The relationship among restless legs syndrome (Willis-Ekbom Disease), hypertension, cardiovascular disease, and cerebrovascular disease. J Neurol. 2014;261:1051-1068. [PMID: 23963470 DOI: 10.1007/s00415-013-7065-1]

Unveiling the pathophysiology of restless legs syndrome through transcriptome analysis

The aim of this study was to analyze signaling pathways associated with differentially expressed messenger RNAs in people with restless legs syndrome (RLS). Seventeen RLS patients and 18 controls were enrolled. Coding RNA expression profiling of 12,857 gene transcripts by next-generation sequencing was performed. Enrichment analysis by pathfindR tool was carried-out, with p-adjusted ≤0.001 and fold-change ≥2.5. Nine main different network groups were significantly dysregulated in RLS: infections, inflammation, immunology, neurodegeneration, cancer, neurotransmission and biological, blood and metabolic mechanisms. Genetic predisposition plays a key role in RLS and evidence indicates its inflammatory nature; the high involvement of mainly neurotropic viruses and the TORCH complex might trigger inflammatory/immune reactions in genetically predisposed subjects and activate a series of biological pathways-especially IL-17, receptor potential channels, nuclear factor kappa-light-chain-enhancer of activated B cells, NOD-like receptor, mitogen-activated protein kinase, p53, mitophagy, and ferroptosis-involved in neurotransmitter mechanisms, synaptic plasticity, axon guidance, neurodegeneration, carcinogenesis, and metabolism.

Systolic blood pressure is associated with abnormal alterations in brain cortical structure: Evidence from a Mendelian randomization study

BACKGROUND

Hypertension has been recognized as a significant risk factor for cerebrovascular diseases and cognitive decline. However, the specific impact of hypertension, systolic/diastolic blood pressure, pulse pressure (PP) and mean arterial pressure (MAP) on brain cortical structure remains unclear. Mendelian randomization (MR) provides a robust approach to investigate the causal relationship between blood pressure components and brain cortical changes.

METHODS

In this MR study, data from large-scale genome-wide association studies for blood pressure components and neuroimaging were utilized to conduct our analyses. We leveraged genetic variants associated specifically with hypertension (122,620 cases and 332,683 controls), systolic (469,767 individuals), diastolic (490,469 individuals) blood pressure, PP (810,865 individuals) and MAP (over 1 million individuals) to evaluate their effects on brain cortex surficial area (51,665 individuals) and cortex thickness (51,665 individuals).

RESULTS

Our findings revealed a significant correlation between systolic blood pressure and abnormal reduction in brain cortex surficial area (β=-1330.69, 95% confident interval [CI]: -2655.35 to -6.02, p = 0.0489); however, no significant relationship was found between systolic blood pressure and brain cortex thickness (β=-0.0078, 95% CI: -0.0178 to 0.0022, p = 0.1287). Additionally, no significant associations were observed between hypertension (β=-200.05, p = 0.6884; β=-0.0051, p = 0.1179, respectively), diastolic blood pressure (β=-460.63, p = 0.5160; β=0.0047, p = 0.2448, respectively), PP (β=1041.84, p = 0.3725; β=-0.0112, p = 0.2212, respectively), MAP (β=-18.84, p = 0.8841; β=0.0002, p = 0.7654, respectively) and both brain cortex surficial area and brain cortex thickness.

CONCLUSION

Our MR study provides evidence supporting the hypothesis that systolic blood pressure, rather than diastolic blood pressure, PP or MAP, is associated with abnormal changes in brain cortical structure.

A nationwide study on the prevalence and contributing factors of obstructive sleep apnea in Iran

Reliable obstructive sleep apnea (OSA) prevalence information in Iran is lacking due to inconsistent local study results. To estimate OSA prevalence and identify clinical phenotypes, we conducted a nationally representative study using multi-stage random cluster sampling. We recruited 3198 individuals and extrapolated the results to the entire Iranian population using complex sample survey analyses. We identified 3 clinical phenotypes as "sleepy," "insomnia," and "restless legs syndrome (RLS)." The prevalence of OSA was 28.7% (95%CI: 26.8-30.6). The prevalence of "sleepy," "insomnia," and "RLS" phenotypes were 82.3%, 77.8%, and 36.5% in women, and 64.8%, 67.5%, and 17.9% in men, respectively. "Sleepy" and "insomnia" phenotypes overlapped the most. Age (OR: 1.9), male sex (OR: 3.8), BMI (OR: 1.13), neck circumference (OR: 1.3), RLS (OR: 2.0), and insomnia (OR: 2.3) were significant OSA predictors (p-values: 0.001). In men, "sleepy" phenotype was associated with youth and unmarried status but not in women. The "insomnia" phenotype was associated with shorter sleep duration in women; cardiovascular diseases (CVD), urban residency, and shorter sleep duration in men. "RLS" phenotype was associated with shorter sleep duration and CVD in women and older age, lower educational level, CVD, and hypertension in men. The findings point to the need for funding of OSA screening in Iran, for a different assessment of men and women, and for future sleep research to consider overlapping phenotypes.

Periodic Limb Movements during Sleep in Acute Stroke: Prevalence, Severity and Impact on Post-Stroke Recovery

BACKGROUND

Periodic Limb Movements during Sleep (PLMS) have been described to be frequently present in stroke patients. We aimed to evaluate the prevalence and severity of PLMS in acute stroke patients and clarify the association between PLMS and coexisting Sleep Disordered Breathing (SDB). Additionally, we focused on identifying variables that could independently predict the presence of PLMS in patients with acute stroke. The potential impact of PLMS on stroke outcome at three months was investigated as well.

METHODS

In this study, we performed overnight polysomnography on consecutive stroke patients within 72 h from symptom onset. Data regarding clinical and imaging characteristics were prospectively collected. National Institute of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS) and Epworth-Sleepiness Scale (ESS) were used to evaluate stroke severity on admission, stroke outcome at three months and history of daytime sleepiness, respectively. We documented PLMS and SDB using standard polysomnography criteria.

RESULTS

We prospectively assessed 126 patients with acute stroke [109 with ischemic and 17 with hemorrhagic stroke, mean age 60 ± 11 years, 68% men, median NIHSS score on admission: 3 (IQR: 2-7)]. The overall rate of PLMS in our cohort was 76%, and the rate of SDB among patients with PLMS was 83%. PLMS detection rates differed significantly (p-value: <0.001) according to SDB, with PLMS prevalence increasing with greater SDB severity. SDB could independently (OR:4.869, 95% CI: 1.884-12.784, p-value: 0.001) predict the presence of PLMS in the acute stroke phase in multivariable analyses adjusting for potential confounders. Moreover, baseline stroke severity (NIHSS-score increase in per-1 point: OR: 0.819, 95% CI: 0.737-0.895, p-value < 0.001) and PLMS (OR:0.099, 95% CI: 0.009-0.482, p-value = 0.015) were significantly associated with the likelihood of excellent functional outcome (mRS-scores: 0-1) at 3 months.

CONCLUSION

The common presence of mostly severe PLMS in patients with acute stroke and their negative effect on stroke outcomes point out the necessity for early PLMS detection and treatment.

Restless legs syndrome after acute ıschemic stroke and ıts relation to lesion location

Purpose

We aimed to investigate the prevalence, clinical profiles and lesion location of Restless Legs Syndrome (RLS) developed after ischemic stroke.

Methods

This study prospectively included 244 patients with acute cerebral infarction. All patients were evaluated for RLS, and those who met all of the essential diagnostic criteria of the International RLS Study Group were diagnosed with RLS. The evaluation of lesion location was performed by magnetic resonance imaging. International Restless Legs Syndrome Rating Scale was performed 1 week, 1 month, and 3 months after the index stroke to determine the symptom severity of the patients and to observe the exacerbation or regression in follow-up.

Results

A total of 14 patients (5.7%) had post-stroke RLS (psRLS). The psRLS group consisted mostly of males (9 males, 5 females). Among the patients with psRLS, 12 had a subcortical stroke (9.2%, 130 patients) whereas only 2 had a cortical stroke (1.8%, 114 patients) (p = 0.01). The subcortical lesion locations in the psRLS group were the pons, basal ganglia and/or corona radiata, thalamus, and cerebellum in order of decreasing frequency. Five patients had symptoms in both legs, and 9 patients had symptoms in unilateral legs (7 contralateral, 2 ipsilateral to the lesion). At follow-up, the symptoms of 6 patients resolved completely without medication, 5 patients responded well to pramipexole and 1 patient responded poorly. Only 2 patients who refused to take medication had worsened symptoms.

Conclusion

The subcortical ischemic lesions are associated with psRLS. Pons, basal ganglia and corona radiata are the structures more likely to cause RLS.

Restless legs syndrome due to brainstem stroke: A systematic review

Restless Legs Syndrome (RLS) is a sleep-related movement disorder, which can also result from brainstem pathology. A systematic review of articles published in the electronic databases PubMed and Web of Science was conducted to summarize the existent literature on RLS associated with a brainstem stroke. We identified eight articles including 19 subjects with RLS due to brainstem ischemic lesion. The symptoms occurred simultaneously with the infarction (66.7%) or few days after (33.3%). The most common location of infarction was pons and less commonly medulla. In most cases (68.4%), symptoms were unilateral. In the majority of those cases (92.3%), the contralateral limb was affected due to a lateral pons infarction. RLS symptoms after infarction improved or resolved in almost 90% of cases within a few days up to 3 months. In almost all patients who received dopaminergic treatment (11 out of 13, 91.7%), the symptoms improved significantly or resolved completely. Screening for RLS has to be considered in patients suffering a brainstem stroke, particularly anteromedial pontine infarction. The appearance of acute unilateral RLS symptoms, usually in association with other sensorimotor deficits, should prompt the clinician to consider a vascular event in the brainstem. RLS in these cases seem to have a favorable outcome and respond well to dopaminergic treatment.

Restless legs syndrome: Over 50 years of European contribution

Restless legs syndrome (RLS) is a sensorimotor neurological disorder characterised by an urge to move the limbs with a circadian pattern (occurring in the evening/at night), more prominent at rest, and relieved with movements. RLS is one of the most prevalent sleep disorders, occurring in 5%-10% of the European population. Thomas Willis first described RLS clinical cases already in the 17th century, and Karl-Axel Ekbom described the disease as a modern clinical entity in the 20th century. Despite variable severity, RLS can markedly affect sleep (partly through the presence of periodic leg movements) and quality of life, with a relevant socio-economic impact. Thus, its recognition and treatment are essential. However, screening methods present limitations and should be improved. Moreover, available RLS treatment options albeit providing sustained relief to many patients are limited in number. Additionally, the development of augmentation with dopamine agonists represents a major treatment problem. A better understanding of RLS pathomechanisms can bring to light novel treatment possibilities. With emerging new avenues of research in pharmacology, imaging, genetics, and animal models of RLS, this is an interesting and constantly growing field of research. This review will update the reader on the current state of RLS clinical practice and research, with a special focus on the contribution of European researchers.

Restless legs syndrome is associated with long-COVID in women

STUDY OBJECTIVES

Sleep disturbance is common in long-COVID (LC). Restless legs syndrome (RLS) is characterized by sleep disturbance and has been reported after viral infections. Therefore, we evaluated RLS symptoms cross-sectionally in individuals with LC at both current and pre-coronavirus disease 2019 (pre-COVID-19) time points.

METHODS

Adults on LC-focused Facebook pages were recruited for an online assessment of symptoms before COVID-19 infection and during their present LC state in a cross-sectional manner. The LC group documented baseline symptoms retrospectively. Questions were included about the presence/severity of RLS symptoms and assessments of fatigue, quality of life, and sleep apnea. A control group was recruited and included individuals ≥ 18 years of age who never had overt symptoms of COVID-19. Pregnancy was an exclusion criterion for both groups.

RESULTS

There were 136 participants with LC (89.7% females, age 46.9 ± 12.9 years) and 136 controls (65.4% females, age 49.2 ± 15.5). RLS prevalence in females with LC was 5.7% pre-COVID-19 and 14.8% post-COVID-19 (P < .01) vs 6.7% in control females. Severity of RLS was moderate in both groups. Logistic regression predicting post-COVID-19 RLS among females with LC failed to find significant effects of hospitalization, sleep apnea, neuropathic pain severity, or use of antihistamines and antidepressants.

CONCLUSIONS

The baseline prevalence of RLS in females with LC was similar to the general population group as well as to patients in epidemiological studies. The prevalence significantly increased in the LC state. Postinfectious immunological mechanisms may be at play in the production for RLS symptoms.

CITATION

Weinstock LB, Brook JB, Walters AS, Goris A, Afrin LB, Molderings GJ. Restless legs syndrome is associated with long-COVID in women. J Clin Sleep Med. 2022;18(5):1413-1418.

Automated identification of sleep disorders using wavelet-based features extracted from electrooculogram and electromyogram signals

Sleep is imperative for a healthy life as it rejuvenates memory, cognitive performance, cell repair and eliminates waste from the muscles. Sleep-related disorders such as insomnia, narcolepsy, sleep-disordered breathing (SDB), periodic leg movement (PLM), and bruxism lead to hormonal imbalance, slower reaction time, memory problems, depression, and headaches. This adversity of sleep disorder gained the attention of many sleep researchers. To examine the reasons for sleep disorders, it is imperative to monitor and analyze the sleep of the affected patients. The conventional method of monitoring sleep and identifying the sleep disorders using polysomnographic (PSG) recording is a complicated and cumbersome task in which multiple physiological signals with multiple modalities are recorded for a long (overnight) duration. The PSG recordings are carried out in sophisticated sleep laboratories and cannot be considered suitable for real-time sleep monitoring. Thus, a simple and patient-convenient system is highly desirable to monitor and analyze the quality of sleep. We proposed an automatic detection of sleep disorders using single modal electrooculogram (EOG) and electromyogram (EMG) signals. We have used a new maximally flat multiplier-less biorthogonal filter bank for obtaining discrete wavelet transform of the signals. We computed Hjorth parameters (HOP) such as activity, mobility, and complexity from the wavelet sub-bands. Highly discriminative HOP features are fed to different machine learning classifiers to develop the model. Our results show that the developed system can classify insomnia, narcolepsy, NFLE, PLM, and REM behaviour disorder (RBD) against normal healthy subjects with an accuracy of 99.7%, 97.6%, 97.5%, 97.5%, and 98.3%, respectively using combined features from EOG and EMG signal. The proposed model has yielded an accuracy of 94.3% in classifying six classes using an ensemble bagged trees classifier (EBTC) with a 10-fold cross-validation technique. Hence, EOG and EMG-based proposed methods can be deployed in a portable home-based environment to identify the type of sleep disorders automatically.

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.

Restless legs syndrome/Willis-Ekbom disease among patients with resistant hypertension versus stroke patients-a prospective study

BACKGROUND

Epidemiological studies have shown an increased prevalence and incidence of hypertension as well as a higher incidence of stroke among patients suffering from RLS. The objective of this study was to estimate the prevalence of RLS among patients with resistant hypertension (RH) and compare the clinical characteristics of these patients with patients of stroke pre-existing RLS and with patients with primary RLS presenting to the Sleep clinic.

METHODS

Consecutive patients with RH (without any identifiable cause on extensive work up) and consecutive in-patients with stroke were enrolled over a 3-year-period. Patients with RH fulfilling revised-IRLSSG-criteria for RLS comprised group 1 and those with stroke and RLS formed group 2. These were compared with patients diagnosed to have idiopathic RLS (iRLS) (Group 3). Prevalence of RLS in groups 1 and 2 and RLS characteristics in all groups were compared.

RESULTS

Sixteen out of 56 RH patients (29%) formed group 1 and 43 out 346 of stroke patients (12%) formed group 2, while 43 consecutive iRLS patients were included in group 3. Age was significantly higher, with male dominance in group 2. Median age at symptom onset was significantly lower in group 1. Positive family history was similar in RH and iRLS patients and was significantly less common in stroke patients. Asymmetrical/unilateral distribution of symptoms was significantly more common in stroke group, compared to RH and iRLS groups.

CONCLUSION

This study demonstrated a high prevalence of RLS among patients with resistant hypertension. RLS characteristics are different from those in patients with stroke, and very similar to primary RLS.

Ischemic Stroke and Sleep: The Linking Genetic Factors

This review summarizes the available data about genetic factors which can link ischemic stroke and sleep. Sleep patterns (subjective and objective measures) are characterized by heritability and comprise up to 38-46%. According to Mendelian randomization analysis, genetic liability for short sleep duration and frequent insomnia symptoms is associated with ischemic stroke (predominantly of large artery subtype). The potential genetic links include variants of circadian genes, genes encoding components of neurotransmitter systems, common cardiovascular risk factors, as well as specific genetic factors related to certain sleep disorders.

Restless Legs Syndrome Shows Increased Silent Postmortem Cerebral Microvascular Disease With Gliosis

Background

Patients with restless legs syndrome (RLS) have increased silent microvascular disease by magnetic resonance imaging. However, there has been no previous autopsy confirmation of these magnetic resonance imaging findings. RLS is also frequently associated with inflammatory and immunologically mediated medical disorders. The postmortem cortex in patients with RLS was therefore evaluated for evidence of microvascular and immunological changes.

Methods and Results

Ten microvascular injury samples of precentral gyrus in 5 patients with RLS (3 men, 2 women; mean age, 81 years) and 9 controls (2 men, 7 women; mean age, 90 years) were studied by hematoxylin and eosin stains in a blinded fashion. None of the subjects had a history of stroke or neurologic insults. In a similar manner, the following immunohistochemistry stains were performed: (1) glial fibrillary acidic protein (representing gliosis, reactive change of glial cells in response to damage); (2) CD3 (a T‐cell marker); (3) CD19 (a B‐cell marker); (4) CD68 (a macrophage marker); and (5) CD117 (a mast cell marker). Patients with RLS had significantly greater silent microvascular disease (P=0.015) and gliosis (P=0.003). T cells were increased in RLS compared with controls (P=0.009) and tended to colocalize with microvascular disease (P=0.003). Other markers did not differ. There was no correlation between microvascular lesion load and RLS severity or duration.

Conclusions

Patients with RLS had statistically significantly more silent cerebral microvascular disease and gliosis than controls compatible with previous magnetic resonance imaging studies and with studies showing a link between RLS and hypertension, clinical stroke, and cardiovascular disease. T‐cell invasion may be a secondary phenomenon.

Treating Restless Legs Syndrome Was Associated With Low Risk of Cardiovascular Disease: A Cohort Study With 3.4 Years of Follow-Up

Background Restless legs syndrome (RLS) is associated with higher cardiovascular disease (CVD) risk. However, it remains unknown whether treatment of RLS lowers the cardiovascular risk associated with RLS. Methods and Results All data were collected retrospectively, but subjects were prospectively followed forward in time to determine outcomes of interest. We used the Truven Health MarketScan Commercial Claims and Encounters database from January 1, 2006, through December 31, 2014. Participants were 169 393 individuals, which included 24 199 nonpregnant participants with an RLS diagnosis (16 694 receiving treatments for RLS and 7505 without treatment) during 2006 to 2008 and 145 194 age- and sex-matched participants without RLS. All participants were free of CVD before January 1, 2009 (analysis baseline). Incident CVD cases (myocardial infarction, angina, stroke, atrial fibrillation, and heart failure) were identified. We adjusted for potential confounders, such as presence of chronic conditions and medication use. We identified 16 574 incident CVD cases during 2009 to 2014. Relative to the non-RLS group, the adjusted hazard ratio (HR) for future CVD was 1.26 (95% CI, 1.20-1.32) (P<0.001) for the RLS with treatment group, and 1.53 (95% CI, 1.42-1.65) (P<0.001) for the RLS without treatment group. Significant lower CVD risk was observed for all different RLS treatments, including dopaminergics, anticonvulsants, benzodiazepines, and opiates (adjusted HRs range, 0.71-0.84; P<0.001 for all), except for ergot-dopamine use. Conclusions RLS was associated with higher future CVD risk. However, RLS was associated with statistically significantly less future cardiovascular risk in RLS patients with treatment than in those without treatment.

Cerebrovascular Risk in Restless Legs Syndrome: Intima-Media Thickness and Cerebral Vasomotor Reactivity: A Case-Control Study

PURPOSE

Although some studies have suggested an association between cardiovascular disease and restless legs syndrome (RLS), the mechanisms underlying this relationship remain unclear. The intima-media thickness (IMT) and vasomotor reactivity are two simple, non-invasive tools to investigate preclinical atherosclerosis and microangiopathy, respectively. The aims of this study were to evaluate carotid IMT and to explore vasomotor reactivity in idiopathic RLS (iRLS) patients.

PATIENTS AND METHODS

We enrolled 44 iRLS after exclusion of patients with secondary causes of RLS, history of vascular events, known uncontrolled vascular risk factors and other neurological disorders. Forty-four age and sex matched controls were therefore recruited. No significant differences in demographic data and vascular risk factors were found between the two groups. Carotid IMT was measured with a high-resolution B-mode ultrasound on the far-wall of common carotid artery, 10 mm and 30 mm to the carotid bulb. Vasomotor reactivity to hypo- and hypercapnia was assessed, by right middle cerebral artery transcranial Doppler, accordingly to the changes in peak systolic velocity, peak diastolic velocity and mean blood flow velocity.

RESULTS

Mean IMT was significantly increased in patients with iRLS when measured immediately proximally to carotid bifurcation (0.73; sd=0.17), versus controls (0.65; sd=0.13); p=0.035. Patients showed higher cerebrovascular flow velocities (CBFVs) compared to controls. After multivariate analysis, age, hypertension and iRLS proved to be independent IMT predictors.

CONCLUSION

Increased IMT and higher CBFVs in iRLS support the association of iRLS with vascular damage, possibly through enhanced atherogenesis and sympathetic hyperactivity. However, to clarify a causal relationship, further longitudinal assessment of these parameters is needed, trying to control all their physiological modifying factors.

New onset of restless legs syndrome in pregnancy in a prospective multiracial cohort: Incidence and risk factors

OBJECTIVE

To determine whether the incidence and risk factors of restless legs syndrome (RLS) in pregnancy differ by race/ethnicity, we estimated relative risks of demographic, socioeconomic, and nutritional factors in association with risk of any incident RLS in pregnancy in a cohort of 2,704 healthy pregnant women without prior RLS.

METHODS

Using data from the multicenter, multiracial National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies-Singletons, we examined the incidence of RLS from early pregnancy to near delivery through up to 6 assessments. Multivariable Poisson models with robust variance were applied to estimate relative risks (RRs).

RESULTS

The cumulative incidence of RLS in pregnancy was 18.1% for all women, 20.3% for White women, 15.4% for Black women, 17.1% for Hispanic women, and 21.1% for Asian women. Among Hispanic women, older age (RR [reference ≤25 years]: 25-35 years, 1.51; 95% confidence interval [CI] 1.05-2.16; ≥35 years, 1.58; 95% CI 0.93-2.68), anemia (RR [reference no]: yes, 2.47; 95% CI 1.31-4.64), and greater total skinfolds of the subscapular and triceps sites, independent of body mass index (RR [reference quartile 1]: quartile 5, 2.54; 95% CI 1.30-4.97; p trend = 0.01) were associated with higher risk of RLS, while multiparity was associated with a lower risk (RR [reference nulliparity]: 0.69; 95% CI 0.50-0.96). In Black women, greater skinfolds and waist circumference were associated with higher risk of pregnancy RLS, although the trends were less clear.

CONCLUSIONS

The incidence of RLS in pregnancy was high and differed by race/ethnicity, which is likely accounted for by differences in other risk factors, such as age, parity, and nutritional factors.

Effectiveness and safety of traditional Chinese medicine Shaoyao Gancao Tang for the treatment of restless leg syndrome: A protocol for systematic review and meta-analysis

BACKGROUND

A growing body of clinical trials has demonstrated that traditional Chinese medicine Shaoyao Gancao Tang may improve restlessness leg syndrome (RLS). This review aims to systematically assess its effectiveness and safety in the treatment of patients with RLS.

METHODS

Eight databases will be searched from the inception to 31 August 2020, including the Chinese Biological Medicine Database, China National Knowledge Infrastructure, Wanfang Database, VIP Information Database, the Cochrane Library, PubMed, EMBASE, and the Web of Science. All published randomized controlled trials that meet the prespecified eligibility criteria will be included. The primary outcomes include the changes in the International Restless Legs Syndrome Rating Scale and the restless sensation assessed by visual analog scales, and the secondary outcomes include effective rate, adverse event rate, quality of life measures, and improvement in the sleep quality index. Study selection, data extraction, and assessment of bias risk will be conducted independently by 2 reviewers. Data synthesis will be carried out with RevMan software (V.5.3.5). Subgroup and sensitivity analysis will be performed when necessary. The strength of the evidence will be assessed by the Grading of Recommendations Assessment, Development and Evaluation System.

RESULTS

A high-quality synthesis of current evidence of Shaoyao Gancao Tang's effectiveness and safety for patients with RLS will be provided.

CONCLUSION

This systematic review will provide evidence of whether Shaoyao Gancao Tang is an effective and safe intervention for RLS.

Ethanolic Extract of Salvia hispanica L. Regulates Blood Pressure by Modulating the Expression of Genes Involved in BP-Regulatory Pathways

Hypertension (HT) is considered to be a potential risk factor for cardiovascular diseases and has been directly related to pathologies such as obesity and dyslipidemias. Angiotensin-converting enzyme inhibitors (ACEIs) blocked the renin-angiotensin-aldosterone cascade diminishing the production of angiotensin II and the level of bradykinin, produced by the kallikrein-kinin system. Although ACEIs are effective therapeutics in regulating HT, they present several side-effects that can be due to their mechanism of action (as hypotension, cough, dizziness, light-headedness or hyperkalemia) to specific drug molecular structure (skin rash, neutropenia and tasting disorders) or due to associated pathologies in the patients (it has been considered a possible nephrotoxic effect when ACEIs are administered in combination with angiotensin receptor blockers, in patients that present comorbidities as diabetes, acute kidney injury or chronic kidney disease). Therefore, it is necessary the searching for new products with ACEI activity that do not produce side effects. Interestingly, species of the plant genus Salvia have been found to possess hypotensive effects. In the present study, we analyzed the effects of the ethanolic extract of Salvia hispanica L. seeds (EESH) on the expression of genes involved in pathways regulating HT. Administration of EESH to hypertensive rats inhibited the angiotensin-converting enzyme (ACE) activity along with a decrease in Ace and elevation of Agtr1a and Nos3 gene expression, as compared to that in healthy rats. Moreover, these results were similar to those observed with captopril, an antihypertensive drug used as a control. No significant change in the expression of Bdkrb2 gene was observed in the different groups of rats. To conclude, our results demonstrate that EESH regulates blood pressure (BP) in hypertensive rats through transcriptionally regulating the expression of genes that participate in different pathways involving ACE.

Increased sympathetic responses induced by chronic obstructive sleep apnea are caused by sleep fragmentation

Obstructive sleep apnea (OSA) is often associated with sympathetic overactivity and hypertension. These associations are mainly attributed to hypoxia acting on arterial chemoreceptors. However, the contribution of arousal from sleep is unclear. We measured the effect of OSA and sleep fragmentation on cardiovascular and sympathetic function and gene expression in the brain in rats. Male Wistar rats were fitted with a tracheal balloon and EEG and electromyogram electrodes and assigned to control (n = 6), OSA (n = 9), or arousal (n = 8) treatments. The OSA group was subjected to obstructive apnea, each time the rat entered sleep, for 8 h/day for 15 days. The arousal group was similarly exposed to vibration, which was produced with a miniature vibration motor mounted on the rat's head. Vibration intensity slowly increased until the rat awoke. One day after the last apnea or arousal, rats were anesthetized and arterial blood pressure and splanchnic sympathetic nerve activity (SSNA) were recorded. Baseline mean and diastolic pressure were increased after OSA. Resting SSNA was similar in the three groups, but both OSA and sleep fragmentation increased sympathetic activation in response to airway obstruction and chemoreflex activation by cyanide. OSA increased superoxide dismutases 1 and 2 in the brainstem, whereas sleep fragmentation did not. Our results suggest that sympathetic overactivity to chemoreceptor stimulation was a consequence of arousal from sleep. Our study suggests that sleep disruption may have an important role in the development of apnea-related sympathetic activation.NEW & NOTEWORTHY Obstructive sleep apnea causes a hyperactive chemoreflex, with increased sympathetic activation. However, it is not clear whether this pathophysiologic mechanism is due to repeated hypoxia or to sleep disruption. The present study suggests that sleep fragmentation contributes importantly to increased sympathetic activation after chemoreceptor stimulation. This suggests that sleep fragmentation has an important role in the sympathetic activation seen in sleep apnea patients.

EAN/ERS/ESO/ESRS statement on the impact of sleep disorders on risk and outcome of stroke

Sleep disorders are highly prevalent in the general population and may be linked in a bidirectional fashion to stroke, which is one of the leading causes of morbidity and mortality.Four major scientific societies established a task force of experts in neurology, stroke, respiratory medicine, sleep medicine and methodology, to critically evaluate the evidence regarding potential links and the impact of therapy. 13 research questions were evaluated in a systematic literature search using a stepwise hierarchical approach: first, systematic reviews and meta-analyses; second, primary studies post-dating the systematic reviews/meta-analyses. A total of 445 studies were evaluated and 88 included. Statements were generated regarding current evidence and clinical practice.Severe obstructive sleep apnoea (OSA) doubles the risk for incident stroke, especially in young to middle-aged patients. Continuous positive airway pressure (CPAP) may reduce stroke risk, especially in treatment-compliant patients. The prevalence of OSA is high in stroke patients and can be assessed by polygraphy. Severe OSA is a risk factor for recurrence of stroke and may be associated with stroke mortality, while CPAP may improve stroke outcome. It is not clear if insomnia increases stroke risk, while pharmacotherapy of insomnia may increase it. Periodic limb movements in sleep (PLMS), but not restless limb syndrome (RLS), may be associated with an increased risk of stroke. Preliminary data suggest a high frequency of post-stroke insomnia and RLS and their association with a less favourable stroke outcome, while treatment data are scarce.Overall, the evidence base is best for OSA relationship with stroke and supports active diagnosis and therapy. Research gaps remain especially regarding insomnia and RLS/PLMS relationships with stroke.

Long Non-Coding RNA Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) Promotes Hypertension by Modulating the Hsa-miR-124-3p/Nuclear Receptor Subfamily 3, Group C, Member 2 (NR3C2) and Hsa-miR-135a-5p/NR3C2 Axis

Background

This study was designed to investigate the role of long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in the proliferation as well as apoptosis of human umbilical vein endothelial cells (HUVECs), to offer a basis for therapy of hypertension.

Material/Methods

The lncRNA MALAT1 expression, hsa-miR-124-3p, hsa-miR-135a-5p, hsa-miR-135b-5p, and hsa-miR-455-5p in plasma were measured from 230 patients with hypertension and 230 non-hypertensive controls. The mechanism for lncRNA MALAT1 modulating the proliferation and apoptosis of HUVECs was explored by cell transfection, Cell Counting Kit-8 (CCK-8), quantitative real-time polymerase chain reaction (qRT-PCR), western blot, and dual-luciferase reporter assays.

Results

The expression of hsa-miR-124-3p and hsa-miR-135a-5p was reduced and the expression of lncRNA MALAT1 was increased in the plasma of hypertensive patients. Moreover, the plasma levels of hsa-miR-124-3p and hsa-miR-135a-5p of hypertensive patients were negatively correlated with lncRNA MALAT1 (r=−0.64, −0.72; P<0.01, P<0.01, respectively). The level of nuclear receptor subfamily 3, group C, member 2 (NR3C2) protein was negatively correlated with hsa-miR-124-3p and hsa-miR-135a-5p (r=−0.74, −0.84; P<0.01, P<0.01, respectively). The proliferation of HUVECs was inhibited after the inhibition of MALAT. Additionally, after knocking down MALAT, the levels of hsa-miR-124-3p and hsa-miR-135a-5p in HUVECs were markedly increased, while the expression level of NR3C2 protein was decreased. The apoptotic rate of HUVECs after the transfection of MALAT1 small interfering RNA (si-MALAT1) (3.64±0.21%) was significantly reduced compared to that of transfected si-MALAT1 no template control (NC) (3.76±0.19%) and the control group (10.51±1.24%).

Conclusions

LncRNA MALAT1 regulates proliferation and apoptosis of HUVECs through the hsa-miR-124-3p/NR3C2 and/or hsa-miR-135a-5p/NR3C2 axis.

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.

[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.

Is Restless Legs Syndrome Associated with an Increased Risk of Mortality? A Meta-Analysis of Cohort Studies

Background

Restless legs syndrome (RLS) is a common sleep disorder,. although controversial, growing evidence relates the presence of RLS to an increased risk of mortality, mainly due to cardiovascular events. The aim of this article was to review the role of RLS as a risk factor of mortality according to independent cohort studies.

Methods

We performed a literature review via PubMed database for articles relating RLS and mortality. We used the random-effects model to calculate the pooled effect estimates on mortality. Heterogeneity between studies was assessed using quantitative and qualitative analysis.

Results

Out of 100 articles identified, 13 were finally included. Although studies were heterogeneous (p = 0.001), no significant publication bias was found. When all cohort studies were considered, the random-effects model yielded a significantly increased risk of mortality in RLS versus non-RLS patients (13 studies, hazard ratio [HR] = 1.52, 95% confidence interval [CI] 1.28-1.80). However, this association was not statistically significant when only cohort studies using the international RLS diagnostic criteria were considered (5 studies, HR = 1.63, 95% CI 0.94-2.81).

Discussion

The results of this meta-analysis suggest that RLS seems to be a risk factor of mortality, although this association is conditioned by the diagnostic criteria used in the studies. Future long-term follow-up standardized mortality studies are needed to address this important question that carries potential impact on population global health.

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 and periodic limb movements during sleep in the Multi-Ethnic Study of Atherosclerosis

Study Objectives

To investigate the prevalence of concurrent periodic limb movements during sleep (PLMS) and restless leg syndrome (RLS), as well as the prevalence of PLMS and RLS separately. Additionally, we document these prevalences by age, race/ethnicity, sex, and obesity status.

Methods

Cross-sectional data from 2041 Multi-Ethnic Study of Atherosclerosis (MESA) Sleep ancillary study participants were used. PLMS (>15 periodic limb movements per hour of sleep) was measured by polysomnography. RLS symptoms were assessed using the 2009 International Restless Legs Syndrome Study Group clinical criteria.

Results

The prevalence of RLS with PLMS was 6.7%, RLS alone 16.1%, and PLMS alone 21.2%. RLS with PLMS was prevalent in 7.0% of whites, 4.9% of blacks, 10.1% of Hispanics, and 3.3% of Chinese-Americans. In adjusted models, odds of RLS with PLMS was higher for those older than 67 years versus those younger (odds ratio [OR] [95% confidence interval [CI]] = 1.62 [1.09-2.40]). Relative to white participants, the prevalence of RLS with PLMS tended to be lower among blacks (0.56 [0.32-0.96]). The prevalence of concurrent RLS and PLMS did not statistically differ by sex or obesity status. RLS alone was more common in women.

Conclusions

Approximately 7% of our sample had RLS with PLMS ("electro-clinical RLS"). This condition was more common among older individuals, did not vary by sex, and was less common among blacks. The findings provide some of the first information about the prevalence of concurrent RLS and PLMS in a community-based sample and show distinct sex and race associations for RLS versus electro-clinical RLS.

Restless Legs Syndrome and Parkinson Disease: A Causal Relationship Between the Two Disorders?

Restless Legs Syndrome/Willis-Ekbom Disease (RLS/WED) is a common sleep related movement disorder that can be idiopathic or occurs in comorbidity with other medical conditions such as polyneuropathy, iron deficiency anemia, multiple sclerosis, hypertension and cardiovascular diseases. In recent years, a growing body of literature investigated the association between RLS/WED and Parkinson's Disease (PD). Several questions regarding the comorbidity between these two disorders are still unanswered. If the insurgence of RLS/WED may precede the onset of PD, or if RLS/WED could represent a secondary condition of PD and if impaired dopaminergic pathway may represent a bridge between these two conditions are still debatable issues. In this review, we critically discuss the relationship between RLS/WED and PD by reviewing cross sectional and longitudinal studies, as well as the role of dopamine in these disorders. A twofold interpretation have to be taken into account: dopaminergic therapy may have a crucial role in the development of RLS/WED in PD patients or RLS/WED can be conceived as an early manifestation of PD rather than a risk factor. Several studies showed a high prevalence of RLS/WED in PD patients and several findings related to dopaminergic and iron alterations in both disorders, however up to now it is difficult to find a point of agreement between studies. A greater number of systematic and strongly controlled longitudinal studies as well as basic pathophysiological investigations particularly in RLS/WED are needed to clarify this complex relationship.

Higher Prevalence of Hypertension among Individuals with Restless Legs Syndrome: A Meta-Analysis

OBJECTIVE

This study investigated the proposed association between restless legs syndrome (RLS) and the prevalence of hypertension.

METHODS

A meta-analysis was conducted based on searches of the PUBMED, EMBASE, Cochrane Library, and Korean electronic databases. Cohort and cross-sectional studies reporting the incidence of hypertension in individuals with RLS were included. Dichotomous data were pooled to obtain an odds ratio (OR) and 95% confidence interval (CI) for the prevalence of hypertension in individuals with RLS. The main outcome measure of the study was prevalence of hypertension in patients with RLS compared with a control group.

RESULTS

One cohort study and eight cross-sectional studies were included in the meta-analysis. Individuals with RLS had an increased prevalence of hypertension (all studies: OR=1.13, 95% CI=1.04-1.23; cross-sectional studies: OR=1.12, 95% CI=1.01-1.24). However, in subgroup analyses controlling for cardiovascular risk factors, such as diabetes mellitus and dyslipidemia, the differences in the prevalence of hypertension between RLS and control patients were no longer significant.

CONCLUSION

Patients with RLS may have a higher prevalence of hypertension, according to a pooled analysis, but the results remain to be confirmed in well-designed prospective studies.

Restless Legs Syndrome and Sleep-Related Movement Disorders

PURPOSE OF REVIEW

This article provides an update on six sleep-related movement disorders: restless legs syndrome (RLS), periodic limb movement disorder, sleep-related leg cramps, bruxism, rhythmic movement disorder, and propriospinal myoclonus, with an emphasis on RLS.

RECENT FINDINGS

RLS is a common sensorimotor disorder that impairs quality of life. RLS is frequently comorbid to neurologic, psychiatric, vascular, and inflammatory diseases. Accumulating evidence implicates the pathophysiology of RLS as a state of dopamine dysfunction and iron deficiency that occurs on a background of genetic susceptibility conferred by 6 gene polymorphisms. Multiple treatments approved by the US Food and Drug Administration (FDA) are available. Dopamine agonists and α2δ calcium channel ligands are considered first-line treatments, but these treatments have very different side effect profiles that should be taken into consideration.

SUMMARY

Sleep-related movement disorders are frequently encountered in clinical practice. For some disorders, particularly RLS and periodic limb movement disorder, our understanding of biology, epidemiology, and treatment is advanced. For others, much work is needed to determine optimal treatment strategies.

Periodic limb movements during sleep in stroke/TIA: Prevalence, course, and cardiovascular burden

OBJECTIVE

To define the prevalence, time course, and associated factors of periodic limb movements during sleep (PLMS) in patients with ischemic stroke or TIA.

METHODS

Patients enrolled in the prospective Sleep-Disordered Breathing in Transient Ischemia Attack (TIA)/Ischemic Stroke and Continuous Positive Airway Pressure (CPAP) Treatment Efficacy (SAS-CARE) study underwent a double polysomnographic investigation in the acute and chronic phases after stroke/TIA, together with a MRI brain scan and a 24-hour blood pressure evaluation. The prevalence of PLMS in patients was compared with that in a matched sample of randomly selected healthy controls from the HypnoLaus cohort. One hundred sixty-nine recordings were performed in the acute phase and 191 after 3 months (210 recordings were obtained from the same 105 patients in both phases) and were compared to those of 162 controls.

RESULTS

The mean number of PLMS per hour and the percentage of participants with a PLMS index >10 and >15 per hour were similar between patients and controls. PLMS remained stable from the acute to the chronic phase after stroke. Factors positively associated with PLMS were age, body mass index, and history of hypertension. Blood pressure over 24 hours and the burden of cerebrovascular damage were similar between the groups with PLMS and without PLMS.

CONCLUSIONS

PLMS are equally frequent in patients with stroke/TIA and the general population. The absence of higher blood pressure values and of a greater vascular brain damage found in patients with PLMS compared to those without PLMS might be due to a greater use of antihypertensive medication among patients with PLMS, which corresponds to a higher prevalence of previous diagnosis of hypertension in these patients.

Diagnosis and treatment of restless legs syndrome

Restless legs syndrome (RLS) is a disorder characterized by an irresistible urge to move the legs during rest, usually accompanied by uncomfortable sensations in the affected extremity or extremities. RLS can manifest at any age but prevalence increases with advancing age. This article describes the symptoms of RLS, associated comorbidities, and how to diagnose and manage RLS.

Prospective study of restless legs syndrome and total and cardiovascular mortality among women

OBJECTIVE

We prospectively examined whether women with physician-diagnosed restless legs syndrome (RLS) had a higher risk of total and cardiovascular disease (CVD) mortality relative to those without RLS.

METHODS

The current study included 57,417 women (mean age 67 years) from the Nurses' Health Study without cancer, renal failure, and CVD at baseline (2002). Main outcomes were total and CVD mortality. We used the Cox proportional hazards model to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and CVD-specific mortality based on RLS status, adjusting for age, presence of major chronic diseases, and other potential confounders.

RESULTS

We documented 6,448 deaths during 10 years of follow-up. We did not observe a significant association between presence of physician-diagnosed RLS and high risk of total mortality (adjusted HR 1.15, 95% CI 0.98-1.34). When cause-specific mortality was studied, participants with RLS had a significantly higher risk of CVD mortality (adjusted HR 1.43, 95% CI 1.02-2.00) relative to those without RLS after adjustment for potential confounders. Longer duration of RLS diagnosis was significantly associated with a higher risk of CVD mortality (p for trend = 0.04). Excluding participants with common RLS comorbidities strengthened the association between RLS and total (adjusted HR 1.43, 95% CI 1.03-1.97) and CVD mortality (adjusted HR 2.27, 95% CI 1.21-4.28). However, we did not find a significant association between RLS and mortality due to cancer and other causes.

CONCLUSIONS

Women with RLS had a higher CVD mortality rate, which may not be fully explained by common co-occurring disorders of RLS.

Respiratory sinus arrhythmia in the fourth decade of life depends on birth weight and the DRD4 gene: Implications for understanding the development of emotion regulation

INTRODUCTION

The long allele of the DRD4 gene can confer different behavioral and emotional phenotypes depending upon environmental exposure, although the physiological changes underlying these phenotypes are not fully known. We sought to extend this work by assessing the interaction of the DRD4 gene and exposure to perinatal adversity (indexed by extremely low birth weight [ELBW]) on resting respiratory sinus arrhythmia (RSA), a neurophysiological measure of emotion regulation, in adulthood.

METHODS

We examined the interaction between the DRD4 gene and perinatal adversity on RSA at age 30-35 in a longitudinal cohort of ELBW survivors (n = 49) and NBW controls (n = 63). Buccal DNA samples were genotyped for short and long carriers of the exon III DRD4 VNTR gene. Resting RSA was assessed by electrocardiogram.

RESULTS

We report an interaction between birth weight status and DRD4 gene (F = 9.42, p = 0.003) in predicting RSA, such that DRD4 long carriers had the highest and lowest resting RSA depending on whether they were born NBW or ELBW, respectively. DRD4 short carriers were less sensitive to birth weight. Additionally, reduced RSA was correlated with a history of major depressive disorder, suggesting it was a reliable index of emotion dysregulation.

DISCUSSION

These results suggest that the perinatal environment influences autonomic nervous system functioning in individuals with genotypes that confer additional sensitivity. Whether the long-term autonomic outcomes of this environmental sensitivity are beneficial or detrimental appears to depend on the quality of the early life environment, and may influence the development of emotion regulatory and psychiatric problems in adulthood.

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.

The Clinical Importance of Periodic Leg Movements in Sleep

OPINION STATEMENT

Periodic leg movements during sleep (PLMS) are commonly found in patients with restless leg syndrome (RLS), but they may occur in other sleep disorders and several medical conditions. Their prevalence increases with age, but they can also be observed in children. During the last decades, very active research has been devoted to determine and understand the pathophysiology, associated events, and clinical significance of PLMS. This chapter tries to sum up the most relevant PLMS-related findings, focusing on the relationship between PLMS and the cardiovascular system, in order to understand the clinical implication of this complex motor phenomenon. PLMS have been associated with sympathetic overactivity, namely surges in nocturnal blood pressure and heart rate, without modification in global autonomic balance. Also, PLMS have been related to inflammatory cellular pathways, with elevated level of inflammatory markers, which are associated with cardiovascular risk. The PLMS-related modulation of the autonomic system and of inflammation may increase cardiovascular and cerebrovascular risk in subjects with frequent PLMS. Moreover, also, comorbidities associated with PLMS may play a synergic role in worsening the cardiovascular risk and the consequent mortality and morbidity. Furthermore, little is known about pathophysiological correlates in children with PLMS and their chronic implication on the cardiovascular and cerebrovascular systems. A few studies have suggested that treating PLMS with dopaminergic drugs may reduce their associated sympathetic overactivity and modify disease progression. Definitely, further research is needed to assess the clinical impact of PLMS, associated or not with RLS, and above all the long-term impact of treating PLMS on cardiovascular risk, morbidity, and mortality.

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.

Advanced signal analysis for the detection of periodic limb movements from bilateral ankle actigraphy

Actigraphy can assist in the detection of periodic limb movements in sleep. Although several actigraphs have been previously reported to accurately detect periodic limb movements, many are no longer available; of the existing actigraphs, most sample too infrequently to accurately detect periodic limb movements. The purpose of this study was to use advanced signal analysis to validate a readily available actigraph that has the capability of sampling at relatively high frequencies. We simultaneously recorded polysomnography and bilateral ankle actigraphy in 96 consecutive patients presenting to our sleep laboratory. After pre-processing and conditioning, the bilateral ankle actigraphy signals were then analysed for 14 simple time, frequency and morphology-based features. These features reduced the signal dimensionality and aided in better representation of the periodic limb movement activity in the actigraph signals. These features were then processed by a Naïve-Bayes binary classifier for distinguishing between normal and abnormal periodic limb movement indices. We trained the Naïve-Bayes classifier using a training set, and subsequently tested its classification accuracy using a testing set. From our experiments, using a periodic limb movement index cut-off of 5, we found that the Naïve-Bayes classifier had a correct classification rate of 78.9%, with a sensitivity of 80.3% and a specificity of 73.7%. The algorithm developed in this study has the potential of facilitating identification of periodic limb movements across a wide spectrum of patient populations via the use of bilateral ankle actigraphy.

Silent Cerebral Small Vessel Disease in Restless Legs Syndrome

STUDY OBJECTIVES

Growing literature suggests that patients with restless legs syndrome (RLS) may be at increased risk for hypertension, heart disease, and stroke. Cerebral small vessel disease (SVD) is a known risk factor for clinical stroke. This study evaluated silent cerebral SVD by MRI in patients with RLS, in the absence of a history of previous clinical stroke or known stroke risk factors and taking into account disease duration.

METHODS

Fifty-three patients with RLS < 10 y were prospectively recruited along with 44 with RLS > 10 y and 74 normal controls. A magnetic resonance imaging study was obtained from all subjects and scans were analyzed for area and volume of SVD.

RESULTS

There was a significant increase in SVD area in the entire group of RLS patients compared to controls (P = 0.036); this was almost entirely driven by the group with RLS > 10 y. SVD area and volume were significantly increased in patients with RLS > 10 y with respect to both controls (P < 0.0001 and P < 0.0014, respectively) and RLS < 10 y (P < 0.00022 and P < 0.003, respectively). Age, duration of RLS, and the interaction of age and duration of RLS were independent predictors of SVD disease. Duration of RLS was an independent predictor of the burden of cerebral SVD (area P < 0.00012 and volume P < 0.0025), whereas sex and insomnia were not.

CONCLUSION

RLS duration should be taken into account when analyzing the association between RLS and cerebrovascular disease; our data support the hypothesis that a long-lasting RLS and its accompanying periodic limb movements in sleep are a risk factor for silent SVD and perhaps for the development of clinical stroke.