Why do restless legs occur at rest?—pathophysiology of neuronal structures in RLS. Neurophysiology of RLS (part 2)

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.

Restless legs syndrome due to brainstem stroke: A systematic review

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

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.

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

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

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

Abnormal Circadian Modification of Aδ-Fiber Pathway Excitability in Idiopathic Restless Legs Syndrome

Restless legs syndrome (RLS) is characterized by unpleasant sensations generally localized to legs, associated with an urge to move. A likely pathogenetic mechanism is a central dopaminergic dysfunction. The exact role of pain system is unclear. The purpose of the study was to investigate the nociceptive pathways in idiopathic RLS patients. We enrolled 11 patients (mean age 53.2 ± 19.7 years; 7 men) suffering from severe, primary RLS. We recorded scalp laser-evoked potentials (LEPs) to stimulation of different sites (hands and feet) and during two different time conditions (daytime and nighttime). Finally, we compared the results with a matched control group of healthy subjects. The Aδ responses obtained from patients did not differ from those recorded from control subjects. However, the N1 and the N2-P2 amplitudes' night/day ratios after foot stimulation were increased in patients, as compared to controls (N1: patients: 133.91 ± 50.42%; controls: 83.74 ± 34.45%; p = 0.016; Aδ-N2-P2: patients: 119.15 ± 15.56%; controls: 88.42 ± 23.41%; p = 0.003). These results suggest that RLS patients present circadian modifications in the pain system, which are not present in healthy controls. Both sensory-discriminative and affective-emotional components of pain experience show parallel changes. This study confirms the structural integrity of Aδ nociceptive system in idiopathic RLS, but it also suggests that RLS patients present circadian modifications in the pain system. These findings could potentially help clinicians and contribute to identify new therapeutic approaches.

Improvement of Subthalamic Nucleus Deep Brain Stimulation in Sleeping Symptoms in Parkinson's Disease: A Meta-Analysis

Introduction

The aim of this meta-analysis was to evaluate the effects of STN DBS on sleep quality and restless leg symptoms in individuals with PD.

Methods

We searched the PubMed, Web of Science, EMBASE, CNKI, and WANFANG databases published between 1990 and 2019. The articles included were those that contained both pre- and postsurgery data acquired using International RLS Study Group criteria and the Pittsburgh sleep quality index (PSQI) questionnaire with patients' follow-up of at least three months. All studies that met the quality requirements were included in a meta-analysis performed using STATA 12.0 software.

Results

Of 73 articles identified, 7 studies comprising 82 patients were qualified for the current meta-analysis. After adjusting for heterogeneity in study effect sizes, the random effects meta-analysis indicated that STN DBS improved sleep quality and restless leg symptoms significantly (SMD = −1.111, 95% CI: −1.918∼−0.304, P=0.007). Subgroup analysis showed that different sleep scoring criteria had different effects on the condition of sleeping after surgery.

Conclusions

STN DBS is a powerful method in the management of sleep quality and restless leg symptoms in PD patients, but its long-term effects with larger populations must be thoroughly assessed.

A study for the mechanism of sensory disorder in restless legs syndrome based on magnetoencephalography

In spite of the relatively high incidence rate, the etiology and pathogenesis of restless legs syndrome (RLS) are still unclear. Long-term drug treatments fail to achieve satisfying curative effects, which is reflected by rebound and augmentation of related symptoms. An electrophysiological endophenotype experiment was done to investigate the mechanism of somatosensory disorder among RLS patients. Together with 15 normal subjects as the control group, with comparable ages and genders to the RLS patients, 15 primitive RLS patients were scanned by Magnetoencephalography (MEG) under natural conditions; furthermore, the somatosensory evoked magnetic field (SEF) with single and paired stimuli, was also measured. Compared to the control group, the SEF intensities of RLS patients' lower limbs were higher, and the paired-pulse depression (PPD) for SEF in RLS patients was attenuated. It was also revealed by time-frequency analysis of somatosensory induced oscillation (SIO) in RLS patients, that 93.3% of somatosensory induced Alpha (8-12 Hz) oscillations were successfully elicited, while 0% somatosensory induced Gamma (30-55 Hz) oscillations were elicited; which was significantly different from the control group. Additionally, in RLS patients exhibit increased excitability of the sensorimotor cortex, a remarkable abnormality existing in early somatosensory gating control (GC) and an attenuated inhibitory interneuron network, which consequently results in a compensatory mechanism through which RLS patients increase their attention-driven lower limb sensory gating control via somatosensory-induced Alpha (8-12 Hz) oscillation. This hyperexcitability, partially due to an electrocortical disinhibition, may have an important therapeutical implication, and become an important target of neuromodulatory interventions.

A direct interaction between two Restless Legs Syndrome predisposing genes: MEIS1 and SKOR1

Restless Legs syndrome (RLS) is a common sleep disorder for which the genetic contribution remains poorly explained. In 2007, the first large scale genome wide association study (GWAS) identified three genomic regions associated with RLS. MEIS1, BTBD9 and MAP2K5/SKOR1 are the only known genes located within these loci and their association with RLS was subsequently confirmed in a number of follow up GWAS. Following this finding, our group reported the MEIS1 risk haplotype to be associated with its decreased expression at the mRNA and protein levels. Here we report the effect of the risk variants of the three other genes strongly associated with RLS. While these variants had no effect on the mRNA levels of the genes harboring them, we find that the homeobox transcription factor MEIS1 positively regulates the expression of the transcription co-repressor SKOR1. This regulation appears mediated through the binding of MEIS1 at two specific sites located in the SKOR1 promoter region and is modified by an RLS associated SNP in the promoter region of the gene. Our findings directly link MEIS1 and SKOR1, two significantly associated genes with RLS and also prioritize SKOR1 over MAP2K5 in the RLS associated intergenic region of MAP2K5/SKOR1 found by GWAS.

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSION

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

Involvement of the central somatosensory system in restless legs syndrome

Objective

To investigate morphologic changes in the somatosensory cortex and the thickness of the corpus callosum subdivisions that provide interhemispheric connections between the 2 somatosensory cortical areas.

Methods

Twenty-eight patients with severe restless legs syndrome (RLS) symptoms and 51 age-matched healthy controls were examined with high-resolution MRI at 3.0 tesla. The vertex-wise analysis in conjunction with a novel cortical surface classification method was performed to assess the cortical thickness across the whole-brain structures. In addition, the thickness of the midbody of the corpus callosum that links postcentral gyri in the 2 hemispheres was measured.

Results

We demonstrated that a morphologic change occurred in the brain somatosensory system in patients with RLS compared to controls. Patients with RLS exhibited a 7.5% decrease in average cortical thickness in the bilateral postcentral gyrus (p < 0.0001). Accordingly, there was a substantial decrease in the corpus callosum posterior midbody (p < 0.008) wherein the callosal fibers are connected to the postcentral gyrus, suggesting altered white matter properties in the somatosensory pathway.

Conclusion

Our results provide in vivo evidence of morphologic changes in the primary somatosensory system, which could be responsible for the sensory functional symptoms of RLS. These results provide a better understanding of the pathophysiology underlying the RLS sensory symptoms and could lead to a potential imaging marker for RLS.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prevalence of restless legs symptoms according to depressive symptoms and depression type: a cross-sectional study

BACKGROUND

Restless legs syndrome is a sensorimotor disorder and it is associated with several other diseases especially mental illnesses.

AIMS

To analyze the relationship between the symptoms of restless legs syndrome and the severity of depressive symptoms and the prevalence of restless legs symptoms in depression subtypes.

METHODS

A cross-sectional study of primary care patients in the Central Finland Hospital District. The prevalence of restless legs symptoms was studied in 706 patients with increased depressive symptoms and 426 controls without a psychiatric diagnosis by using a structured questionnaire. The depressive symptoms were evaluated with the Beck Depression Inventory (BDI) and the psychiatric diagnosis was confirmed by means of a diagnostic interview (Mini-International Neuropsychiatric Interview). The subjects with increased depressive symptoms were divided into three groups (subjects with depressive symptoms without a depression diagnosis, melancholic depression and non-melancholic depression).

RESULTS

In the whole study population, the prevalence of restless legs symptoms increased with the severity of depressive symptoms. The prevalence of restless legs symptoms was highest in the melancholic and non-melancholic depressive patients (52 and 46%, respectively) and then in subjects with depressive symptoms without a depression diagnosis (43.4%), but the prevalence was also substantial (24.6%) in subjects without a psychiatric diagnosis.

CONCLUSIONS

Restless legs symptoms are very common in primary care among subjects with depression, regardless of the depression type. The prevalence of restless legs symptoms increased with increasing severity of depressive symptoms, regardless of the diagnosis. These findings should be considered in clinical evaluation and treatment of patients visiting their physician due to restless legs or depressive symptoms.

Nerve Decompression and Restless Legs Syndrome: A Retrospective Analysis

Introduction

Restless legs syndrome (RLS) is a prevalent sleep disorder affecting quality of life and is often comorbid with other neurological diseases, including peripheral neuropathy. The mechanisms related to RLS symptoms remain unclear, and treatment options are often aimed at symptom relief rather than etiology. RLS may present in distinct phenotypes often described as “primary” vs. “secondary” RLS. Secondary RLS is often associated with peripheral neuropathy. Nerve decompression surgery of the common and superficial fibular nerves is used to treat peripheral neuropathy. Anecdotally, surgeons sometimes report improved RLS symptoms following nerve decompression for peripheral neuropathy. The purpose of this retrospective analysis was to quantify the change in symptoms commonly associated with RLS using visual analog scales (VAS).

Methods

Forty-two patients completed VAS scales (0–10) for pain, burning, numbness, tingling, weakness, balance, tightness, aching, pulling, cramping, twitchy/jumpy, uneasy, creepy/crawly, and throbbing, both before and 15 weeks after surgical decompression.

Results

Subjects reported significant improvement among all VAS categories, except for “pulling” (P = 0.14). The change in VAS following surgery was negatively correlated with the pre-surgery VAS for both the summed VAS (r = −0.58, P < 0.001) and the individual VAS scores (all P < 0.01), such that patients who reported the worst symptoms before surgery exhibited relatively greater reductions in symptoms after surgery.

Conclusion

This is the first study to suggest improvement in RLS symptoms following surgical decompression of the common and superficial fibular nerves. Further investigation is needed to quantify improvement using RLS-specific metrics and sleep quality assessments.

Optic nerve head, retinal nerve fiber layer and macular thickness analysis in restless legs syndrome

PURPOSE

The human retina contains dopaminergic neurons within the inner retinal layer. Several studies demonstrated dopaminergic neuronal loss in Parkinson's disease (PD) using optical coherence tomography (OCT). Hypothetically, restless legs syndrome (RLS) may have an underlying dopaminergic mechanism and a probable relation to PD is assumed. Therefore, we aimed to analyze retinal morphology in RLS patients.

METHODS

In this cross-sectional study we used spectral domain OCT to measure the features of various retinal layers such as thicknesses of peripapillary retinal nerve fiber layer (RNFL), macular and foveal layers, ganglion cell complex (GCC), and optic nerve head parameters of 36 patients with idiopathic RLS, together with 36 age and sex-matched controls. Differences in the thicknesses of RNFL, macula, GCC and optic disc parameters are statistically compared between patients and controls.

RESULTS

The average peripapillary RNFL thickness, mean macular volume and total retinal thickness were reduced in RLS compared with healthy controls (p = 0.032, p = 0.029, and p = 0.026, respectively). After Bonferroni correction, only the reduction in the inferior inner and outer quadrants of the macula remained significant (p = 0.0040, for both). Optic nerve head parameters (cup volume, cup/disc area ratio, rim area and disc area) and GCC thickness showed no significant difference between patients and healthy controls.

CONCLUSION

Our study revealed significant retinal thinning in the macula region in RLS. Our results may support the dopaminergic dysfunction in the pathogenesis of RLS. Prospective longitudinal studies with a larger sample are needed to corroborate our results.

A Review of Sleep and Its Disorders in Patients with Parkinson's Disease in Relation to Various Brain Structures

Sleep is an indispensable normal physiology of the human body fundamental for healthy functioning. It has been observed that Parkinson's disease (PD) not only exhibits motor symptoms, but also non-motor symptoms such as metabolic irregularities, altered olfaction, cardiovascular dysfunction, gastrointestinal complications and especially sleep disorders which is the focus of this review. A good understanding and knowledge of the different brain structures involved and how they function in the development of sleep disorders should be well comprehended in order to treat and alleviate these symptoms and enhance quality of life for PD patients. Therefore it is vital that the normal functioning of the body in relation to sleep is well understood before proceeding on to the pathophysiology of PD correlating to its symptoms. Suitable treatment can then be administered toward enhancing the quality of life of these patients, perhaps even discovering the cause for this disease.

Is There an Association between Restless Legs Syndrome and Urticaria?

Restless legs syndrome (RLS) is a disease characterized by the urge to move the legs and sleep disturbances. Similarly, chronic spontaneous urticaria (CSU) is a dermatological disease characterized by pruritus and sleep disorders. In this study, we aimed to determine the prevalence and severity of RLS in patients with chronic spontaneous urticaria (CSU) and to compare the quality of sleep of patients with and without RLS in the CSU group using the Pittsburgh Sleep Quality Index. A total of 130 patients with CSU and 100 healthy controls were included in this study. The frequency of RLS, frequency of sleep disturbances, and average score of RLS in patients with CSU were statistically significantly higher than control groups (respectively P = 0.008, P = 0.009, P = 0.004). Subjective sleep quality, sleep latency and habitual sleep efficiency scores in patients with RLS were statistically significantly higher than patients without RLS (respectively P = 0.016, P = 0.007, P = 0.035). We claimed that pruritus of urticaria may decrease the quality of sleep in patients with RLS and it may trigger and worsen the restless legs syndrome. Furthermore, RLS and CSU may share a common etiology.

[Sleep and sleep disorders in the elderly: Part 3: Restless legs syndrome]

Restless legs syndrome (RLS) is a commonly occurring condition with a prevalence of approximately 10%. Women are more often affected than men. There is a primary and a secondary form. Secondary RLS is triggered by iron deficiency, severe renal insufficiency and many drugs and medications. The treatment for RLS is always symptomatic. In addition to treating associated diseases, dopaminergic therapy is paramount. Pharmacotherapy encompasses levodopa (L-dopa) and dopamine agonists, such as pramipexole, ropinirole and rotigotine. A serious complication of dopaminergic therapy is the so-called augmentation. In the case of insufficient efficacy, severe discomfort or augmentation, oxycodone/naloxone is now approved for the treatment of RLS.

Prevalence of restless legs syndrome in somatoform pain disorder and its effect on quality of life

Background:

Persistent somatoform pain disorder (SPD) is a condition in which the patient suffers from persistent, severe and distressing pain; and from associated physical and psychological distress. While presence of restless leg syndrome (RLS) in SPD is understudied, their association might have an impact on general well-being and quality of life (QoL) in SPD.

Aims and Objectives:

Present study aimed at evaluating the prevalence of RLS in SPD patients attending outpatient department services at a tertiary care institute in eastern India.

Materials and Methods:

Two hundred and forty consecutive patients with SPD were screened initially and after applying appropriate inclusion and exclusion criteria, 192 subjects (male = 85, female = 107) were included in the study. Severity of RLS was assessed using a questionnaire of the International Restless Legs Syndrome Study Group and QoL was measured on QoL Enjoyment and Satisfaction Questionnaire-Short Form (Q-LES-Q-SF).

Results:

Revealed a 28% prevalence of RLS is in patients with SPD, which is much higher than its estimated population prevalence. A larger proportion of those with RLS had continuous course of SPD, longer duration of SPD, and higher daytime sleepiness. They also had poorer scores on Q-LES-Q-SF, indicating a poorer QoL overall.

Discussion and Conclusion:

This is the first report, to the best of our knowledge, on this aspect from India. While this association between RLS and SPD may have biological explanation based on abnormal monoaminergic neurotransmission system, the findings call for more vigilant approach to SPD patients in order to improve their QoL and add to their well-being.

Gray matter alteration in patients with restless legs syndrome: a voxel-based morphometry study

The purpose of this study was to demonstrate whether or not restless legs syndrome (RLS) is associated with any morphological change in gray matter. Forty-six RLS subjects and 46 controls were enrolled. We performed voxel-based morphometry analysis and compared the results of the two groups. The RLS subjects showed significant regional decreases of gray matter volume in the left hippocampal gyrus, both parietal lobes, medial frontal areas and cerebellum (uncorrected, P<.001). We found that RLS patients showed structural alteration in the brain and alterations in certain parts of the brain in RLS patients are relevant to RLS.

Transcranial magnetic stimulation in sleep fragmentation: a model to better understand sleep disorders

OBJECTIVE

To investigate practice-dependent plasticity and cortical inhibition/excitability in good sleepers after a night of sleep fragmentation (SF), by means of transcranial magnetic stimulation (TMS).

METHODS

In basal condition (BC), after a full night of spontaneous sleep, and in fragmented condition (FC), after a fragmented night of sleep, motor evoked potential (MEP) amplitude, motor threshold (MT), silent period (SP), and intracortical inhibition were assessed. In both conditions subjects performed, also, a bimanual motor task: MEPs were recorded before and after exercise, and after rest. We evaluated the presence of post-exercise facilitation and delayed facilitation. Subjects reported their alertness level (Stanford Sleepiness Scale-SSS).

RESULTS

MT and SSS were significantly increased in SF. Instead, no significant differences for MEP amplitude or SP or intracortical inhibition were found. In both conditions post-exercise facilitation and delayed facilitation were present.

CONCLUSION

SF produces disruption of nocturnal sleep and increases daytime sleepiness. Confirmatory features of this clinical behaviour could be that in FC we observed a significant increase in SSS and in MT. SF was unable to modify cortical inhibition\excitability and\or to influence plasticity-related parameters. These results seem inconsistent with some of TMS alterations observed in sleep deprivation (SD) and restless legs syndrome (RLS). We suggest that SD and SF represent different phenomena that can depend on various networks acting on motor cortex. We speculate that alterations in cortical excitability found in RLS are intrinsically related to the underlying disease itself and are not instead directly associated with the SF present in RLS.

Restless leg syndrome and sleep quality in lumbar radiculopathy patients

Background. To investigate the frequency of restless leg syndrome (RLS), sleep quality impairment, depression, fatigue, and sleep behavior disorder and to determine the effects of surgery on these parameters in radiculopathy patients resistant to conservative treatment. Methods. The present study included 66 lumbar radiculopathy patients, who were resistant to conservative treatment and had indication of surgery. Five different questionnaires were performed to assess depression (the Beck Depression Inventory (BDI)), sleep quality (the Pittsburgh Sleep Quality Index (PSQI)), fatigue (the Fatigue Severity Scale (FSS)), and presence of RLS and rapid eye movement sleep behavior disorder (RBD). The same questionnaires were also performed on a control group (n = 61). Results. Of the radiculopathy patients, 68.1% had RLS and 92.4% had fatigue. Of the controls, 16.4% had RLS and 59% had fatigue. RBD was present in 8 (12.1%) patients and 3 (4.9%) controls. The PSQI revealed that sleep quality was impaired in 46 (69.7%) patients and 35 (57.4%) controls (P > 0.05). The number of individuals having substantial depression according to the BDI was significantly higher in the patients than in the controls. Conclusions. There was a significant increase in the frequency of RLS, which was significantly decreased in the postoperative period in the radiculopathy patients.

The association of Restless Legs Syndrome with hypertension and cardiovascular disease

Restless Legs Syndrome (RLS), is a sensory-motor neurological disorder that appears to be surprisingly common in the community. Periodic limb movements in sleep are typically encountered in more than 80% of RLS patients and comprise involuntary muscular jerks in the lower limbs, such as flexion of the knees or ankles.  Iron deficiency and dopaminergic neuronal dysfunction in the central nervous system are currently thought to be the likely pathophysiological culprits. There is evidence linking RLS to hypertension and cardiovascular disease. This short review will first present a synopsis of epidemiological, clinical and pathophysiological data concerning the syndrome, and then information on the possible links between RLS and cardiovascular disorders.

Treatment of restless legs syndrome

OPINION STATEMENT

Restless legs syndrome (RLS) is a common, sensorimotor, circadian sleep disorder characterized by the urge to move the legs, particularly at nighttime. It is important to differentiate primary and secondary RLS from other conditions, which can mimic the symptoms of RLS, in particular neuropathy and cramps. Despite considerable advances, the understanding of RLS pathophysiology remains incomplete. Many hypotheses focus on central nervous system structures, although there is increasing evidence that peripheral structures may also be important. There is insufficient evidence at the moment to recommend changes in lifestyle, nutritional supplements and any specific nonpharmacologic treatments. The first-line drugs continue to be dopaminergic medications, including pramipexole, ropinirole, rotigotine transdermal patch and levodopa. However, the phenomenon of RLS augmentation, a paradoxical worsening of symptoms by dopaminergic treatment remains as major problem in treatment of RLS, and prevention of augmentation is one of the main goals in the management of RLS. RLS requires treatment only if it has a significant impact on the patient's nighttime sleep or daily activities. Doses of dopamine agonists should be kept to the minimum required for acceptable symptom reduction. Augmentation may require treatment withdrawal, with prescription of alternate medication. Alternative or additional pharmacologic treatment with a lower level of overall quality of evidence includes opioids (codeine, tramadol, and oxycodone) and anticonvulsants (gabapentin, gabapentin enacarbil, and pregabalin). The choice of the medication should be based on the severity of RLS and the effectiveness of medication for the short-term or long-term treatment of RLS. Iron deficiency must be identified at diagnosis; treatment may improve RLS symptoms and potentially may lower risk of augmentation. There is no clear evidence for treatment of secondary RLS, but agents used in primary RLS should be tried. Comparative long-term trials are required to assess differences in efficacy and augmentation rates between medications used for treatment of RLS.

What treatment works best for restless legs syndrome? Meta-analyses of dopaminergic and non-dopaminergic medications

BACKGROUND

At the time of writing only dopamine agonists are licensed for the treatment of restless legs syndrome (RLS) in various countries, but randomized controlled trials (RCTs) have been performed with other treatments. We performed comprehensive meta-analyses and indirect comparisons of RCTs for all currently recommended treatments of RLS.

METHODS

We searched the Central, Medline, Embase, PsycINFO and CINAHL databases. Outcome measures were the international RLS study group severity scale (IRLS), clinical global impression-improvement, (CGI-I), periodic limb movement index (PLMI), and psychosocial parameters such as quality of life (QoL). We also conducted indirect comparisons by testing for heterogeneity between the substance groups.

RESULTS

Placebo (58 trials) and actively (4 trials) controlled RCTs with dopamine agonists (38 trials), levodopa (4 trials), anticonvulsants (13 trials), most of them with α₂δ ligands (11 trials), opioids (1 trial), and iron treatments (6 trials) were included (9596 patients). Although treatment effects showed large variations, changes in the IRLS in the substance groups were comparable (P = 0.78), with a mean reduction in the IRLS of -5.47 points for dopamine agonists, -5.12 points for anticonvulsants (α₂δ ligands and levetiracetam), and -4.59 points for iron treatments. The CGI-I indicated slightly different treatment effects between the substance groups, while PLMI changes during treatment differed (P = 0.002), showing a marked decrease with dopamine agonists (-22.50/h), levodopa (-26.01/h), and oxycodone (-34.46/h) compared with a slight decrease for anticonvulsants (α₂δ ligands and levetiracetam; -8.48/h) and iron treatments (-13.10/h). Quality of sleep and QoL improved moderately in most of the RCTs investigating these parameters (standardized mean difference, SMD) 0.40 and 0.33, respectively). In the few studies evaluating the change of depressive (n = 4) or anxiety symptoms (n = 3), these symptoms improved slightly (SMD -0.24, and -0.21). Adverse effects and dropouts were comparable in number across all substance groups. In meta-regressions, the treatment effect was predicted by the design of the trial (the more sites involved in a trial the lower the effect) and by the duration of action of a medication (the longer the duration of action, expressed as the half-life time of a substance, the greater the improvement), the latter indicating potential superiority of treatments with stable blood concentration.

CONCLUSION

This first meta-analysis of all RCTs for the pharmacological treatment of RLS provides evidence that, besides the well-defined efficacy of dopaminergic treatment, other treatments with different pharmacological principles show efficacy in small samples and may be well-tolerated alternatives for the treatment of RLS. In the group of anticonvulsants, only the trials performed with α₂δ ligands such as gabapentin, gabapentin enacarbil, and pregabalin showed good efficacy. This indicates a specific mechanism of action of these substances in RLS. The group of iron treatments consisted of a few trials with different compounds in oral and intravenous application form, respectively. For a more differentiated evaluation of the efficacy of iron treatments further studies are necessary. The large efficacy of one opioid RCT in RLS has to be confirmed in further studies.

Alterations in pain responses in treated and untreated patients with restless legs syndrome: associations with sleep disruption

OBJECTIVE

There has been recent interest in characterizing potential abnormalities of pain processing in patients with sleep disorders such as Restless Legs Syndrome (RLS). The aim of this study was to evaluate psychophysical responses to noxious heat and pressure stimuli in both treated and untreated RLS patients, compared to matched controls.

METHODS

This study is a cross-sectional group comparison of RLS patients with matched controls. A total of 31 patients (15 treated, 16 untreated) with a confirmed diagnosis of RLS were compared to 18 controls with no history of RLS or related sleep disorders.

RESULTS

RLS patients (both treated and untreated) demonstrated reduced pain thresholds and reported greater clinical pain relative to controls. Moreover, RLS patients demonstrated enhanced temporal summation of heat pain (p<.05), which may reflect aberrant central nervous system facilitation of pain transmission. Both treated and untreated RLS patients reported disrupted sleep relative to controls, and mediation analyses suggested that the reduced pain thresholds in RLS were attributable to sleep disturbance. However, the effect of RLS on the magnitude of temporal summation of heat pain was independent of sleep disturbance.

CONCLUSIONS

These findings suggest that central nervous system pain processing may be amplified in RLS, perhaps partially as a consequence of sleep disruption. RLS patients, even those whose symptoms are managed pharmacologically, may be at elevated long-term risk for the development or maintenance of persistent pain conditions. Further studies in larger samples could help to improve the prospects for pain management in RLS patients.

Dopamine agonists for restless legs syndrome

BACKGROUND

According to clinical guidelines, dopamine agonists are the first-line treatment of restless legs syndrome (RLS).

OBJECTIVES

To evaluate efficacy and safety of dopamine agonists for RLS.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2008, Issue 4), MEDLINE, EMBASE, PsycINFO and CINAHL, from January 1985 to December 2008, plus reference lists of articles. We contacted pharmaceutical companies.

SELECTION CRITERIA

We included double-blind randomised controlled trials (RCTs) of dopamine agonist treatment versus placebo or other treatment for a period of at least seven days in patients with RLS (≥ 18 years). Outcomes included the International RLS Severity Rating Scale (IRLS), Clinical Global Impressions (CGI-I), polysomnography and self rated sleep quality, quality of life, daytime functioning, and safety parameters.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data separately; assessed risk of bias; and contacted pharmaceutical companies and authors for additional information. We collected dropout rates due to adverse events and experience of adverse events.

MAIN RESULTS

We included 35 placebo controlled and three active controlled RCTs (N = 7365). The mean reduction on the IRLS was -5.7 points lower in dopamine agonist treatment compared to placebo (95% confidence interval (CI) -6.7 to -4.7). Periodic limb movements in sleep per hour of sleep (PLMS-Index; PLMSI) were -22.4/h lower than in placebo (95% CI -27.8 to -16.9). Self rated quality of sleep and disease specific quality of life were improved by a standardised mean difference (SMD) of 0.40 (95% CI 0.33 to 0.47) and 0.34 (95% CI 0.23 to 0.44), respectively. Patients were more likely to drop out (odds ratio (OR) 1.82, 95% CI 1.35 to 2.45) and experienced more adverse events under dopamine agonist treatment than with placebo (OR 1.82, 95% CI 1.59 to 2.08). Visual inspection of forest plots showed the highest efficacy in three studies investigating cabergoline and pergolide (N = 3). Active controlled trials investigated effects of cabergoline, pergolide, and pramipexole in a number of outcomes. The IRLS score was lower with cabergoline and pramipexole compared to levodopa (MD -5.3, 95% CI -8.4 to -2.1). Only four studies investigated treatment efficacy up to seven months. The most severe side effect, augmentation, was not assessed reliably.

AUTHORS' CONCLUSIONS

The meta-analyses show the superiority of dopamine agonists over placebo in RCTs up to seven months. Cabergoline and pramipexole showed larger efficacy compared to levodopa in some but not all outcomes.

Levodopa for restless legs syndrome

BACKGROUND

Levodopa plus dopamine decarboxylase inhibitor is a common treatment for restless legs syndrome (RLS).

OBJECTIVES

To evaluate efficacy and safety of levodopa for RLS compared to placebo and other active agents.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2008, Issue 4), MEDLINE, EMBASE, PsycINFO and CINAHL, from January 1985 to December 2008, reference lists of articles, and contacted pharmaceutical companies.

SELECTION CRITERIA

We included double-blind randomised controlled trials (RCT) investigating levodopa treatment versus placebo or other treatment for at least seven days in patients with RLS (age ≥ 18 years). Outcomes included symptom severity, CGI-I, objective as well as self rated sleep parameters, quality of life, and safety parameters.

DATA COLLECTION AND ANALYSIS

Two authors extracted data, assessed risk of bias, and contacted pharmaceutical companies and authors for additional information. We collected dropouts due to adverse events and patients experiencing adverse events.

MAIN RESULTS

Six placebo controlled and three active controlled RCTs were included (521 participants). Symptom severity (11 point rating scale, 0 points indicating no symptoms, 10 points indicating maximally severe symptoms) was more reduced with levodopa than placebo in two studies (mean difference (MD) -1.34, 95% confidence interval (CI) -2.18 to -0.5, P = 0.002). Periodic limb movements in sleep per hour of sleep (PLMS-Index; PLMSI) improved by -26.28/h compared to placebo (95% CI -30.53 to -22.02, P < 0.00001).The CGI-I changed more with levodopa than placebo in two studies (MD -1.25, 95% CI -1.89 to -0.62, P = 0.0001). In two studies, sleep quality (sleep questionnaire, visual analogue scale) showed a large effect (standardised mean difference (SMD) 0.92, 95% CI 0.52 to 1.33, P < 0.00001) whereas quality of life (50 mm Visual Analogue Scales) improved by 3.23 compared to placebo (95% CI 1.64 to 4.82, P < 0.0001). Few patients dropped out of treatment (3 of 218 patients) but more levodopa treated patients experienced adverse events than with placebo (odds ratio 2.61, 95% CI 1.35 to 5.04, P = 0.004). Two dopamine agonist controlled studies showed smaller effects with levodopa than cabergoline and pramipexole on the IRLS (MD 5.25, 95% CI 2.10 to 8.40, P =0.001), CGI-I (MD 0.62, 95% CI 0.37 to 0.87, P < 0.00001), and quality of life (MD 5.54, 95% CI 2.65 to 8.43, P = 0.0002).

AUTHORS' CONCLUSIONS

Levodopa is efficacious for the short-term treatment of RLS. Augmentation, the clinically most relevant adverse event, was not investigated sufficiently.

Prevalence and clinical profile of restless legs syndrome in Parkinson's disease

Parkinson's disease (PD) and restless legs syndrome (RLS) have a dopaminergic link. More insight in the clinical profile of RLS in patients with PD may benefit our understanding of this link. The aims of this study were to evaluate the frequency and clinical profile of RLS in a large cohort of PD patients. In 269 nondemented Caucasian PD patients, the four diagnostic criteria for RLS were administered by a RLS trained researcher. In patients with definite RLS, the severity of these symptoms was assessed. Furthermore, in all patients, relevant motor and nonmotor symptoms in PD were evaluated. Definite RLS was present in 11% of the patients. RLS patients were more often female (69% vs. 32%, P < 0.001), but no other significant differences existed between PD patients with and without RLS. Within the PD patients with RLS, severity of RLS correlated positively with PD severity, motor fluctuations, depressive symptoms, daytime sleepiness, cognitive problems, autonomic symptoms, and psychotic symptoms. This study in a large PD cohort shows that prevalence of RLS is similar to that in the general population, which might be caused by underestimation of RLS due to dopaminergic treatment. No relations were found between the presence of RLS and PD symptoms, but the severity of RLS was related to the severity of PD-related, mainly nondopaminergic, symptoms. It is hypothesized that, nondopaminergic systems, such as the noradrenergic system may play a role in the possible link between PD and RLS.

Use of near-infrared light to reduce symptoms associated with restless legs syndrome in a woman: a case report

Introduction

We describe a potential new treatment option for patients suffering from restless legs syndrome. Contemporary treatment for restless legs syndrome consists mostly of dopaminergic drugs that leave some patients feeling nauseated and dizzy. A non-invasive, drug-free option would open new doors for patients suffering from restless legs syndrome.

Case presentation

A 69-year-old Caucasian woman met International Restless Legs Syndrome Study Group criteria for the diagnosis of restless legs syndrome. She had been afflicted with restless legs syndrome for over 30 years and tried many of the available pharmaceutical remedies without success. For this study she received 30-minute treatment sessions with near-infrared light, three times a week for four weeks. The restless legs syndrome rating scale was used to track symptom changes; at baseline she scored "27" on the 0 to 40 point scale, which is considered to be "severe". Our patient was almost symptom free at week two, indicated by a score of "2" on the rating scale. By week four she was completely symptom free. The symptoms slowly returned during week three post treatment.

Conclusions

The findings suggest that near-infrared light may be a feasible method for treating patients suffering from restless legs syndrome. Undesirable side-effects from medication are non-existent. This study might revive the neglected vascular mechanism theory behind restless legs syndrome and encourage further research into this area.

Changes of cortical excitability after dopaminergic treatment in restless legs syndrome

OBJECTIVE

Dopaminergic pathways are most likely involved in the pathophysiology of restless legs syndrome (RLS). In previous investigations, an alteration of cortical excitability was suggested to be related to a dopaminergic dysfunction in RLS. The purpose of our study was to compare practice-dependent plasticity in RLS patients before and after a month of dopaminergic treatment.

METHODS

Single-pulse transcranial magnetic stimulation (TMS) was used to define motor evoked potential (MEP) amplitude, motor threshold, and silent period (SP) as well. Subjects performed three exercise blocks (bimanual motor task). MEP amplitude, registered immediately after each exercise block and after a rest period, was compared to baseline. The time course of intra-cortical inhibition was tested using paired-pulse TMS at short inter-stimulus intervals. For the single-pulse TMS procedures, we enrolled 12 patients affected by primary RLS and 12 normal subjects. For the paired-pulse TMS procedures, only six patients underwent the examination. RLS patients underwent the examination in both pre- and post-dopaminergic treatment conditions.

RESULTS

In RLS patients MEP amplitude increased after the rest period only in the post-treatment condition, showing a delayed facilitation. After exercise, MEP amplitude increased, but not enough to be significant, showing a positive trend but not a clear-cut post-exercise facilitation. In the pre-treatment condition instead, MEP amplitude did not change either after rest period or after exercise. RLS patients showed a marked increase of the central motor inhibition, assessed by using paired-pulse TMS at short inter-stimulus intervals after pramipexole treatment. On the contrary, the duration of the SP did not change compared to the pre-treatment condition.

CONCLUSIONS

In RLS patients after dopaminergic treatment, the main finding was the changing of MEP amplitude after rest following a motor task. Since dopaminergic treatment can reverse delayed facilitation in RLS, we hypothesized that cortical plasticity related to dopaminergic systems may play a crucial role in RLS pathophysiology.

Proposed dose equivalence between clonazepam and pramipexole in patients with restless legs syndrome

BACKGROUND

Dopamine agonists are accepted as the first-line medications for restless legs syndrome (RLS). In some Asian countries, clonazepam is one of the prevalent medications for RLS because of its effect on sleep disturbances. To date, there have not been any studies that examined equivalent doses of pramipexole and clonazepam. To evaluate equivalent doses of pramipexole and clonazepam in RLS, we investigated the efficacy and tolerability after conversion from clonazepam to pramipexole, and examined dose equivalence between the two prescriptions.

METHODS

In a prospective, open-label, multicenter study, 26 RLS patients treated with clonazepam (mean age: 69.2+/-11.0years old) were enrolled and then rapidly switched to pramipexole using a conversion calculation of 4:1 for daily doses. Then the daily dose of pramipexole was up titrated or tapered by 0.125mg/day at each subsequent examination. RLS symptoms and daytime somnolence were evaluated using the International RLS Study Group rating scale (IRLS), Clinical Global Impressions - Severity of illness (CGI-S) and the Epworth Sleepiness Scale (ESS), respectively.

RESULTS

Conversion from clonazepam to pramipexole resulted in significant reductions of IRLS (16.3+/-8.7 to 9.1+/-6.3) and ESS (6.5+/-4.2 to 4.4+/-3.2). CGI scores demonstrated improvement after conversion. In 4 patients (15%), adverse events such as somnolence, sensation of oppression in the lower limbs, diarrhea, or nausea were present. Correlation analysis demonstrated a significant relationship between these daily doses. Spearman's correlation coefficient was 0.662. Our study, however, has some limitations since it is an open-label trial and includes only 26 patients. Further studies using a double-blind design or a crossover design are recommended.

CONCLUSIONS

Statistical analysis demonstrated a 4:1 conversion for clonazepam to pramipexole. When switchover from clonazepam to pramipexole is done, this conversion ratio may be helpful to determine the initial dose of pramipexole for treating RLS.

Update on the management of restless legs syndrome: existing and emerging treatment options

Restless legs syndrome (RLS) is a sensorimotor disorder, characterized by a circadian variation of symptoms involving an urge to move the limbs (usually the legs) as well as paresthesias. There is a primary (familial) and a secondary (acquired) form, which affects a wide variety of individuals, such as pregnant women, patients with end-stage renal disease, iron deficiency, rheumatic disease, and persons taking medications. The symptoms reflect a circadian fluctuation of dopamine in the substantia nigra. RLS patients have lower dopamine and iron levels in the substantia nigra and respond to both dopaminergic therapy and iron administration. Iron, as a cofactor of dopamine production and a regulator of the expression of dopamine type 2-receptor, has an important role in the RLS etiology. In the management of the disease, the first step is to investigate possible secondary causes and their treatment. Dopaminergic agents are considered as the first-line therapy for moderate to severe RLS. If dopaminergic drugs are contraindicated or not efficacious, or if symptoms are resistant and unremitting, gabapentin or other antiepileptic agents, benzodiazepines, or opioids can be used for RLS therapy. Undiagnosed, wrongly diagnosed, and untreated RLS is associated with a significant impairment of the quality of life.

Cortical involvement in the sensory and motor symptoms of primary restless legs syndrome

BACKGROUND

Restless legs syndrome (RLS) is characterized by closely interrelated motor and sensory disorders. Two types of involuntary movement can be observed: periodic leg movements during wakefulness (PLMW) and periodic leg movements during sleep (PLMS). Basal ganglia dysfunction in primary RLS has often been suggested. However, clinical observations raise the hypothesis of sensorimotor cortical involvement in RLS symptoms. Here, we explored cortical function via movement-related beta and mu rhythm reactivity.

METHODS

Twelve patients with idiopathic, primary RLS were investigated and compared with 10 healthy subjects. In the patient group, we analyzed event-related beta and mu (de)synchronization (ERD/S) for PLMS and PLMW during a suggested immobilization test (SIT). An ERD/S analysis was also performed in patients and controls during self-paced right ankle dorsal flexion at 8:30 PM (i.e., the symptomatic period for patients) and 8:30 AM (the asymptomatic period).

RESULTS

Before PLMS, there was no ERD. Intense ERS was recorded after PLMS. As with voluntary movement, cortical ERD was always observed before PLMW. After PLMW, ERS had a diffuse scalp distribution. Furthermore, the ERS and ERD amplitudes and durations for voluntary movement were greater during the symptomatic period than during the asymptomatic period and in comparison with healthy controls, who presented an evening decrease in these parameters. Patients and controls had similar ERD and ERS patterns in the morning.

CONCLUSION

On the basis of a rhythm reactivity study, we conclude that the symptoms of RLS are related to cortical sensorimotor dysfunction.

Ropinirole treatment for restless legs syndrome

Restless legs syndrome (RLS) is a chronic neurological disorder associated with sleep disturbance. Ropinirole, a non-ergot dopamine agonist, has been widely studied for the treatment of moderate-to-severe primary RLS in a comprehensive clinical development program. In these studies, ropinirole was effective in significantly improving the symptoms of RLS, compared with placebo, in patients with moderate-to-severe primary RLS. These improvements are supported by data from individual studies, as well as by pooled analyses. Significant improvements in RLS symptoms were observed within 2 nights of treatment. Ropinirole also produced significant benefits on objective measures of RLS motor symptoms, such as periodic leg movements; and on subjective measures of sleep, ropinirole was generally well tolerated. A newly developed extended-release formulation of ropinirole may benefit patients who warrant an extended duration of therapy.

Ropinirole treatment for restless legs syndrome

BACKGROUND

Restless legs syndrome (RLS) is a chronic neurological disorder associated with sleep disturbance.

OBJECTIVE

Prepare a drug evaluation of the non-ergot dopamine agonist ropinirole in RLS.

METHODS

Review of scientific literature on RLS, particularly focusing on treatment with ropinirole.

CONCLUSION

Ropinirole has been studied for treatment of moderate to severe primary RLS in a comprehensive clinical development program. Ropinirole significantly improved symptoms of RLS, versus placebo, in patients with primary RLS. These improvements are supported by data from individual studies and pooled analyses. Significant improvements in RLS symptoms were observed within two nights of treatment. Ropinirole also produced significant benefits on objective measures of RLS motor symptoms, such as periodic leg movements, and subjective measures of sleep. Ropinirole was generally well tolerated.

Update of the pathophysiology of the restless-legs-syndrome

The Restless Legs Syndrome (RLS) is a heterogeneous disease. Symptomatic or secondary forms encompass iron deficiency, uremia, pregnancy, polyneuropathy, and other causes. The so-called idiopathic RLS syndrome preferentially affects patients with a younger onset before the age of 30. Here we summarize pathophysiological results along the anatomical route, beginning at the cortex and followed by the basal ganglia, thalamus, A11 neurones, substantia nigra, brainstem nuclei, and spinal cord. Genetic risk variants for RLS have recently been identified in two genes, one of them the homeobox gene MEIS1, known to be involved in embryonic development and variants in a second locus containing the genes encoding mitogen-activated protein kinase MAP2K5, and the transcription factor LBXCOR1. A third one, the BTBD9 gene with unknown function encodes a BTB(POZ) domain. Accordingly, new concepts on pathophysiology have to bridge conventional knowledge with possible consequences deriving from these findings. Furthermore, this may create a framework to help understand why dopamine, opioid, and some anticonvulsant therapies are effective in RLS patients.

Restless legs syndrome in older adults

Restless legs syndrome (RLS) is a common neurological disorder characterized by an urge to move the legs. The symptoms show a strong circadian rhythmicity, with onset or increase in the evening or at night; thus, sleep disturbances are the most frequent reason for patients seeking medical aid. The prevalence of the disorder increases strongly with age, with an estimated 9% to 20% of sufferers being among the elderly. Dopaminergic drugs are the first-line treatment option in RLS; opioids and anticonvulsants can also be used either as add-on or stand alone therapy options. Secondary forms of RLS and possible interaction with other medications require particular consideration in the elderly.