Restless legs syndrome

The Prevalence of Restless Legs Syndrome in Patients Undergoing Hemodialysis: A Systematic Review and Meta-analysis Study

INTRODUCTION

Restless legs syndrome is a sensory-motor disorder that causes sleep disorder. The syndrome in patients undergoing hemodialysis associates with depression, sleep deprivation, performance disorder, day fatigue, excessive daytime sleepiness, stress, anxiety, and higher risk of cardiovascular diseases. The objective of this systematic meta-analysis study was to estimate prevalence of restless legs syndrome in patients undergoing hemodialysis.

METHODS

Twenty-six relevant articles published between 2000 and 2015 indexed in Iranian (MagIran and IranMedex) and international databases (SID, Google Scholar, ScienceDirect, PubMed, Pre Quest, and Scopus) were selected. Data analysis was carried out through meta-analysis (random effect model) and heterogeneity of the studies was determined using I2 index. The obtained data were analyzed in STAT (11.2).

RESULTS

Prevalence of the syndrome according to the found articles was 50% (95% CI: 38-61) in Iranian and 30% (95% CI:23-37) in international databases. There was an ascending trend of prevalence of the syndrome corresponding to the publication year of the articles (P=0.419), while the trend based on age of the patients was descending (P=0.604). However, the variations were not significant.

CONCLUSION

Given the high prevalence and considerable effects of restless legs syndrome on patients undergoing hemodialysis, it is recommended that these patients be screened for the syndrome.

The Synergistic Relationship between Alzheimer's Disease and Sleep Disorders: An Update

Sleep disorders are frequently reported in Alzheimer's disease (AD), with a significant impact on patients and caregivers and a major risk factor for early institutionalization. Although changes in sleep organization are a hallmark of the normal aging processes, sleep macro- and micro-architectural alterations are more evident in patients affected by AD. Degeneration of neural pathways regulating sleep-wake patterns and sleep architecture may contribute to sleep alterations. In return, several recent studies suggested that common sleep disorders may precede clinical symptoms of dementia and represent risk factors for cognitive decline, through impairment of sleep-dependent memory consolidation processes. Thus, a close relationship between sleep disorders and AD has been largely hypothesized. Here, sleep alterations in AD and its pre-dementia stage, mild cognitive impairment, and their complex interactions are reviewed.

Gender differences in sleep in older men and women

Sleep disturbances increase with increasing age in both males and females and become fairly common in the older community when compared to their younger counterparts. Even though these sleep disturbances increase with advancing age, there are nevertheless inherent differences in sleep disturbances between males and females. When compared to older men, older women will have a longer sleep latency (number of minutes it takes to fall asleep), more daytime sleepiness, will sleep about 20 min less per day, have less NREM stages 1 and 2 sleep, have more slow-wave sleep, and are more predisposed to REM sleep. Women have at least a 40% increased risk for developing insomnia, are at twice the risk for restless legs syndrome, will have different obstructive sleep apnea symptoms and more partial obstructions during sleep compared to men. They are also less likely to use antidepressants but will metabolize zolpidem 50% slower than men.

Restless legs syndrome in migraine patients: prevalence and severity

BACKGROUND AND PURPOSE

Our aim was to study not only the prevalence but more importantly the severity and the correlation between sleep quality and restless legs syndrome (RLS) in a large population of well-defined migraine patients as poor sleep presumably triggers migraine attacks.

METHODS

In a large cross-sectional and observational study, data on migraine and RLS were collected from 2385 migraine patients (according to the International Classification of Headache Disorders ICHD-IIIb) and 332 non-headache controls. RLS severity (International RLS Study Group severity scale) and sleep quality (Pittsburgh Sleep Quality Index) were assessed. Risk factors for RLS and RLS severity were calculated using multivariable-adjusted regression models.

RESULTS

Restless legs syndrome prevalence in migraine was higher than in controls (16.9% vs. 8.7%; multivariable-adjusted odds ratio 1.83; 95% confidence interval 1.18-2.86; P = 0.008) and more severe (adjusted severity score 14.5 ± 0.5 vs. 12.0 ± 1.1; P = 0.036). Poor sleepers were overrepresented amongst migraineurs (50.1% vs. 25.6%; P < 0.001). Poorer sleep quality was independently associated with RLS occurrence (odds ratio 1.08; P < 0.001) and RLS severity (P < 0.001) in migraine patients.

CONCLUSION

Restless legs syndrome is not only twice as prevalent but also more severe in migraine patients, and associated with decreased sleep quality.

Mitochondrial ferritin in the regulation of brain iron homeostasis and neurodegenerative diseases

Mitochondrial ferritin (FtMt) is a novel iron-storage protein in mitochondria. Evidences have shown that FtMt is structurally and functionally similar to the cytosolic H-chain ferritin. It protects mitochondria from iron-induced oxidative damage presumably through sequestration of potentially harmful excess free iron. It also participates in the regulation of iron distribution between cytosol and mitochondrial contents. Unlike the ubiquitously expressed H-ferritin, FtMt is mainly expressed in testis and brain, which suggests its tissue-related roles. FtMt is involved in pathogenesis of neurodegenerative diseases, as its increased expression has been observed in Alzheimer’s disease, restless legs syndrome and Friedreich’s ataxia. Studies from our laboratory showed that in Alzheimer’s disease, FtMt overexpression attenuated the β-amyloid induced neurotoxicity, which on the other hand increased significantly when FtMt expression was knocked down. It is also found that, by maintaining mitochondrial iron homeostasis, FtMt could prevent 6-hydroxydopamine induced dopaminergic cell damage in Parkinson’s disease. These recent findings on FtMt regarding its functions in regulation of brain iron homeostasis and its protective role in pathogenesis of neurodegenerative diseases are summarized and reviewed.

Restless legs syndrome induced by quetiapine: report of seven cases and review of the literature

We report on seven cases of restless legs syndrome (RLS) in patients treated with quetiapine. Small doses (50-250 mg at bedtime) provoked RLS in a dose-dependent way. Most patients suffered from an affective disorder and all were treated concomitantly with antidepressants. A search of the literature revealed a further nine cases of RLS concerning quetiapine, also afflicting only patients with affective disorders. Quetiapine seems to carry a special risk for RLS in this sort of patient. Possible causes for this concurrence are discussed.

Restless legs syndrome in a group of patients with Alzheimer's disease

BACKGROUND

Restless legs syndrome (RLS) is a neurological disorder characterized by the urge to move the legs associated with peculiar unpleasant sensations during periods of rest and inactivity that are relieved by movement. A few studies analyzed RLS in neurodegenerative diseases such as Alzheimer's Disease (AD). The aim of our study was to assess the prevalence and the clinical characteristics of RLS in a cohort of AD patients.

METHODS

Three hundred and thirty-nine subjects with a diagnosis of AD were recruited. Cognitive, functional, and neuropsychiatric measures were collected at baseline and six-monthly for a 2-years follow-up

RESULTS

Fourteen subjects met the RLS criteria. RLS subjects were more frequently male (p:0,006) and younger than AD subject without RLS (p:0,029). MMSE, ADL and IADL were not significantly different. NPI total scores did not differ significantly, however, AD patients with RLS were found to be more apathetic (p:0,001) than AD subjects without RLS.

CONCLUSION

RLS prevalence in our AD cohort was estimated to be about 4%. RLS appeared to be associated with neuropsychiatric symptoms such as apathy. RLS and apathy might share a common pathophysiological basis represented by a dysfunction of the central dopaminergic system.

Reduced neural synchrony in patients with restless legs syndrome during a visual oddball task

Background

Restless legs syndrome (RLS) is a sensorimotor neurological disorder characterized by an irresistible urge to move the legs. It has been reported that RLS patients show cognitive deficits, presumably due to hyperactivity causing loss of attention, or malfunctions in the frontal region resulting from sleep deprivation. However, the mechanism underlying cognitive deficits in RLS patients is mostly unknown. As an effort to clarifying this, we investigated the differences in neural activity and phase synchrony between healthy controls and RLS patients during cognitive task performances.

Methodology/Principal Findings

Seventeen female drug-naive RLS patients were enrolled in the study, and an age-matched group of thirteen healthy female volunteers served as controls. Multichannel event-related potentials (ERPs) were recorded from RLS patients and normal controls while performing a visual oddball task. In addition to conventional analyses of ERP waveforms and spectra, interregional gamma-band phase synchrony (GBPS) was investigated to observe the differences in interregional neural synchronies between normal and RLS patient groups. Strong GBPS was observed primarily between anterior and posterior regions along the midline for both groups. Along with significant reduction and delay of P300 ERP and induced gamma-band activity (GBA), the GBPS was considerably decreased in RLS patients compared to normal subjects, especially at frontal region.

Conclusions

Overall, our results support that cognitive dysfunction in RLS patients is associated with reduced interregional neural synchrony as well as alterations in local neural activity.

Prevalence of restless legs syndrome in North American and Western European populations: a systematic review

BACKGROUND

Restless legs syndrome (RLS) is a potentially debilitating sleep disorder that affects a significant percentage of North American and European adults. Although standardized RLS diagnostic criteria are now established and widely accepted, reported prevalence estimates have varied widely. In this paper, we review the literature regarding RLS prevalence in North American and Western European adult populations, examine potential sources of variation, briefly discuss the impact of RLS, and offer recommendations for future research.

METHODS

To identify qualifying studies, we searched 6 scientific databases and scanned bibliographies of relevant review papers and all identified articles. Studies including fewer than 300 participants, that did not use any of the 4 standard diagnostic criteria, were published prior to 1995 or targeted clinical populations were excluded.

RESULTS

Thirty-four papers detailing results of large, population-based studies in 16 North American and Western European countries met our inclusion criteria, including 5 multi-country studies (N=69,992 participants) and 29 single country studies (N=163,188 participants); all but one were cross-sectional. Reported general prevalence rates ranged from 4% to 29% of adults, averaging 14.5±8.0% across studies. Reported prevalence averaged higher in primary care populations than in populations derived from random sampling or geographically defined cohorts (19.5±7.9% vs. 12.3±7.2%). Diagnostic and severity criteria differed considerably among studies, as did inclusion criteria, with corresponding variation in prevalence estimates. Prevalence averaged higher in women and older adults; more limited data suggest race/ethnicity, parity, health status, and other factors may also contribute to the observed variation in prevalence. RLS has profound, negative effects on health, well-being, and quality of life, yet detection rates remain low.

CONCLUSIONS

Collectively, these studies indicate that RLS is a common disorder of major clinical and public health significance in the Western industrialized world, affecting between 4% and 29% of adults. The wide variation in reported prevalence likely reflects differences in demographic factors, health status, and other population characteristics; study population source and sampling frame; and inconsistencies in RLS diagnostic criteria and procedures. Prospective studies and corresponding incidence data on RLS are lacking, hindering the evaluation of both causal factors and sequelae.

Sleep problems in children and adolescents with common medical conditions

Untreated sleep disturbances and sleep disorders pose significant adverse daytime consequences and place children at considerable risk for poor health outcomes. Sleep disturbances occur at a greater frequency in children with acute and chronic medical conditions compared with otherwise healthy peers. Sleep disturbances in medically ill children can be associated with sleep disorders, comorbid with acute and chronic conditions, or secondary to underlying disease-related mechanisms, treatment regimens, or hospitalization. Clinical management should include a multidisciplinary approach with particular emphasis on routine, regular sleep assessments and prevention of daytime consequences, and promotion of healthy sleep habits and health outcomes.

Restless legs syndrome

Restless legs syndrome (RLS) is a common neurological sensory-motor disorder that is characterized by intense restlessness and unpleasant creeping sensations deep inside the lower legs. Symptoms appear when the legs are at rest and are worst in the evening and at night. They force patients to keep moving their legs, and often to get out of bed and wander about. Periodic limb movements (PLMS) are also common during sleep amongst those suffering from RLS, and sleep efficiency is severely reduced. There are idiopathic as well as symptomatic forms of RLS, the latter being associated with e.g. pregnancy, iron deficiency and chronic renal failure. A family history of RLS is very common and pedigrees in these cases suggest an autosomal-dominant transmission with high penetrance. Genetic investigations have been performed in order to identify genes associated with RLS. Several loci have been found (on chromosomes 12q, 14q, 9p, 2q, 20p and 16p). Pathophysiology of RLS remains incompletely understood. However, advanced brain imaging studies and positive results of dopaminergic treatment suggest that RLS may be generated by dopamine dysfunction locally within the central nervous system. At present, there is a wide range of treatment options including levodopa, dopamine agonists, opioids, benzodiazepines, antiepileptic drugs and iron supplements.

Progressive development of augmentation during long-term treatment with levodopa in restless legs syndrome: results of a prospective multi-center study

The European Restless Legs Syndrome (RLS) Study Group performed the first multi-center, long-term study systematically evaluating RLS augmentation under levodopa treatment. This prospective, open-label 6-month study was conducted in six European countries and included 65 patients (85% treatment naive) with idiopathic RLS. Levodopa was flexibly up-titrated to a maximum dose of 600 mg/day. Presence of augmentation was diagnosed independently by two international experts using established criteria. In addition to the augmentation severity rating scale (ASRS), changes in RLS severity (International RLS severity rating scale (IRLS), clinical global impression (CGI)) were analyzed. Sixty patients provided evaluable data, 35 completed the trial and 25 dropped out. Augmentation occurred in 60% (36/60) of patients, causing 11.7% (7/60) to drop out. Median time to occurrence of augmentation was 71 days. The mean maximum dose of levodopa was 311 mg/day (SD: 105). Patients with augmentation compared to those without were significantly more likely to be on higher doses of levodopa (> or =300 mg, 83 vs. 54%, P = 0.03) and to show less improvement of symptom severity (IRLS, P = 0.039). Augmentation was common with levodopa, but could be tolerated by most patients during this 6-month trial. Patients should be followed over longer periods to determine if dropout rates increase with time.

Rotigotine transdermal patch: in restless legs syndrome

Rotigotine is a non-ergolinic dopamine receptor agonist, formulated as a silicone-based transdermal patch, which has been evaluated for use in the treatment of adults with moderate to severe restless legs syndrome (RLS). Transdermal rotigotine improved the symptoms of RLS in two well designed 6-month trials in adults with idiopathic, moderate to severe RLS. Rotigotine (1-3 mg/24 h in one study and 2 or 3 mg/24 h in the other) decreased the International RLS Study Group Severity Rating Scale (IRLS) sum score and the Clinical Global Impression (CGI) item-1 assessment (severity of symptoms) from baseline (co-primary endpoints) to a significantly greater extent than placebo. Over half of rotigotine recipients were classified as treatment responders according to the IRLS sum score and CGI item-1 and item-2 ratings. Improvements in RLS symptoms have been maintained in the long term with rotigotine, according to the 3-year results of an open-label extension trial. Transdermal rotigotine was generally well tolerated in clinical trials and long-term extension studies in patients with moderate to severe RLS. There was a low risk of augmentation (i.e. intensification of RLS symptoms) with rotigotine, although further evaluations are required to ascertain if continuous dopaminergic stimulation has the effect of limiting or preventing augmentation.

One year open-label safety and efficacy trial with rotigotine transdermal patch in moderate to severe idiopathic restless legs syndrome

BACKGROUND

Long-term efficacy and tolerability data are not yet available for patch formulations of dopamine agonists in restless legs syndrome.

METHODS

Efficacy and safety of rotigotine (0.5-4mg/24h), formulated as a once-daily transdermal system (patch), were investigated in an open extension (SP710) of a preceding 6-week placebo-controlled trial (SP709, 341 randomized patients) in patients with idiopathic restless legs syndrome. For efficacy assessment the international RLS severity scale (IRLS), the RLS-6 scales, the clinical global impressions (CGI) and the QoL-RLS questionnaire were administered. In addition, long-term tolerability and safety were assessed.

RESULTS

Of 310 patients who finished the controlled trial, 295 (mean age 58+/-10 years, 66% females) with a mean IRLS score of 27.8+/-5.9 at baseline of SP709 were included. We report results after one year of this ongoing long-term trial. Two hundred twenty patients (retention rate=74.6%) completed the 12-month follow-up period. The mean daily dose was 2.8+/-1.2mg/24h with 4mg/24h (40.6%) being the most frequently applied dose; 14.8% were sufficiently treated with 0.5 or 1.0mg/24h. The IRLS total score improved by ?17.4+/-9.9 points between baseline and end of Year 1 (p<0.001). The other measures of severity, sleep satisfaction and quality of life supported the efficacy of rotigotine (p<0.001 for pre-post-comparisons of all efficacy variables). The tolerability was described as "good" or "very good" by 80.3% of all patients. The most common adverse events were application site reactions (40.0%), which led to withdrawal in 13.2%. Further relatively frequent adverse events were nausea (9.5%) and fatigue (6.4%). Two drug-related serious adverse events, nausea and syncope, required hospitalization. Symptoms of augmentation were not reported by the patients.

CONCLUSION

Rotigotine provided a stable, clinically relevant improvement in all efficacy measures throughout one year of maintenance therapy. The transdermal patch was safe and generally well tolerated by the majority of patients. Comparable to any transdermal therapy, application site reactions were the main treatment complication.

The effect of endovenous laser ablation on restless legs syndrome

OBJECTIVES

Venous disease was proposed as a cause of restless legs syndrome (RLS) by Dr Karl A Ekbom in 1944, but has since remained largely unexplored. This study examines the effect of endovenous laser ablation (ELA) in patients with concurrent RLS and duplex-proven superficial venous insufficiency (SVI).

METHODS

Thirty-five patients with moderate to very severe RLS (as defined by the 2003 National Institute of Health (NIH) RLS criteria) and duplex-proven SVI completed an international RLS rating scale questionnaire (IRLS) and underwent standard duplex examination to objectively measure the baseline severity of their conditions. They were separated into non-operative and operative cohorts. The operative cohort underwent ELA of refluxing superficial axial veins using the CoolTouch CTEV 1320 nm laser and ultrasound-guided sclerotherapy of the associated varicose veins with foamed sodium tetradecyl sulphate (STS). All patients then completed a follow-up IRLS questionnaire. Baseline and follow-up IRLS scores were compared.

RESULTS

Operative correction of the SVI decreased the mean IRLS score by 21.4 points from 26.9 to 5.5, corresponding to an average of 80% improvement in symptoms. A total of 89% of patients enjoyed a decrease in their score of > or =15 points. Fifty-three percent of patients had a follow-up score of < or =5, indicating their symptoms had been largely alleviated and 31% had a follow-up score of zero, indicating a complete relief of RLS symptoms.

CONCLUSIONS

ELA of refluxing axial veins with the CTEV 1320 nm laser and foamed STS sclerotherapy of associated varicosities alleviates RLS symptoms in patients with SVI and moderate to very severe RLS.

RECOMMENDATIONS

SVI should be ruled-out in all patients with RLS before initiation or continuation of drug therapy.

Clinical trials in restless legs syndrome--recommendations of the European RLS Study Group (EURLSSG)

The European Restless Legs Syndrome (RLS) Study Group (EURLSSG) is an association of European RLS experts who are actively involved in RLS research. A major aim of the Study Group is the development and continuous improvement of standards for diagnosis and treatment of RLS. Several members developed study designs and evaluation methods in investigator-initiated trials early in the 1990s, and all members have since contributed to many pivotal and nonpivotal drug trials for the treatment of RLS. The recommendations on clinical investigations of pharmacological treatment of RLS patients summarize the group's expertise and knowledge acquired through clinical trials. The recommendations primarily address how to plan and conduct confirmatory, randomized clinical studies in patients with idiopathic RLS. Advice is presented for the diagnosis of RLS and clinical and polysomnographic inclusion and exclusion criteria. Primary and secondary endpoints for an evaluation of efficacy are based on a critical description of validated methods for both short- and long-term trials, also in special populations (children, pregnant women, elderly patients). The recommendations include the assessment of augmentation. Finally, general issues including the evaluation of safety and tolerability, as well as specific neurological and cardiovascular risks and sleep attacks/daytime somnolence, are discussed. The aim of these recommendations is to support research groups or pharmaceutical companies in the design of optimized study protocols.

Definition of restless legs syndrome, how to diagnose it, and how to differentiate it from RLS mimics

Restless legs syndrome (RLS) is a clinical diagnosis based primarily on self-reports of individuals. The International RLS Study Group has published diagnostic criteria that are essential for an operational diagnosis of RLS; further clinical features are considered by the group supportive for or associated with RLS. However, sensitivity and specificity are not perfect and "mimics" of RLS have been reported, i.e., other conditions like nocturnal cramps sometimes can appear to fulfill the essential diagnostic criteria indicating the need for more thorough understanding of the diagnostic criteria and better differential diagnoses. To contribute to the accuracy of diagnostic processes in RLS, we recapitulate the definition of RLS as an urge to move focused on the legs (and arms in some patients). This urge to move often but not always occurs together with dysesthesia, i.e. unpleasant abnormal sensations appearing without any apparent sensory stimulation. The urge to move and any accompanying dysesthesia must be engendered by rest, relieved by movement and worse in the evening or night. Succinctly, RLS can be summarized in medical terminology as a "movement-responsive quiescegenic nocturnal focal akathisia usually with dysesthesias." Empirical approaches to investigate the independence of the essential criteria "worsening at night" and "worsening at rest" are reported. Possible differential diagnoses of RLS are discussed under the perspective of the NIH diagnostic criteria of RLS. Standardized methods to assess a RLS diagnosis are presented which might improve differential diagnosis and in general the reliability and validity of RLS diagnosis.

Cabergoline compared to levodopa in the treatment of patients with severe restless legs syndrome: Results from a multi-center, randomized, active controlled trial

We report the first large-scale double-blind, randomly assigned study to compare two active dopaminergic therapies for Restless Legs Syndrome (RLS), the dopamine agonist cabergoline (CAB) and levodopa/benserazide (levodopa). Patients with idiopathic RLS were treated with fixed daily doses of 2 or 3 mg CAB or 200 or 300 mg levodopa for 30 weeks. Efficacy was assessed by changes in the IRLS (International RLS Severity Scale) and by time to discontinuation of treatment due to loss of efficacy or augmentation. 361 of 418 screened patients (age 58 +/- 12 years, 71% females) were randomly assigned and treated (CAB: n = 178; levodopa: n = 183) in 51 centers of four European countries. Baseline IRLS total score was 25.7 +/- 6.8. The baseline-adjusted mean change from baseline to week 6 in IRLS sum score was d = -16.1 in the CAB group and d = -9.5 in the levodopa group (d = -6.6, P < 0.0001). More patients in the levodopa group (24.0%) than in the CAB group (11.9%, P = 0.0029, log-rank test) discontinued because of loss of efficacy (14.2% vs. 7.9%, P = 0.0290) or augmentation (9.8% vs. 4.0%, P = 0.0412). Adverse events (AEs) occurred in 83.1% of the CAB group and in 77.6% of the levodopa group. In both groups, most frequent AEs were gastrointestinal symptoms (CAB: 55.6%, levodopa: 30.6%, P < 0.0001). This first large-scale active controlled study in RLS showed superior efficacy of cabergoline versus levodopa after a 30-week long-term therapy. Tolerability was found more favorable with levodopa than with cabergoline.

Clinical characteristics of Restless legs syndrome in patients with Parkinson's disease

To assess the characteristics, clinical significance and pathology of Restless legs syndrome (RLS) in patients with Parkinson's disease (PD), we studied clinical backgrounds, RLS symptoms, polysomnographic (PSG) variables and therapeutic outcomes in 13 PD patients with RLS (pRLS), and compared them with those of 22 idiopathic RLS patients (iRLS). In all but one pRLS patient, RLS symptoms arose within 5 years of PD onset. pRLS patients had a lower prevalence of family history of RLS, and the age at onset was higher than in iRLS subjects. Scores for the severity scale established by the International Restless Legs Syndrome Study Group (IRLS), the Pittsburgh Sleep Quality Index, and the suggested immobilization test did not differ between groups. However, the periodic limb movements index measured by polysomnogram was smaller in pRLS subjects. After RLS treatment, symptoms improved significantly in both groups; however, pRLS subjects showed higher IRLS scores despite receiving similar doses of RLS medications. The severity of RLS before treatment was quite similar between the two groups, but the response to treatment could be poorer in pRLS than in iRLS. Thus, degeneration of the diencephalospinal dopaminergic pathway due to PD itself and physiological aging could overlap in the pathology of pRLS.