The restless legs syndrome

Pathways of sleep disturbances in juvenile idiopathic arthritis and recommendations for clinical management approaches: A critical review

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease affecting young people. It has a profound impact on their physical, mental and social lives, leading to long-term disability. With the growing awareness of the importance of sleep in all areas of functioning in young people, an emerging literature has drawn attention to the role of sleep in the pathogenesis of JIA. Sleep disturbances in children and adolescents with JIA arise from a wide range of symptoms and pathways, leading to a vicious cycle that exacerbates subclinical inflammation, symptoms and disease progression. Putative factors contributing to sleep disturbances include chronic inflammation, JIA-associated sleep disorders, JIA symptoms (e.g. pain), psychological comorbidities and potential circadian disruption, which may be exacerbated by the transition to adolescence. Here, we review these pathways and advocate key strategies and alternatives for sleep management in young people with JIA in clinical settings. We identify gaps in knowledge and suggest future directions to improve our understanding of JIA sleep disorders, including clinical trials investigating potential strategies to improve sleep health in this young population.

Case report: A new treatment for restless leg syndrome: three cases

Restless legs syndrome is a movement disorder that seriously affects the quality of life of patients. It is characterized by marked discomfort mainly occurring in the deep tissues of the lower extremities, including deep muscle or bone chafing, as well as crawling sensations or pulling sensations. These sensations often cause patients to awaken after falling asleep and to feel the urge to walk around, which seriously affects their sleep quality. Patients with restless leg syndrome exhibit significantly enhanced sympathetic nerve activity and immune disorders, while stellate ganglion blockage can block sympathetic nerves and regulate immune cells and cytokines to maintain immune system homeostasis. We report three patients with restless legs syndrome complicated with severe nephrotic syndrome. After treatment with stellate ganglion block, the symptoms in the restless legs were relieved within 1 month, and the quality of sleep was significantly improved. Our findings suggest that stellate ganglion block has broad promise in the management of restless legs syndrome patients with severe comorbidities.

Advancements in Restless Leg Syndrome Management: A Review of Physiotherapeutic Modalities and Their Efficacy

The goal of this review is to compile information on the use of physiotherapeutic treatments for the treatment of restless leg syndrome (RLS) and to classify the effectiveness of conservative methods in relieving the discomfort due to RLS. English literature found on PubMed, Google Scholar, and Scopus was used in the present review. According to the titles and matters of the abstracts, each literature item connected to RLS was retrieved, analyzed, and reviewed. The 24 papers that were considered admissible were those that included manual approaches, exercises, and alternative RLS management, which were then analyzed for data by the authors. A consistent trend in the data demonstrated benefits in lessening RLS symptom severity across the 24 papers that met the selection criteria. Patients were chosen based on clinical diagnostic standards, and the effectiveness of stretching, exercise therapy, yoga, vibration therapy, reflexology and massage, muscular relaxation techniques, and electrical stimulation was determined. Our findings indicated that each type of therapy significantly affected the manifestations of the illness. Stretching, fitness training, and reflexology were very beneficial, with no side effects and shorter intervention periods.

Effectiveness of exercise and pramipexole in the treatment of restless leg syndrome: Implications on the dopaminergic system and PTPRD

OBJECTIVE

Dopaminergic dysfunction, iron reduction and variations in the PTPRD gene (protein tyrosine phosphatase receptor type delta) may be associated with restless leg syndrome (RLS). Here, we evaluate the effect of pramipexole (PPX) and exercise on genes and proteins associated with RLS and on sleep patterns in spontaneously hypertensive rats (SHR).

METHODS

Animals were distributed into 4 groups: 1) Control (CTRL); 2) Exercise (EX); 3) Exercise and pramipexole (EX + PPX); and 4) Pramipexole (PPX). PPX treatment was performed daily (0.125 mg/kg), while exercise was conducted over 5 sessions per week, both for 4 weeks.

RESULTS

EX + PPX increased the protein levels of PTPRD, reduced the protein levels of the enzyme tyrosine hydroxylase (TH) and improved sleep parameters in both cycles; on the other hand, the use of PPX reduced mRNA and protein levels of PTPRD and TH but improved the sleep pattern in the light cycle. However, in the dark cycle, pramipexole caused the worsening of symptoms.

CONCLUSIONS

We suggest that the improvement in sleep pattern by EX + PPX may be associated with the increased protein levels of PTPRD and that EX + PPX can reverse the negative effects of PPX.

White matter microstructure alterations in idiopathic restless legs syndrome: a study combining crossing fiber-based and tensor-based approaches

Introduction

Restless legs syndrome (RLS) is a common sensorimotor disorder characterized by an irrepressible urge to move the legs and frequently accompanied by unpleasant sensations in the legs. The pathophysiological mechanisms underlying RLS remain unclear, and RLS is hypothesized to be associated with alterations in white matter tracts.

Methods

Diffusion MRI is a unique noninvasive method widely used to study white matter tracts in the human brain. Thus, diffusion-weighted images were acquired from 18 idiopathic RLS patients and 31 age- and sex-matched healthy controls (HCs). Whole brain tract-based spatial statistics (TBSS) and atlas-based analyzes combining crossing fiber-based metrics and tensor-based metrics were performed to investigate the white matter patterns in individuals with RLS.

Results

TBSS analysis revealed significantly higher fractional anisotropy (FA) and partial volume fraction of primary (F1) fiber populations in multiple tracts associated with the sensorimotor network in patients with RLS than in HCs. In the atlas based analysis, the bilateral anterior thalamus radiation, bilateral corticospinal tract, bilateral inferior fronto-occipital fasciculus, left hippocampal cingulum, left inferior longitudinal fasciculus, and left uncinate fasciculus showed significantl increased F1, but only the left hippocampal cingulum showed significantly higher FA.

Discussion

The results demonstrated that F1 identified extensive alterations in white matter tracts compared with FA and confirmed the hypothesis that crossing fiber-based metrics are more sensitive than tensor-based metrics in detecting white matter abnormalities in RLS. The present findings provide evidence that the increased F1 metric observed in sensorimotor tracts may be a critical neural substrate of RLS, enhancing our understanding of the underlying pathological changes.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Neurological Insights into Sleep Disorders in Parkinson's Disease

Parkinson's disease (PD) is a common multidimensional neurological disorder characterized by motor and non-motor features and is more prevalent in the elderly. Sleep disorders and cognitive disturbances are also significant characteristics of PD. Sleep is an important physiological process for normal human cognition and physical functioning. Sleep deprivation negatively impacts human physical, mental, and behavioral functions. Sleep disturbances include problems falling asleep, disturbances occurring during sleep, abnormal movements during sleep, insufficient sleep, and excessive sleep. The most recognizable and known sleep disorders, such as rapid-eye-movement behavior disorder (RBD), insomnia, excessive daytime sleepiness (EDS), restless legs syndrome (RLS), sleep-related breathing disorders (SRBDs), and circadian-rhythm-related sleep-wake disorders (CRSWDs), have been associated with PD. RBD and associated emotional disorders are common non-motor symptoms of PD. In individuals, sleep disorders and cognitive impairment are important prognostic factors for predicting progressing neurodegeneration and developing dementia conditions in PD. Studies have focused on RBD and its associated neurological changes and functional deficits in PD patients. Other risks, such as cognitive decline, anxiety, and depression, are related to RBD. Sleep-disorder diagnosis is challenging, especially in identifying the essential factors that disturb the sleep-wake cycle and the co-existence of other concomitant sleep issues, motor symptoms, and breathing disorders. Focusing on sleep patterns and their disturbances, including genetic and other neurochemical changes, helps us to better understand the central causes of sleep alterations and cognitive functions in PD patients. Relations between α-synuclein aggregation in the brain and gender differences in sleep disorders have been reported. The existing correlation between sleep disorders and levels of α-synuclein in the cerebrospinal fluid indicates the risk of progression of synucleinopathies. Multidirectional approaches are required to correlate sleep disorders and neuropsychiatric symptoms and diagnose sensitive biomarkers for neurodegeneration. The evaluation of sleep pattern disturbances and cognitive impairment may aid in the development of novel and effective treatments for PD.

Therapeutic effects of magnesium and vitamin B6 in alleviating the symptoms of restless legs syndrome: a randomized controlled clinical trial

BACKGROUND AND OBJECTIVE

Restless legs syndrome/Willis-Ekbom Disease (RLS/WED) is one of the most prevalent sleep disorders. There are contradicting data about the effectiveness of magnesium and vitamin B6 in alleviating the symptoms of this condition. Therefore, this study aimed to assess the efficacy of magnesium and vitamin B6 in alleviating the symptoms of RLS/WED.

METHODS

A single-blind study was conducted on individuals with this illness for at least three months. Randomly, 75 patients were assigned into three groups: magnesium, vitamin B6, and placebo. The experimental group received daily doses of 40 mg vitamin B6 or 250 mg magnesium oxide. While others in the control group merely received a placebo. Patients' disease severity and sleep quality were evaluated three times using standard questionnaires (at the beginning of the study, one and two months after therapy). Utilizing SPSS22 software and the ANOVA, t-test, and repeated measure tests, statistical analysis was conducted.

RESULTS

The mean and standard deviation of sleep quality and disease severity at the beginning of the trial and throughout the first month following the intervention did not differ statistically between the three groups. In the second month following the intervention, the mean and standard deviation of sleep quality and disease severity were significantly different (P = 0.001).

CONCLUSION

Taking magnesium and vitamin B6 supplements can reduce the severity of symptoms of RLS/WED patients and improve their sleep quality.

Olanzapine-induced restless leg syndrome (Willis-Ekbom disease): A case report

Restless leg syndrome, also known as Willis-Ekbom disease, is a neurological sensorimotor disorder accompanied by an irresistible urge to move the legs with a fluctuating course of symptoms. It is a common disorder affecting all ages, with existing comorbidities and positive family history being associated with increased prevalence. Herein, we present a case of a 51-year-old female diagnosed with the bipolar affective disorder who developed restless leg syndrome following the use of olanzapine. Olanzapine is a second-generation antipsychotic which can cause restless leg syndrome due to its anti-dopaminergic action on the nervous system, particularly the spinal cord. Existing literature on olanzapine-induced restless leg syndrome has suggested managing this disorder by reducing the dose or replacing olanzapine with other drugs such as clonazepam, quetiapine, and aripiprazole. In our case, olanzapine was not replaced with other medications as the patient showed a significant improvement in bipolar affective disorder symptoms using olanzapine. Instead, clonazepam was added to the treatment regimen which was scheduled to be taken before olanzapine.

Restless Leg Syndrome in Hemodialysis Patients: A Narrative Review

BACKGROUND

Restless legs syndrome (RLS) is a clinical entity characterized by sensory-motor manifestations commonly observed in end-stage renal illness. Evidence suggests that RLS is a multifactorial phenomenon that can be influenced by many critical factors, including genetic predisposition, dietary patterns, and deficiency in some vitamins. Iron metabolism disorders and metabolic derangements have been generally accepted as predisposing elements in RLS. Furthermore, both pharmacological and neuroimaging studies demonstrated dopamine deficiency and dopamine receptors decrease in basal ganglia during RLS.

REVIEW SUMMARY

A literature search was done in three databases (PubMed, Google Scholar, and Cochrane) to identify the pertinent articles discussing the epidemiology, pathogenesis, and management of RLS in hemodialysis patients. RLS can affect the morbidity and mortality of patients treated with dialysis. It also has significant impacts on the quality of life since it can lead to insomnia, increased fatigue, mental health troubles, and other movement problems. Appropriate measures should be considered in this particular population so to prevent and treat RLS. Many drugs and other nonpharmacological methods have been investigated to attenuate the disease's severity. No treatment, however, could offer long-term effects.

CONCLUSION

Further efforts are still required to improve the understanding of RLS pathogenic trends to find more specific and efficient therapies. A wide range of treatment options is available. However, it can be individualized according to the patients' several factors.

Prevalence and associated factors of restless leg syndrome (RLS) in Pakistani women during pregnancy

There is a dearth of literature studying restless leg syndrome (RLS) among pregnant patients in Pakistan. The objective of this study was to determine the prevalence and associated factors of RLS among pregnant Pakistani patients. It was conducted in 2018 among 478 women attending ante-natal check-up in the outpatient department of five hospitals in Karachi, Pakistan. Individuals were interviewed for socio-demographic information, the key criteria for RLS and its associated factors. RLS was reported in 54 (11%) individuals based on International Restless Legs Syndrome Study Group (IRLSSG) criteria. The mean age was 33.44 ± 4.42 years. Association between pregnant women with RLS and those without reveals statistically significant differences with increasing age (p=.01), gravida (p<.01) and para (p<.001). RLS was significant among working women (p=.001), during third trimester (p=.001), with insomnia (p<.001), use of tobacco (p<.001) and among women with gestational diabetes (p<.001), hypertension (p<.001). The study showed a low prevalence of RLS among women during pregnancy. It further reported gestational diabetes, hypertension, insomnia and tobacco use to be independently linked to RLS. Impact StatementWhat is already known on this subject? Pregnancy has been demonstrated to be strongly associated with development of secondary restless leg syndrome (RLS). RLS in pregnancy has also been shown to portend poor maternal and neonatal outcomes such as postpartum depression and preterm birth. Various conditions and lifestyle factors in pregnancy have been shown to be associated with the development of RLS, but there are variations in these across different populations.What do the results of this study add? The prevalence of RLS was only reported twice in pregnant patients in Pakistan and our research helps to address this data shortage. In addition, the results of our study document a strong association of RLS with gestational hypertension and gestational diabetes and also show that smoking and exercise were correlated with RLS during pregnancy, both of which were previously unstudied in the pregnant Pakistani population.What are the implications of these findings for clinical practice and/or further research? Demonstrating the prevalence of RLS in pregnant Pakistani patients highlights the need to screen these patients, particularly those with associated conditions identified in our findings, for RLS during antenatal visits and to treat their condition to improve maternal and neonatal outcomes.

Prevalence of restless legs syndrome in people with diabetes mellitus: A pooling analysis of observational studies

BACKGROUND

Diabetes mellitus (DM) is associated with different clinical complications. The aim of this study was to explore the prevalence of RLS in people with diabetes mellitus and compare the risk of restless leg syndrome (RLS) between diabetic and non-diabetic population.

METHODS

We searched for studies of RLS prevalence in DM through PubMed, Embase, and Web of Science. Two authors independently completed the literature screening, data extraction, and bias risk assessment of eligible studies. All observational studies that assessed the prevalence or risk of RLS in DM were included, where the diagnosis of RLS was based on the International Restless Legs Syndrome Study Group (IRLSSG). Percentages, odds ratio (OR) with 95% confidence intervals (CI) were used to assess pooled estimates of RLS prevalence and risk based on random-effects models. Newcastle-Ottawa-scale (NOS) or a modified NOS were used to evaluate the quality of studies.

FINDINGS

A total of 42 studies, including 835,986 participants, met the eligibility criteria for the meta-analysis. Among them, 30 studies were included in meta-analysis to analyze the prevalence of RLS. A second meta-analysis was conducted using 31 studies to determine RLS risk between diabetes and non-diabetes. The results indicate that between 25% (95% confidence interval 21%-29%) of people with diabetes showed signs of RLS, and people with diabetes had an increased risk of developing RLS compare to people without diabetes (OR 1.98, 95%CI 1.66- 2.34, p < 0.001). However, the available evidence was limited due to potential risk of bias and variability between studies (I² >75%), all of observational design.

INTERPRETATION

Our study suggests that the prevalence and risk of RLS might be higher in DM patients than in non-diabetes population. However, given limitations in the analysis and study design, the findings need to be corroborated in future studies.

FUNDING

This work was supported by the Basic Conditions Platform Construction Project of Sichuan Science and Technology Department (2019JDPT0015), and the "1・3・5 project for disciplines of excellence, West China Hospital, Sichuan University" (ZYJC18003).

Transcranial sonography depicts a larger substantia nigra echogenic area in renal transplant patients on calcineurin inhibitors than on rapamycin

BACKGROUND

After kidney transplantation neurologic manifestations may develop, including Parkinson's disease (PD). An enlarged substantia nigra (SN) by transcranial sonography has been recognized as a marker of PD.

METHODS

In renal transplant recipients (RTRs = 95) and controls (n = 20), measurement of mesencephalon, SN, third ventricle, spleen and carotid intima-media thickness (cIMT) and middle cerebral artery (MCA), kidney and spleen arteries Doppler resistive index (RI) were performed.

RESULTS

RTRs had larger SN, third ventricle and cIMT and higher renal RI than controls. The SN was larger in the CNIs group than in controls and rapamycin group, while the third ventricle was similar between patients but larger than in controls. In RTRs, SN showed a direct linear correlation with spleen and the third ventricle with age, cIMT and RI of the MCA, kidney and spleen. In CNIs group the SN correlated positively with age and cIMT, while the third ventricle reproduced RTRs correlations. Rapamycin group showed a direct linear relationship between the third ventricle and age and RI of the MCA, kidney and spleen; SN showed no correlations.

CONCLUSION

RTRs on CNIs present a larger SN area than on rapamycin, probably due to the antiproliferative effect of rapamycin. This finding might be relevant when interpreting TCS in RTRs.

Epidemiology of haemodialysis outcomes

Haemodialysis (HD) is the commonest form of kidney replacement therapy in the world, accounting for approximately 69% of all kidney replacement therapy and 89% of all dialysis. Over the last six decades since the inception of HD, dialysis technology and patient access to the therapy have advanced considerably, particularly in high-income countries. However, HD availability, accessibility, cost and outcomes vary widely across the world and, overall, the rates of impaired quality of life, morbidity and mortality are high. Cardiovascular disease affects more than two-thirds of people receiving HD, is the major cause of morbidity and accounts for almost 50% of mortality. In addition, patients on HD have high symptom loads and are often under considerable financial strain. Despite the many advances in HD technology and delivery systems that have been achieved since the treatment was first developed, poor outcomes among patients receiving HD remain a major public health concern. Understanding the epidemiology of HD outcomes, why they might vary across different populations and how they might be improved is therefore crucial, although this goal is hampered by the considerable heterogeneity in the monitoring and reporting of these outcomes across settings.

This Review examines the epidemiology of haemodialysis outcomes — clinical, patient-reported and surrogate outcomes — across world regions and populations, including vulnerable individuals. The authors also discuss the current status of monitoring and reporting of haemodialysis outcomes and potential strategies for improvement.

Nearly 4 million people in the world are living on kidney replacement therapy (KRT), and haemodialysis (HD) remains the commonest form of KRT, accounting for approximately 69% of all KRT and 89% of all dialysis.

Dialysis technology and patient access to KRT have advanced substantially since the 1960s, particularly in high-income countries. However, HD availability, accessibility, cost and outcomes continue to vary widely across countries, particularly among disadvantaged populations (including Indigenous peoples, women and people at the extremes of age).

Cardiovascular disease affects over two-thirds of people receiving HD, is the major cause of morbidity and accounts for almost 50% of mortality; mortality among patients on HD is significantly higher than that of their counterparts in the general population, and treated kidney failure has a higher mortality than many types of cancer. Patients on HD also experience high burdens of symptoms, poor quality of life and financial difficulties.

Careful monitoring of the outcomes of patients on HD is essential to develop effective strategies for risk reduction. Outcome measures are highly variable across regions, countries, centres and segments of the population. Establishing kidney registries that collect a variety of clinical and patient-reported outcomes using harmonized definitions is therefore crucial.

Evaluation of HD outcomes should include the impact on family and friends, and personal finances, and should examine inequities in disadvantaged populations, who comprise a large proportion of the HD population.

Usefulness of Restless Legs Symptoms to Predict Adverse Cardiovascular Outcomes in Men With Coronary Artery Disease

The relationship between restless legs syndrome (RLS) and cardiovascular disease remains enigmatic in the general population, and its prognostic value in patients with coronary artery disease (CAD) is unknown. In this study, the frequency of RLS-like symptoms was assessed using a validated instrument in 3,266 patients undergoing cardiac catheterization (mean age 64 years, 62% male, 23% Black, and 74% with obstructive CAD). Patients were followed for primary end points of cardiovascular death or incident myocardial infarction. Fine and Gray hazard models explored the association between RLS and incident events after adjustment for demographic and clinical risk factors. In the total cohort, 29% of patients reported mild (rare or sometimes) symptoms, and 15% of patients had moderate/severe (often to almost always) symptoms of RLS. Female sex (odds ratio [OR] 2.11, 95% confidence interval (CI), 1.68 to 2.57), body mass index (OR 1.12 per 5 kg/m², 95% CI, 1.04 to 1.22), diabetes (OR 1.43, 95%,1.15 to 1.79), and β-blocker use (OR 1.35, 95% CI, 1.07 to 1.72) were independently associated with moderate/severe symptoms of RLS compared with no symptoms. Over a 5-year follow-up period, 991 patients suffered an adverse event. Compared with those with no symptoms, patients with moderate/severe RLS had significantly higher risk of the primary end point (hazard ratio [HR] = 1.33, 95%),CI 1.01 to 1.76) after adjustment for demographic and clinical risk factors. The association was more significant in men than women, HR 1.98, 95% CI, 1.41 to 2.78 versus HR 0.99 (,95% CI, 0.64 to 1.52, p interaction= 0.013. In conclusion, among men with CAD, moderate-to-severe symptoms of RLS are associated with significantly higher risk of adverse cardiovascular outcomes, independent of traditional risk factors.

D3 Receptors and Restless Legs Syndrome

Restless Legs Syndrome (RLS) is a sensorimotor disorder that severely affects sleep. It is characterized by an urge to move the legs that is often accompanied by periodic limb movements during sleep (PLMS). RLS has a high prevalence in the population and is usually a life-long condition. While its origins remain unclear, RLS is initially highly responsive to treatment with dopaminergics that target the D3 receptor. However, over time patients often develop a gradual tolerance that can lead to the emergence of adverse effects and the augmentation of the symptoms. While the basal ganglia and the striatum control leg movements, the lumbar spinal cord is the gateway for the sensory processing of the symptoms and critical for the associated leg movements. D3 receptors are highly expressed in nucleus accumbens (NAc) of the striatum and the sensory-processing areas of the spinal dorsal horn. In contrast, D1 receptors are strongly expressed throughout the entire striatum and in the ventral horn of the spinal cord. Long-term treatment with D3 receptor full agonists is associated with an upregulation of the D1 receptor subtype, and D3 and D1 receptors can form functional heteromers, in which the D3R controls the D1R function. It is conceivable that the switch from beneficial treatment to augmentation observed in RLS patients after prolonged D3R agonist exposure may be the result of unmasked D1-like receptor actions.

Chronic kidney disease and neurological disorders: are uraemic toxins the missing piece of the puzzle?

Chronic kidney disease (CKD) perturbs the crosstalk with others organs, with the interaction between the kidneys and the heart having been studied most intensively. However, a growing body of data indicates that there is an association between kidney dysfunction and disorders of the central nervous system. In epidemiological studies, CKD is associated with a high prevalence of neurological complications, such as cerebrovascular disorders, movement disorders, cognitive impairment and depression. Along with traditional cardiovascular risk factors (such as diabetes, inflammation, hypertension and dyslipidaemia), non-traditional risk factors related to kidney damage (such as uraemic toxins) may predispose patients with CKD to neurological disorders. There is increasing evidence to show that uraemic toxins, for example indoxyl sulphate, have a neurotoxic effect. A better understanding of factors responsible for the elevated prevalence of neurological disorders among patients with CKD might facilitate the development of novel treatments. Here, we review (i) the potential clinical impact of CKD on cerebrovascular and neurological complications, (ii) the mechanisms underlying the uraemic toxins' putative action (based on pre-clinical and clinical research) and (iii) the potential impact of these findings on patient care.

Uncovering the dynamics of a circadian-dopamine model influenced by the light-dark cycle

The neurotransmitter dopamine (DA) is known to be influenced by the circadian timekeeping system in the mammalian brain. We have previously created a single-cell differential equations model to understand the mechanisms behind circadian rhythms of extracellular DA. In this paper, we investigate the dynamics in our model and study different behaviors such as entrainment to the 24-hour light-dark cycle and robust periodicity versus decoupling, quasiperiodicity, and chaos. Imbalances in DA are often accompanied by disrupted circadian rhythms, such as in Parkinson's disease, hyperactivity, and mood disorders. Our model provides new insights into the links between the circadian clock and DA. We show that the daily rhythmicity of DA can be disrupted by decoupling between interlocked loops of the clock circuitry or by quasiperiodic clock behaviors caused by misalignment with the light-dark cycle. The model can be used to further study how the circadian clock affects the dopaminergic system, and to help develop therapeutic strategies for disrupted DA rhythms. .

The Efficacy and Safety of Pharmacological Treatments for Restless Legs Syndrome: Systemic Review and Network Meta-Analysis

Although various drugs are currently used for restless legs syndrome (RLS) in clinic, selecting appropriate drugs for patients is difficult. This network meta-analysis (NMA) aimed to compare the efficacy and safety of different drugs. After literature searching and screening, 46 trials, including 10,674 participants are included in this NMA. The pooled results showed that, compared with placebo, only levodopa is inefficient to relieve symptoms of RLS. Cabergoline decreases IRLS scores to the greatest extent among all drugs (MD −11.98, 95% CI −16.19 to −7.78). Additionally, pramipexole is superior to ropinirole in alleviating symptoms of RLS (MD −2.52, 95% CI −4.69 to −0.35). Moreover, iron supplement alleviates RLS symptoms significantly compared with placebo in patient with iron deficiency (MD −5.15, 95% CI −8.99 to −1.31), but not for RLS patients with normal serum ferritin level (MD −2.22, 95% CI −6.99 to 2.56). For primary RLS, these drugs are also effective, while there is insufficient data to analyze drug efficacy in secondary RLS. We analyzed risk of common adverse effects of drugs including nausea, somnolence, fatigue, headache and nasopharyngitis. Alpha-2-delta ligands and DAs are favorable choices for both primary and secondary RLS because of their significant efficacy and good tolerability. Iron supplement can significantly alleviate symptoms of RLS patients with iron deficiency than placebo. We recommend gabapentin, gabapentin enacarbil, and pregabalin for clinicians for first consideration mainly because that they rarely cause augmentation. Oxycodone-naloxone could be considered in patients with severe or very severe RLS who failed in treatment with above drugs.

Association of quality of life, anxiety, and depression with restless leg syndrome in the hemodialysis patients

OBJECTIVES

Restless Legs Syndrome (RLS) is commonly known to cause morbidity in patients on hemodialysis, making them prone to chronic mental health illnesses such as depression and anxiety, and also adversely impact quality of life. In this study, we examined the association of quality of life, anxiety, and depression with restless leg syndrome in the hemodialysis patients at Karachi Institute of Kidney Diseases.

RESULTS

About 26.7% of the participants reported RLS among the sample size Presence of RLS was not associated with quality of life, depression, and anxiety. However, p-values < 0.05 were significant for body-mass index (BMI), diabetes mellitus as a cause of end-stage renal disease, and serum albumin levels. Majority (82.5%) of the RLS-diagnosed patients had moderate to severe symptoms with 16 (40%) and 17 (42.5%) clients, respectively.

Signs of sympathetic and endothelial cell activation in the skin of patients with restless legs syndrome

OBJECTIVES

To evaluate skin biopsies of patients with early- and late onset restless legs syndrome (RLS) for concomitant small fiber neuropathy (SFN) and to determine cutaneous sympathetic innervation and microvascularization in comparison to healthy individuals.

METHODS

Density of intraepidermal nerve fibers (IENFD), adrenergic nerve fibers and dermal capillaries was analyzed by immunofluorescence for PGP9.5, tyrosine hydroxylase and endothelial markers CD31 and CD105 in skin biopsies of 11 individuals with RLS and 8 age- and sex-matched controls.

RESULTS

IENFD did not differ between RLS and controls, but two RLS patients with comorbid impaired glucose metabolism fulfilled morphometric criteria of SFN according to published normative values. In contrast, dermal nerve bundles of RLS patients showed an increased density of tyrosine hydroxylase⁺ adrenergic nerve fibers (p < 0.005). Moreover, an increased ratio between immature CD105⁺ and mature CD31⁺ endothelial cells within dermal capillaries was observed in RLS (p < 0.02).

CONCLUSIONS

SFN, as a potential contributing factor for RLS, should be considered in patients with predisposing comorbidities presenting with burning or shooting pain, dysesthesias and impaired sensory and temperature perception. Evidence of an increased adrenergic innervation of the skin in RLS patients is in accordance with sympathetic hyperactivity while signs of endothelial cell activation may reflect an adaptive response to tissue hypoxia.

Cerebral blood flow alterations in hemodialysis patients with and without restless legs syndrome: an arterial spin labeling study

Hemodialysis with restless legs syndrome (HD-RLS) is associated with alterations in neuronal function, the blood-brain barrier and iron deposition, thus affecting cerebral metabolism and perfusion. This study utilized three-dimensional arterial spin labeling (ASL) to identify HD-RLS-related perfusion patterns and potential relationships with disease severity. Twenty-six HD-RLS patients, 30 hemodialysis patients without restless legs syndrome (HD-nRLS) and 30 age-, sex-, and education-matched healthy controls were included in this study. One-way analysis of covariance and post hoc analyses were used to assess differences in cerebral blood flow (CBF) values, demographics and clinical data among the three groups. Pearson's correlation analysis was conducted between altered CBF values in the HD-RLS group and clinical data. Compared with HD-nRLS patients, HD-RLS patients showed increased CBF in the right primary motor cortex (false discovery rate [FDR]-corrected P < 0.05). Compared with the normal controls, both HD subgroups (i.e., those with and without RLS) exhibited consistent CBF changes, including increased CBF in the left medial superior frontal gyrus and bilateral thalamus and decreased CBF in the left insular cortices (FDR-corrected P < 0.05). This abnormal hyperperfusion in the sensorimotor cortex and basal ganglia provides evidence for a sensory processing disorder in RLS that may be involved in the pathogenesis of RLS in HD patients.

Cognitive profile in Restless Legs Syndrome: A signal-to-noise ratio account

Restless legs syndrome (RLS) is a common neurological disorder characterized by a sensorimotor condition, where patients feel an uncontrollable urge to move the lower limbs in the evening and/or during the night. RLS does not only have a profound impact on quality of life due to the disturbed night-time sleep, but there is growing evidence that untreated or insufficiently managed RLS might also cause cognitive changes in patients affected by this syndrome. It has been proposed that RLS is caused by alterations in the signal-to-noise ratio (SNR) and in dopamine (DA) neurotransmission in the nervous system. Based on this evidence, we propose the “SNR-DA hypothesis” as an explanation of how RLS could affect cognitive performance. According to this hypothesis, variations/reductions in the SNR underlie RLS-associated cognitive deficits, which follow an inverted U-shaped function: In unmedicated patients, low dopamine levels worsen the SNR, which eventually impairs cognition. Pharmacological treatment enhances DA levels in medicated patients, which likely improves/normalizes the SNR in case of optimal doses, thus restoring cognition to a normal level. However, overmedication might push patients past the optimal point on the inverted U-shaped curve, where an exaggerated SNR potentially impairs cognitive performance relying on cortical noise such as cognitive flexibility. Based on these assumptions of SNR alterations, we propose to directly measure neural noise via “1/f noise” and related metrics to use transcranial random noise stimulation (tRNS), a noninvasive brain stimulation method which manipulates the SNR, as a research tool and potential treatment option for RLS.

•

Restless legs syndrome (RLS) is a common neurological disorder.

•

RLS is caused by alterations in the SNR ratio and in DA neurotransmission.

•

The SNR- DA hypothesis how RLS affects cognitive performance is presented.

[Restless legs syndrome in Parkinson's disease]

Disturbances in sleep and wakefulness are important symptoms of Parkinson's disease (PD) and are associated with negative effects on patients' quality of life. The analysis of literature on the relationship between RLS and PD revealed three main hypotheses explaining the relatively high incidence of RLS in PD: (1) RLS can be considered as an early (prodromal) manifestation or a predictor of PD that can outpace its main symptoms by several years (by analogy with conduct disorder during sleep with REM); (2) the high incidence of RLS in the advanced stage of PD may be associated with augmentation of previously latent RLS symptoms during prolonged dopaminergic therapy of PD; (3) a significant proportion of RLS cases in PD patients are not «classical» RLS, but represent, for example, manifestations of motor or non-motor fluctuations or a special form of stereotypy in the legs. Further research is needed to determine if any of these statements are true.

PTPRD as a candidate druggable target for therapies for restless legs syndrome?

The gene that encodes the protein tyrosine phosphatase D (PTPRD) may be related to brain circuits associated with sleep, and has been seen as an interesting molecule, a "druggable" drug target. This gene is a potential candidate for increasing therapeutic advances in restless legs syndrome, a sleep-related movement disorder, that manifests as an uncontrollable desire to move limbs (legs) to relieve uncomfortable sensations. Changes in the PTPRD gene expression may increase the chance of developing this syndrome. Treatment with pramipexole is used in restless legs syndrome. This study aims to verify the effect of treatment with pramipexole on the PTPRD expression, as well as on the sleep pattern in an animal model for restless legs syndrome. For this, an animal model of sleep-related movement disorders (spontaneously hypertensive rats) was distributed in groups: (a) spontaneously hypertensive rats-control; (b) spontaneously hypertensive rats-pramipexole (0.125 mg kg^-1 for 4 weeks). The analyses of PTPRD gene and protein expression were performed in the striatum and spinal cord by quantitative real-time polymerase chain reaction and indirect enzyme-linked immunosorbent assay, respectively. Electrocorticographic and electromyographic analyses were performed. There was no difference in the PTPRD mRNA levels, as well as in the protein levels, although a tendency has been observed for decreased gene expression in the striatum and increased protein expression in the spinal cord in the spontaneously hypertensive rats-pramipexole group. Pramipexole improved the animals' sleep pattern. Thus, the treatment with pramipexole in the evaluated dose and time tended to alter the expression of the PTPRD protein in the spinal cord, in addition to significantly improving the sleep pattern.

Which Factors in Spinocerebellar Ataxia Type 3 Patients Are Associated with Restless Legs Syndrome/Willis-Ekbom Disease?

There is evidence of a higher prevalence of restless legs syndrome/Willis-Ekbom disease (RLS/WED) in individuals with spinocerebellar ataxia type 3 (SCA3), although the factors underlying this association remain unknown. The present study aimed to determine the prevalence of RLS/WED in SCA3 patients and to investigate which factors of SCA3 patients are associated with presence of RLS/WED. From February to August of 2006, we carried out clinical interviews in 40 controls and 40 SCA3 patients, diagnosed and followed up at Faculty of Medicine of Ribeirão Preto, University of São Paulo. Twenty-seven SCA3 patients were submitted to a detailed clinical protocol, electroneuromyography, blood work up, polysomnography (PSG), suggested immobilization test (SIT), and magnetic resonance image (MRI). RLS/WED was found in 27.5% of SCA3 patients and 2.5% of normal controls (p = 0.003). The factors related to RLS/WED in SCA3 patients were female gender, age at start of the symptoms of ataxia after 30 years, presence of peripheral neuropathy, and documented iron deficiency. Among SCA3 patients, those with RLS showed higher values of maximal discomfort level and discomfort level sum compared to non-RLS individuals on SIT. There is a relation between RLS/WED and SCA3, which seems to be resultant of different factors whose identification could improve the quality of assistance to those patients as well as to promote a better comprehension of the pathophysiology of both RLS/WED and SCA3.

Sleep in adults with autism spectrum disorder and attention deficit/hyperactivity disorder: A systematic review and meta-analysis

Sleep-related problems have been frequently reported in neurodevelopmental disorders, with special emphasis in Autism Spectrum Disorder (ASD) and Attention Deficit/Hyperactivity Disorder (ADHD). The aim of the present study is to conduct a systematic review and meta-analysis on sleep disturbances in adults with ASD and/or ADHD (PROSPERO's CRD42019132916). PubMed and PsycINFO were searched for studies reporting data on sleep objective/subjective measures, as well as prevalence data of sleep disorders, in adults with ASD and/or ADHD. A manual search was conducted throughout reference lists of eligible studies. A total of 1126 studies and 66 references were identified by electronic and manual searches, respectively. Of these, 42 studies were included in the meta-analysis. Results showed that both disorders share a similar sleep-impaired profile with higher sleep onset latency, poorer sleep efficiency, greater number of awakenings during sleep, and a general lower self-perceived sleep quality compared with healthy controls. A higher proportion of N1 sleep was found in ASD participants, while a greater Periodic Limb Movements in Sleep is specific in ADHD adults. More studies are needed, especially those directly comparing ASD and ADHD participants. Controlling for medication, intellectual disability, and concurrent psychiatric disorders is mandatory.

Transcutaneous Spinal Cord Direct-Current Stimulation Modulates Functional Activity and Integration in Idiopathic Restless Legs Syndrome

Idiopathic restless legs syndrome (RLS) is a sensorimotor disorder and is suggested to be caused by central nervous system abnormalities. Non-invasive transcutaneous spinal direct-current stimulation (tsDCS) was recently used for RLS therapy. However, the neurophysiological basis of tsDCS treatment is still unknown. In this study, we explored the neural basis of tsDCS in 15 RLS patients and 20 gender- and age-matched healthy controls using resting-state functional magnetic resonance imaging. We calculated the whole-brain voxel-wise fractional amplitude of low-frequency fluctuations (fALFF), regional homogeneity (ReHo), and weighted degree centrality (DC) to characterize the intrinsic functional activities and the local and global functional integration. We found that tsDCS can effectively improve the sleep and RLS symptoms in RLS patients. Moreover, after tsDCS therapy, the RLS patients showed decreased fALFF in the right anterior insula/temporal pole, decreased ReHo in the supplementary motor area, increased weighted DC in the left primary visual cortex, and decreased weighted DC in the right posterior cerebellum. The changed patterns were consistent with that found between RLS patients and healthy controls. The weighted DC in the left primary visual cortex after treatment and the fALFF in the right anterior insula/temporal pole before treatment were significantly and marginally correlated with sleep and RLS symptom scores, respectively. These results revealed that tsDCS can normalize the functional patterns of RLS patients and is an effective way for RLS therapy. Our findings provide the neurophysiological basis for tsDCS treatment and may facilitate understanding the neuropathology of RLS and directing other neuromodulation treatments.

Patterns of Gray Matter Volume Alterations in Hemodialysis Patients With and Without Restless Legs Syndrome: Evidence From a Voxel-Based Morphometry Study

PURPOSE

The purpose of this study was to investigate the differences of gray matter volume (GMV) alteration patterns between hemodialysis with restless legs syndrome (HD-RLS) and hemodialysis without restless legs syndrome (HD-nRLS) patients using voxel-based morphometry.

METHODS

Twenty-three HD-RLS patients, 27 HD-nRLS patients, and 27 age-, sex-, and education-matched healthy controls were included in this study. One-way analysis of covariance and post hoc analyses were used to assess differences in GMV, demographics, and clinical data among the 3 groups. Pearson correlation analysis was conducted between altered GMV in the HD-RLS group and clinical data.

RESULTS

Compared with HD-nRLS patients, HD-RLS patients showed decreased GMV in the left primary motor cortex (false discovery rate corrected, P < 0.05). Compared with the healthy controls, both HD subgroups (ie, those with and without RLS) exhibited consistent GMV changes, including decreased GMV in the bilateral anterior cingulate and paracingulate gyrus and left middle temporal gyrus (false discovery rate corrected, P < 0.05). The GMV values in the left precentral gyrus were negatively correlated with the RLS rating scores (r = 0.2138, P = 0.0263).

CONCLUSIONS

This abnormal decreased GMV in the sensorimotor cortex provides evidence for a sensory processing disorder in RLS that may be involved in the pathogenesis of RLS in HD patients.

Statistical shape analysis of corpus callosum in restless leg syndrome

OBJECTIVES

In this study we aimed to investigate corpus callosum shape differences between restless leg syndrome patients and healthy controls, and to determine whether disease severity and duration are indicators for corpus callosum deformation in RLS patients.

METHODS

This study was conducted using the magnetic resonance imaging scans of 33 restless leg syndrome patients and 33 control subjects. Landmarks were marked on the digital images and callosal landmark coordinate data were used to assess shape difference by performing Generalized Procrustes analysis. The shape deformation from controls to the patients was evaluated performing the Thin Plate Spline approach.

RESULTS

There was a statistically significant shape difference between the groups. Highest deformation was determined at the posterior midbody of the corpus callosum. Growth curve analyses showed that with the increase in disease duration and severity, the CC size decreased.

DISCUSSION

The present study demonstrated callosal shape differences in restless leg syndrome using a landmark-based geometric morphometric approach, considering the topographic distribution of corpus callosum for the first time.

BTBD9 and dopaminergic dysfunction in the pathogenesis of restless legs syndrome

Restless legs syndrome (RLS) is characterized by an urge to move legs, usually accompanied by uncomfortable sensations. RLS symptoms generally happen at night and can be relieved by movements. Genetic studies have linked polymorphisms in BTBD9 to a higher risk of RLS. Knockout of BTBD9 homolog in mice (Btbd9) and fly results in RLS-like phenotypes. A dysfunctional dopaminergic system is associated with RLS. However, the function of BTBD9 in the dopaminergic system and RLS is not clear. Here, we made use of the simple Caenorhabditis elegans nervous system. Loss of hpo-9, the worm homolog of BTBD9, resulted in hyperactive egg-laying behavior. Analysis of genetic interactions between hpo-9 and genes for dopamine receptors (dop-1, dop-3) indicated that hpo-9 and dop-1 worked similarly. Reporter assays of dop-1 and dop-3 revealed that hpo-9 knockout led to a significant increase of DOP-3 expression. This appears to be evolutionarily conserved in mice with an increased D₂ receptor (D₂R) mRNA in the striatum of the Btbd9 knockout mice. Furthermore, the striatal D₂R protein was significantly decreased and Dynamin I was increased. Overall, activities of DA neurons in the substantia nigra were not altered, but the peripheral D₁R pathway was potentiated in the Btbd9 knockout mice. Finally, we generated and characterized the dopamine neuron-specific Btbd9 knockout mice and detected an active-phase sleepiness, suggesting that dopamine neuron-specific loss of Btbd9 is sufficient to disturb the sleep. Our results suggest that increased activities in the D₁R pathway, decreased activities in the D₂R pathway, or both may contribute to RLS.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Restless legs syndrome in end stage renal disease patients undergoing hemodialysis

BACKGROUND

The prevalence of Restless legs syndrome (RLS) in End Stage Renal Disease (ESRD) patients is higher than that in the general population. However, the associations of RLS within the ESRD population are inconsistent and RLS is usually neglected in dialysis centers, although it impairs the life quality among ESRD patients. We aim to investigate the prevalence of RLS in patients with ESRD undergoing maintenance hemodialysis and evaluate the risk factors of developing RLS and the effect of RLS on quality of life among ESRD patients.

METHODS

ESRD patients undergoing maintenance hemodialysis in Shanghai General Hospital dialysis unit from July 2016 to October 2016 were enrolled in the study. RLS was diagnosed according to the criteria of the International Restless Legs Syndrome Study Group (IRLSSG). IRLSSG Severity Scale was used to evaluate the severity of RLS. Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep quality, and Hospital Anxiety and Depression Scale (HADS) was used to estimate anxiety and depression. Serologic and historic variables were analyzed to determine predictors of RLS in the ESRD population.

RESULTS

A total of 137 ESRD patients were enrolled. The prevalence of RLS among the ESRD patients was 20.44%. The risk of RLS was increased significantly in females (OR = 2.729, p = 0.032) and daily alcohol drinkers (OR = 4.716, p = 0.022). RLS increased the risks of sleep disorders (25/28, 89.3% vs 73/109, 67.0%, p = 0.02) and sedative hypnotics intake (7/28, 25.0% vs 10/109, 9.2%, p = 0.047) and impaired the sleep quality (7/109 vs 11/28, p = 0.001) according to PSQI sum scores.

CONCLUSION

A high RLS prevalence among the ESRD patients undergoing hemodialysis was confirmed. ESRD patients who are women and drinking alcohol have a higher risk of RLS. The sleep quality was significantly impaired and sleeping medication use was more common among the ESRD patients with RLS.

Caenorhabditis elegans and its applicability to studies on restless legs syndrome

Restless legs syndrome (RLS) is a common neurological disorder in the United States. This disorder is characterized by an irresistible urge to move the legs, although the symptoms vary in a wide range. The pathobiology of RLS has been linked to iron (Fe) deficiency and dopaminergic (DAergic) dysfunction. Several genetic factors have been reported to increase the risk of RLS. Caenorhabditis elegans (C. elegans) is a well-established animal model with a fully sequenced genome, which is highly conserved with mammals. Given the detailed knowledge of its genomic architecture, ease of genetic manipulation and conserved biosynthetic and metabolic pathways, as well as its small size, ease of maintenance, speedy generation time and large brood size, C. elegans provides numerous advantages in studying RLS-associated gene-environment interactions. Here we will review current knowledge about RLS symptoms, pathology and treatments, and discuss the application of C. elegans in RLS study, including the worm homologous genes and methods that could be performed to advance the pathophysiology RLS.

Chronic pulmonary disease is associated with pain spreading and restless legs syndrome in middle-aged women-a population-based study

INTRODUCTION

Recent studies suggest an increased prevalence of chronic pain conditions and restless legs syndrome (RLS) in patients with chronic pulmonary disease (CPD). We analyzed the prevalence and risk factors for pain and RLS in a population-based sample of females with comorbid CPD.

METHOD

Questionnaire-based data from 2745 women aged 18-64 years were analyzed regarding comorbid CPD status (severe bronchitis, emphysema, asthma). Pain status was assessed according to symptoms reflecting severity (Visual Analogue Scale, VAS rating 0-10) and duration and spreading (limited spread or widespread) of pain. A diagnosis of RLS was defined by four validated diagnostic criteria. Anthropometrics and co-morbidities were assessed as covariates in univariate and multivariate analyses.

RESULTS

Widespread pain was overrepresented in women with CPD (44.6 vs. 24.6%, p < 0.001). The odds ratio for widespread pain in women with CPD was 1.6 (95% confidence interval (CI) 1.2-2.2, p < 0.001) in the fully adjusted model. Severe pain (VAS rating ≥ 7) was more prevalent in females with known CPD (28.8 vs. 15.4%, p < 0.001, odd ratio 1.4 (95% CI 1.0-1.9, p = 0.029)). The prevalence of RLS was 37.4 and 23.8% in subjects with or without CPD, respectively (p < 0.001). In multivariate analysis, CPD was associated with a 30% risk increase for RLS (odds ratio 1.3 (95% CI 1.0-1.7, p = 0.04)).

CONCLUSION

This population-based study identified CPD as an independent risk factor for severe and widespread pain as well as for RLS. Further research addressing pathophysiological mechanisms linking CPD and chronic pain conditions/RLS is warranted.

Evaluation of Optical Coherence Tomography Results and Cognitive Functions in Patients with Restless Legs Syndrome

Introduction

The aim of this study was to evaluate whether retinal neural network was impaired and cognitive functions were disturbed in restless legs syndrome (RLS) considering the hypothesis that there may be a dysfunction in dopaminergic pathways in RLS like in Parkinson's disease. Therefore, we evaluated retinal neural network with optical coherence tomography (OCT) and presence of cognitive impairment with Montreal Cognitive Assessment (MOCA).

Methods

OCT evaluations were performed for 30 RLS patients and 30 healthy controls. Ganglion cell complex was segmented to retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) automatically by the device, and recorded. Additionally, all the patients and the controls were evaluated using MOCA.

Results

No statistically significant difference was detected between RLS and controls in RNFL, GCL, IPL, and choroidal thicknesses. However, total MOCA score and all of its subscale scores were significantly lower in the RLS patients compared with the controls. No significant correlation was detected between OCT and MOCA parameters.

Conclusion

No degeneration was detected in retinal neurons (RNFL, GCL, and IPL) of RLS patients. However, impairments were seen in MOCA total and subscale scores of these patients. On the other hand, no significant correlation was detected between MOCA scores and RNFL, GCL, or IPL thicknesses. These findings suggest decrease in cognitive functions of RLS patients probably due to dopaminergic dysfunction regardless of anatomical neural degeneration. Longitudinal follow-up studies are warranted to evaluate whether neuronal degeneration will develop.

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSION

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

Mapping the changed hubs and corresponding functional connectivity in idiopathic restless legs syndrome

OBJECTIVE

The hubs of the brain network play a key role in integrating and transferring information between different functional modules. However, whether the changed pattern in functional network hubs contributes to the onset of leg discomfort symptoms in restless legs syndrome (RLS) patients remains unclear. Using resting-state functional magnetic resonance imaging (rs-fMRI) and graph theory methods, we investigated whether alterations of hubs can be detected in RLS.

METHODS

First, we constructed the whole-brain voxelwise functional connectivity and calculated a functional connectivity strength (FCS) map in each of 16 drug-naive idiopathic RLS patients and 26 gender- and age-matched healthy control (HC) subjects. Next, a two-sample t test was applied to compare the FCS maps between HC and RLS patients, and to identify significant changes in FCS in RLS patients. To further elucidate the corresponding changes in the functional connectivity patterns of the aberrant hubs in RLS patients, whole-brain resting-state functional connectivity analyses for the hub areas were performed.

RESULTS

The hub analysis revealed decreased FCS in the cuneus, fusiform gyrus, paracentral lobe, and precuneus, and increased FCS in the superior frontal gyrus and thalamus in idiopathic drug-naive RLS patients. Subsequent functional connectivity analyses revealed decreased functional connectivity in sensorimotor and visual processing networks and increased functional connectivity in the affective cognitive network and cerebellar-thalamic circuit. Furthermore, the mean FCS value in the superior frontal gyrus was significantly correlated with Hamilton Anxiety Rating Scale scores in RLS patients, and the mean FCS value in the fusiform gyrus was significantly correlated with Hamilton Depression Rating Scale scores.

CONCLUSIONS

These findings may provide novel insight into the pathophysiology of RLS.

Association Between Restless Legs Syndrome and Adult ADHD in a German Community-Based Sample

OBJECTIVE

Previous research in clinical samples indicated a significant association between ADHD and restless legs syndrome (RLS). The present study examined the association between adult ADHD and RLS in the German population.

METHOD

Self-rating instruments to assess RLS, childhood ADHD, and adult ADHD were administered to a community-based sample ( N = 1,632). In addition, current depression and anxiety, sleep disturbances, weight, and height were assessed by self-report.

RESULTS

Adult ADHD was associated with statistically significant increases in the odds of meeting diagnostic criteria for RLS even when adjusting for potential confounding variables such as weight (odds ratio [OR] = 3.18, 95% confidence interval [CI] = [1.29, 7.63], p< .001). However, the association did not hold true after adjusting for the presence of sleep disturbances (OR = 2.02, 95% CI = [0.82, 4.96], p = .13).

CONCLUSION

The findings suggest a strong link between RLS and adult ADHD symptoms. Clinicians should be aware of RLS among adult ADHD patients, especially as there might be a negative interactive effect.

Investigation of alexithymia and levels of anxiety and depression among patients with restless legs syndrome

PURPOSE

The purpose of this study was to examine alexithymia among restless legs syndrome (RLS) patients, compare with healthy controls, and argue the clinical inferences of this relationship. We searched for anxiety and depression and their clinical outcomes among patients and searched whether the results are similar to previous studies.

PATIENTS AND METHODS

Eighty-seven RLS patients and 88 age, gender, and educationally matched healthy controls were assessed in Bezmialem Foundation University Hospital. RLS patients and healthy controls were assessed with the Sociodemographic Data Form constructed for the present study, 20-item Toronto Alexithymia Scale (TAS-20), Beck Depression Inventory (BDI), and Beck Anxiety Scale (BAS). The patient group was also assessed with the International Restless Legs Syndrome Study Group (IRLSSG) RLS Severity Scale.

RESULTS

RLS patients were found to have greater TAS-20, BDI, and BAS scores compared with the control group (P < 0.05). RLS severity score was positively correlated with the scores of anxiety and depression scales. However, no significant relationship was found between scores of IRLSSG RLS scale and TAS-20 total and subscale scores.

CONCLUSION

RLS patients were found to be more alexithymic than healthy controls, whereas no significant relationship was found between RLS severity and levels of alexithymia. Still, alexithymia might be a predictor for early diagnosis and may be considered in the treatment and follow-up of RLS. RLS patients have higher depression and anxiety scores than healthy individuals. Thus, depression and anxiety should be taken into consideration throughout the RLS treatment.

Sleep disorders in patients with ADHD: impact and management challenges

Attention deficit/hyperactivity disorder (ADHD) is one of the most commonly diagnosed disorders in childhood, enduring through adolescence and adulthood and presenting with symptoms of inattention, hyperactivity, and/or impulsivity and significantly impairing functioning. Primary sleep disorders such as sleep-disordered breathing, restless leg syndrome, circadian rhythm sleep disorder, insomnia, and narcolepsy are commonly comorbid in these individuals but not often assessed and are therefore often left untreated. Sleep disturbances in individuals with ADHD can result in significant functional impairments that affect mood, attention, behavior, and ultimately school/work performance and quality of life. Previous reviews have described findings related to sleep but have neglected to examine potential impacts of these sleep disorders and ADHD on daytime functioning. This review investigates empirical findings pertaining to sleep abnormalities and related cognitive, behavioral, emotional, and physical impairments in individuals with ADHD and comorbid primary sleep disorders across the life span. It discusses implications to management and highlights existing limitations and recommended future directions.

Individuals with Restless Legs Syndrome Tend to have Severe Depressive Symptoms: Findings from a Community-Based Cohort Study

Restless legs syndrome (RLS) is a sensorimotor neurological disturbance causing physical and psychological distress. Here, we investigated the severity and effect of depressive symptoms in RLS among a Korean cohort population. Depressive symptoms were more prevalent in the RLS group than in the non-RLS group [≥mild depression: odds ratio (OR)=1.95, p<0.001; ≥ moderate depression: OR=6.15, p<0.001; and ≥severe depression: OR=56.54, p<0.001], with a predominant proportion of severe depression (97%) in the RLS group. We found that difficulty falling asleep (OR=8.16, p<0.001), broken sleep (OR=11.66, p=0.001), early morning awakening (OR=8.5, p<0.001), and excessive daytime sleepiness (OR=3.04, p=0.031) were significantly frequent in individuals with severe depression in the RLS group. Red blood cell count was significantly low in individuals with severe depression in the RLS group (p=0.041). We found that severe depression was associated with RLS, suggesting the evaluation and management of mood symptoms and sleep-related and hematological features when treating RLS.