Restless legs syndrome

Translation from Preclinical Research to Clinical Trials: Transdermal Drug Delivery for Neurodegenerative and Mental Disorders

Neurodegenerative diseases (NDs), particularly dementia, provide significant problems to worldwide healthcare systems. The development of therapeutic materials for various diseases has a severe challenge in the form of the blood-brain barrier (BBB). Transdermal treatment has recently garnered widespread favor as an alternative method of delivering active chemicals to the brain. This approach has several advantages, including low invasiveness, self-administration, avoidance of first-pass metabolism, preservation of steady plasma concentrations, regulated release, safety, efficacy, and better patient compliance. Topics include the transdermal method for therapeutic NDs, their classification, and the mechanisms that allow the medicine to enter the bloodstream through the skin. The paper also discusses the obstacles and potential outcomes of transdermal therapy, emphasizing the benefits and drawbacks of different approaches.

The global and regional prevalence of restless legs syndrome among adults: A systematic review and modelling analysis

Background

Restless legs syndrome (RLS) is a prevalent neuro-sensory disorder that impairs quality of life. In this systematic review and modelling study, we estimated the global and regional prevalence of RLS and its associated factors.

Methods

We searched PubMed, Embase, and Medline for population-based studies on RLS prevalence published up to 12 November 2023. The included studies reported prevalence using the International Restless Leg Syndrome Study Group's (IRLSSG) minimal diagnostic criteria without limitations on frequency, duration, or severity. We applied a multilevel multivariable mixed-effects meta-regression to generate the age-specific and sex-specific prevalence of RLS for high socio-demographic index (H-SDI) and low and middle socio-demographic index (LM-SDI) regions. We pooled odds ratios (ORs) for RLS associated factors using random-effects models. Finally, we derived the regional prevalence and cases of RLS based on an associated factor-based model.

Results

From 52 articles across 23 countries, the global RLS prevalence in 2019 was estimated to be 7.12% (95% confidence interval (CI) = 5.15-9.76) among adults 20-79 years of age, equating to 356.07 million (95% CI = 257.61-488.09) affected individuals. Prevalence was similar in H-SDI (7.29%; 95% CI = 5.04-10.41) and LM-SDI (7.10%; 95% CI = 5.16-9.70) regions, with the majority of cases in LM-SDI countries (323.06 million; 90.73%). Europe had the highest (7.60%; 95% CI = 5.44-10.52) and Africa the lowest regional prevalence (6.48%; 95% CI = 4.70-8.87). The Western Pacific Region, meanwhile, had the most cases (111.91 million; 95% CI = 80.93-153.42). Factors positively associated with RLS included advanced age (OR = 1.13; 95% CI = 1.04-1.24), smoking (OR = 1.46; 95% CI = 1.29-1.64), depression (OR = 1.71; 95% CI = 1.26-2.32), and diabetes (OR = 1.54; 95% CI = 1.19-1.97).

Conclusions

A considerable global burden of RLS exists. Effective strategies are needed to increase awareness and optimise resource allocation to address this often-overlooked condition. High-quality epidemiological investigations employing standardised and rigorous criteria for RLS are essential for addressing RLS burden more effectively.

Registration

PROSPERO: CRD42020161860.

Genome-wide meta-analyses of restless legs syndrome yield insights into genetic architecture, disease biology and risk prediction

Restless legs syndrome (RLS) affects up to 10% of older adults. Their healthcare is impeded by delayed diagnosis and insufficient treatment. To advance disease prediction and find new entry points for therapy, we performed meta-analyses of genome-wide association studies in 116,647 individuals with RLS (cases) and 1,546,466 controls of European ancestry. The pooled analysis increased the number of risk loci eightfold to 164, including three on chromosome X. Sex-specific meta-analyses revealed largely overlapping genetic predispositions of the sexes (rg = 0.96). Locus annotation prioritized druggable genes such as glutamate receptors 1 and 4, and Mendelian randomization indicated RLS as a causal risk factor for diabetes. Machine learning approaches combining genetic and nongenetic information performed best in risk prediction (area under the curve (AUC) = 0.82-0.91). In summary, we identified targets for drug development and repurposing, prioritized potential causal relationships between RLS and relevant comorbidities and risk factors for follow-up and provided evidence that nonlinear interactions are likely relevant to RLS risk prediction.

Why cells need iron: a compendium of iron utilisation

Iron deficiency is globally prevalent, causing an array of developmental, haematological, immunological, neurological, and cardiometabolic impairments, and is associated with symptoms ranging from chronic fatigue to hair loss. Within cells, iron is utilised in a variety of ways by hundreds of different proteins. Here, we review links between molecular activities regulated by iron and the pathophysiological effects of iron deficiency. We identify specific enzyme groups, biochemical pathways, cellular functions, and cell lineages that are particularly iron dependent. We provide examples of how iron deprivation influences multiple key systems and tissues, including immunity, hormone synthesis, and cholesterol metabolism. We propose that greater mechanistic understanding of how cellular iron influences physiological processes may lead to new therapeutic opportunities across a range of diseases.

Suspected duloxetine-induced restless legs syndrome phenotypic variant: a case report

BACKGROUND

Restless arms syndrome (RAS) is the most common variant of restless legs syndrome (RLS), which is easy to be ignored in clinical practice due to the lack of specific diagnostic criteria. When effective therapeutic agents induced RAS and symptoms persisted after briefly observation, clinicians will face the challenge of weighing efficacy against side effects.

CASE PRESENTATION

A 67-year-old woman was admitted to a geriatric psychiatric ward with depression. Upon admission, the escitalopram dose was reduced from 15 mg to 10 mg per day, and the duloxetine dose was increased from 60 mg to 80 mg per day. The next night before bedtime, she developed itching and creeping sensations deep inside bilateral shoulders and arms, with the urge to move, worsening at rest, and alleviation after hammering. The symptoms persisted when escitalopram was discontinued. A history of RLS was confirmed. Treatment with 40 mg of duloxetine and 0.125 mg of pramipexole significantly improved depression, and the paresthesia disappeared, with no recurrence occurring 6 months after discharge.

DISCUSSION AND CONCLUSIONS

This case suggests that psychiatrists should pay attention to RLS variants when increasing doses of duloxetine. Long-term improvement can be achieved through dosage reduction combined with dopaminergic drugs instead of immediate discontinuation.

Successful treatment of restless legs syndrome accompanied by headaches for 30 years with herbal prescriptions containing Paeoniae Radix: A case report

BACKGROUND

Restless legs syndrome (RLS) is a neurological disorder that causes unpleasant symptoms in the legs when resting, which are relieved by movement. Pharmacotherapy is the standard treatment. However, current treatment provides only symptomatic relief and may result in adverse effects with long-term use. Treatment protocols using herbal medicines have emerged to compensate for this limitation.

CASE PRESENTATION

A 70-year-old Asian woman visited our hospital with worsening headaches that had persisted for 30 years. Her headaches were aggravated by night-time lower-extremity discomfort. The patient was diagnosed with RLS based on the 2012 Revised International Restless Leg Syndrome Study Group Diagnostic Criteria (IRIS). The patient was prescribed herbal medicines, Shihogyeji-tang, Gyejibokryeong-hwan, and Jakyakgamcho-tang, all of which contain Paeoniae Radix. Fourteen days after starting herbal medicine treatment, the IRIS score decreased from 30 to 18. The patient experienced less leg discomfort. Moreover, her sleep time increased, and her headaches resolved. After 28 days of herbal treatment, the IRIS score decreased to 9. Importantly, the patient reported no sleep disturbance or headaches. Subsequently, conventional medications were discontinued. The patient remained stable (IRIS score: 9-10). Herbal treatment was discontinued on day 163. At the last follow-up, (day 364), the patient has not reported any symptom recurrence.

CONCLUSIONS

We described a female patient with a 30-year history of RLS symptoms and related sleep disturbances that induced chronic uncontrolled headaches, who experienced improvements shortly after using herbal medicines containing Paeoniae Radix. Conventional medications were discontinued and the patient had no recurrence of symptoms. Considering these, herbal medicines containing Paeoniae Radix may be a suitable alternative treatment for RLS and its related symptoms.

Restless leg syndrome as a complication of primary hyperparathyroidism: insights from a retrospective study

INTRODUCTION

Restless leg syndrome (RLS) is an invalidating neurological disorder with a complex, largely unknown pathophysiology. While RLS is observed in Parkinson's disease and in renal failure, idiopathic cases are common. Limited reports associate RLS with parathyroid hormone (PTH). This study analyzes a cohort of patients with primary hyperparathyroidism (PHPT) and chronic post-surgical hypoparathyroidism (hypo PTH), to investigate RLS prevalence, and associated risk factors.

METHODS

Ninety-five patients (54 PHPT, 41 hypo PTH) were consecutively enrolled at the bone metabolism outpatient clinic. The revised IRLSSG diagnostic criteria were used to diagnose RLS, with assessments conducted through face-to-face interviews and neurological examination. When RLS was confirmed, the RLS severity scale was applied. Retrospective records included calcium-phosphate metabolism-related parameters, surgery details, renal lithiasis, fragility fractures, and densitometric features (T-score).

RESULTS

RLS was diagnosed in 22.2% PHPT patients, compared to 4.9% of patients with hypo PTH (p = 0.02). Of RLS diagnosed patients, 91.7% had a history of parathyroidectomy, compared to 47.6% of patients without RLS (p = 0.01). Most of the operated patients reported that surgery determined an improvement of symptoms; however, mean score severity of RLS at our evaluation was 15/40, defined as moderate. PTH and calcium levels were not statistically associated to the presence of RLS.

CONCLUSION

Our study suggests that PHPT may be one of the etiologies of RLS. Parathyroidectomy alleviates symptoms in the vast majority of the cases but does not remove them.

Unveiling the pathophysiology of restless legs syndrome through transcriptome analysis

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

A survey-based approach on restless legs syndrome: practices and perspectives among Italian neurologists

INTRODUCTION

Restless Legs Syndrome (RLS) is a widely prevalent and complex neurological disorder. Despite notable advancements in managing RLS, the disorder continues to face challenges related to its recognition and management.

OBJECTIVE

This study seeks to gain comprehensive insights into the knowledge and clinical practices among Italian neurologists regarding RLS diagnosis, management, and treatment, comparing approaches among general neurologists, movement disorder specialists, and sleep experts.

METHODS

Members of the Italian Society of Neurology, the Italian Society of Parkinson and Movement Disorders, and the Italian Association of Sleep Medicine were invited to participate in a 19-question online survey.

RESULTS

Among the 343 surveyed neurologists, 60% categorized RLS as a "sleep-related movement disorder." Forty% indicated managing 5-15 RLS patients annually, with sleep specialists handling the highest patient volume. Of note, only 34% adhered strictly to all five essential diagnostic criteria. The majority (69%) favored low-dosage dopamine agonists as their first-line treatment, with movement disorder specialists predominantly endorsing this approach, while sleep experts preferred iron supplementation. Regular screening for iron levels was widespread (91%), with supplementation typically guided by serum iron alterations. In cases of ineffective initial treatments, escalating dopamine agonist dosage was the preferred strategy (40%).

CONCLUSIONS

These findings underscore a lack of a clear conceptualization of RLS, with a widespread misconception of the disorder as solely a movement disorder significantly influencing treatment approaches. Disparities in RLS understanding across neurology subspecialties underscore the necessity for improved diagnostic accuracy, targeted educational initiatives, and management guidelines to ensure consistent and effective RLS management.

Guidelines for the assessment and management of residual sleepiness in obstructive apnea-hypopnea syndrome: Endorsed by the French Sleep Research and Medicine Society (SFRMS) and the French Speaking Society of Respiratory Diseases (SPLF)

Excessive daytime sleepiness (EDS) is frequent among patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and can persist despite the optimal correction of respiratory events (apnea, hypopnea and respiratory efforts), using continuous positive airway pressure (CPAP) or mandibular advancement device. Symptoms like apathy and fatigue may be mistaken for EDS. In addition, EDS has multi-factorial origin, which makes its evaluation complex. The marketing authorization [Autorisation de Mise sur le Marché (AMM)] for two wake-promoting agents (solriamfetol and pitolisant) raises several practical issues for clinicians. This consensus paper presents recommendations of good clinical practice to identify and evaluate EDS in this context, and to manage and follow-up the patients. It was conducted under the mandate of the French Societies for sleep medicine and for pneumology [Société Française de Recherche et de Médecine du Sommeil (SFRMS) and Société de Pneumologie de Langue Française (SPLF)]. A management algorithm is suggested, as well as a list of conditions during which the patient should be referred to a sleep center or a sleep specialist. The benefit/risk balance of a wake-promoting drug in residual EDS in OSAHS patients must be regularly reevaluated, especially in elderly patients with increased cardiovascular and psychiatric disorders risks. This consensus is based on the scientific knowledge at the time of the publication and may be revised according to their evolution.

Stakeholder involvement in the optimization of a patient-centered exercise intervention for people with restless legs syndrome

STUDY OBJECTIVES

Previous research supports exercise as a behavioral approach to manage symptoms of restless legs syndrome (RLS); however, completion rates in exercise studies are low. This study obtained key stakeholder feedback from people with RLS to modify and optimize a 12-week, evidence-based exercise program for RLS.

METHODS

Participants with RLS (n = 513) completed a nationwide survey to provide feedback on the necessity, interest, feasibility, and efficacy of the program as well as perceived barriers and proposed modifications to improve the exercise program.

RESULTS

Most respondents (67%) expressed the need for an exercise program designed specifically for people with RLS and 64% were interested in the program. Only 6% of participants thought the program would not be well tolerated and 6% responded that it would likely exacerbate symptoms. However, only 58% said they would be likely to participate in the program if it was available to them locally. Key barriers to participation were (1) accessibility, (2) personal factors, (3) trustworthiness, and (4) fear of injury, illness, or symptom exacerbations. Respondents highlighted modification considerations for the individualization of exercise features, adaptations for specific impairments/personal factors, inclusion of flexibility and balance exercises, and flexibility for more home-based activities.

CONCLUSIONS

Interest in the program was driven by the desire to reduce medications and improve overall quality of life. Appropriately educated and trained exercise providers knowledgeable about RLS are integral to buy-in from stakeholders. This study provides an imperative step in clinical research that can increase the success of subsequent implementation efforts and may accelerate the adoption of exercise programs into practice.

CITATION

Cederberg KLJ, Sikes EM, Mignot E. Stakeholder involvement in the optimization of a patient-centered exercise intervention for people with restless legs syndrome. J Clin Sleep Med. 2024;20(4):535-543.

An expedited model for identifying potential patients with periodic leg movements

Periodic leg movements during sleep (PLMS) may have crucial consequences in adults. This study aimed to identify baseline characteristics, symptoms, or questionnaires that could help to identify sleep-disordered breathing patients with significant PLMS. Patients aged 20-80 years who underwent polysomnography for assessing sleep disturbance were included. Various factors such as sex, age, body measurements, symptoms, apnea-hypopnea index (AHI), and sleep quality scales were analysed to determine the presence of PLMS. The study included 1480 patients with a mean age of 46.4 ± 13.4 years, among whom 110 (7.4%) had significant PLMS with a PLM index of 15 or higher. There were no significant differences observed in terms of sex or BMI between patients with and without significant PLMS. However, the odds ratios (OR) for PLMS were 4.33, 4.41, and 4.23 in patients who were aged over 50 years, had insomnia, or had an ESS score of less than 10, respectively. Notably, the OR increased up to 67.89 times in patients who presented with all three risk factors. Our analysis identified significant risk factors for PLMS: age over 50, self-reported insomnia, and lower daytime sleepiness levels. These findings aid in identifying potential PLMS patients, facilitating confirmatory examinations and managing associated comorbidities.

Restless legs syndrome in the dominant Parkinson's side related to subthalamic deep-brain stimulation

BACKGROUND

Restless legs syndrome (RLS) has an increased estimated prevalence in patients with Parkinson's disease (PS). RLS frequently mimics symptoms intrinsic to PD, such as motor restlessness, contributing to making its diagnosis challenging in this population. We report the case of a patient with new-onset RLS following subthalamic deep-brain stimulation (DBS-STN). We assessed symptoms using suggested immobilization test (SIT) with both DBS-STN activated and switched off.

CASE DESCRIPTION

A 59-year-old man with idiopathic PD developed disabling RLS following DBS-STN at age 58, with PD onset at 50 manifesting as left arm tremor. Despite improved motor symptoms during the month following surgery, the patient experienced left leg discomfort at rest, transiently alleviated by movements due to an irrepressible urge to move, and worsened at night. Symptoms had no temporal relationship with oral dopa-therapy and disappeared when DBS-STN was deactivated. A 1 h SIT assessed motor behavior with irrepressible urge to move, as well as sensory symptoms by visual analog scale. After 30 m DBS-STN was switched off followed by the appearance of tremor in the left arm while both motor and sensory symptoms of RLS disappeared in the left leg.

DISCUSSION

The mechanisms of DBS-STN's impact on RLS remain controversial. We hypothesize the DBS-STN to induce in our patient a hyperdopaminergic tone. DBS-induced and DBS-ameliorated RLS represent interesting conditions to further understand the pathophysiology of RLS. Moreover, the present observation suggests that SIT can be a valuable tool to assess RLS in PD patients before and after DBS-STN in future prospective studies.

A comprehensive update on the ADMET considerations for α2δ calcium channel ligand medications for treating restless legs syndrome

INTRODUCTION

Restless legs syndrome/Willis-Ekbom disease (RLS/WED) is a sleep-related sensory-motor disorder associated with poor sleep quality and impaired daily functioning. In patients affected by chronic RLS/WED, a pharmacological therapy is recommended. International guidelines suggest to start the treatment with a α2δ calcium channel ligand in most cases, unless contraindicated.

AREAS COVERED

The present review is based on an extensive Internet and PubMed search from 1986 to 2024. Our purpose is to describe the absorption, distribution, metabolism, and toxicology (ADMET) of the α2δ ligands, with common consideration for the therapeutic class, specificities of different compounds, efficacy, and safety in relation to other treatment options.

EXPERT OPINION

α2δ ligands are quite similar in their ADMET profiles, sharing most of the pharmacokinetics and potential adverse effects. However, we highlight the linear kinetic of gabapentin enacarbil and pregabalin, differently from gabapentin. α2δ ligands are safe and effective for the treatment of RLS/WED. Additional benefits can be obtained in comorbid insomnia, chronic pain syndromes, history of impulse control disorder, and comorbid anxiety. The use of α2δ ligands is associated with poor risk of augmentation. We still need new long-term safe and effective treatments, which could be developed along with our knowledge of RLS/WED pathophysiology.

Changes in time structure of periodic leg movements during sleep in restless legs syndrome: Effects of sex and age

BACKGROUND

The objective of this study was to check the hypothesis that in women with restless legs syndrome (RLS) different changes occur in periodic leg movements during sleep (PLMS) during the post-menopausal period (using >50 years as a proxy) than in men of the same age.

METHODS

We recruited 36 untreated patients aged 18-50 years (19 men, median age 40 years, and 17 women, median age 37 years) while the remaining 67 were >50 years old (24 men, median age 66.6 years, and 43 women, median age 60.0 years). Leg movement activity during sleep was analyzed by means of an approach utilizing indexes especially suitable to assess leg movement periodicity.

RESULTS

No significant difference was seen between men in the two age groups; conversely, in women, a clear and significant increase in Periodicity Index was observed in the older group, along with a decrease in isolated leg movements. In women, a clear age-related enhancement of PLMS was found in the intermovement interval graphs, especially in the 16-22 s range, which was more evident than that observed in men. The results remained unchanged also when they were replicated by selecting only subjects aged 18-45 years vs. those aged >55 years.

CONCLUSIONS

Our findings indicate that assessing PLMS in women after menopause is clinically relevant because they are probably connected with the hormonal fluctuations of this period of life. Translationally, identifying and addressing PLMS in post-menopausal women is crucial for optimizing their sleep health and addressing potential health risks associated with sleep disturbances.

Correlates of Restless Legs Syndrome in Older People

Background: We examined the association between restless legs syndrome (RLS) and comprehensive geriatric assessment (CGA) data in two older European populations. The second goal was to evaluate correlates of their quality of life (QoL). Methods: Diagnostic criteria of the International RLS Study Group (IRLSSG) and elements of CGA were used in this study. Results: Among the examined 246 participants, 77 (31.3%) suffered from RLS, more often in the UK (39.4%) than in Poland (25.4%) (p = 0.019). In the multivariate logistic regression model, female sex [OR (CI) = 3.29 (1.51-7.21); p = 0.0014], the number of medications per day [OR (CI) = 1.11 (1.02-1.20); p = 0.011] and alcohol consumption [OR (CI) = 5.41 (2.67-10.95); p < 0.001] increased the probability of RLS. Residing in Poland [OR (CI) = 3.06 (1.36-6.88); p = 0.005], the presence of RLS [OR (CI) = 2.90 (1.36-6.17); p = 0.004], chronic heart failure, [OR (CI) = 3.60 (1.75-7.41); p < 0.001], osteoarthritis [OR (CI) = 2.85 (1.47-5.49); p = 0.0016], and urinary incontinence [OR (CI) = 4.74 (1.87-11.9); p < 0.001] were associated with a higher probability of mobility dimension problems in the QoL. Higher physical activity was related to a lower probability of mobility problems [OR (CI) = 0.85 (0.78-0.92); p < 0.001]. Conclusions: female sex, the number of medications and alcohol consumption are independent correlates of RLS in older adults. RLS together with several chronic medical conditions and a low physical activity level were independent correlates of the mobility dimension of the QoL.

Proteomic insights into the pathophysiology of periodic limb movements and restless legs syndrome

OBJECTIVES

We used a high-throughput assay of 5000 plasma proteins to identify biomarkers associated with periodic limb movements (PLM) and restless legs syndrome (RLS) in adults.

METHODS

Participants (n = 1410) of the Stanford Technology Analytics and Genomics in Sleep (STAGES) study had blood collected, completed a sleep questionnaire, and underwent overnight polysomnography with the scoring of PLMs. An aptamer-based array (SomaScan) was used to quantify 5000 proteins in plasma. A second cohort (n = 697) that had serum assayed using a previous iteration of SomaScan (1300 proteins) was used for replication and in a combined analysis (n = 2107). A 5% false discovery rate was used to assess significance.

RESULTS

Multivariate analyses in STAGES identified 68 proteins associated with the PLM index after correction for multiple testing (ie, base model). Most significantly decreased proteins were iron-related and included Hepcidin (LEAP-1), Ferritin, and Ferritin light chain. Most significantly increased proteins included RANTES, Cathepsin A, and SULT 1A3. Of 68 proteins significant in the base model, 17 were present in the 1300 panel, and 15 of 17 were replicated. The most significant proteins in the combined model were Hepcidin (LEAP-1), Cathepsin A, Ferritin, and RANTES. Exploration of proteins in RLS versus non-RLS identified Cathepsin Z, Heme oxygenase 2 (HO-2), Interleukin-17A (upregulated in the combined cohort), and Megalin (upregulated in STAGES only) although results were less significant than for proteins associated with PLM index.

CONCLUSIONS

These results confirm the association of PLM with low iron status and suggest the involvement of catabolic enzymes in PLM/RLS.

Perceptions of exercise and restless legs syndrome: Results from a nationwide survey

Restless legs syndrome is a prevalent, sensorimotor sleep disorder temporarily relieved by movement, with evidence of symptomatic improvement with regular exercise. The present study describes perceptions of the effects of exercise on symptoms of restless legs syndrome. Participants (N = 528) completed a mixed-methods (i.e. numerical and narrative), nationwide survey including items assessing personal experiences with exercise and restless legs syndrome (both positive and negative), as well as restless legs syndrome diagnosis, restless legs syndrome severity, and demographic and clinical characteristics. Responses varied widely on specific experiences with exercise, but a higher percentage of participants indicated positive experiences with exercise than those who reported negative experiences (72%-40%, respectively) with exercise. Further, 54% of respondents reported that exercise only improves restless legs syndrome, while 24% reported exercise only worsens symptoms. Participants described that any abrupt change in exercise routine would almost always elicit restless legs syndrome symptoms (e.g. hiking for a long time, stopping an exercise routine), and that a consistent pattern of exercise improved restless legs syndrome symptoms with an overall beneficial effect on the frequency of symptomatic bouts. Participants further described time of day as impactful for their exercise experience, with > 50% indicating morning exercise improves symptoms and evening exercise worsens symptoms. Participants described several questions that they wanted answered regarding the evidence for exercise in restless legs syndrome and specific exercise prescription recommendations. The present study describes information crucial to the creation of stakeholder-informed health promotion programs for individuals with restless legs syndrome to optimize personalized treatment plans that could prevent and manage symptoms.

Functional recovery after ischemic stroke: Impact of different sleep health parameters

Sleep disturbances after ischaemic stroke include alterations of sleep architecture, obstructive sleep apnea, restless legs syndrome, daytime sleepiness and insomnia. Our aim was to explore their impacts on functional outcomes at month 3 after stroke, and to assess the benefit of continuous positive airway pressure in patients with severe obstructive sleep apnea. Ninety patients with supra-tentorial ischaemic stroke underwent clinical screening for sleep disorders and polysomnography at day 15 ± 4 after stroke in a multisite study. Patients with severe obstructive apnea (apnea-hypopnea index ≥ 30 per hr) were randomized into two groups: continuous positive airway pressure-treated and sham (1:1 ratio). Functional independence was assessed with the Barthel Index at month 3 after stroke in function of apnea-hypopnea index severity and treatment group. Secondary objectives were disability (modified Rankin score) and National Institute of Health Stroke Scale according to apnea-hypopnea index. Sixty-one patients (71.8 years, 42.6% men) completed the study: 51 (83.6%) had obstructive apnea (21.3% severe apnea), 10 (16.7%) daytime sleepiness, 13 (24.1%) insomnia, 3 (5.7%) depression, and 20 (34.5%) restless legs syndrome. Barthel Index, modified Rankin score and Stroke Scale were similar at baseline and 3 months post-stroke in the different obstructive sleep apnea groups. Changes at 3 months in those three scores were similar in continuous positive airway pressure versus sham-continuous positive airway pressure patients. In patients with worse clinical outcomes at month 3, mean nocturnal oxygen saturation was lower whereas there was no association with apnea-hypopnea index. Poorer outcomes at 3 months were also associated with insomnia, restless legs syndrome, depressive symptoms, and decreased total sleep time and rapid eye movement sleep.

From brain to spinal cord: neuromodulation by direct current stimulation and its promising effects as a treatment option for restless legs syndrome

Neuromodulation is a fast-growing field of mostly non-invasive therapies, which includes spinal cord stimulation (SCS), transcranial direct current stimulation (tDCS), vagal nerve stimulation (VNS), peripheral nerve stimulation, transcranial magnetic stimulation (TMS) and transcutaneous spinal direct current stimulation (tsDCS). This narrative review offers an overview of the therapy options, especially of tDCS and tsDCS for chronic pain and spinal cord injury. Finally, we discuss the potential of tsDCS in Restless Legs Syndrome as a promising non-invasive, alternative therapy to medication therapy.

Investigation of the Albumin/Globulin Ratio as a Biomarker in Restless Legs Syndrome

Background Measurement of serum/plasma levels of inflammatory factors in restless legs syndrome (RLS) has been the subject of a few studies, as various inflammatory diseases may demonstrate an association with RLS. The albumin/globulin ratio (AGR) is a parameter that considers two proteins that are indicators of inflammation and has been shown to increase in some inflammatory diseases. No study has evaluated the relationship between RLS and AGR yet. In our study, we examined the usability of AGR as a diagnostic biomarker in RLS patients. Methodology A total of 88 patients and 89 control individuals were included in the study retrospectively. The two groups were compared in terms of AGR levels. RLS patients were divided into four groups according to the International Restless Legs Syndrome Study Group Rating Scale score and the relationship between disease severity and AGR values ​​was examined. Results Albumin levels of the study group were higher than the control group. There was no statistically significant difference between the groups regarding globulin and AGR levels. Conclusions Serum albumin levels could be useful in RLS compared to globulin or AGR values. This needs to be supported by new studies with larger patient series, multicenter design, and including multiple parameters such as patients' muscle mass, nutritional habits, and exercise status.

Sleep in the Athlete

Sleep is important for not only general health but also for lowering injury risk and maintaining athletic performance. Sleep disorders are prevalent in athletes, and taking a sleep history, evaluating sleep quality, and addressing other related factors including mental health are essential in diagnosing and understanding sleep disorders. Other methods such as polysomnography, actigraphy, and sheet sensors can also be used. Treatment options for sleep disorders include sleep hygiene, cognitive behavioral therapy, medication, and addressing contributing factors. For athletes, sleep can also be affected by factors such as travel fatigue and jet lag, which should be taken into consideration.

Cost-Effectiveness of Tonic Motor Activation (TOMAC) Therapy for Patients with Restless Legs Syndrome: An Exploratory Analysis

INTRODUCTION

Tonic motor activation (TOMAC) therapy is a novel non-pharmacologic treatment approach for patients suffering from medication-refractory restless legs syndrome (RLS). The objective of this study was to explore the potential cost-effectiveness of TOMAC in the US healthcare system.

METHODS

A decision-analytic Markov model was constructed to project strategy-specific treatment costs and benefits over 3 years and lifetime. Cohort characteristics (mean age 57.4 years, 39.8% male) and treatment effects were derived from the sham-controlled RESTFUL study. Study-observed International RLS Study Group (IRLS) scores were used to estimate changes in healthcare resource utilization and quality of life based on mapping algorithms informed by published data. The incremental cost-effectiveness ratio (ICER) was evaluated against established willingness-to-pay thresholds of $50,000/$150,000 per QALY to determine cost-effectiveness. Extensive scenario analyses were performed, including longer-term extension study data.

RESULTS

 TOMAC and sham reduced IRLS scores from baseline 25.3 to 18.10 and 21.60, respectively, at 4 weeks (treatment effect - 3.4 vs. sham), with an increase in utility from 0.80 to 0.84 (0.75-0.84 vs. baseline). Over 3 years and lifetime, the TOMAC vs. sham effect size corresponded to an added 0.10 and 0.49 QALYs (2.36 vs. 2.26; 12.59 vs. 12.10) at incremental costs of $8061 and $36,373 ($36,707 vs. $28,646; $224,040 vs.$187,667), resulting in ICER estimates of $83,822 and $73,600, respectively. Compared to baseline, TOMAC resulted in ICER estimates of $29,569 and $23,690 over 3 years and lifetime, respectively. TOMAC remained cost-effective or dominant across all scenarios, with ICERs ranging from $10,530-$83,822 and - $8061 to $29,569 vs. sham and baseline, respectively. Larger TOMAC effect sizes, achieved per extension study data, further increased cost-effectiveness.

CONCLUSION

 Based on this exploratory analysis of published trial data, TOMAC therapy appears to offer meaningful improvements in patient health-related quality at net costs that render it a cost-effective intervention. Further analyses are warranted.

Association of low serum ferritin levels with augmentation in patients with restless legs syndrome: A systematic review and meta-analysis

BACKGROUND

Augmentation of restless legs syndrome (RLS) is an iatrogenic side effect induced by dopaminergic agents, and it is a major cause of therapeutic failure. Iron deficiency is a risk factor for RLS, but its effects on the development of RLS augmentation are unclear. This meta-analysis aimed to elucidate the association between serum ferritin and RLS augmentation.

METHODS

We searched the PubMed, Cochrane Library, Embase, ClinicalKey, ScienceDirect, and ProQuest databases for studies comparing the serum ferritin levels of patients with augmented RLS and nonaugmented RLS. A meta-analysis based on a random-effects model was conducted. Levodopa equivalent dose (LED), International Restless Legs Study Group Severity Rating Scale (IRLS), and serum hemoglobin levels were also analyzed.

RESULTS

Six observational studies fulfilled the eligibility criteria of this meta-analysis. A total of 220 RLS patients with augmentation and 687 RLS patients without augmentation were included. The results revealed that augmented RLS was significantly associated with low serum ferritin levels (p = 0.002), high LEDs (p = 0.026), and nonsignificantly associated with high IRLS scores (p = 0.227).

CONCLUSIONS

A low serum ferritin level is associated with RLS augmentation. For patients with RLS who are iron deficient, iron supplements can not only relieve their fundamental RLS symptoms but also lower the risk of RLS augmentation. Moreover, non-dopminergic agents should be considered as the first-line treatment for patients with persistent low serum ferritin levels or those with moderate to severe RLS to prevent augmentation.

Redefining the role of the cerebellum in restless legs syndrome

OBJECTIVES

We aimed to investigate alterations in cerebellar volume and the intrinsic cerebellar network in patients with restless legs syndrome (RLS).

METHODS

We recruited 69 patients with RLS and 50 healthy controls who underwent brain magnetic resonance imaging (MRI), including three-dimensional T1-weighted imaging. The total cerebellar volume and cerebellar volume subdivisions were analyzed through automatic cerebellum anatomical parcellation using U-Net with locally constrained optimization program. The intrinsic cerebellar network was calculated through brain analysis using a graph theory program based on the cerebellar volume subdivisions. The cerebellar volumes and intrinsic cerebellar networks were compared between patients with RLS and healthy controls.

RESULTS

The cerebellar volume and subdivisions in patients with RLS did not show significant differences compared to those in healthy controls. However, significant alterations were observed in the intrinsic cerebellar network of patients with RLS. Increased mean clustering coefficient (0.185 vs. 0.114; p = 0.047) and small-worldness index (0.927 vs. 0.800; p = 0.047) were observed in patients with RLS. Additionally, total cerebellar volume was negatively correlated with the Pittsburgh Sleep Quality Index (r = -0.398; p = 0.020) and Insomnia Severity Index (ISI; r = -0.396; p = 0.011). Negative correlations were additionally observed between the right X lobule volume and the International Restless Legs Syndrome Severity Scale (r = -0.425; p = 0.008) and between the vermis VIII volume and ISI score (r = -0.399; p = 0.011).

CONCLUSION

We demonstrated alterations in the intrinsic cerebellar network in patients with RLS compared with healthy controls, showing increased connectivity with increased segregation in patients with RLS. This suggests a potential role of the cerebellum in RLS pathophysiology.

Prevalence and clinical characteristics of sleep disorders in chronic obstructive pulmonary disease: A systematic review and meta-analysis

BACKGROUND

Sleep disorders, including obstructive sleep apnea (OSA), restless leg syndrome (RLS) and insomnia, are present in chronic obstructive pulmonary disease (COPD) with varied prevalence. The aim of this systematic review and meta-analysis was to investigate prevalence of OSA, RLS and insomnia in patients with COPD and summarize their clinical characteristics.

METHODS

We searched PubMed, Web of Science and Scopus for eligible articles reporting the prevalence of OSA, RLS, and insomnia in COPD patients. The Newcastle‒Ottawa scale was applied for quality assessment. Odds ratios or mean differences with 95 % confidence intervals (CIs) were applied for the overall prevalence calculation and clinical characteristics assessment. Sensitivity analysis, subgroup analysis and meta-regression were conducted to evaluate the heterogeneity of the results.

RESULTS

Sixty articles reporting the prevalence of sleep disorders in patients with COPD were included, and the prevalence of OSA, RLS, and insomnia reached 29.1 %(95%CI 27.2%-30.9 %), 21.6 %(95%CI 11.8%-33.3 %) and 29.5 %(95%CI 16.9%-44.0 %), respectively. COPD patients with OSA were characterized by male sex (OR 1.631 95 % CI: 1.231-2.161), obesity(kg/m2) (MD 4.435, 95 % CI 3.218-5.652), higher Epworth Sleepiness Scale (MD: 3.741, 95 % CI: 0.655-6.828, p = 0.018), better pulmonary function (MD 5.66, 95 % CI 3.546-7.774) and higher risks of hypertension (OR 1.933 95 % CI 1.382-2.70) and diabetes (OR 1.898 95 % CI 1.264-2.849). COPD patients with RLS were associated with a higher Epworth sleepiness scale (ESS) score (MD 3.444, 95 % CI 1.880-5.008) and a longer COPD duration(year) (MD: 3.656, 95 % CI: 2.209-5.103). COPD patients with insomnia were characterized by female sex(OR 0.556, 95%CI 0.545,0.567, p < 0.001).

CONCLUSION

Our study suggests that OSA, RLS and insomnia are common in COPD patients with specific clinical characteristics. Further studies are needed to explore the interactions between COPD and sleep disorders.

Glymphatic system dysfunction in restless legs syndrome: evidenced by diffusion tensor imaging along the perivascular space

STUDY OBJECTIVES

There is growing evidence pointing at glymphatic system dysfunction in diseases with circadian disruption, such as sleep disorders. Lower diffusivity in the direction of perivascular space has been shown in several neurological and sleep-related disorders; however, its role in restless legs syndrome (RLS) is unclear. We hypothesized that similarly, in RLS the diffusivity in glymphatic system is decreased. Here, we aimed to evaluate glymphatic system functionality in patients with RLS, compare it to healthy controls, and analyze the correlation between its function and clinical characteristics.

METHODS

Sixty-nine patients with primary RLS and 51 healthy controls were recruited at a tertiary hospital. All participants underwent diffusion tensor imaging (DTI) and magnetic resonance imaging (MRI) using a 3T MRI scanner, and the DTI along the perivascular space (DTI-ALPS) index was calculated using DTI data. We compared the DTI-ALPS index between the patients with RLS and healthy controls. We also conducted the correlation analysis between the DTI-ALPS index and clinical characteristics, including age, age of onset, symptom duration, and RLS severity.

RESULTS

DTI-ALPS index differed significantly between the patients with RLS and healthy controls; the DTI-ALPS index in the patients with RLS was lower than that in the healthy controls (1.48 vs. 0.60, p = 0.008). There was no significant correlation between the DTI-ALPS index and clinical characteristics.

CONCLUSION

A significantly lower DTI-ALPS index in patients with RLS suggests that the glymphatic system function is impaired in patients with RLS.

The Relationship between Serum Selenium Levels and Restless Leg Syndrome in Chronic Kidney Disease Patients

Background and Objectives: Chronic kidney disease (CKD) is a global public health issue with rising incidence linked to substantial morbidity and mortality. Selenium, an antioxidant trace element, has been linked to low serum levels in end-stage renal disease. Restless Leg Syndrome (RLS), a sleep disorder, is prevalent in CKD patients and significantly impacts their quality of life. The objective of this study was to examine the correlation between serum selenium levels and the prevalence of restless leg syndrome in individuals with chronic kidney disease. Materials and Methods: Forty-six CKD patients undergoing serum selenium level assessments between 1 January 2020 and 28 February 2022, at the Hitit University Faculty of Medicine Department of Nephrology Outpatient Clinic or Hemodialysis Unit, were included. Patients over 18 years of age with no history of hematological or oncological diseases or acute or chronic inflammatory conditions were included in the study groups. Patients taking selenium supplements were excluded. Demographic data, comorbidities, and laboratory values were collected, and RLS presence and severity were evaluated. Statistical analyses include descriptive statistics, correlation analysis, the Mann-Whitney U test, Student's t test, and Chi-square test. Results: Among the 46 patients, 16 (34.78%) had RLS symptoms. The patient group included 34.78% predialysis, 34.78% peritoneal dialysis, and 30.44% hemodialysis patients, with a median age of 47.98 years. There was no difference in age, gender, and Charlson comorbidity between patients with or without RLS (p = 0.881, p = 0.702, p = 0.650). RLS prevalence varied across CKD subgroups, with hemodialysis patients having a higher prevalence (p = 0.036). Clinical parameters such as blood urea nitrogen, creatinine, calcium, phosphorus, platelet counts, and parathyroid hormone levels exhibited significant differences between patients with and without RLS (p < 0.05). Serum selenium levels were not significantly different between patients with and without RLS (p = 0.327). Conclusions: With an increased comorbidity burden, CKD poses a significant healthcare challenge. When accompanied by RLS, this burden can be debilitating. The difference in CKD stages between groups has shed light on a critical determinant of RLS in this population, emphasizing the role of the chronic kidney disease stage. In our study, serum selenium levels were not associated with the presence and severity of RLS. However, prospective studies with larger numbers of participants are needed to draw a definitive conclusion.

Restless legs syndrome: From clinic to personalized medicine

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

The multifaceted aspects of sleep and sleep-wake disorders following stroke

Sleep-wake disorders (SWD) are acknowledged risk factors for both ischemic stroke and poor cardiovascular and functional outcome after stroke. SWD are frequent following stroke, with sleep apnea (SA) being the most frequent SWD affecting more than half of stroke survivors. While sleep disturbances and SWD are frequently reported in the acute phase, they may persist in the chronic phase after an ischemic stroke. Despite the frequency and risk associated with SWD following stroke, screening for SWD remains rare in the clinical setting, due to challenges in the assessment of post-stroke SWD, uncertainty regarding the optimal timing for their diagnosis, and a lack of clear treatment guidelines (i.e., when to treat and the optimal treatment strategy). However, little evidence support the feasibility of SWD treatment even in the acute phase of stroke and its favorable effect on long-term cardiovascular and functional outcomes. Thus, sleep health recommendations and SWD treatment should be systematically embedded in secondary stroke prevention strategy. We therefore propose that the management of SWD associated with stroke should rely on a multidisciplinary approach, with an integrated diagnostic, treatment, and follow-up strategy. The challenges in the field are to improve post-stroke SWD diagnosis, prognosis and treatment, through a better appraisal of their pathophysiology and temporal evolution.

Cerebellum drives functional dysfunctions in restless leg syndrome

OBJECTIVE

Restless legs syndrome (RLS) has serious effects on patients' sleep quality, physical and mental health. However, the pathophysiological mechanisms of RLS remain unclear. This study utilized both static and dynamic functional activity and connectivity analyses approaches as well as effective connectivity analysis to reveal the neurophysiological basis of RLS.

METHODS

The resting-state functional MRI (rs-fMRI) data from 32 patients with RLS and 33 age-, and gender-matched healthy control (HC) were collected. Dynamic and static amplitude of low frequency fluctuation (ALFF), functional connectivity (FC), and Granger causality analysis (GCA) were employed to reveal the abnormal functional activities and couplings in patients with RLS.

RESULTS

RLS patients showed over-activities in left parahippocampus and right cerebellum, hyper-connectivities of right cerebellum with left basal ganglia, left postcentral gyrus and right precentral gyrus, and enhanced effective connectivity from right cerebellum to left postcentral gyrus compared to HC.

CONCLUSIONS

Abnormal cerebellum-basal ganglia-sensorimotor cortex circuit may be the underlying neuropathological basis of RLS. Our findings highlight the important role of right cerebellum in the onset of RLS and suggest right cerebellum may be a potential target for precision therapy.

Incident mental health episodes after initiation of gabapentinoids vs. dopamine agonists for early-onset idiopathic restless legs syndrome

Limited long-term safety information exists for gabapentinoid treatment of idiopathic restless legs syndrome (RLS). We estimated incident mental health-related emergency department visits and hospitalizations with a primary mental health diagnosis (primary outcome) among early-onset idiopathic RLS patients following first-line treatment initiation and examined outcome risk with gabapentinoids compared with dopamine agonists (DAs). A retrospective cohort study was conducted using administrative claims data from 2012 to 2019. Adults with early-onset (18-44 years) idiopathic RLS initiating either gabapentinoids or DAs within 60 days of new diagnosis were followed up to two years. Incidence rates were calculated and a log-binomial regression model with propensity score weighting estimated relative risk of the outcome and of substance use disorders (SUDs) as a secondary analysis with gabapentinoids. Among a cohort of 6,672 patients, 4,986 (74.7%) initiated DAs and 1,686 (25.3%) gabapentinoids. Incidence of the primary outcome (49.8 [95% CI 40.8-69.3] per 1,000 person-years) and SUDs (49.5 [95% CI 40.6-59.9] per 1,000 person-years) were higher in the gabapentinoid group compared with the DA group. A statistically significant risk of mental health diagnoses with gabapentinoids was not detected, but SUD risk was significant after covariate adjustment. High-risk mental health comorbidities (i.e., SUDs) should be considered when initiating RLS treatments.

Exploring the causes of augmentation in restless legs syndrome

Long-term drug treatment for Restless Legs Syndrome (RLS) patients can frequently result in augmentation, which is the deterioration of symptoms with an increased drug dose. The cause of augmentation, especially derived from dopamine therapy, remains elusive. Here, we review recent research and clinical progress on the possible mechanism underlying RLS augmentation. Dysfunction of the dopamine system highly possibly plays a role in the development of RLS augmentation, as dopamine agonists improve desensitization of dopamine receptors, disturb receptor interactions within or outside the dopamine receptor family, and interfere with the natural regulation of dopamine synthesis and release in the neural system. Iron deficiency is also indicated to contribute to RLS augmentation, as low iron levels can affect the function of the dopamine system. Furthermore, genetic risk factors, such as variations in the BTBD9 and MEIS1 genes, have been linked to an increased risk of RLS initiation and augmentation. Additionally, circadian rhythm, which controls the sleep-wake cycle, may also contribute to the worsening of RLS symptoms and the development of augmentation. Recently, Vitamin D deficiency has been suggested to be involved in RLS augmentation. Based on these findings, we propose that the progressive reduction of selective receptors, influenced by various pathological factors, reverses the overcompensation of the dopamine intensity promoted by short-term, low-dose dopaminergic therapy in the development of augmentation. More research is needed to uncover a deeper understanding of the mechanisms underlying the RLS symptom and to develop effective RLS augmentation treatments.

Exploring Astrocyte-Mediated Mechanisms in Sleep Disorders and Comorbidity

Astrocytes, the most abundant cells in the brain, are integral to sleep regulation. In the context of a healthy neural environment, these glial cells exert a profound influence on the sleep-wake cycle, modulating both rapid eye movement (REM) and non-REM sleep phases. However, emerging literature underscores perturbations in astrocytic function as potential etiological factors in sleep disorders, either as protopathy or comorbidity. As known, sleep disorders significantly increase the risk of neurodegenerative, cardiovascular, metabolic, or psychiatric diseases. Meanwhile, sleep disorders are commonly screened as comorbidities in various neurodegenerative diseases, epilepsy, and others. Building on existing research that examines the role of astrocytes in sleep disorders, this review aims to elucidate the potential mechanisms by which astrocytes influence sleep regulation and contribute to sleep disorders in the varied settings of brain diseases. The review emphasizes the significance of astrocyte-mediated mechanisms in sleep disorders and their associated comorbidities, highlighting the need for further research.

Defect of the Endogenous Inhibitory Pain System in Idiopathic Restless Legs Syndrome: A Laser Evoked Potentials Study

BACKGROUND

Restless legs syndrome (RLS) is a complex sensorimotor disorder. Symptoms worsen toward evening and at rest and are temporarily relieved by movement. Symptoms are perceived as painful in up to 45% of cases, and nociception system may be involved.

OBJECTIVES

To assess the descending diffuse noxious inhibitory control in RLS patients.

METHODS

Twenty-one RLS patients and twenty age and sex-matched healthy controls (HC) underwent a conditioned pain modulation protocol. Cutaneous heat stimuli were delivered via laser evoked potentials (LEPs) on the dorsum of the right hand (UL) and foot (LL). N2 and P2 latencies, N2/P2 amplitude and pain ratings (NRS) were recorded before (baseline), during, and after a heterotopic noxious conditioning stimulation (HNCS) application. The baseline/HNCS ratio was calculated for both UL and LL.

RESULTS

N2 and P2 latencies did not vary between groups at each condition and limbs. Both groups showed a physiological N2/P2 amplitude and NRS reduction during the HNCS condition in UL and LL in comparison to baseline and post conditions (all, P < 0.003). Between-groups comparisons revealed a significant lower amplitude reduction in RLS at the N2/P2 amplitude during the HNCS condition only for LL (RLS, 13.6 μV; HC, 10.1 μV; P = 0.004). Such result was confirmed by the significant difference at the ratio (RLS, 69%, HC, 52.5%; P = 0.038).

CONCLUSIONS

The lower physiological reduction during the HNCS condition at LL in RLS patients suggests a defect in the endogenous inhibitory pain system. Further studies should clarify the causal link of this finding, also investigating the circadian modulation of this paradigm. © 2023 International Parkinson and Movement Disorder Society.

Epigenetic Association Analyses and Risk Prediction of RLS

BACKGROUND

As opposed to other neurobehavioral disorders, epigenetic analyses and biomarkers are largely missing in the case of idiopathic restless legs syndrome (RLS).

OBJECTIVES

Our aims were to develop a biomarker for RLS based on DNA methylation in blood and to examine DNA methylation in brain tissues for dissecting RLS pathophysiology.

METHODS

Methylation of blood DNA from three independent cohorts (n = 2283) and post-mortem brain DNA from two cohorts (n = 61) was assessed by Infinium EPIC 850 K BeadChip. Epigenome-wide association study (EWAS) results of individual cohorts were combined by random-effect meta-analysis. A three-stage selection procedure (discovery, n = 884; testing, n = 520; validation, n = 879) established an epigenetic risk score including 30 CpG sites. Epigenetic age was assessed by Horvath's multi-tissue clock and Shireby's cortical clock.

RESULTS

EWAS meta-analysis revealed 149 CpG sites linked to 136 genes (P < 0.05 after Bonferroni correction) in blood and 23 CpG linked to 18 genes in brain (false discovery rate [FDR] < 5%). Gene-set analyses of blood EWAS results suggested enrichments in brain tissue types and in subunits of the kainate-selective glutamate receptor complex. Individual candidate genes of the brain EWAS could be assigned to neurodevelopmental or metabolic traits. The blood epigenetic risk score achieved an area under the curve (AUC) of 0.70 (0.67-0.73) in the validation set, comparable to analogous scores in other neurobehavioral disorders. A significant difference in biological age in blood or brain of RLS patients was not detectable.

CONCLUSIONS

DNA methylation supports the notion of altered neurodevelopment in RLS. Epigenetic risk scores are reliably associated with RLS but require even higher accuracy to be useful as biomarkers. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Bilateral high-frequency noninvasive peroneal nerve stimulation evokes tonic leg muscle activation for sleep-compatible reduction of restless legs syndrome symptoms

STUDY OBJECTIVES

Restless legs syndrome (RLS) is a prevalent sleep disorder with limited treatment options. Bilateral high-frequency noninvasive peroneal nerve stimulation (NPNS) reduces RLS symptoms. Here, we sought to characterize the mechanism of action for NPNS and identify predictors of treatment response. We hypothesized that, similar to voluntary leg movements, NPNS reduces RLS symptoms by activating leg muscles.

METHODS

For 20 adults with moderate-severe RLS, we tested this hypothesis by recording surface electromyography (EMG) from the tibialis anterior leg muscle while administering NPNS at varying amplitudes to determine the minimum NPNS amplitude that evoked EMG activity (motor threshold) and maximal NPNS amplitude that was not distracting (therapeutic intensity level). Afterwards, participants self-administered NPNS (at the therapeutic intensity level) and sham control for 14 days, each in randomized order. Efficacy was defined as International RLS Study Group Rating Scale (IRLS) score difference for NPNS compared with sham.

RESULTS

NPNS consistently activated leg muscles; NPNS evoked EMG activity at the therapeutic intensity level for 19 of 20 participants (mean TIL: 26.6 mA, mean MT: 18.3 mA). Evoked EMG activity was tonic (not phasic) and sustained over time. Evoked EMG activity predicted efficacy; participants with lower motor thresholds had greater IRLS improvement (r = .45, P = .046). NPNS treatment did not interfere with self-reported sleep onset (NPNS: 16% of nights; sham: 11%; P = .629) and frequently improved self-reported sleep onset (NPNS: 52% of nights; sham: 15%; P = .002).

CONCLUSIONS

These results demonstrate that NPNS reduces RLS symptoms by activating afferent pathways, thereby generating tonic and sustained leg muscle activity without interfering with sleep.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Noninvasive Peripheral Nerve Stimulation for Restless Legs Syndrome; URL: https://clinicaltrials.gov/ct2/show/NCT04700683; Identifier: NCT04700683.

CITATION

Charlesworth JD, Adlou B, Singh H, Buchfuhrer MJ. Bilateral high-frequency noninvasive peroneal nerve stimulation evokes tonic leg muscle activation for sleep-compatible reduction of restless legs syndrome symptoms. J Clin Sleep Med. 2023;19(7):1199-1209.

Reduced Interoception Abilities in Patients with Restless Legs Syndrome

Background

Restless legs syndrome (RLS) is a complex sensorimotor disorder occurring with a typical circadian fashion. Association with additional features, like alexithymia and nocturnal compulsive behaviors further complicates the framework.

Objectives

To assess interoception in RLS.

Methods

A total of 25 RLS patients and 28 controls underwent the heartbeat tracking task (interoceptive accuracy [IAC]). RLS symptoms' frequency, disturbance and duration, nocturnal behaviors, interoceptive awareness (IAW), alexithymia, depressive and anxiety symptoms were also collected.

Results

RLS patients showed significant lower IAC (P = 0.0003) and IAW (P = 0.012), and reported more nocturnal eating behaviors (P < 0.001). IAC positively correlated with IAW (R = 0.32), and negatively correlated with age (R = -0.58). Nocturnal eating behavior negatively correlated with IAC (R = -0.44) and IAW (R = -0.50).

Conclusions

RLS patients presented reduced interoceptive abilities correlating with higher nocturnal eating behaviors. Future studies are needed to explore the role of interoception in RLS pathophysiology, also in relation to other sensorimotor aspects.

Hydrotherapy and acupressure in restless legs syndrome: A randomized, controlled, 3-armed, explorative clinical trial

BACKGROUND

Restless legs syndrome (RLS) is a common neurological disease that has a significant impact on daily activities and quality of life, for which there is often no satisfactory therapy. Complementary medicine, such as acupressure and hydrotherapy, is used to treat patients with RLS; however, the clinical evidence is unclear. This study aims to investigate the effects and feasibility of self-administered hydrotherapy and acupressure in patients with RLS.

METHODS

This is a randomized, controlled, open-label, exploratory, clinical study with 3 parallel arms, comparing both self-applied hydrotherapy (according to the German non-medical naturopath Sebastian Kneipp) and acupressure in addition to routine care in comparison to routine care alone (waiting list control) in patients with RLS. Fifty-one patients with at least moderate restless-legs syndrome will be randomized. Patients in the hydrotherapy group will be trained in the self-application of cold knee/lower leg affusions twice daily for 6 weeks. The acupressure group will be trained in the self-application of 6-point-acupressure therapy once daily for 6 weeks. Both interventions take approximately 20 minutes daily. The 6-week mandatory study intervention phase, which is in addition to the patient preexisting routine care treatment, is followed by a 6-week follow-up phase with optional interventions. The waitlist group will not receive any study intervention in addition to their routine care before the end of week 12. Outcome parameters including RLS-severity, disease and health-related quality of life (RLS-QoL, SF-12), Hospital Anxiety and Depression Score in German version, general self-efficacy scale, and study intervention safety will be measured at baseline and after 6 and 12 weeks. The statistical analyses will be descriptive and exploratory.

CONCLUSION

In the case of clinically relevant therapeutic effects, feasibility, and therapeutic safety, the results will be the basis for planning a future confirmatory randomized trial and for helping to develop further RLS self-treatment concepts.

Sleep disturbances in individuals with down syndrome: An overview

Down Syndrome, or Trisomy 21, is one of the most common birth defects, with 6,000 babies born annually with Down Syndrome in the U.S. One of many health risk factors individuals with Down Syndrome experience is sleep issues, ranging from poor sleep quality to high prevalence of obstructive sleep apnea. This literature review aims to review these sleep challenges in this population and explore consequences and treatment options.

Recent Progress in Long-Term Sleep Monitoring Technology

Sleep is an essential physiological activity, accounting for about one-third of our lives, which significantly impacts our memory, mood, health, and children's growth. Especially after the COVID-19 epidemic, sleep health issues have attracted more attention. In recent years, with the development of wearable electronic devices, there have been more and more studies, products, or solutions related to sleep monitoring. Many mature technologies, such as polysomnography, have been applied to clinical practice. However, it is urgent to develop wearable or non-contacting electronic devices suitable for household continuous sleep monitoring. This paper first introduces the basic knowledge of sleep and the significance of sleep monitoring. Then, according to the types of physiological signals monitored, this paper describes the research progress of bioelectrical signals, biomechanical signals, and biochemical signals used for sleep monitoring. However, it is not ideal to monitor the sleep quality for the whole night based on only one signal. Therefore, this paper reviews the research on multi-signal monitoring and introduces systematic sleep monitoring schemes. Finally, a conclusion and discussion of sleep monitoring are presented to propose potential future directions and prospects for sleep monitoring.

Restless legs syndrome and cognitive function among adults: a systematic review and meta-analysis

BACKGROUND

Changes in the cognitive function of patients with restless legs syndrome is a growing area of research. Although several studies have been performed to investigate the association between restless legs syndrome (RLS) and cognitive function, the outcomes are still controversial. The meta-analysis aimed to elucidate the relationship between RLS and cognition, including global cognition and various cognitive domains including memory, attention, executive function, and spatial cognition.

METHODS

We searched the MEDLINE, EMBASE, and Web of Science databases from inception to November 2022 to screen eligible records. The means and standard deviations of cognitive test scores were obtained to calculate the standard mean difference and 95% confidence intervals.

RESULTS

A total of 1437 records were collected from the initial search and 16 records involving 4635 individuals were ultimately included in the systematic review and meta-analysis. Our data suggest negative associations between RLS and global cognition (SMD, - 0.42; 95% CI - 0.72 to - 0.11; I² = 76.6%) and attention (SMD, - 0.43; 95% CI - 0.73 to - 0.12; I² = 85.3%). No significant differences in memory (SMD, - 0.01; 95% CI - 0.31 to 0.28; I² = 68.0%), executive function (SMD, - 0.10; 95% CI, - 0.30 to 0.11; I² = 52.1%), or spatial cognition (SMD, - 0.17; 95% CI - 0.38 to 0.03; I² = 58.5%) were observed between the RLS and control groups. Moreover, the strength of the results was modified by age but not by sex or region.

CONCLUSIONS

Our findings suggest that RLS is negatively correlated with cognitive function, particularly global cognition and attention. However, the causal relationship, considering more confounders, is worthy of further exploration.

Frequency, risk factors, and impacts on quality of life of the restless legs syndrome and side effects among antidepressant users in a tertiary hospital: an observational cross-sectional study

Restless leg syndrome (RLS) is a common but underestimated sensorimotor disorder that significantly affects the quality of life (QoL) which can be induced by antidepressants. This study aims to investigate the frequency and potential risk factors of RLS and side effects in selective serotonin reuptake inhibitors/serotonin and noradrenaline reuptake inhibitors (SSRI/SNRI) users. This cross-sectional study included 198 outpatients who received SSRI/SNRI for 4-8 weeks. Clinical evaluation was performed using the International Restless Leg Syndrome Study Group rating scale for RLS, Udvalg for Kliniske Undersøgelser side effects rating scale, and a short form 36 (SF-36) questionnaire for QoL. The frequency of RLS was 25%. RLS significantly increased with smoking and habituality. Also, habituality increased neurologic side effects reporting. The use of antipsychotics and calcium channel blockers decreased reporting of autonomic side effects. QoL decreased with RLS, psychiatric, neurologic, autonomic, and other side effects in different domains of SF-36. These findings suggested that SSRI/SNRI use could be associated with a higher risk of RLS, especially in smokers. QoL could be influenced negatively by RLS and all side effects. However, further prospective studies are needed to confirm these associations in large samples.

Presynaptic adenosine receptor heteromers as key modulators of glutamatergic and dopaminergic neurotransmission in the striatum

Adenosine plays a very significant role in modulating striatal glutamatergic and dopaminergic neurotransmission. In the present essay we first review the extensive evidence that indicates this modulation is mediated by adenosine A₁ and A_2A receptors (A₁Rs and A_2ARs) differentially expressed by the components of the striatal microcircuit that include cortico-striatal glutamatergic and mesencephalic dopaminergic terminals, and the cholinergic interneuron. This microcircuit mediates the ability of striatal glutamate release to locally promote dopamine release through the intermediate activation of cholinergic interneurons. A₁Rs and A_2ARs are colocalized in the cortico-striatal glutamatergic terminals, where they form A₁R-A_2AR and A_2AR-cannabinoid CB₁ receptor (CB₁R) heteromers. We then evaluate recent findings on the unique properties of A₁R-A_2AR and A_2AR-CB₁R heteromers, which depend on their different quaternary tetrameric structure. These properties involve different allosteric mechanisms in the two receptor heteromers that provide fine-tune modulation of adenosine and endocannabinoid-mediated striatal glutamate release. Finally, we evaluate the evidence supporting the use of different heteromers containing striatal adenosine receptors as targets for drug development for neuropsychiatric disorders, such as Parkinson's disease and restless legs syndrome, based on the ability or inability of the A_2AR to demonstrate constitutive activity in the different heteromers, and the ability of some A_2AR ligands to act preferentially as neutral antagonists or inverse agonists, or to have preferential affinity for a specific A_2AR heteromer.

Recent advances in dopamine D2 receptor ligands in the treatment of neuropsychiatric disorders

Dopamine is a biologically active amine synthesized in the central and peripheral nervous system. This biogenic monoamine acts by activating five types of dopamine receptors (D_1-5 Rs), which belong to the G protein-coupled receptor family. Antagonists and partial agonists of D₂ Rs are used to treat schizophrenia, Parkinson's disease, depression, and anxiety. The typical pharmacophore with high D₂ R affinity comprises four main areas, namely aromatic moiety, cyclic amine, central linker and aromatic/heteroaromatic lipophilic fragment. From the literature reviewed herein, we can conclude that 4-(2,3-dichlorophenyl), 4-(2-methoxyphenyl)-, 4-(benzo[b]thiophen-4-yl)-1-substituted piperazine, and 4-(6-fluorobenzo[d]isoxazol-3-yl)piperidine moieties are critical for high D₂ R affinity. Four to six atoms chains are optimal for D₂ R affinity with 4-butoxyl as the most pronounced one. The bicyclic aromatic/heteroaromatic systems are most frequently occurring as lipophilic appendages to retain high D₂ R affinity. In this review, we provide a thorough overview of the therapeutic potential of D₂ R modulators in the treatment of the aforementioned disorders. In addition, this review summarizes current knowledge about these diseases, with a focus on the dopaminergic pathway underlying these pathologies. Major attention is paid to the structure, function, and pharmacology of novel D₂ R ligands, which have been developed in the last decade (2010-2021), and belong to the 1,4-disubstituted aromatic cyclic amine group. Due to the abundance of data, allosteric D₂ R ligands and D₂ R modulators from patents are not discussed in this review.

Clonazepam for the management of sleep disorders

BACKGROUND

The objectives of this review and meta-analysis of polysomnographic data are those to focus on the clinical use of clonazepam for the management of sleep disorders by re-analyzing clinical trials and randomized clinical trials which have been published in peer-reviewed journals.

METHODS

A review of the literature including clinical trials and randomized controlled trials was performed in PubMed®, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement protocol. A random effects model meta-analysis was then carried out for the four more frequently reported polysomnographic measures: total sleep time, sleep latency, sleep efficiency, and periodic leg movement during sleep (PLMS) index.

RESULTS

A total of 33 articles were retrieved and screened in full text, of which 18 met the criteria for review; among the latter, nine met the criteria for meta-analysis. The studies included in the review involved patients with insomnia, REM sleep behavior disorder, sleep bruxism, and restless leg syndrome or PLMS which reported, most often, an increase in total sleep time with clonazepam. A clear sleep-promoting effect of clonazepam was found also by meta-analysis.

DISCUSSION AND CONCLUSIONS

Our results indicate that the pharmacological treatment of sleep disorders with clonazepam must always be personalized according to the type of patient, the risk of addiction and the concomitant presence of respiratory disorders are key factors to take into account. However, in light of the clinical evidence of the few studies in the literature on the different types of disorders, more studies on the use of clonazepam (also in association with first choice treatments) are definitely needed.

Effects of bupropion and SSRI antidepressants on leg movement activity and chin muscle tone during sleep in adolescents

STUDY OBJECTIVES

To evaluate the effects of bupropion on periodic limb movements during sleep (PLMS) and chin electromyography tone in children taking it for their mood disorder, compared to the effects of selective serotonin reuptake inhibitors (SSRIs) and of bupropion combined with SSRIs.

METHODS

Six adolescents (aged 16.0 ± 0.63 years) taking bupropion alone and 6 adolescents (aged 15.9 ± 1.36 years) taking bupropion in combination with an SSRI antidepressant were recruited, along with 10 adolescents (aged 16.2 ± 0.2 years) taking different SSRIs, and they were also enrolled together with 17 age- and sex-matched control patients (aged 15.5 ± 1.26 years). Polysomnographic studies were obtained, and participants' leg movement activity during sleep and muscle tone were assessed quantitatively (atonia index) during all sleep stages.

RESULTS

Participants taking SSRIs showed PLMS indices significantly higher than those of control patients, whereas adolescents taking bupropion showed only slightly increased indexes of nonperiodic leg movements during sleep. No differences in PLMS were observed between adolescents taking bupropion alone or in association with SSRIs. The atonia index showed, within each sleep stage, the lowest values in the 2 groups taking SSRIs and the highest in the control patients; adolescents taking bupropion alone tended to show values slightly smaller than those of the control patients.

CONCLUSIONS

We found that similar to adults, in adolescents SSRIs but not bupropion are associated with increased PLMS. Bupropion also seems to counteract the SSRI-induced increase of PLMS, when administered in combination; thus, the dopaminergic effect of bupropion seems to outmatch the antidopaminergic action of SSRIs. Conversely, bupropion does not counteract the effects of SSRIs on chin electromyography tone.

CITATION

DelRosso LM, Mogavero MP, Fickensher A, Bruni O, Schenck CH, Ferri R. Effects of bupropion and SSRI antidepressants on leg movement activity and chin muscle tone during sleep in adolescents. J Clin Sleep Med. 2023;19(1):151-161.