Update in restless legs syndrome. Curr Opin Neurol. 2010;23:401-406. [PMID: 20581683 DOI: 10.1097/wco.0b013e32833bcdd8]

Aripiprazole, a Novel Option in the Management of Restless Legs Syndrome (RLS) Patients with Augmentation and/or Severe RLS Symptoms: A Report of 4 Cases

Purpose

Restless Legs Syndrome (RLS) is a sensorimotor disorder associated with an unpleasant urge to move the limbs, relieved with movement, occurring in the evenings and with prolonged rest/inactivity. Treatment with dopamine agonists is effective for up to 60-90% of affected individuals. However, augmentation, ie, the paradoxical worsening of RLS symptoms after prolonged RLS treatment, is frequently reported, typically after 3-10 years of treatment. Here, we present 4 patients with RLS who were successfully treated with dopamine agonists but later developed augmentation. A trial of aripiprazole, a dopamine receptor partial agonist (DRPA), was initiated for treatment of augmentation symptoms.

Patients and Methods

Four patients treated for RLS with dopamine agonists developed augmentation. In each instance, augmentation symptoms did not respond adequately to a variety of medications including α2δ drugs, opioids or other agents. A trial of aripiprazole was initiated for each patient, and effects were evaluated.

Results

All four patients with severe RLS and augmentation with dopamine agonists achieved symptom control with aripiprazole. Patients endorsed 90-100% efficacy with aripiprazole by subjective self-report after failures with other agents. Further evaluation with the International Restless Legs Syndrome Study Group RLS Rating Scale (IRLS-SGRS) showed that benefits (from moderate to very severe, to mild to moderate severity) were largely maintained for 1-2 years. Aripiprazole doses to control augmentation symptoms were low (1-4 mg). No significant side effects were reported.

Conclusion

Aripiprazole may have utility for augmentation in RLS. We speculate that the partial agonist and antagonist properties of aripiprazole may limit potential for dopamine hyposensitization to progress to cause augmentation. Further research is needed to see if aripiprazole and/or other DRPAs are a viable long-term treatment option for patients experiencing augmentation and/or severe RLS with dopamine agonist therapy.

Sleep disorders and non-sleep circadian disorders predict depression: a systematic review and meta-analysis of longitudinal studies

Patients with depression often suffer from sleep disorders and non-sleep circadian disorders. However, whether they precede and predict subsequent depression is unclear. We conducted a meta-analysis of studies on sleep disorders and non-sleep circadian disorders. We found insomnia, hypersomnia, short and long sleep duration, obstructive sleep apnea, restless legs syndrome and eveningness orientation at baseline all led to subsequent depression. Those with propensity to late meal patterns, heightened levels of cortisol in awakening response and low robustness of rest-activity rhythm at baseline had higher risks for later depression. Among insomnia subtypes, difficulty initiating sleep and difficulty maintaining sleep predicted future depression. Notably, persistent insomnia at baseline contributed to more than two-fold risk of incident depression compared to insomnia. Moreover, insomnia symptom numbers showed dose-dependent relationship with the incident depression. In conclusion, different types of sleep disorders and non-sleep circadian disorders were proven to be risk factors of subsequent depression, and mechanisms underlying the relationship between sleep disorders, non-sleep circadian disorders and subsequent depression should be further elucidated in the future.

Gastrointestinal disorders in hyperkinetic movement disorders and ataxia

BACKGROUND

Gastrointestinal (GI) disorders have been thoroughly investigated in hypokinetic disorders such as Parkinson's disease, but much less is known about GI disorders in hyperkinetic movement disorders and ataxia. The aim of this review is to draw attention to the GI disorders that are associated with these movement disorders.

METHODS

References for this systematic review were identified by searches of PubMed through May 2020. Only publications in English were reviewed.

RESULTS

Data from 249 articles were critically reviewed, compared, and integrated. The most frequently reported GI symptoms overall in hyperkinetic movement disorders and ataxia are dysphagia, sialorrhea, weight changes, esophago-gastritis, gastroparesis, constipation, diarrhea, and malabsorption. We report in detail on the frequency, characteristics, pathophysiology, and management of GI symptoms in essential tremor, restless legs syndrome, chorea, and spinocerebellar ataxias. The limited available data on GI disorders in dystonias, paroxysmal movement disorders, tardive dyskinesias, myoclonus, and non-SCA ataxias are also summarized.

CONCLUSION

The purpose of our systematic review is to draw attention that, although primarily motor disorders, hyperkinetic movement disorders and ataxia can involve the GI system. Raising awareness about the GI symptom burden in hyperkinetic movement disorders and ataxia could contribute to a new research interest in that field, as well as improved patient care.

Prevalence of restless legs syndrome and quality of sleep in type 2 diabetics

INTRODUCTION

Restless legs syndrome (RLS) is characterized by an irresistible urge to move, with or without paraesthesia occurring or worsening at rest and relieved by activity. Only a few reports of prevalence of RLS with type 2 diabetes are available in India.

AIMS

To estimate the occurrence and risk factors of RLS among Indian patients with type 2 diabetes mellitus.

METHOD

This cross-sectional study was done in consecutive adult patients with type 2 diabetes. Demographic and comorbidity profile were collected. RLS diagnosis was made based on revised international RLS study group (IRLSSG) criteria.

RESULTS

Two hundred and ten diabetic patients were interviewed. Mean age was 56 ± 13.5 years. Male-female ratio was 139: 71. Mean duration of diabetes was 8.3 years. Treatment received for diabetes included oral hypoglycaemic agents (153 patients) and insulin (85 patients). Forty-five patients had polyneuropathy, 18 had retinopathy and 22 had nephropathy. Majority (103) of subjects reported their bedtime as 9-10 pm. Average sleep duration was 8.4 h per night. RLS was diagnosed in 17 (8%) subjects. Mean sleep onset in subjects with RLS was 56 min versus 29 min in diabetics without RLS (p-0.01). The mean Pittsburgh Sleep Quality Index score was 5 in RLS and 3.3 in non-RLS patients (p-0.01).

DISCUSSION AND CONCLUSIONS

RLS resulted in poor sleep quality and affected overall quality of life in diabetics. As poor sleep is a known risk factor for uncontrolled diabetes, early identification and treatment of RLS would help improve glycaemic control and quality of life in these patients.

Reuniting overnutrition and undernutrition, macronutrients, and micronutrients

Over-nutrition and its late consequences are a dominant theme in medicine today. In addition to the health hazards brought on by over-nutrition, the medical community has recently accumulated a roster of health benefits with obesity, grouped under "obesity paradox." Throughout the world and throughout history until the 20^th century, under-nutrition was a dominant evolutionary force. Under-nutrition brings with it a mix of benefits and detriments that are opposite to and continuous with those of over-nutrition. This continuum yields J-shaped or U-shaped curves relating body mass index to mortality. The overweight have an elevated risk of dying in middle age of degenerative diseases while the underweight are at increased risk of premature death from infectious conditions. Micronutrient deficiencies, major concerns of nutritional science in the 20^th century, are being neglected. This "hidden hunger" is now surprisingly prevalent in all weight groups, even among the overweight. Because micronutrient replacement is safe, inexpensive, and predictably effective, it is now an exceptionally attractive target for therapy across the spectrum of weight and age. Nutrition-related conditions worthy of special attention from caregivers include excess vitamin A, excess vitamin D, and deficiency of magnesium.

The association between obesity and restless legs syndrome: A systemic review and meta-analysis of observational studies

OBJECTIVE

Restless legs syndrome (RLS) has been reported to occur more frequently in obese individuals than in those with normal weight. In this study, a systematic review and meta-analysis was performed to explore the relationship between obesity and RLS.

METHODS

Published articles were identified through a comprehensive review of PUBMED and EMBASE from inception to the 16th December 2017. Data from studies reporting relative risks, odds ratios, or hazard ratios comparing the risk of RLS among individuals with obesity versus people with normal weight were analyzed. A random-effect model was used to calculate pooled odds ratios and 95% confident intervals (CI) for the association between obesity and RLS.

RESULTS

Findings for a total of 197,204 participants were pooled across 15 studies and were examined. Our analyses demonstrated a positive association between obesity and RLS, with an odds ratio (OR) of 1.44 (95%CI: 1.31-1.58, I² = 62.3%). Overweight subjects were also likely to have RLS, with an odds ratio of 1.29 (95%CI: 1.22-1.36, I² = 0). In subgroup analysis, women (OR = 1.42) with obesity were more likely to have RLS as compared with men (OR = 1.19).

CONCLUSIONS

Adults with obesity are more likely to suffer from RLS, with women at higher risk.

Management of restless legs syndrome in chronic liver disease: A challenge for the correct diagnosis and therapy

AIM

To investigate the association between restless legs syndrome (RLS) and well-defined chronic liver disease, and the possible therapeutic options.

METHODS

Two hundred and eleven patients with chronic liver disease, complaining of sleep disturbances, painful leg sensation and daily sleepiness, were included. Patients with persistent alcohol intake, recent worsening of clinical conditions, or hepatitis C virus were excluded. Diagnosis of RLS was suggested by the Johns Hopkins questionnaire and verified by fulfilling the diagnostic criteria by Allen. All patients were tested, both at baseline and during follow-up, with the Hamilton rating scale for depression, sleep quality assessment (PSQI), Epworth sleepiness scale (ESS), International Restless Legs Syndrome Study Group evaluation, and international RLS severity (IRLS) scoring system. Iron-free level, ferritin, folate, vitamin B12 and D-OH25 were detected. Neurological examinations and blood test occurred at the beginning of the therapy, after 2 wk, and at the 28^th, 75^th, 105^th, 135^th, 165^th and 205^th day. Regarding therapy, pramipexole or gabapentin were used.

RESULTS

Patients were moderately depressed, with evident nocturnal sleep problems and concomitant daily sleepiness. Sleep problems and involuntary leg movements had been underestimated, and RLS syndrome had not been considered before the neurological visit. All (211/211) patients fulfilled the RLS diagnostic criteria. Twenty-two patients considered their symptoms as mild, according to IRSL, but 189 found them moderate to very severe. No correlation was found between ammonium level and ESS or PSQI. Augmentation was rather precocious in our patients (135^th day), and more frequent (35%) than previous data (8.3%-9.1%). The dosage of dopamine agonists was found to be associated with augmentation and appears in range with the literature. Previous intake of alcohol and lower levels of vitamins have been related to the phenomenon in our study.

CONCLUSION

RLS is a common disorder, requiring rapid diagnosis and treatment. Further research is therefore fundamental.

Morning cortisol and fasting glucose are elevated in women with chronic widespread pain independent of comorbid restless legs syndrome

Background and aims:

Chronic widespread pain (CWP) is associated with poor quality of sleep, but the detailed underlying mechanisms are still not fully understood. In this study we investigated the influence of CWP on morning cortisol and fasting glucose concentrations as well as sleep disordered breathing.

Methods:

In this case-control study, subjects with CWP (n=31) and a control group without CWP (n=23) were randomly selected from a population-based cohort of women. Current pain intensity, sleep quality, excessive daytime sleepiness [Epworth sleepiness scale (ESS)], psychiatric comorbidity and occurrence of restless legs syndrome (RLS) were assessed. Overnight polygraphy was applied to quantify sleep apnoea, airflow limitation and attenuations of finger pulse wave amplitude (>50%) as a surrogate marker for increased skin sympathetic activity. Morning cortisol and fasting glucose concentrations were determined. Generalised linear models were used for multivariate analyses.

Results:

CWP was associated with higher cortisol (464±141 vs. 366±111 nmol/L, p=0.011) and fasting glucose (6.0±0.8 vs. 5.4±0.7 mmol/L, p=0.007) compared with controls. The significance remained after adjustment for age, body mass index, RLS and anxiety status (β=122±47 nmol/L and 0.89±0.28 mmol/L, p=0.009 and 0.001, respectively). The duration of flow limitation in sleep was longer (35±22 vs. 21±34 min, p=0.022), and pulse wave attenuation was more frequent (11±8 vs. 6±2 events/h, p=0.048) in CWP subjects compared with controls. RLS was associated with higher ESS independent of CWP (β=3.1±1.3, p=0.018).

Conclusions:

Elevated morning cortisol, impaired fasting glucose concentration and increased skin sympathetic activity during sleep suggested an activated adrenal medullary system in subjects with CWP, which was not influenced by comorbid RLS.

Implications:

CWP is associated with activated stress markers that may deteriorate sleep.

Non-headache symptoms in migraine patients

Migraine is one of the most common neurological disorders. In addition to severe headaches, non-headache symptoms associated with migraine attacks as well as co-morbid disorders frequently aggravate the disabling of migraine patients. Some of these symptoms are related to poor outcomes. In this review, we update the advances of studies on certain non-headache symptoms, including visual disturbance, gastrointestinal symptoms, allodynia, vestibular symptoms, and symptoms of co-morbid restless legs syndrome and psychiatric disorders.

Prevalence and Clinical Characteristics of the Restless Legs Syndrome (RLS) in Patients Diagnosed with Attention-Deficit Hyperactivity Disorder (ADHD) in Antioquia

Introduction:

Attention Deficit Hyperactivity Disorder (ADHD) is the most common behavioral issue for children. One of the sleeping disorders most frequently related to ADHD is the Restless Legs Syndrome (RLS), characterized by an irresistible urge to move the legs, something that is generally associated with paresthesias and motor restlessness. The prevalence rate of RLS in children diagnosed with ADHD is close to 18%, but in Colombia, these cases have been hardly studied.

Objective:

To determine the frequency of RLS, in children with ADHD.

Methods:

A cross-sectional study, filled out by parents of children diagnosed with ADHD, were analyzed. This questionnaire contained clinical criteria for classifying ADHD according to the DSM-IV, as well as diagnostic criteria for RLS by the National Institutes of Health (2003).

Results:

A predominance rate of 65.6% in combined ADHD was observed in children with RLS criteria. Upon carrying out an exploratory data analysis, it was found that having a family history of RLS and belonging to the middle or low socioeconomic strata are conditions associated with the presence of RLS in children with ADHD, with a significant p (p < 0.000) and a PR of 4.47 (3.16-6.32).

Conclusions:

The prevalence of RLS was similar to the findings of other clinical investigations. However, it highlights new prevalence values in relation to the comorbidity between ADHD and RLS, suggesting the need for new clinical and therapeutic alternatives amidst the presence of both syndromes.

The role of nerve inflammation and exogenous iron load in experimental peripheral diabetic neuropathy (PDN)

BACKGROUND

Iron is an essential but potentially toxic metal in mammals. Here we investigated a pathogenic role of exogenous iron in peripheral diabetic neuropathy (PDN) in an animal model for type 1 diabetes.

METHODS

Diabetes was induced by a single injection of streptozotocin (STZ) in 4-month-old Sprague-Dawley rats. STZ-diabetic rats and non-diabetic rats were fed with high, standard, or low iron diet. After three months of feeding, animals were tested.

RESULTS

STZ-rats on standard iron diet showed overt diabetes, slowed motor nerve conduction, marked degeneration of distal intraepidermal nerve fibers, mild intraneural infiltration with macrophages and T-cells in the sciatic nerve, and increased iron levels in serum and dorsal root ganglion (DRG) neurons. While motor fibers were afflicted in all STZ-groups, only a low iron-diet led also to reduced sensory conduction velocities in the sciatic nerve. In addition, only STZ-rats on a low iron diet showed damaged mitochondria in numerous DRG neurons, a more profound intraepidermal nerve fiber degeneration indicating small fiber neuropathy, and even more inflammatory cells in sciatic nerves than seen in any other experimental group.

CONCLUSIONS

These results indicate that dietary iron-deficiency rather than iron overload, and mild inflammation may both promote neuropathy in STZ-induced experimental PDN.

Bidirectional triggering association between migraine and restless legs syndrome: A diary study

OBJECTIVE

Migraine is comorbid with restless legs syndrome (RLS). However, the temporal association between these two episodic disorders remains elusive. The current study investigated the temporal relationship between migraine and RLS attacks.

METHODS

Migraine patients with RLS were recruited from a headache clinic. Patients with symptomatic RLS, RLS mimics, daily headaches, or daily RLS attacks were excluded. The patients recorded their headaches and RLS attacks for two weeks in a diary. The severity of each headache or RLS attack was rated on a four-point (0-3) Likert scale. Logit-normal, random-effects models were employed to estimate the odds ratios (ORs) for the temporal association between migraine and RLS attacks.

RESULTS

Thirty migraine patients with RLS (28 F/2 M, mean age 35.5 ± 9.0 years) completed the study. On the basis of 420 daily diary records, migraine attacks were associated with subsequent RLS attacks occurring on the same and next nights (OR = 6.94, 95% confidence interval (CI) = 4.39-11.0 and OR = 3.00, CI = 1.92-4.68; both ITALIC! p < 0.001). RLS attacks were associated with subsequent migraine attacks only on Day 1 (OR = 1.97 (CI = 1.3-2.98; ITALIC! p = 0.01). Overall, the frequencies of migraine and RLS attacks in two weeks were correlated (Spearman's correlation = 0.56, ITALIC! p = 0.001).

CONCLUSIONS

Our study results showed a bidirectional triggering association between migraine and RLS attacks. The association was stronger and lasted longer for migraine triggering subsequent RLS than that for vice versa.

Serum Ferritin Levels in Parkinson's Disease Patients with and without Restless Legs Syndrome

Background

The frequency of RLS in Parkinson's disease (PD) patients has been reported to be between 10% and 26%. Several hypotheses have sought to link these two diseases; however, the pathophysiology of RLS in PD patients has yet to be completely defined. Many patients with idiopathic RLS have low serum ferritin levels, which negatively influence RLS symptomatology. Our objective was to investigate the role of iron deficiency in PD patients with and without RLS.

Methods

We consecutively included 42 PD inpatients undergoing pharmacological treatment. Patients with anemia, renal insufficiency, or polyneuropathy were excluded from the study. The control group consisted of 42 PD inpatients without RLS (PD-nonRLS), matched for age and severity of PD. RLS was diagnosed clinically according to diagnostic criteria. Serum ferritin levels were measured at admission for all patients.

Results

Mean serum ferritin values were 142.20 ± 91.17 ng/dL for PD patients with RLS (PD+RLS) and 160.65 ± 142.57 ng/dL in PD-nonRLS (P = 0.704). There was no difference concerning the total dopaminergic dose (levodopa equivalent dose) between PD+RLS and PD-nonRLS patients (828.22 ± 389.02 vs. 775.32 ± 324.69 mg; P = 0.501). The frequency of dopamine agonist (DA) use did not differ between the two groups (P = 0.306).

Conclusions

There were no significant differences in serum ferritin levels between PD+RLS and PD-nonRLS in our study. This suggests a different pathophysiology of RLS in PD patients, where iron deficiency is not necessarily observed. DA use was not found to be associated with the occurrence of RLS symptoms.

Evaluation of temperament and character features as risk factors for depressive symptoms in patients with restless legs syndrome

BACKGROUND AND PURPOSE

Restless legs syndrome (RLS) is a common sleep-related movement disorder that is frequently associated with psychological disturbances. Personality traits are of considerable importance with respect to coping with chronic illness and disease vulnerability. This study assessed the temperament and character traits of RLS patients using an approach that involves the psychobiological model of personality.

METHODS

The personality features of 65 newly diagnosed and untreated RLS patients with no neurological or psychiatric diseases and 109 healthy controls were determined using the Temperament and Character Inventory and compared using covariance analyses. The International RLS Study Group Severity Scale was used to assess the severity of the RLS symptoms, and the Beck Depression Inventory was used to assess the presence and severity of depressive symptoms.

RESULTS

RLS patients scored significantly higher than healthy controls on the temperament dimension of harm avoidance (HA, p=0.02) and significantly lower on self-directedness (SD, p=0.001). No significant difference was observed in terms of the temperament dimension of novelty seeking (p=0.435). HA scores were significantly correlated with the BDI score but not with the RLS severity or duration.

CONCLUSIONS

High HA and low SD scores are the main characterizing personality features of RLS patients. These personality dimensions may be among the factors predisposing patients to development of the depressive symptoms that are frequently associated with RLS.

Iron homeostasis in peripheral nervous system, still a black box?

SIGNIFICANCE

Iron is the most abundant transition metal in biology and an essential cofactor for many cellular enzymes. Iron homeostasis impairment is also a component of peripheral neuropathies.

RECENT ADVANCES

During the past years, much effort has been paid to understand the molecular mechanism involved in maintaining systemic iron homeostasis in mammals. This has been stimulated by the evidence that iron dyshomeostasis is an initial cause of several disorders, including genetic and sporadic neurodegenerative disorders.

CRITICAL ISSUES

However, very little has been done to investigate the physiological role of iron in peripheral nervous system (PNS), despite the development of suitable cellular and animal models.

FUTURE DIRECTIONS

To stimulate research on iron metabolism and peripheral neuropathy, we provide a summary of the knowledge on iron homeostasis in the PNS, on its transport across the blood-nerve barrier, its involvement in myelination, and we identify unresolved questions. Furthermore, we comment on the role of iron in iron-related disorder with peripheral component, in demyelinating and metabolic peripheral neuropathies.

Restless leg syndrome in different types of demyelinating neuropathies: a single-center pilot study

OBJECTIVE

to determine the prevalence of restless legs syndrome (RLS) in a cohort of patients with demyelinating neuropathies.

METHODS

Patients were retrospectively recruited from our cohort of different forms of demyelinating neuropathies, including chronic inflammatory demyelinating neuropathy (CIDP), Charcot-Marie-Tooth 1A (CMT1A), and hereditary neuropathy with liability to pressure palsies (HNPP) referred to our Department of Neurology in a 10-year period. The validated 4-item RLS questionnaire was used for diagnosis of RLS. All patients with RLS who fulfilled criteria underwent a suggested immobilization test to confirm the diagnosis. A group of outpatients referred to the sleep disorders unit and data from published literature were used as controls.

RESULTS

Prevalence of RLS in demyelinating neuropathy group was higher than prevalence observed in control population (p = 0.0142) or in the literature data (p = 0.0007). In particular, in comparison with both control population and literature data, prevalence of RLS was higher in CIDP group (p = 0.0266 and p = 0.0063, respectively) and in CMT1A group (p = 0.0312 and p = 0.0105, respectively), but not in HNPP (p = 1.000 and p = 0.9320, respectively).

CONCLUSIONS

our study confirms a high prevalence of RLS in inflammatory neuropathies as CIDP and, among inherited neuropathies, in CMT1A but not in HNPP. Considering that this is only a small cohort from a single-center retrospective experience, the link between RLS and neuropathy remains uncertain, and larger multicenter studies are probably needed to clarify the real meaning of the association between RLS and neuropathy.

The effects of periodic limb movements in sleep (PLMS) on cardiovascular disease

Periodic limb movements in sleep (PLMS) are uncontrollable nocturnal movements that occur during sleep and increase with age. Research has implicated PLMS as a contributing factor to the development of cardiovascular disease (CVD). The purpose of this manuscript is to 1) explain the sleep disorder of PLMS and implications on CVD; 2) identify the impact of PLMS on CVD; 3) discuss treatment options for PLMS; 4) present future research needs for PLMS/RLS; 5) provide implications to health care providers to improve the care and health outcomes of persons with PLMS.

Treatment of restless legs syndrome

Restless legs syndrome (RLS) is a common disorder diagnosed by the clinical characteristics of restlessness in the legs associated often with abnormal sensations that start at rest and are improved by activity, occurring with a diurnal pattern of worsened symptoms at night and improvement in the morning. RLS is the cause of impaired quality of life in those more severely afflicted. Treatment of RLS has undergone considerable change over the last few years. Several classes of medications have demonstrated efficacy, including the dopaminergic agents and the alpha-2-delta ligands. Levodopa was the first dopaminergic agent found to be successful. However, chronic use of levodopa is frequently associated with augmentation that is defined as an earlier occurrence of symptoms frequently associated with worsening severity and sometimes spread to other body areas. The direct dopamine agonists, including ropinirole, pramipexole, and rotigotine patch, are also effective, although side effects, including daytime sleepiness, impulse control disorders, and augmentation, may limit usefulness. The alpha-2-delta ligands, including gabapentin, gabapentin enacarbil, and pregabalin, are effective for RLS without known occurrence of augmentation or impulse control disorders, although sedation and dizziness can occur. Other agents, including the opioids and clonazepam do not have sufficient evidence to recommend them as treatment for RLS, although in an individual patient, they may provide benefit.

Human L-ferritin deficiency is characterized by idiopathic generalized seizures and atypical restless leg syndrome

Human L-ferritin deficiency causes reduced cellular iron availability and increased ROS production with enhanced oxidized proteins, which results in idiopathic generalized seizures and atypical restless leg syndrome.

The ubiquitously expressed iron storage protein ferritin plays a central role in maintaining cellular iron homeostasis. Cytosolic ferritins are composed of heavy (H) and light (L) subunits that co-assemble into a hollow spherical shell with an internal cavity where iron is stored. The ferroxidase activity of the ferritin H chain is critical to store iron in its Fe3+ oxidation state, while the L chain shows iron nucleation properties. We describe a unique case of a 23-yr-old female patient affected by a homozygous loss of function mutation in the L-ferritin gene, idiopathic generalized seizures, and atypical restless leg syndrome (RLS). We show that L chain ferritin is undetectable in primary fibroblasts from the patient, and thus ferritin consists only of H chains. Increased iron incorporation into the FtH homopolymer leads to reduced cellular iron availability, diminished levels of cytosolic catalase, SOD1 protein levels, enhanced ROS production and higher levels of oxidized proteins. Importantly, key phenotypic features observed in fibroblasts are also mirrored in reprogrammed neurons from the patient’s fibroblasts. Our results demonstrate for the first time the pathophysiological consequences of L-ferritin deficiency in a human and help to define the concept for a new disease entity hallmarked by idiopathic generalized seizure and atypical RLS.

Is preeclampsia associated with restless legs syndrome?

OBJECTIVE

Restless legs syndrome (RLS) is a common neurologic disorder. Secondary RLS includes pregnancy and iron deficiency. Prevalence of RLS in pregnancy ranges from 11% to 27%. We aimed to assess the frequency and characteristics of RLS in pregnancy in a Peruvian population and to evaluate the possible pregnancy or delivery complications due to RLS.

METHODS

We assessed 218 consecutive expectant mothers at the inpatient clinic of the Hospital San Bartolome in Lima, Peru. Assessment was performed by using the standard diagnostic criteria for RLS and by using a clinical and diagnostic interview. Questionnaires for RLS severity, idiopathic RLS (IRLS), and excessive daytime sleepiness (EDS) according to the Epworth sleepiness scale (ESS) were used. Blood examination was performed for hemoglobin and hematocrit. For comparison, RLS patients were matched for age and body mass index (BMI) with pregnant women without RLS.

RESULTS

Out of 218 patients, 40 (18.4%) fulfilled diagnostic criteria for RLS. In RLS patients, prophylactic iron supplementation therapy during pregnancy was less frequently taken (P=.02). Pregnant women with RLS had a higher ESS score than pregnant controls (10.6 +/- 3.1 vs 7.6. +/- 3.6; P<.001). Preeclampsia was more frequent in RLS (7/40 vs 1/39; P=.03).

CONCLUSIONS

In our study, RLS was frequent in pregnant Peruvian women, especially in those without prophylactic iron supplementation. RLS patients described more EDS. Preeclampsia was more common in RLS. Our study is the first study to indicate a possible association between RLS and preeclampsia.

The sleep-immunity relationship

Research models show a strong interrelationship between sleep quality and immune function. The proinflammatory cytokines, interleukin-1, interleukin-6, and tumor necrosis factor α are classified as official sleep-regulatory substances. However, sleep-promoting properties are also possessed by several other immune and proinflammatory cellular classes. This article reviews the current physiologic evidence for the prominent somnogenic and sleep-regulatory properties inherent to these immune substances. Clinical examples of this relationship are discussed from the perspective of infectious and primarily immune-related conditions associated with significant sleep disruption and from the perspective of immune dysregulation associated with several primary sleep disorders.

An emerging role for Cullin-3 mediated ubiquitination in sleep and circadian rhythm: insights from Drosophila

Although the neurophysiological correlates of sleep have been thoroughly described, genetic mechanisms that control sleep architecture, long surmised from ethological studies, family histories and clinical observations, have only been investigated during the past decade. Key contributions to the molecular understanding of sleep have come from studies in Drosophila, benefitting from a strong history of circadian rhythm research. For instance, a number of recent papers have highlighted the role of the E3 ubiquitin ligase Cullin-3 in the regulation of circadian rhythm and sleep. We propose that different Cullin-3 substrate adaptors may affect specific molecular pathways and diverse aspects of circadian rhythm and sleep. We have previously shown that mutations in BTBD9, a risk factor for Restless Legs Syndrome (RLS) encoding a Cullin-3 substrate adaptor, lead to reduced dopamine, increased locomotion and sleep fragmentation. Here, we propose that Cullin-3 acts together with BTBD9 to limit the accumulation of iron regulatory proteins in conditions of iron deficiency. Our model is consistent with clinical observations implicating iron homeostasis in the pathophysiology of RLS and predicts that lack of BTBD9 leads to misregulation of cellular iron storage, inactivating the critical biosynthetic enzyme Tyrosine Hydroxylase in dopaminergic neurons, with consequent phenotypic effects on sleep.

Prospective study of restless legs syndrome and risk of depression in women

Most research on the association between restless legs syndrome (RLS) and depression has involved cross-sectional data. The objective of the present study was to evaluate this issue prospectively among Nurses' Health Study participants. A total of 56,399 women (mean age = 68 years) who were free of depression symptoms at baseline (2002) were followed until 2008. Physician-diagnosed RLS was self-reported. During 300,155 person-years of follow-up, the authors identified 1,268 incident cases of clinical depression (regular use of antidepressant medication and physician-diagnosed depression). Women with RLS at baseline were more likely to develop clinical depression (multivariate-adjusted relative risk (RR) = 1.5, 95% confidence interval (CI): 1.1, 2.1; P = 0.02) than those without RLS. The presence of RLS at baseline was also associated with higher scores on the 10-item Center for Epidemiologic Studies Depression Scale (CESD-10) and the 15-item Geriatric Depression Scale (GDS-15) thereafter. Multivariable-adjusted mean differences were 1.00 (standard error, 0.12) for CESD-10 score and 0.47 (standard error, 0.07) for GDS-15 score between women with RLS and those without RLS (P < 0.0001). In conclusion, women with physician-diagnosed RLS had an increased risk of developing clinical depression and clinically relevant depression symptoms. Further prospective studies using refined approaches to ascertainment of RLS and depression are warranted.

Restless legs syndrome: Treatment overview

Restless Legs Syndrome (RLS) is a neurological movement disorder which affects a significant proportion of the general population. This article reviews the neurochemical basis and diagnosis of RLS, and reviews pharmacologic treatment options for the disorder.

Association of multiple sclerosis with restless legs syndrome and other sleep disorders in women

OBJECTIVE

To assess the association of multiple sclerosis (MS) with concurrent restless legs syndrome (RLS) and daytime sleepiness. We also prospectively examined whether women with MS had an increased risk of developing RLS during 4 years of follow-up.

METHODS

The main analysis was based on a cross-sectional study of 65,544 women (aged 41-58 years) free of diabetes, arthritis, and pregnancy, who were participating in the Nurses' Health Study II cohort. Participants were considered to have RLS if they met 4 RLS diagnostic criteria recommended by the International Restless Leg Syndrome Study Group and had restless legs ≥ 5 times/month. MS was self-reported and confirmed by medical record review.

RESULTS

Among women with MS, the prevalence of RLS and severe RLS (15+ times/month) were 15.5% and 9.9% in 2005, respectively, relative to 6.4% and 2.6% among women without MS. After adjustment for potential confounders and the presence of other sleep disorders, women with MS had a higher likelihood of having RLS (odds ratio [OR] = 2.72, 95% confidence interval [CI] 1.89-3.93), severe RLS (OR = 4.12, 95% CI 2.65-6.42), and daily daytime sleepiness (OR = 2.11, 95% CI 1.31-3.42) compared with women without MS. Among the 172 women who had MS and were free of RLS in 2005, 9 developed RLS (5.2%) during a 4-year period and all had severe RLS. The adjusted relative risk of severe RLS was 3.58 (95% CI 1.53-8.35), comparing women with MS at baseline with those without MS.

CONCLUSION

Women with MS had a significantly higher prevalence of RLS and daytime sleepiness and an increased risk of developing RLS in the future.

Treatment for restless legs syndrome secondary to chronic liver disease: a case report

We report a patient with restless legs syndrome (RLS) and chronic liver disease (CLD), whose RLS symptoms fluctuated in correlation with serum ammonia level. RLS in this patient seemed to be secondary to CLD because palliative medications for the liver dysfunction showed an additional effect on RLS symptoms that were partially controlled by levodopa. CLD should be born in mind as one of the factors to cause RLS symptoms; the therapeutic mechanism of RLS enhanced by palliative medications for CLD is discussed.

Restless legs syndrome: a comprehensive overview on its epidemiology, risk factors, and treatment

PURPOSES

Restless legs syndrome (RLS) is underdiagnosed and poorly understood by clinicians and the general public alike; accordingly, a broad literature review with information most relevant to general practice is needed to help dispel misconceptions and improve level of care.

METHODS

Specifically, this review comprehensively provides an epidemiological analysis of RLS and examines the risk factors and treatment options for RLS by compiling the findings of past RLS studies. These RLS studies were identified through a retrospective PubMed search. The epidemiological analysis was conducted by calculating a weighted mean average of all the relevant general population RLS prevalence studies, separated into geographical/racial categories.

RESULTS

A comprehensive analysis of RLS epidemiological studies finds the prevalence rate of RLS to be 5-15% in the general population with 2.5% of adults having symptoms severe enough to require medical intervention. Some of the risk factors for RLS include female gender, pregnancy, low iron levels, lower socioeconomic status, poor health, elderly age, comorbidity with Parkinson's disease, positive family history of RLS, and comorbidity with psychiatric disorders. A wide array of treatment options exist for RLS including pharmacological and nonpharmacologic interventions.

CONCLUSIONS

Clinicians' understanding of RLS enigma has recently improved due to the increased intensity of RLS research over the past decade. This review summarizes the current findings in the RLS field as well as providing guidelines for future RLS-related research.

Genetics of sleep and sleep disorders

Sleep remains one of the least understood phenomena in biology--even its role in synaptic plasticity remains debatable. Since sleep was recognized to be regulated genetically, intense research has launched on two fronts: the development of model organisms for deciphering the molecular mechanisms of sleep and attempts to identify genetic underpinnings of human sleep disorders. In this Review, we describe how unbiased, high-throughput screens in model organisms are uncovering sleep regulatory mechanisms and how pathways, such as the circadian clock network and specific neurotransmitter signals, have conserved effects on sleep from Drosophila to humans. At the same time, genome-wide association studies (GWAS) have uncovered ∼14 loci increasing susceptibility to sleep disorders, such as narcolepsy and restless leg syndrome. To conclude, we discuss how these different strategies will be critical to unambiguously defining the function of sleep.

A study of the prevalence of restless legs syndrome in previously untreated Parkinson's disease patients: absence of co-morbid association

OBJECTIVE

The co-morbidity between Parkinson's disease (PD) and restless legs syndrome (RLS) is currently controversial, mainly because in most of the studies so far conducted, the patients were already on therapy with dopamine(DA)ergic drugs. This study has been carried out to assess the prevalence of RLS in de novo PD patients previously unexposed to DAergic drugs.

METHODS

One hundred nine cognitively unimpaired outpatients with PD (70M/39F), mean age 66.89 years±9.37 SD were included in the study. The mean duration of PD was 15.81 months±11.24 SD, and the median Hoehn and Yahr (H&Y) stage was 2 (range 1.5-3). All patients underwent interview to assess the occurrence of overall life-time and current "primary" form of RLS according to the criteria of the International RLS Study Group (IRLSSG). One hundred sixteen age and sex matched subjects (74M/42F, mean age 66.52.years±8.65 SD) free from a history of neurological diseases, were taken as controls and likewise interviewed. "Secondary" forms of RLS in both patients and controls were subsequently excluded.

RESULTS

No significant difference was found (chi-square test) in the frequency of overall life-time and of current "primary" RLS between PD patients and controls (6 out of 109 versus 5 out of 116 and 3 out of 109 versus 3 out of 116, respectively).

CONCLUSIONS

This survey does not support the concept of a co-morbid association between the two conditions and confirm indirectly the findings of previous studies reporting the onset of RLS after diagnosis of PD has been made in the great majority of patients and so likely on ongoing DAergic treatment. Therefore, we speculate that RLS occurring in these patients could be related to DAergic therapy for PD.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Restless legs syndrome and conditions associated with metabolic dysregulation, sympathoadrenal dysfunction, and cardiovascular disease risk: a systematic review

Restless legs syndrome (RLS) is a distressing sleep and sensorimotor disorder that affects a large percentage of adults in the western industrialized world and is associated with profound reductions in quality of life. However, the etiology of RLS remains incompletely understood. Enhanced understanding regarding both the antecedents and sequelae of RLS could shed new light on the pathogenesis of RLS. Evidence from an emerging body of literature suggests associations between RLS and diabetes, hypertension, obesity, and related conditions linked to sympathetic activation and metabolic dysregulation, raising the possibility that these factors may likewise play a significant role in the development and progression of RLS, and could help explain the recently documented associations between RLS and subsequent cardiovascular disease. However, the relation between RLS and these chronic conditions has received relatively little attention to date, although potential implications for the pathogenesis and treatment of RLS could be considerable. In this paper, we systematically review the recently published literature regarding the association of RLS to cardiovascular disease and related risk factors characterized by sympathoadrenal and metabolic dysregulation, discuss potential underlying mechanisms, and outline some possible directions for future research.

Restless Legs Syndrome in Behçet's Disease

The prevalence of restless legs syndrome (RLS) and its association with the clinical features of Behçet's disease (BD) has not previously been elucidated. The inflammatory character, central nervous system involvement and neuropathies of BD led to this investigation of RLS risk in BD patients. A total of 116 BD patients and 104 healthy control subjects were included; seven BD patients were excluded because of concurrent diseases, pregnancy or alcohol misuse that might cause RLS symptoms, and the remaining 109 BD patients were included in the analysis. The prevalence of RLS was significantly higher in patients with BD (32/109; 29.4%) than in controls (5/104; 4.8%). No significant differences were found between BD patients with and without RLS with regard to the clinical features of BD. RLS severity positively correlated with age in BD patients. In conclusion, BD-related RLS should be considered in symptomatic RLS secondary to rheumatological disorders and BD patients should be examined for RLS. Further studies are needed to clarify the pathogenetic mechanisms underlying BD-related RLS.

Ferritin overexpression in Drosophila glia leads to iron deposition in the optic lobes and late-onset behavioral defects

Cellular and organismal iron storage depends on the function of the ferritin protein complex in insects and mammals alike. In the central nervous system of insects, the distribution and relevance of ferritin remain unclear, though ferritin has been implicated in Drosophila models of Alzheimers' and Parkinsons' disease and in Aluminum-induced neurodegeneration. Here we show that transgene-derived expression of ferritin subunits in glial cells of Drosophila melanogaster causes a late-onset behavioral decline, characterized by loss of circadian rhythms in constant darkness and impairment of elicited locomotor responses. Anatomical analysis of the affected brains revealed crystalline inclusions of iron-loaded ferritin in a subpopulation of glial cells but not significant neurodegeneration. Although transgene-induced glial ferritin expression was well tolerated throughout development and in young flies, it turned disadvantageous at older age. The flies we characterize in this report contribute to the study of ferritin in the Drosophila brain and can be used to assess the contribution of glial iron metabolism in neurodegenerative models of disease.

The prevalence of restless legs syndrome in adult Saudis attending primary health care

OBJECTIVE

This study assessed the prevalence and severity of restless leg syndrome (RLS) among patients attending primary health care (PHC) facilities.

METHODS

We interviewed 1303 consecutive patients attending PHC face-to-face using the International Restless Legs Syndrome Study Group (IRLSSG) criteria. We assessed the severity of RLS using the IRLSSG severity scale for RLS.

RESULTS

The prevalence of RLS in our sample was 5.2% and was highest among participants between 45 and 60 years of age. The overall prevalence was roughly equal between males and females; however, RLS was more prevalent in females older than 45 years compared to males in the same age group. Eight participants (11.8%) reported mild symptoms, 29 (42.6%) moderate, 29 (42.6%) severe, and 2 (2.9%) very severe. None of the participants had been diagnosed or treated for RLS.

CONCLUSION

Restless leg syndrome is common among Saudis (Arabs). Our study supports the findings of reports in other countries demonstrating that primary care physicians do not often recognize RLS.