Restless legs syndrome: pathophysiology, diagnosis and treatment

Factors related to restless leg syndrome in neuromyelitis optica spectrum disorder

OBJECTIVE

Although the feeling of unrest in the legs is frequently reported as a sensory symptom by people with Neuromyelitis Optica Spectrum Disorder (NMOSD, pwNMOSD), there are limited studies to investigate the relationship between Restless Legs Syndrome (RLS) and NMOSD. The study's primary aim is to determine the frequency and severity of RLS in pwNMOSD. The other aim is to compare the sleep quality, daytime sleepiness level, quality of life, fatigue, magnetic resonance imaging results, and cognitive functions in RLS-positive and negative pwNMOSD.

METHODS

The RLS diagnosis was performed with RLS-Diagnostic Index criteria. The patient-reported outcomes were RLS Severity Rating Score, The Preference-Based Multiple Sclerosis Index (PBMSI), the Modified Fatigue Impact Scale (MFIS), Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale (ESS). Cognitive function was assessed with The Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) battery. The neurologist recorded the demographic and clinical characteristics of the participants.

RESULTS

The RLS was detected in 17 (21.5 %) of the 79 pwNMOSD participants. Fifty-six pwNMOSD were reached to assess cognitive functions and patient-reported outcomes. The rate of RLS was 60.71 % in this group. The PBMSI, PSQI, MFIS, and ESS scores were significantly different in RLS-positive participants than in RLS-negative (p < 0.05). Moreover, while participants' visuospatial and verbal learning was similar, the processing speed was slow in the RLS-positive group (p > 0.05).

CONCLUSIONS

Our preliminary results have shown that the RLS frequency is high in pwNMOSD. This study suggests a connection between the presence of RLS and worse sleep quality, fatigue level, processing speed, and quality of life in the NMOSD population. However, our results should be considered with the fact that the study has a small sample size and needs future studies to confirm our results for solid evidence.

Restless leg syndrome in multiple sclerosis: a case-control study

Objectives

This study assessed the prevalence of restless leg syndrome (RLS) among patients with multiple sclerosis (pwMS) and the association between RLS and MS disease duration, sleep disturbance, and daytime fatigue.

Methods

In this cross-sectional study, we interviewed 123 patients via phone calls using preset questionnaires containing the International Restless Legs Syndrome Study Group (IRLSSG) diagnostic criteria, Pittsburgh Sleep Quality Index (PSQI), and Fatigue Severity Scale (FSS) diagnostic criteria validated in both Arabic and English. The prevalence of RLS in MS was compared to a group of healthy controls.

Results

The prevalence of RLS in pwMS, defined by meeting all four requirements included in the IRLSSG diagnostic criteria, was 30.3% compared to 8.3% in the control group. About 27.3% had mild RLS, 36.4% presented with moderate, and the remaining had severe or very severe symptoms. Patients with MS who experience RLS had a 2.8 times higher risk of fatigue compared to pwMS without RLS. pwMS with RLS had worse sleep quality, with a mean difference of 0.64 in the global PSQI score. Sleep disturbance and latency had the most significant impact on sleep quality.

Conclusion

The prevalence of RLS among MS patients was significantly higher compared to the control group. We recommend educating neurologists and general physicians to increase their awareness of the increasing prevalence of RLS and its association with fatigue and sleep disturbance in patients with MS.

Clonazepam for the management of sleep disorders

BACKGROUND

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

METHODS

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

RESULTS

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

DISCUSSION AND CONCLUSIONS

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

Restless legs syndrome in people with multiple sclerosis: An updated systematic review and meta-analyses

BACKGROUND

Restless legs syndrome (RLS) is a sensory-motor disorder characterized by an uncomfortable sensation felt in the lower extremity. The aim of this systematic review and meta-analyses was (i) to provide updated information on the prevalence and clinical characteristics of RLS amongst people with multiple sclerosis (PwMS) and (ii) clarify RLS-related factors in PwMS.

METHODS

MEDLINE (PubMed), Scopus, and EMBASE were searched from their inception through April 2021 for the following keywords: 'restless legs syndrome' or 'RLS' and 'multiple sclerosis' or 'MS'. For the analysis of RLS prevalence, we calculated the percentage of RLS sufferers amongst the PwMS and people without MS. The prevalence of RLS was pooled separately for PwMS and healthy controls, regardless of the heterogeneity between studies. The odds ratios (ORs) and 95% CIs were extracted from the data in order to analyze the association between MS and RLS.

RESULTS

Nineteen studies were included in the review (9 case-controlled and 10 cross-sectional).The mean prevalence of RLS in the MS population was 27.5%, ranging from 13.2% to 65.1%, higher than the healthy controls. Based on the case control studies, the pooled RLS prevalence was much higher in PwMS than in healthy controls (OR 4.535, 95% CI 3.043-6.759, p<0.001). The majority of studies found no significant relationship between the presence of RLS in PwMS with disability, disease duration, type of MS, age, or gender.

CONCLUSIONS

Our updated systematic review strengthens the evidence of the increased risk of RLS amongst PwMS. Nevertheless, significant data reporting on characteristics of the MS disease, which increases the risk of suffering from RLS, is still lacking.

Effect of gabapentin on sleep patterns disturbed by epilepsy

For a long time, numerous sleep alterations induced by nocturnal epilepsy have been described. Such alterations include sleep fragmentation, decrement of sleep efficiency, increment of the wake time after sleep onset (WASO), increment of light sleep, and decrement of sleep depth. On the other hand, gabapentin (GBP), an antiepileptic drug analog of γ-aminobutyric acid (GABA) used as adjunctive and eventually, as a monotherapeutic treatment, induces a significant improvement in patients with both focal and secondarily generalized partial seizures. In experimental epilepsy models, this drug protects against pentylenetetrazol (PTZ)-induced convulsions. In consideration of such GBP properties, the aim of this work was to investigate its efficacy to protect against sleep disturbances provoked by convulsive seizures induced by the administration of PTZ. Nine-hour (9-hour) polygraphic studies were carried out in chronically implanted male adult Wistar rats separated into 4 different groups of 6 individuals. Control recordings in each group were done after saline administration. One group received a SC Subcutaneous (SC) injection of 50 mg/kg of PTZ alone while the other three groups were injected with either 15, 30, or 60 mg/kg IP Intraperitoneal (IP) of GBP 30 min prior to PTZ (50 mg/kg SC) administration. Animals displayed the whole range of electrophysiological and behavioral manifestations of the disease during the epileptic episodes induced by PTZ administration, and the states of vigilance were significantly altered. Insomnia occurred immediately after PTZ injection preceding the appearance of the first epileptic symptoms. Thus, both slow wave sleep (SWS) and rapid eye movement sleep (REM sleep) were completely inhibited during a relatively long period of time. The disturbing effects of epilepsy on sleep decreased when animals were under GBP treatment. Improvement of sleep was dependent on the administered dose of this antiepileptic drug.

The prevalence of restless leg syndrome among pregnant Saudi women

Objectives:

Restless legs syndrome (RLS) is common among pregnant women, but it has not been documented in pregnant Saudi Arabian women. The main purpose of this study was to estimate the extent of the prevalence of RLS and identify both the associated factors and the associated risk factors among pregnant Saudi women.

Methods:

A cross-sectional study was conducted among pregnant women visiting obstetric clinics at King Abdulaziz Medical City in Riyadh (KAMC-Riyadh) over the period from June 1 to November 1, 2014. We interviewed the participants and collected demographic data, number of pregnancies, duration of pregnancy, comorbidities, and symptoms of RLS. The diagnosis of RLS is based on the four criteria designated by the International RLS Study Group.

Results:

The total number of participants enrolled was 517, and the mean age was 30.11 ± 5.42 years. The prevalence of RLS was 21.3% (110/517) (95% confidence interval [CI]: 17.83%-25.06%). RLS symptoms were more common among women in the third trimester (24.1%) compared to the second trimester (14.3%) and first trimester (13.6%), P = 0.043. The stepwise multivariate logistic model identified insomnia (odds ratio [OR]: 3.6, 95% CI: 2.167–6.017, P = 0.001), and poor sleep quality (OR: 4.9, 95% CI: 1.473-16.454, P = 0.010) were associated with RLS.

Conclusion:

RLS occurs in two of ten pregnant women visiting obstetric clinics at KAMC-Riyadh and is strongly associated with insomnia and poor sleep quality. Studies are needed to explore the causality of these associations.

Biological and Clinical Implications of Comorbidities in Parkinson's Disease

A wide spectrum of comorbidities has been associated with Parkinson's disease (PD), a progressive neurodegenerative disease that affects more than seven million people worldwide. Emerging evidence indicates that chronic diseases including diabetes, depression, anemia and cancer may be implicated in the pathogenesis and progression of PD. Recent epidemiological studies suggest that some of these comorbidities may increase the risk of PD and precede the onset of motor symptoms. Further, drugs to treat diabetes and cancer have elicited neuroprotective effects in PD models. Nonetheless, the mechanisms underlying the occurrence of these comorbidities remain elusive. Herein, we discuss the biological and clinical implications of comorbidities in the pathogenesis, progression, and clinical management, with an emphasis on personalized medicine applications for PD.

Gender differences in sleep in older men and women

Sleep disturbances increase with increasing age in both males and females and become fairly common in the older community when compared to their younger counterparts. Even though these sleep disturbances increase with advancing age, there are nevertheless inherent differences in sleep disturbances between males and females. When compared to older men, older women will have a longer sleep latency (number of minutes it takes to fall asleep), more daytime sleepiness, will sleep about 20 min less per day, have less NREM stages 1 and 2 sleep, have more slow-wave sleep, and are more predisposed to REM sleep. Women have at least a 40% increased risk for developing insomnia, are at twice the risk for restless legs syndrome, will have different obstructive sleep apnea symptoms and more partial obstructions during sleep compared to men. They are also less likely to use antidepressants but will metabolize zolpidem 50% slower than men.

Budget impact of parenteral iron treatment of iron deficiency: methodological issues raised by using real-life data

OBJECTIVES

Iron deficiency is common in pregnancy, postpartum, inflammatory bowel disease, chronic kidney disease, chronic heart failure, heavy uterine bleeding, cancer and following surgery. We estimate the budget impact (BI) on the Swiss mandatory health insurance associated with substituting iron sucrose (standard) with ferric carboxymaltose (new treatment) using real-life data.

METHODS

Resource use was based on recent primary data (Polyquest Prescriber Analysis, Anemia Patient Record Study in Switzerland). Personnel costs were estimated using the Swiss Tarmed fee-for-service reimbursement system. Drug costs and costs of materials used were based on official tariffs (Spezialitätenliste, MiGeL). Actual IMS sales data of both products were used to verify the BI model (1 CHF ≈ 1 USD, Jan 2013).

RESULTS

Ferric carboxymaltose was associated with cost savings of 30-44 % per patient per treatment cycle compared to iron sucrose. Costs per 200/500/1,000 mg total dosage treatment cycle were CHF 101/210/420 for ferric carboxymaltose and CHF 144/375/721 for iron sucrose. This results in cost savings of CHF 22-31 million across all indications in 2009. Savings were driven by personnel cost reductions (application time and number of applications). Sensitivity analyses confirmed these cost savings, even for the higher application costs of ferric carboxymaltose, with minimum savings of CHF 17 million per year.

CONCLUSIONS

Treating iron deficiency involves substantial costs to the Swiss MHI which may be reduced by substituting iron sucrose with ferric carboxymaltose. The use of real-life data raises methodological questions about the fundamental compatibility of this data with the conceptual framework of BI analysis.

Patients suffering from restless legs syndrome have low internal locus of control and poor psychological functioning compared to healthy controls

BACKGROUND

Restless legs syndrome (RLS) is a disturbing sensorimotor disorder negatively influencing both sleep and psychological functioning. The aim of the present study was to assess RLS patients with respect to locus of control, sleep-related personality traits, quality of life, and sleep as compared to healthy controls.

METHOD

Thirty-eight patients (18 females and 20 males; mean age: 56.06 years) diagnosed with RLS and an age- and gender-matched control group (n = 42) were recruited. Participants completed a series of questionnaires related to locus of control, personality traits, quality of life, and sleep.

RESULTS

Compared to healthy controls, RLS patients had a lower internal locus of control, unfavourable sleep-related personality traits such as low self-confidence and higher mental arousal, poorer quality of life, and more depressive symptoms. Sleep was also affected. Multiple regression analyses showed that a low internal and a high external locus of control were predicted by RLS.

CONCLUSIONS

The pattern of results suggests that RLS is associated with a low locus of control, negative personality traits, and poor quality of life as compared to healthy controls.

The higher prevalence of non-right handers among patients with restless leg syndrome

Restless leg syndrome (RLS) is a common disorder described as an urge to move the legs. Dopamine, the main neuro-transmitter in the pathophysiology of RLS, is likely related to the development of brain laterality and human handedness. We aimed to compare the prevalence of RLS in right and non-right handers. A checklist including Edinburgh questioner for handedness, questions for RLS diagnosis and basic characteristics was filled out by a sample of population. The exclusion criteria included prolonged use of dopaminergic or psychologic drugs and having diseases with similar symptoms to RLS. The frequency of non-right handers in RLS patients was compared with the controls by Chi square test. P value less than 0.05 was considered significant. 164 persons were divided into RLS patients (69) and non-RLS controls (95). There was no significant difference between demographic characteristics. The prevalence of non-right handers in RLS patients was significantly more than non-RLS controls (P: 0.03). Our finding regarding the higher prevalence of non-right handers in RLS patients needs more justifications based on neuroscientists' guides. RLS as a disease in which dopaminergic system involves is highly assumed to be linked with handedness. This is just a hypothesis that impaired modulation of immune system in left handers may be accompanied with lower dopamine levels in RLS.

Effects of short- and long-term variations in RLS severity on perceived health status - the COR-study

In a cohort study among 2751 members (71.5% females) of the German and Swiss RLS patient organizations changes in restless legs syndrome (RLS) severity over time was assessed and the impact on quality of life, sleep quality and depressive symptoms was analysed. A standard set of scales (RLS severity scale IRLS, SF-36, Pittsburgh Sleep Quality Index and the Centre for Epidemiologic Studies Depression Scale) in mailed questionnaires was repeatedly used to assess RLS severity and health status over time and a 7-day diary once to assess short-term variations. A clinically relevant change of the RLS severity was defined by a change of at least 5 points on the IRLS scale. During 36 months follow-up minimal improvement of RLS severity between assessments was observed. Men consistently reported higher severity scores. RLS severity increased with age reaching a plateau in the age group 45–54 years. During 3 years 60.2% of the participants had no relevant (±5 points) change in RLS severity. RLS worsening was significantly related to an increase in depressive symptoms and a decrease in sleep quality and quality of life. The short-term variation showed distinctive circadian patterns with rhythm magnitudes strongly related to RLS severity. The majority of participants had a stable course of severe RLS over three years. An increase in RLS severity was accompanied by a small to moderate negative, a decrease by a small positive influence on quality of life, depressive symptoms and sleep quality.

Restless Eating, Restless Legs, and Sleep Related Eating Disorder

Restless legs syndrome (RLS) often presents with a primary complaint of sleep initiation difficulty with only ambiguous allusions to motor symptoms. This may result in the condition being misdiagnosed as a psychophysiological insomnia. Further, nocturnal eating is common in RLS and like the classic motor symptoms, patients will describe an inability to initiate sleep until their urge (to eat) is addressed. Restless nocturnal eating arises, intensifies, and subsides in parallel to motor symptoms. Once misdiagnosed as psychophysiological insomnia, RLS patients are frequently treated with benzodiazepine receptor agonists. The CNS actions of these sedating agents, suppression of memory and executive function, unleash predisposed amnestic behaviors. In the case of RLS this would be expected to include the inappropriate ambulatory and eating behaviors of sleep related eating disorder (SRED). The evidence and implications of a link between the restless eating of RLS and SRED is presented here.

Restless legs syndrome induced by quetiapine: report of seven cases and review of the literature

We report on seven cases of restless legs syndrome (RLS) in patients treated with quetiapine. Small doses (50-250 mg at bedtime) provoked RLS in a dose-dependent way. Most patients suffered from an affective disorder and all were treated concomitantly with antidepressants. A search of the literature revealed a further nine cases of RLS concerning quetiapine, also afflicting only patients with affective disorders. Quetiapine seems to carry a special risk for RLS in this sort of patient. Possible causes for this concurrence are discussed.

Gabapentin enacarbil: in patients with restless legs syndrome

Oral gabapentin enacarbil is approved in adult patients for the treatment of moderate to severe primary restless legs syndrome (RLS) [featured indication] and the management of postherpetic neuralgia. In the 12-week Patient Improvements in Vital Outcomes following Treatment (PIVOT) RLS I and II trials in adult patients with moderate to severe primary RLS (n > 500 total evaluable), once-daily gabapentin enacarbil 600 or 1,200 mg significantly improved mean International Restless Legs Scale (IRLS) total scores compared with placebo, with significantly higher investigator-rated Clinical Global Impression-Improvement (CGI-I) responder rates in gabapentin enacarbil groups than in placebo groups. Improvements in other sleep outcomes (assessed using various scales) also generally favoured gabapentin enacarbil treatment. These data are supported by results from a polysomnography, crossover (two 4-week treatment periods) trial (n > 100 evaluable). Improvements in RLS symptoms with gabapentin enacarbil were maintained in a 52-week extension study of clinical trials, including PIVOT RLS I and II. The longer-term efficacy of gabapentin enacarbil in patients with moderate to severe RLS was also demonstrated in the 36-week PIVOT RLS Maintenance study and a 52-week noncomparative study conducted in Japan. Gabapentin enacarbil was generally well tolerated in adult patients with RLS participating in short- and longer-term clinical trials. The most common treatment-emergent adverse events were somnolence/sedation and dizziness. Most adverse events were of mild to moderate severity, with relatively few patients discontinuing treatment because of an adverse event.

Parasomnias: an updated review

Parasomnias are abnormal behaviors emanating from or associated with sleep. Sleepwalking and related disorders result from an incomplete dissociation of wakefulness from nonrapid eye movement (NREM) sleep. Conditions that provoke repeated cortical arousals, or promote sleep inertia lead to NREM parasomnias by impairing normal arousal mechanisms. Changes in the cyclic alternating pattern, a biomarker of arousal instability in NREM sleep, are noted in sleepwalking disorders. Sleep-related eating disorder (SRED) is characterized by a disruption of the nocturnal fast with episodes of feeding after an arousal from sleep. SRED is often associated with the use of sedative-hypnotic medications; in particular, the widely prescribed benzodiazepine receptor agonists. Recently, compelling evidence suggests that nocturnal eating may in some cases be a nonmotor manifestation of Restless Legs Syndrome (RLS). rapid eye movement (REM) Sleep Behavior Disorder (RBD) is characterized by a loss of REM paralysis leading to potentially injurious dream enactment. The loss of atonia in RBD often predates the development of Parkinson's disease and other disorders of synuclein pathology. Parasomnia behaviors are related to an activation (in NREM parasomnias) or a disinhibition (in RBD) of central pattern generators (CPGs). Initial management should focus on decreasing the potential for sleep-related injury followed by treating comorbid sleep disorders. Clonazepam and melatonin appear to be effective therapies in RBD, whereas paroxetine has been reported effective in some cases of sleep terrors. At this point, pharmacotherapy for other parasomnias is less certain, and further investigations are necessary.

Review of the treatment of restless legs syndrome: focus on gabapentin enacarbil

The FDA approved gabapentin enacarbil in 2011 as the first non-dopaminergic agent for the treatment of restless legs syndrome (RLS) symptoms. Although gabapentin enacarbil is a pro-drug of gabapentin, its pharmacokinetics differ. Absorption of gabapentin enacarbil is more predictable, and inter-patient variability in bioavailability is lower than that of gabapentin. Studies have demonstrated superiority of gabapentin enacarbil compared to placebo. Comparisons to currently available RLS treatments are lacking, but clinical trials demonstrate comparable improvement in RLS symptoms to the dopamine agonists ropinirole and pramipexole, which are usually considered first-line therapy for daily RLS symptoms. Gabapentin enacarbil was well tolerated in clinical trials. The role of the drug in RLS treatment remains undefined, although it will likely be used as an alternative for refractory RLS when other treatments have failed. Additionally, gabapentin enacarbil may be recommended for patients with daily RLS symptoms that are less intense or are associated with pain as an alternative to dopamine agonists.

In vivo mesolimbic D2/3 receptor binding predicts posttherapeutic clinical responses in restless legs syndrome: a positron emission tomography study

Although D2/3 agonists have been used as a first-line medication for idiopathic restless legs syndrome (iRLS), findings on D2/3 receptors have been inconsistent. Here, we aimed to clarify the contribution of D2/3 receptor function to the clinical symptoms of iRLS by comparing the binding potential (BP(ND)) of [(11)C]raclopride with clinical improvements after D2/3 stimulation by pramipexole. Eight drug-naïve, iRLS patients and eight age-matched healthy subjects were scanned with positron emission tomography (PET). After PET scans, all patients received pramipexole (0.125 mg) orally for 2 weeks. Patients were evaluated every day with several standardized clinical tests. The BP(ND) values were compared using regions of interest and voxel-based methods. Results showed that the mean magnitude of [(11)C]raclopride BP(ND) in the mesolimbic dopamine region (nucleus accumbens (NA) and caudate) was significantly lower in the iRLS group. No significant differences between groups were observed in the putamen. The NA [(11)C]raclopride BP(ND) levels correlated negatively with clinical severity scores and positively with the degree of posttreatment improvement in iRLS. The present results suggest that alterations in mesolimbic D2/3 receptor function reflect the pathophysiology of iRLS, and the baseline availability of D2/3 receptors may predict the clinical outcome after D2/3 agonist treatment.

Prevalence of restless legs syndrome in patients with irritable bowel syndrome

AIM: To determine the prevalence of restless legs syndrome (RLS) in patients with irritable bowel syndrome (IBS).

METHODS: Patients with diarrhea-predominant IBS (n = 30), constipation-predominant IBS (n = 30), or mixed-symptom IBS (n = 30) were recruited from the community between March 2008 and February 2009. Rifaximin 200 mg three times daily was administered empirically to alleviate small intestinal bowel overgrowth in all patients. The presence of RLS was assessed via an RLS questionnaire and polysomnography.

RESULTS: Twenty-six patients with IBS (29%) were diagnosed with RLS using the RLS questionnaire. Twenty-four of the 26 patients (92%) underwent polysomnography, and all had confirmation of RLS. A greater percentage of patients with RLS had diarrhea-predominant IBS (62%) compared with patients with constipation-predominant IBS (4%) or mixed-symptom IBS (33%).

CONCLUSION: Restless legs syndrome is prevalent in patients with IBS, especially those with diarrheal symptoms. Assessment of concomitant disorders may improve diagnosis and expand relevant treatment options for patients.

Dopamine D3 receptor specifically modulates motor and sensory symptoms in iron-deficient mice

Restless legs syndrome (RLS) is a common neurological disorder whose exact pathophysiological mechanism remains unclear despite the successful use of dopaminergic treatment and recent discovery of predisposing genetic factors. As iron deficiency has been associated with RLS for some patients and there is evidence for decreased spinal dopamine D(3)-receptor (D3R) signaling in RLS, we aimed at establishing whether D3R activity and iron deficiency share common pathways within the pathophysiology of RLS sensory and motor symptoms. Using a combined mouse model of iron deficiency and dopamine D(3)-receptor deficiency (D3R-/-), circadian motor symptoms were evaluated by continuous recording of spontaneous wheel running activity. Testing the acute and persistent pain responses with the hot-plate test and formalin test, respectively, assessed sensory symptoms. A 15 week iron-deficient (ID) diet alone increased acute and persistent pain responses as compared to control diet. As compared to C57BL/6 (WT), homozygous D3R-/- mice already exhibited elevated responses to acute and persistent pain stimuli, where the latter was further elevated by concurrent iron deficiency. ID changed the circadian activity pattern toward an increased running wheel usage before the resting period, which resembled the RLS symptom of restlessness before sleep. Interestingly, D3R-/- shifted this effect of iron deficiency to a time point 3-4 h earlier. The results confirm the ability of iron deficiency and D3R-/- to evoke sensory and motor symptoms in mice resembling those observed in RLS patients. Furthermore this study suggests an increase of ID-related sensory symptoms and modification of ID-related motor symptoms by D3R-/-.

Pharmacology of sleep disorders in children and adolescents

There is a high prevalence of sleep disorders in children and an apparent increasing need for pharmacologic management. However, because of the paucity of data available with regards to dosing, efficacy, tolerability, and safety profiles of medications as well as a lack of adequate well-designed clinical trials, medications are currently not approved for the pediatric population by the US Food and Drug Administration. There are no pharmacologic guidelines for the specific sleep disorders or the different pediatric age ranges. Additional research is needed for evidence-based pediatric sleep pharmacotherapy. This article reviews pediatric sleep disorders and the pharmacologic therapeutic options.

Movement disorders in patients with multiple sclerosis

Apart from tremor and restless-legs syndrome, abnormal involuntary movements are uncommon in patients with multiple sclerosis. A review of the literature in multiple sclerosis reveals case reports of a variety of other movement disorders such as myoclonus, spasmodic torticollis, paroxysmal dystonia, chorea, ballism, and parkinsonism. This chapter presents a thorough review of these movement disorders in multiple sclerosis patients and provides readers with potential underlying pathogenetic mechanisms.

The relationship with iron and health outcomes in persons with restless legs syndrome

BACKGROUND

Restless Legs Syndrome (RLS) is a sleep disorder cause by inadequate iron metabolism. However, no studies have identified the impact of iron in RLS patients on sleep, depression, fatigue, or quality of life (QoL).

OBJECTIVE

The aims of this secondary data analysis was to determine relationships (a) between serum iron with RLS symptom severity, sleep quality, daytime sleepiness, depression, fatigue, and quality of life (QoL); and (b) based on demographics, specifically age and ethnicity.

METHOD

Data were collected on iron and ferritin concentrations in 48 persons with RLS.

RESULTS

Low serum iron levels were measured in 32% of the participants with only 1 person (4%) treated with iron supplementation. General linear models identified age and race as covariants: (a) being White (p = .047) and higher iron levels (p = .019) were independent predictors of higher social functioning; (b) being White (p = .047) and higher iron levels (p = .004) were independent predictors of less sleepiness; (c) younger age (p = .001) and lower iron levels (p = .025) were independent predictors of depression; and (d) younger age (p = .006) and lower iron levels (p = .005) were independent predictors of fatigue.

DISCUSSION

Findings from this study show that iron supplementation for persons with RLS not only improves motor and sensory symptoms but might also improve sleep, sleepiness, depression, fatigue, and QoL and should be considered by health care providers for treatment of RLS.

Successful treatment of central pain in a multiple sclerosis patient with epidural stimulation of the dorsal root entry zone

OBJECTIVE

We report a case of central pain successfully treated by epidural placement of spinal cord stimulator electrodes. Neuromodulation of primary afferent fibers and the underlying dorsal root entry zone provided effective analgesia whereas traditional lead placement over the dorsal columns on a prior occasion had not been effective. The rationale for this technique based on current understanding of the mechanisms of central pain and the risk/benefit considerations are discussed.

CASE REPORT

A 52-year-old woman presented with a 2-year history of pain in the lateral hand secondary to a demyelinating episode in the C2-4 spinal cord secondary to multiple sclerosis. Medications, sympathetic blocks, and acupuncture had been ineffective. One year after an unsuccessful single-lead trial of spinal cord stimulation over the cervical dorsal columns, a dual-lead trial of spinal cord stimulation over the lateral cervical spinal cord and dorsal roots provided significant analgesia, prompting a successful permanent implant.

OUTCOME MEASURES

Responses on the Brief Pain Inventory short form and quantitative thermosensory testing data were collected at two timepoints 16 days apart under two conditions: no stimulation and single-lead stimulation of cervical primary afferents and underlying spinal cord.

RESULTS

The patient's questionnaire responses indicated significantly improved pain scores with lateral-lead neuromodulation that was associated with a reduction in her baseline heat hypoalgesia.

CONCLUSIONS

Lateral-lead spinal cord stimulation may be effective for some central pain syndromes through a partial restoration of homeostatic small-fiber signaling. Neuroanatomical and physiological data in a larger population of patients will be required to predict the best responders to this therapeutic modality.

Restless legs syndrome is frequent in narcolepsy with cataplexy patients

STUDY OBJECTIVES

To investigate the occurrence of restless legs syndrome (RLS) in narcolepsy with cataplexy (NC).

DESIGN

A case-control study assessing the frequency of comorbidity of RLS and NC in three European sleep disorder centers.

PATIENTS

Three sleep research centers recruited 184 NC patients and 235 age-matched controls.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

NC patients and controls underwent a face-to-face interview investigating demographics, medical and drug history, sleep habits, and sleep disorders, in particular RLS based on the 4 international criteria and on a frequency > or =2 times/week, with a detailed description of RLS symptoms when present. RLS was significantly more prevalent among NC patients (14.7%) than in controls (3.0%). The age at onset of RLS in NC patients fits with the age at onset in idiopathic RLS, and RLS appeared more than 10 years after NC onset. Unlike idiopathic RLS, RLS in NC subjects was not more prevalent in women and was less familial (15.4% of cases). Lastly, NC patients with RLS showed a moderate disease severity and an almost daily occurrence of symptoms, which were also diurnal in 35% of cases. Older age, higher blood ferritin levels, and sleep paralysis seem to have a predictive value for RLS in NC. The higher ferritin levels indicate that different pathophysiological mechanisms underlie secondary RLS associated with NC.

CONCLUSIONS

This study highlights the association between RLS and NC. The nature of this association is still investigational, but it does indicate that RLS must be addressed in the evaluation and management of nocturnal sleep impairment in NC patients.

Celiac disease is associated with restless legs syndrome

PURPOSE

Celiac disease may be associated with restless legs syndrome (RLS) because of an association with iron deficiency. Often, RLS negatively affects quality of life but may remain undiagnosed. This study evaluated the association between celiac disease and RLS.

RESULTS

The incidence of RLS among 85 patients with celiac disease was 35%, with a prevalence of 25% compared with 10% of spouses (P<0.02). In 79% of patients with RLS and celiac disease, neuromuscular symptoms began during or after onset of gastrointestinal symptoms. Iron deficiency was present in 40% of celiac patients with active RLS compared with 6% of patients without RLS (P<0.001). After 6 months of a gluten-free diet, RLS symptoms improved in 50% of 28 patients.

CONCLUSION

Screening for celiac disease in patients with RLS is important since this commonly overlooked silent disease may be a correctable factor for some patients with idiopathic RLS.

Rationale and design of Ferinject assessment in patients with IRon deficiency and chronic Heart Failure (FAIR-HF) study: a randomized, placebo-controlled study of intravenous iron supplementation in patients with and without anaemia

Aims

Iron deficiency (ID) and anaemia are common in patients with chronic heart failure (CHF). The presence of anaemia is associated with increased morbidity and mortality in CHF, and ID is a major reason for the development of anaemia. Preliminary studies using intravenous (i.v.) iron supplementation alone in patients with CHF and ID have shown improvements in symptom status. FAIR-HF (Clinical Trials.gov NCT00520780) was designed to determine the effect of i.v. iron repletion therapy using ferric carboxymaltose on self-reported patient global assessment (PGA) and New York Heart Association (NYHA) in patients with CHF and ID.

Methods and results

This is a multi-centre, randomized, double-blind, placebo-controlled study recruiting ambulatory patients with symptomatic CHF with LVEF ≤ 40% (NYHA II) or ≤45% (NYHA III), ID [ferritin <100 ng/mL or ferritin 100–300 ng/mL when transferrin saturation (TSAT) < 20%], and haemoglobin 9.5–13.5 g/dL. Patients were randomized in a 2:1 ratio to receive ferric carboxymaltose (Ferinject^®) 200 mg iron i.v. or saline i.v. weekly until iron repletion (correction phase), then monthly until Week 24 (maintenance phase). Primary endpoints are (i) self-reported PGA at Week 24 and (ii) NYHA class at Week 24, adjusted for baseline NYHA class.

Conclusion

This study will provide evidence on the efficacy and safety of iron repletion with ferric carboxymaltose in CHF patients with ID with and without anaemia.

Restless legs syndrome with carbamazepine-induced osteomalacia: causal or casual association

Restless legs syndrome (RLS) is a sensorimotor sleep-related disorder which can be idiopathic or secondary. Secondary RLS is associated with a variety of conditions. Here we report a 16-year-old girl with RLS secondary to vitamin D deficiency (VDD) caused by chronic administration of carbamazepine. We also speculate on the possible mechanisms for the development of RLS in patient with VDD.

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.

Ferric carboxymaltose in patients with heart failure and iron deficiency

BACKGROUND

Iron deficiency may impair aerobic performance. This study aimed to determine whether treatment with intravenous iron (ferric carboxymaltose) would improve symptoms in patients who had heart failure, reduced left ventricular ejection fraction, and iron deficiency, either with or without anemia.

METHODS

We enrolled 459 patients with chronic heart failure of New York Heart Association (NYHA) functional class II or III, a left ventricular ejection fraction of 40% or less (for patients with NYHA class II) or 45% or less (for NYHA class III), iron deficiency (ferritin level <100 microg per liter or between 100 and 299 microg per liter, if the transferrin saturation was <20%), and a hemoglobin level of 95 to 135 g per liter. Patients were randomly assigned, in a 2:1 ratio, to receive 200 mg of intravenous iron (ferric carboxymaltose) or saline (placebo). The primary end points were the self-reported Patient Global Assessment and NYHA functional class, both at week 24. Secondary end points included the distance walked in 6 minutes and the health-related quality of life.

RESULTS

Among the patients receiving ferric carboxymaltose, 50% reported being much or moderately improved, as compared with 28% of patients receiving placebo, according to the Patient Global Assessment (odds ratio for improvement, 2.51; 95% confidence interval [CI], 1.75 to 3.61). Among the patients assigned to ferric carboxymaltose, 47% had an NYHA functional class I or II at week 24, as compared with 30% of patients assigned to placebo (odds ratio for improvement by one class, 2.40; 95% CI, 1.55 to 3.71). Results were similar in patients with anemia and those without anemia. Significant improvements were seen with ferric carboxymaltose in the distance on the 6-minute walk test and quality-of-life assessments. The rates of death, adverse events, and serious adverse events were similar in the two study groups.

CONCLUSIONS

Treatment with intravenous ferric carboxymaltose in patients with chronic heart failure and iron deficiency, with or without anemia, improves symptoms, functional capacity, and quality of life; the side-effect profile is acceptable. (ClinicalTrials.gov number, NCT00520780).

Anemia or low hemoglobin levels preceding Parkinson disease: a case-control study

OBJECTIVE

It has been suggested that anemia may be a risk factor for dementia, for restless legs syndrome, and for Parkinson disease (PD). Thus, we investigated the association of anemia with the subsequent risk of PD using a case-control study design.

METHODS

We used the medical records-linkage system of the Rochester Epidemiology Project to identify 196 subjects who developed PD in Olmsted County, Minnesota, from 1976 through 1995. Each incident case was matched by age (+/-1 year) and sex to a general population control. We reviewed the complete medical records of cases and controls in the system to detect anemia defined using the World Health Organization criteria.

RESULTS

Anemia was more common in the history of cases than of controls (odds ratio 2.00, 95% confidence interval 1.31-3.06, p = 0.001). The association remained significant after adjustment for cigarette smoking, exposure to pesticides, or hysterectomy (in women). The association was not significantly different between men and women, or between PD patients with or without rest tremor. Analyses stratified by time of onset of anemia showed a greater association for anemia that started 20 to 29 years before the onset of PD. Hemoglobin levels were slightly but consistently lower in cases than in controls across all ages.

CONCLUSIONS

Our results support an association between anemia experienced early in life and the later development of Parkinson disease. The interpretation of this association remains uncertain.

Mechanisms of sex difference: a historical perspective

OBJECTIVE

The history of the discovery of mechanisms contributing to sex difference helps to better appreciate gender factors in a variety of disease states. The objective of this article is to illustrate four mechanisms of sex differences in disease incidence: X-linkage (including inactivation, escape from inactivating, skewed inactivation), sex-specific exposure to disease-producing pathogens, fetal microchimerism, and iron depletion.

METHODS

This is a historic review.

RESULTS

An emphasis on sex difference led to the uncovering of four different mechanisms by which illness rates differ in men and women.

CONCLUSIONS

Research into many disease states can benefit from a focus on potential mechanisms that yield sex differences in illness susceptibility, progression, and outcome.

Movement disorders

Abnormal involuntary movements are major features of a large group of neurologic disorders, some of which are neurodegenerative and pose a significant diagnostic and treatment challenge to treating physicians. This article presents a concise review of clinical features, pathogenesis, epidemiology, and management of seven of the most common movement disorders encountered in a primary care clinic routinely. The disorders discussed are Parkinson disease, essential tremor, restless legs syndrome, Huntington disease, drug-induced movement disorder, Wilson disease, and Tourette syndrome.