Socioeconomic impact of restless legs syndrome and inadequate restless legs syndrome management across European settings

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.

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.

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.

An analysis of YouTube videos about restless leg syndrome: Choosing the right guide

Individuals often resort to YouTube as a means of accessing insights into their medical conditions and potential avenues for treatment. Among prevalent and incapacitating afflictions within the general populace, restless leg syndrome assumes significance. The focal objective of this investigation is to scrutinize the caliber inherent in videos pertaining to restless leg syndrome disseminated via the YouTube platform. The sorting of videos was accomplished by gauging their pertinence subsequent to conducting a search for "restless leg syndrome" on YouTube, specifically on the 20th of August, 2023. The evaluation encompassed videos curated from the selection of the top 50 English language videos deemed most relevant. The review process entailed the comprehensive assessment of relevance and content by 2 distinct medical professionals operating independently. Furthermore, pertinent descriptive attributes of each video, such as upload date, view count, likes, dislikes, and comments, were meticulously documented within the dataset. To ascertain video quality, the DISCERN Score, global quality score, and Journal of the American Medical Association rating scales were employed as evaluative tools. Significant statistical disparities were observed in terms of DISCERN scores between videos uploaded by medical doctors and those uploaded by individuals without medical qualifications (P < .001). Correspondingly, upon comparing the 2 aforementioned groups, videos uploaded by healthcare professionals exhibited statistically superior quality scores in both the Journal of the American Medical Association and global quality score assessments (P < .001 for both comparisons). The informational quality regarding restless leg syndrome on YouTube presents a spectrum of variability. Notably, videos that offer valuable insights, as well as those that could potentially mislead viewers, do not display discernible variations in terms of their viewership and popularity. For patients seeking reliable information, a useful and safe approach involves favoring videos uploaded by medical professionals. It is imperative to prioritize the professional identity of the content uploader rather than being swayed by the video's popularity or the quantity of comments it has amassed.

Case report: An OSAS patient with comorbid RLS/PLMS - a closer look at the causes of PAP intolerance

Since 2017, hypoglossal nerve stimulation has been included in the S3-guidelines on restorative sleep/sleep disorders as an alternative treatment for patients with obstructive sleep related breathing disorders who cannot tolerate conventional PAP-therapy. Under certain conditions, some of these patients have the option to have a tongue pacemaker implanted during a surgical procedure to regain a restful night's sleep. However, in some cases it does not solve the problem. In this case report, we present a patient who continued to have restless sleep despite implantation of a hypoglossus nerve stimulator. We provide a closer look at the underlying causes of PAP intolerance and emphasize the importance of a combined pneumological and neurological approach to sleep medicine in sleep-specific therapy evaluation.

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.

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.

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.

Exploration of restless legs syndrome under the new concept: A review

Restless leg syndrome (Restless legs syndrome, RLS) is a common neurological disorder. The pathogenesis of RLS remains unknown, and recent pathophysiological developments have shown the contribution of various genetic markers, neurotransmitter dysfunction, and iron deficiency to the disease, as well as other unidentified contributing mechanisms, particularly chronic renal dysfunction. RLS enhancement syndrome is frequently observed in patients with RLS who have received long-term dopamine agonist therapy, manifesting as a worsening of RLS symptoms, usually associated with an increase in the dose of dopamine agonist. Some patients with RLS can adequately control their symptoms with non-pharmacological measures such as massage and warm baths. First-line treatment options include iron supplementation for those with evidence of reduced iron stores, or gabapentin or pregabalin, as well as dopamine agonists, such as pramipexole. Second-line therapies include opioids such as tramadol. RLS seriously affects the quality of life of patients, and because its pathogenesis is unclear, more biological evidence and treatment methods need to be explored.

Myoclonus and other jerky movement disorders

Myoclonus and other jerky movements form a large heterogeneous group of disorders. Clinical neurophysiology studies can have an important contribution to support diagnosis but also to gain insight in the pathophysiology of different kind of jerks. This review focuses on myoclonus, tics, startle disorders, restless legs syndrome, and periodic leg movements during sleep. Myoclonus is defined as brief, shock-like movements, and subtypes can be classified based the anatomical origin. Both the clinical phenotype and the neurophysiological tests support this classification: cortical, cortical-subcortical, subcortical/non-segmental, segmental, peripheral, and functional jerks. The most important techniques used are polymyography and the combination of electromyography-electroencephalography focused on jerk-locked back-averaging, cortico-muscular coherence, and the Bereitschaftspotential. Clinically, the differential diagnosis of myoclonus includes tics, and this diagnosis is mainly based on the history with premonitory urges and the ability to suppress the tic. Electrophysiological tests are mainly applied in a research setting and include the Bereitschaftspotential, local field potentials, transcranial magnetic stimulation, and pre-pulse inhibition. Jerks due to a startling stimulus form the group of startle syndromes. This group includes disorders with an exaggerated startle reflex, such as hyperekplexia and stiff person syndrome, but also neuropsychiatric and stimulus-induced disorders. For these disorders polymyography combined with a startling stimulus can be useful to determine the pattern of muscle activation and thus the diagnosis. Assessment of symptoms in restless legs syndrome and periodic leg movements during sleep can be performed with different validated scoring criteria with the help of electromyography.

Restless legs syndrome: Over 50 years of European contribution

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

Restless Legs Syndrome: Known Knowns and Known Unknowns

Although restless legs syndrome (RLS) is a common neurological disorder, it remains poorly understood from both clinical and pathophysiological perspectives. RLS is classified among sleep-related movement disorders, namely, conditions characterized by simple, often stereotyped movements occurring during sleep. However, several clinical, neurophysiological and neuroimaging observations question this view. The aim of the present review is to summarize and query some of the current concepts (known knowns) and to identify open questions (known unknowns) on RLS pathophysiology. Based on several lines of evidence, we propose that RLS should be viewed as a disorder of sensorimotor interaction with a typical circadian pattern of occurrence, possibly arising from neurochemical dysfunction and abnormal excitability in different brain structures.

Effect of massage therapy with lavender oil on severity of restless legs syndrome and quality of life in hemodialysis patients

PURPOSE

This study assessed the effects of massage therapy using 5% lavender oil on the severity of restless legs syndrome (RLS) and the quality of life (QoL) of patients on hemodialysis (HD).

DESIGN AND METHODS

This is a randomized placebo-controlled study with a pretest-posttest design. This study was conducted from January 30, 2019, to May 6, 2019, at HD centers in Turkey, and it includes 58 participants-31 study patients and 27 controls. Data were collected using patient identification form, RLS severity rating scale, Kidney Disease Quality of Life Scale (KDQOL^TM -36) and patient follow-up charts. As per the massage therapy protocol, the patients in the study and control groups received massage therapy with lavender oil and baby oil, respectively.

FINDINGS

RLS severity significantly decreased in all follow-up weeks in the study group and in the first, second, and third follow-up weeks in the control group. There were significant differences between the groups in terms of KDQOL^TM -36 subscales and total scores at the initial and final follow-ups.

CONCLUSION

In HD patients, massage with lavender oil lessened the severity of RLS and improved the QoL. Accordingly, this therapy can be recommended to HD patients.

CLINICAL RELEVANCE

Massage therapy during HD sessions is easy, inexpensive, and patient-friendly with no side effects. It is known to reduce symptoms and enable the patients to easily perform daily activities of living. Massage therapy with lavender oil is effective and can be easily applied to patients with RLS by nurses.

TRIAL REGISTRATION

This study was registered under the Clinical Trials protocol registration system (NCT04630470) upon completion.

Restless legs syndrome

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

The relationship between sleep disorders, anxiety, depression, and cognitive function with restless legs syndrome (RLS) in the elderly

OBJECTIVES

Restless legs syndrome (RLS) has a significant effect on sleep and quality of life. Delays in diagnosis and treatment are frequent due to a lack of awareness. In this study, a clinical analysis was performed to examine the relationship between sleep, mood, and cognitive function in RLS.

METHODS

According to the Pittsburgh Sleep Quality Index score (PSQI), patients with RLS were divided into a sleep disorders group (SD, PSQI > 7) and non-sleep disorders group (NSD, PSQI ≤ 7). Healthy controls were selected as a control group matched for age, cultural background, and marital status. We compared differences between the three groups using the Hamilton Anxiety Scale (HAMA), Hamilton Depression (HAMD), Mini-Mental State Examination (MMSE), and Montreal Cognitive Assessment (MoCA). The SD and NSD groups were also assessed with the Restless Leg Syndrome Rating Scale (RLSRS) and the severity of RLS between the two groups was compared. The analysis used t-test, ANOVA, and Pearson correlation.

RESULTS

(1) Among the 54 RLS patients, 30 people in the control group, 35 patients with sleep disorders (SD, 65%), and 19 patients without sleep disorders (NSD, 35%), there were no significant differences in age, educational level, marital status, or trauma history. (2) The comparison results of the case group (SD and NSD) and the control group showed highly significant differences (P < 0.01) in the PSQI-HAMA-HAMD score but no significant differences between the NSD group, the SD group, and the control group in MMSE score. There was no difference between the NSD group and the control group in the MoCA, but a significant difference (P < 0.05) between the SD group and the control group was found. (3) The comparison between the NSD and the SD groups revealed significant differences in the RLSRS, HAMA, and HAMD scores (P < 0.05), but there were no statistical differences (P > 0.05) between two groups on MMSE and MoCA score. (4) Correlation and regression showed that there was a linear correlation between PSQI scores and RLSRS and HAMD scores in patients with RLS (P < 0.05). The regression equation was PSQI =  - 2.393 + 0.494 RLSRS + 0.170 HAMD.

CONCLUSIONS

RLS patients were prone to sleep disorders, anxiety, and depression. Sleep disorders increased with the severity of the RLS and had some influence on the patient's cognitive function. Sleep disorders were closely related to RLSRS and HAMD.

Therapy satisfaction and willingness-to-pay in Polish patients with restless legs syndrome

PURPOSE

Restless legs syndrome (RLS) is a serious burden for patients which can be measured in economic terms by assessing the money spent on therapy and the willingness to pay. The aim of this study was to assess whether or not patients feel satisfied with the therapy relative to the money they spent on the treatment, and to assess patients' willingness to pay for therapy that fully eliminates all RLS symptoms.

METHODS

Adult subjects with RLS confirmed by actual international consensus criteria, a positive RLS-Diagnostic Index (RLS-DI) score, and clinical examinations and observations were assessed to generate a disease severity index. An original set of questions was used to collect data on patient satisfaction with therapy and their willingness to pay.

RESULTS

Among 100 subjects, 27% were not satisfied with therapy; this subgroup was characterized by lower indices of severity of the disease. Patients spent approximately 3% of their income in treating RLS. They are willing to pay up to 8.3% of their income to eliminate symptoms.

CONCLUSIONS

The cost of RLS therapy is a significant part of patient expenditure. Nevertheless, RLS may at times remain so troublesome for patients that they are willing to spend more on therapy to eliminate symptoms.

The Social And Economic Cost Of Sleep Disorders

STUDY OBJECTIVES

To estimate economic cost of common sleep disorders in Australia for 2019-2020.

METHODS

Costs were estimated for obstructive sleep apnea (OSA), insomnia, and restless legs syndrome (RLS) using prevalence, financial, and nonfinancial data from national databases. These included: (1) financial costs associated with health care, informal care, productivity losses, non-medical accident costs, deadweight loss from taxation/welfare inefficiencies; and (2) nonfinancial costs associated with loss of well-being. They were expressed in US dollars ($).

RESULTS

Estimated overall cost of sleep disorders in Australia in 2019-2020 (population: 25.5 million) was $35.4 billion (OSA $13.1 billion; insomnia $13.3 billion, RLS $9.0 billion). Of this, the financial cost component was $10.0 billion, comprised of: health system costs $0.7 billion; productivity losses $7.7 billion; informal care $0.2 billion; other, mainly non-medical accident costs, $0.4 billion; and deadweight losses $1.0 billion. For moderate to severe OSA syndrome, insomnia unrelated to other conditions and RLS, financial costs represented $16,717, $21,982, and $16,624 per adult with the condition for the year, respectively. The nonfinancial cost was $25.4 billion.

CONCLUSIONS

The economic costs associated with sleep disorders are substantial. The financial component of $10.0 billion is equivalent to 0.73% of Australian gross domestic product. The nonfinancial cost of $25.4 billion represents 3.2% of total Australian burden of disease for the year. Health system costs of these disorders are low relative to those associated with their consequences, suggesting greater expenditure on detection, treatment and prevention is warranted.

Grey matter alterations in restless legs syndrome: A coordinate-based meta-analysis

Brain structural abnormalities in idiopathic restless legs syndrome have long been debated. Voxel-based morphometry is an objective structural magnetic resonance imaging technique to investigate regional grey matter volume or density differences between groups. In the last decade, voxel-based morphometry studies have exhibited inconsistent and conflicting findings regarding the presence and localization of brain grey matter alterations in restless legs syndrome. We therefore conducted a coordinate-based meta-analysis to quantitatively examine whether there were consistent grey matter findings in restless legs syndrome using the latest algorithms, seed-based d mapping with permutation of subject images. We included 12 voxel-based morphometry studies (13 datasets, 375 patients and 385 healthy controls). Our coordinate-based meta-analysis did not identify evidence of consistent grey matter alterations in restless legs syndrome. Grey matter alterations via voxel-based morphometry analysis are not therefore recommended to be used as a reliable surrogate neuroimaging marker for restless legs syndrome. This lack of consistency may be attributed to differences in sample size, genetics, gender distribution and age at onset, clinical heterogeneity (clinical course, anatomical distribution of symptoms, disease severity, disease duration, abnormal sensory profiles and comorbidity), and variations in imaging acquisition, data processing and statistical strategies. Longitudinal studies with multimodal neuroimaging techniques are needed to determine whether structural changes are dynamic and secondary to functional abnormalities.

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.