabolism involvement and its interaction with recognized individual genetic factors. Therefore, this syndrome allows clinicians to verify how lifespan and time can modify diagnosis and treatment of a neurological disorder.

The Importance of Sleep Fragmentation on the Hemodynamic Dipping in Obstructive Sleep Apnea Patients

Introduction

Obstructive sleep apnea (OSA) has been associated with non-dipping blood pressure (BP). The precise mechanism is still under investigation, but repetitive oxygen desaturation and arousal induced sleep fragmentation are considered the main contributors.

Methods

We analyzed beat-to-beat measurements of hemodynamic parameters (HPs) during a 25-min period of wake–sleep transition. Differences in the mean HP values for heart rate (HR), systolic BP (SBP), and stroke volume (SV) during wake and sleep and their standard deviations (SDs) were compared between 34 controls (C) and 22 OSA patients. The Student’s t-test for independent samples and the effect size by Cohen’s d (d) were calculated. HP evolution was investigated by plotting the measured HP values against each consecutive pulse wave. After a simple regression analysis, the calculated coefficient beta (SCB) was used to indicate the HP evolution. We furthermore explored by a hierarchical block regression which variables increased the prediction for the SCB: model 1 BMI and age, model 2 + apnea/hypopnea index (AHI), and model 3 + arousal index (AI).

Results

Between the two groups, the SBP increased in OSA and decreased in C resulting in a significant difference (p = 0.001; d = 0.92). The SV demonstrated a similar development (p = 0.047; d = 0.56). The wake/sleep variation of the HP measured by the SD was higher in the OSA group—HR: p < 0.001; d = 1.2; SBP: p = 0.001; d = 0.94; and SV: p = 0.005; d = 0.82. The hierarchical regression analysis of the SCB demonstrated in SBP that the addition of AI to AHI resulted in ΔR²: +0.163 and ΔF + 13.257 (p = 0.001) and for SV ΔR²: +0.07 and ΔF 4.83 (p = 0.003). The AI but not the AHI remained statistically significant in the regression analysis model 3—SBP: β = 0.717, p = 0.001; SV: β = 0.469, p = 0.033.

Conclusion

In this study, we demonstrated that in OSA, the physiological dipping in SBP and SV decreased, and the variation of all investigated parameters increased. Hierarchical regression analysis indicates that the addition of the AI to BMI, age, and AHI increases the prediction of the HP evolution following sleep onset for both SBP and SV and may be the most important variable.