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Li YS, Yeh WC, Chang YH, Hsu CY. Restless legs syndrome in patients with epilepsy: risk analysis, polysomnography, and quality of life evaluation. Sleep 2024; 47:zsad054. [PMID: 36861219 DOI: 10.1093/sleep/zsad054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 01/14/2023] [Indexed: 03/03/2023] Open
Abstract
STUDY OBJECTIVES Restless legs syndrome (RLS) is a circadian rhythm related sensorimotor disorder due to brain iron deficiency, with lesion sites at the putamen and substantia nigra. However, epilepsy is a disease with abnormal electric discharge from the cortex and can be triggered with iron disequilibrium. We designed a case-control study to discover the association between epilepsy and RLS. METHODS A total of 24 patients with epilepsy and RLS and 72 patients with epilepsy without RLS were included. Most of the patients underwent polysomnography and video electroencephalogram tests and took sleep questionnaires. We collected information on seizure characteristics, including general or focal onset, epileptogenic focus, current antiseizure medications, medically responsive epilepsy or refractory epilepsy, and nocturnal attacks. The sleep architectures of the two groups were compared. We analyzed the risk factors for RLS using multivariate logistic regression. RESULTS Among the patients with epilepsy, the occurrence of RLS was associated with refractory epilepsy (OR 6.422, p = 0.002) and nocturnal seizures (OR 4.960, p = 0.005). Sleep parameters were not significantly associated with RLS status. Quality of life was significantly impaired in the group with RLS in both the physical and mental domains. CONCLUSIONS Refractory epilepsy and nocturnal seizures were strongly correlated with RLS in patients with epilepsy. RLS should be considered a predictable comorbidity in patients with epilepsy. The management of RLS not only led to better control of the patient's epilepsy but also improved their quality of life.
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Affiliation(s)
- Ying-Sheng Li
- Sleep Disorders Center, Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung City, Taiwan
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan
| | - Wei-Chih Yeh
- Department of Neurology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University Hospital, Kaohsiung City, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan
| | - Ya-Hsien Chang
- Department of Pediatrics, Yucheng Otolaryngological and Pediatric Clinic, Kaohsiung City, Taiwan
| | - Chung-Yao Hsu
- Sleep Disorders Center, Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung City, Taiwan
- Department of Neurology, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan
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Walters AS, Li Y, Koo BB, Ondo WG, Weinstock LB, Champion D, Afrin LB, Karroum EG, Bagai K, Spruyt K. Review of the role of the endogenous opioid and melanocortin systems in the restless legs syndrome. Brain 2024; 147:26-38. [PMID: 37633259 PMCID: PMC10796165 DOI: 10.1093/brain/awad283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 07/23/2023] [Accepted: 08/01/2023] [Indexed: 08/28/2023] Open
Abstract
Restless legs syndrome (RLS) is responsive to opioid, dopaminergic and iron-based treatments. Receptor blocker studies in RLS patients suggest that the therapeutic efficacy of opioids is specific to the opioid receptor and mediated indirectly through the dopaminergic system. An RLS autopsy study reveals decreases in endogenous opioids, β-endorphin and perhaps Met-enkephalin in the thalamus of RLS patients. A total opioid receptor knock-out (mu, delta and kappa) and a mu-opioid receptor knock-out mouse model of RLS show circadian motor changes akin to RLS and, although both models show sensory changes, the mu-opioid receptor knock mouse shows circadian sensory changes closest to those seen in idiopathic RLS. Both models show changes in striatal dopamine, anaemia and low serum iron. However, only in the total receptor knock-out mouse do we see the decreases in serum ferritin that are normally found in RLS. There are also decreases in serum iron when wild-type mice are administered a mu-opioid receptor blocker. In addition, the mu-opioid receptor knock-out mouse also shows increases in striatal zinc paralleling similar changes in RLS. Adrenocorticotropic hormone and α-melanocyte stimulating hormone are derived from pro-opiomelanocortin as is β-endorphin. However, they cause RLS-like symptoms and periodic limb movements when injected intraventricularly into rats. These results collectively suggest that an endogenous opioid deficiency is pathogenetic to RLS and that an altered melanocortin system may be causal to RLS as well.
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Affiliation(s)
- Arthur S Walters
- Sleep Division, Department of Neurology, Vanderbilt University Medical Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Brian B Koo
- Sleep Medicine Laboratory, VA Connecticut Health Care System, West Haven, CT 06516, USA
- Yale Center for Restless Legs Syndrome, Yale School of Medicine, New Haven, CT 06520, USA
| | - William G Ondo
- Department of Neurology, Methodist Hospital, Weill Cornell Medical School, Houston, TX 77030, USA
| | - Leonard B Weinstock
- Department of Internal Medicine, Washington University School of Medicine, St.Louis, MO 63130, USA
| | - David Champion
- Sydney Children's Hospital, Department of Pain Medicine, Randwick, NSW 2031, Australia
| | - Lawrence B Afrin
- Hematology/Oncology, AIM Center for Personalized Medicine, Purchase, NY 10577, USA
| | - Elias G Karroum
- Department of Neurology and Rehabilitation Medicine, The George Washington University School of Medicine and Health Sciences, George Washington University, Washington, D.C. 20052, USA
| | - Kanika Bagai
- Sleep Division, Department of Neurology, Vanderbilt University Medical Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Karen Spruyt
- Université Paris Cité, NeuroDiderot Inserm, Paris 75019, France
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Chenini S, Barateau L, Dauvilliers Y. Restless legs syndrome: From clinic to personalized medicine. Rev Neurol (Paris) 2023; 179:703-714. [PMID: 37689536 DOI: 10.1016/j.neurol.2023.08.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/11/2023]
Abstract
Restless legs syndrome (RLS) is a common neurological sensorimotor disorder that impairs sleep, mood and quality of life. RLS is defined by an urge to move the legs at rest that increases in the evening and at night, and is frequently associated with metabolic and cardiovascular diseases. Symptoms frequency, age at RLS onset, severity, familial history and consequences of RLS vary widely between patients. A genetic susceptibility, iron deficiency, dopamine deregulation, and possible hypo-adenosinergic state may play a role in the pathophysiology of RLS. Polysomnographic recordings found often periodic leg movements during sleep and wakefulness in patients with RLS. RLS can be classified as primary or comorbid with major diseases: iron deficiency, renal, neurological, rheumatological and lung diseases. First-line treatments are low-dose dopamine agonists, and alpha-2-delta ligands depending on the clinical context, and second/third line opiates for pharmacoresistant forms of RLS. Augmentation syndrome is a serious complication of dopamine agonists and should be prevented by using the recommended low dose. Despite an increase in knowledge, RLS is still underdiagnosed, poorly recognized, resulting in substantial individual health burden and socioeconomic coast, and education is urgently needed to increase awareness of this disabling disorder.
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Affiliation(s)
- S Chenini
- National Reference Centre for Orphan Diseases Narcolepsy and Rare Hypersomnias, Sleep Unit, Department of Neurology, CHU Montpellier, University of Montpellier, Montpellier, France; Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, Montpellier, France.
| | - L Barateau
- National Reference Centre for Orphan Diseases Narcolepsy and Rare Hypersomnias, Sleep Unit, Department of Neurology, CHU Montpellier, University of Montpellier, Montpellier, France; Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, Montpellier, France
| | - Y Dauvilliers
- National Reference Centre for Orphan Diseases Narcolepsy and Rare Hypersomnias, Sleep Unit, Department of Neurology, CHU Montpellier, University of Montpellier, Montpellier, France; Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, Montpellier, France.
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Zeng P, Wang T, Zhang L, Guo F. Exploring the causes of augmentation in restless legs syndrome. Front Neurol 2023; 14:1160112. [PMID: 37840917 PMCID: PMC10571710 DOI: 10.3389/fneur.2023.1160112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 09/13/2023] [Indexed: 10/17/2023] Open
Abstract
Long-term drug treatment for Restless Legs Syndrome (RLS) patients can frequently result in augmentation, which is the deterioration of symptoms with an increased drug dose. The cause of augmentation, especially derived from dopamine therapy, remains elusive. Here, we review recent research and clinical progress on the possible mechanism underlying RLS augmentation. Dysfunction of the dopamine system highly possibly plays a role in the development of RLS augmentation, as dopamine agonists improve desensitization of dopamine receptors, disturb receptor interactions within or outside the dopamine receptor family, and interfere with the natural regulation of dopamine synthesis and release in the neural system. Iron deficiency is also indicated to contribute to RLS augmentation, as low iron levels can affect the function of the dopamine system. Furthermore, genetic risk factors, such as variations in the BTBD9 and MEIS1 genes, have been linked to an increased risk of RLS initiation and augmentation. Additionally, circadian rhythm, which controls the sleep-wake cycle, may also contribute to the worsening of RLS symptoms and the development of augmentation. Recently, Vitamin D deficiency has been suggested to be involved in RLS augmentation. Based on these findings, we propose that the progressive reduction of selective receptors, influenced by various pathological factors, reverses the overcompensation of the dopamine intensity promoted by short-term, low-dose dopaminergic therapy in the development of augmentation. More research is needed to uncover a deeper understanding of the mechanisms underlying the RLS symptom and to develop effective RLS augmentation treatments.
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Affiliation(s)
- Pengyu Zeng
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Tiantian Wang
- Department of Pharmacy, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Center for Sleep Medicine, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Lisan Zhang
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Center for Sleep Medicine, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Fang Guo
- Department of Neurobiology, Department of Neurology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
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5
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Restless legs syndrome and cognitive function among adults: a systematic review and meta-analysis. J Neurol 2023; 270:1361-1370. [PMID: 36472687 DOI: 10.1007/s00415-022-11484-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND Changes in the cognitive function of patients with restless legs syndrome is a growing area of research. Although several studies have been performed to investigate the association between restless legs syndrome (RLS) and cognitive function, the outcomes are still controversial. The meta-analysis aimed to elucidate the relationship between RLS and cognition, including global cognition and various cognitive domains including memory, attention, executive function, and spatial cognition. METHODS We searched the MEDLINE, EMBASE, and Web of Science databases from inception to November 2022 to screen eligible records. The means and standard deviations of cognitive test scores were obtained to calculate the standard mean difference and 95% confidence intervals. RESULTS A total of 1437 records were collected from the initial search and 16 records involving 4635 individuals were ultimately included in the systematic review and meta-analysis. Our data suggest negative associations between RLS and global cognition (SMD, - 0.42; 95% CI - 0.72 to - 0.11; I2 = 76.6%) and attention (SMD, - 0.43; 95% CI - 0.73 to - 0.12; I2 = 85.3%). No significant differences in memory (SMD, - 0.01; 95% CI - 0.31 to 0.28; I2 = 68.0%), executive function (SMD, - 0.10; 95% CI, - 0.30 to 0.11; I2 = 52.1%), or spatial cognition (SMD, - 0.17; 95% CI - 0.38 to 0.03; I2 = 58.5%) were observed between the RLS and control groups. Moreover, the strength of the results was modified by age but not by sex or region. CONCLUSIONS Our findings suggest that RLS is negatively correlated with cognitive function, particularly global cognition and attention. However, the causal relationship, considering more confounders, is worthy of further exploration.
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Kim R, Nijhout HF, Reed MC. Mathematical insights into the role of dopamine signaling in circadian entrainment. Math Biosci 2023; 356:108956. [PMID: 36581152 DOI: 10.1016/j.mbs.2022.108956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/27/2022]
Abstract
The circadian clock in the mammalian brain comprises interlocked molecular feedback loops that have downstream effects on important physiological functions such as the sleep-wake cycle and hormone regulation. Experiments have shown that the circadian clock also modulates the synthesis and breakdown of the neurotransmitter dopamine. Imbalances in dopamine are linked to a host of neurological conditions including Parkinson's disease, attention-deficit/hyperactivity disorder, and mood disorders, and these conditions are often accompanied by circadian disruptions. We have previously created a mathematical model using nonlinear ordinary differential equations to describe the influences of the circadian clock on dopamine at the molecular level. Recent experiments suggest that dopamine reciprocally influences the circadian clock. Dopamine receptor D1 (DRD1) signaling has been shown to aid in the entrainment of the clock to the 24-hour light-dark cycle, but the underlying mechanisms are not well understood. In this paper, we use our mathematical model to support the experimental hypothesis that DRD1 signaling promotes circadian entrainment by modulating the clock's response to light. We model the effects of a phase advance or delay, as well as the therapeutic potential of a REV-ERB agonist. In addition to phase shifts, we study the influences of photoperiod, or day length, in the mathematical model, connect our findings with the experimental and clinical literature, and determine the parameter that affects the critical photoperiod that signals seasonal changes to physiology.
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Affiliation(s)
- Ruby Kim
- Department of Mathematics, University of Michigan, 530 Church Street, Ann Arbor, 48109, MI, USA.
| | - H Frederik Nijhout
- Department of Biology, Duke University, 130 Science Drive, Durham, 27708, NC, USA
| | - Michael C Reed
- Department of Mathematics, Duke University, 120 Science Drive, Durham, 27708, NC, USA
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7
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Walters AS, Zee PC. Why the worsening at rest and worsening at night criteria for Restless Legs Syndrome are listed separately: review of the circadian literature on RLS and suggestions for future directions. Front Neurol 2023; 14:1153273. [PMID: 37181571 PMCID: PMC10172647 DOI: 10.3389/fneur.2023.1153273] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 04/03/2023] [Indexed: 05/16/2023] Open
Abstract
The field of circadian research on Restless Legs Syndrome (RLS) and periodic limb movements (PLMs) is reviewed in general. RLS has five obligatory criteria for diagnosis: (1) an urge to move the legs often accompanied by uncomfortable leg sensations; (2) symptoms are worse at rest, i.e., lying or sitting; (3) there is a least partial and temporary relief of symptoms by activity, e.g., walking or stretching or bending the legs; (4) symptoms are worse later in the day or at night; and (5) mimics of RLS such as leg cramps and positional discomfort should be excluded by history and physical. In addition, RLS is frequently accompanied by PLMs, either periodic limb movements of sleep (PLMS) as determined by polysomnography or periodic limb movements while awake (PLMW) as determined by the suggested immobilization test (SIT). Since the criteria for RLS were based upon clinical experience only, an early question after the development of the criteria was whether criteria 2 and 4 were the same or different phenomena. In other words, were RLS patients worse at night only because they were lying down, and were RLS patients worse lying down only because it was night? Early circadian studies performed during recumbency at different times of the day suggest that the uncomfortable sensations, PLMS, and PLMW as well as voluntary movement in response to leg discomfort follow a similar circadian pattern with worsening at night independent of body position and independent of sleep timing or duration. Other studies demonstrated that RLS patients get worse when sitting or lying down independent of the time of day. These studies as a whole suggest that the worsening at rest and the worsening at night criteria for RLS are related but separate phenomena and that criteria 2 and 4 for RLS should be kept separate based upon the circadian studies, as had been the case previously based upon clinical grounds alone. To more fully prove the circadian rhythmicity of RLS, studies should be conducted to see if bright light shifts the signs and symptoms of RLS to a different circadian time in concert with circadian markers.
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Affiliation(s)
- Arthur S. Walters
- Department of Neurology, Division of Sleep Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
- *Correspondence: Arthur S. Walters
| | - Phyllis C. Zee
- Division of Sleep Medicine, Department of Neurology and Center for Circadian and Sleep Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Phyllis C. Zee
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Earley CJ, Jones BC, Ferré S. Brain-iron deficiency models of restless legs syndrome. Exp Neurol 2022; 356:114158. [PMID: 35779614 PMCID: PMC9357217 DOI: 10.1016/j.expneurol.2022.114158] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/24/2022] [Accepted: 06/25/2022] [Indexed: 11/04/2022]
Abstract
Restless legs syndrome (RLS) is a common sensorimotor disorder for which two main pathological elements are fairly well accepted: Brain iron deficiency (BID) and an altered dopaminergic system. The ability to better understand the causal and consequential factors related to these two pathological elements, would hopefully lead to the development of better therapeutic strategies for treating, if not curing, this disease. The current understanding of the relationship between these two elements is that BID leads to some alterations in neurotransmitters and subsequent changes in the dopaminergic system. Therefore, rodent models based on diet-induced BID, provide a biological substrate to understand the consequences of BID on dopaminergic pathway and on alternative pathways that may be involved. In this review, we present the current research on dopaminergic changes found in RLS subjects and compare that to what is seen in the BID rodent model to provide a validation of the BID rodent model. We also demonstrate the ability of the BID model to predict changes in other neurotransmitter systems and how that has led to new treatment options. Finally, we will present arguments for the utility of recombinant inbred mouse strains that demonstrate natural variation in brain iron, to explore the genetic basis of altered brain iron homeostasis as a model to understand why in idiopathic RLS there can exist a BID despite normal peripheral iron store. This review is the first to draw on 25 years of human and basic research into the pathophysiology of RLS to provide strong supportive data as to the validity of BID model as an important translational model of the disease. As we will demonstrate here, not only does the BID model closely and accurately mimic what we see in the dopaminergic system of RLS, it is the first model to identify alternative systems from which new treatments have recently been developed.
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Affiliation(s)
- Christopher J Earley
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Byron C Jones
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Sergi Ferré
- Integrative Neurobiology Section, National Institutes of Health/National Institute on Drug Abuse, Baltimore, MD, USA
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Salminen AV, Clemens S, García-Borreguero D, Ghorayeb I, Li Y, Manconi M, Ondo W, Rye D, Siegel JM, Silvani A, Winkelman JW, Allen RP, Ferré S. Consensus guidelines on the construct validity of rodent models of restless legs syndrome. Dis Model Mech 2022; 15:dmm049615. [PMID: 35946581 PMCID: PMC9393041 DOI: 10.1242/dmm.049615] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/10/2022] [Indexed: 12/16/2022] Open
Abstract
Our understanding of the causes and natural course of restless legs syndrome (RLS) is incomplete. The lack of objective diagnostic biomarkers remains a challenge for clinical research and for the development of valid animal models. As a task force of preclinical and clinical scientists, we have previously defined face validity parameters for rodent models of RLS. In this article, we establish new guidelines for the construct validity of RLS rodent models. To do so, we first determined and agreed on the risk, and triggering factors and pathophysiological mechanisms that influence RLS expressivity. We then selected 20 items considered to have sufficient support in the literature, which we grouped by sex and genetic factors, iron-related mechanisms, electrophysiological mechanisms, dopaminergic mechanisms, exposure to medications active in the central nervous system, and others. These factors and biological mechanisms were then translated into rodent bioequivalents deemed to be most appropriate for a rodent model of RLS. We also identified parameters by which to assess and quantify these bioequivalents. Investigating these factors, both individually and in combination, will help to identify their specific roles in the expression of rodent RLS-like phenotypes, which should provide significant translational implications for the diagnosis and treatment of RLS.
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Affiliation(s)
- Aaro V. Salminen
- Institute of Neurogenomics, Helmholtz Zentrum München GmbH - German Research Center for Environmental Health, 85764 Neuherberg, Germany
- Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | | | - Imad Ghorayeb
- Département de Neurophysiologie Clinique, Pôle Neurosciences Cliniques, CHU de Bordeaux, 33076 Bordeaux, France
- Université de Bordeaux, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, 33076 Bordeaux, France
- CNRS, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, 33076 Bordeaux, France
| | - Yuqing Li
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Mauro Manconi
- Sleep Medicine Unit, Regional Hospital of Lugano, Neurocenter of Southern Switzerland, 6900 Lugano, Switzerland
- Faculty of Biomedical Sciences, Università della Svizzera Italiana, 6900 Lugano, Switzerland
- Department of Neurology, University Hospital Inselspital, 3010 Bern, Switzerland
| | - William Ondo
- Houston Methodist Hospital Neurological Institute, Weill Cornell Medical School, Houston, TX 77070, USA
| | - David Rye
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jerome M. Siegel
- Neuropsychiatric Institute and Brain Research Institute, University of California, Los Angeles, CA 90095, USA
- Neurobiology Research, Veterans Administration Greater Los Angeles Healthcare System, North Hills, CA 91343, USA
| | - Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences Alma Mater Studiorum, Università di Bologna, 48121 Ravenna Campus, Ravenna, Italy
| | - John W. Winkelman
- Departments of Psychiatry and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Richard P. Allen
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21224, USA
| | - Sergi Ferré
- Integrative Neurobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
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Weber FC, Danker-Hopfe H, Dogan-Sander E, Frase L, Hansel A, Mauche N, Mikutta C, Nemeth D, Richter K, Schilling C, Sebestova M, Spath MM, Nissen C, Wetter TC. Restless Legs Syndrome Prevalence and Clinical Correlates Among Psychiatric Inpatients: A Multicenter Study. Front Psychiatry 2022; 13:846165. [PMID: 35370821 PMCID: PMC8967168 DOI: 10.3389/fpsyt.2022.846165] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 02/18/2022] [Indexed: 11/13/2022] Open
Abstract
Background There are only limited reports on the prevalence of restless legs syndrome (RLS) in patients with psychiatric disorders. The present study aimed to evaluate the prevalence and clinical correlates in psychiatric inpatients in Germany and Switzerland. Methods This is a multicenter cross-sectional study of psychiatric inpatients with an age above 18 years that were diagnosed and evaluated face-to-face using the International RLS Study Group criteria (IRLSSG) and the International RLS severity scale (IRLS). In addition to sociodemographic and biometric data, sleep quality and mood were assessed using the Pittsburgh Sleep Quality Index (PSQI), the Insomnia Severity Index (ISI), the Epworth Sleepiness Scale (ESS), and the Patient Health Questionnaire (PHQ-9). In addition to univariate statistics used to describe and statistically analyze differences in variables of interest between patients with and without RLS, a logistic model was employed to identify predictors for the occurrence of RLS. Results The prevalence of RLS in a sample of 317 psychiatric inpatients was 16.4%, and 76.9% of these were diagnosed with RLS for the first time. RLS severity was moderate to severe (IRLS ± SD: 20.3 ± 8.4). The prevalences in women (p = 0.0036) and in first-degree relatives with RLS (p = 0.0108) as well as the body mass index (BMI, p = 0.0161) were significantly higher among patients with RLS, while alcohol consumption was significantly lower in the RLS group. With the exception of atypical antipsychotics, treatment with psychotropic drugs was not associated with RLS symptoms. Regarding subjective sleep quality and mood, scores of the PSQI (p = 0.0007), ISI (p = 0.0003), and ESS (p = 0.0005) were higher in patients with RLS, while PHQ-9 scores were not different. A logistic regression analysis identified gender (OR 2.67; 95% CI [1.25; 5.72]), first-degree relatives with RLS (OR 3.29; 95% CI [1.11; 9.73], ESS score (OR 1.09; 95% CI [1.01; 1.17]), and rare alcohol consumption (OR 0.45; 95% CI [0.22; 0.94] as predictors for RLS. Conclusions Clinically significant RLS had a high prevalence in psychiatric patients. RLS was associated with higher BMI, impaired sleep quality, and lower alcohol consumption. A systematic assessment of restless legs symptoms might contribute to improve the treatment of psychiatric patients.
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Affiliation(s)
- Franziska C. Weber
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany
| | - Heidi Danker-Hopfe
- Charité-Universitätsmedizin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Competence Center of Sleep Medicine Berlin, Berlin, Germany
| | - Ezgi Dogan-Sander
- Department of Psychiatry and Psychotherapy, University of Leipzig Medical Center, Leipzig, Germany
| | - Lukas Frase
- Department of Psychiatry and Psychotherapy, Medical Center, University of Freiburg – Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anna Hansel
- Department of Psychiatry and Psychotherapy, Medical Center, University of Freiburg – Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Nicole Mauche
- Department of Psychiatry and Psychotherapy, University Leipzig, Medical Faculty, Leipzig, Germany
| | - Christian Mikutta
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
- Privatklinik Meiringen, Meiringen, Switzerland
| | - Diana Nemeth
- Department of Psychiatry and Psychotherapy, Paracelsus Medical University, Nuremberg, Germany
| | - Kneginja Richter
- Department of Psychiatry and Psychotherapy, Paracelsus Medical University, Nuremberg, Germany
| | - Claudia Schilling
- Central Institute of Mental Health, Department of Psychiatry and Psychotherapy, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | | | - Marian M. Spath
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| | - Christoph Nissen
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| | - Thomas C. Wetter
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany
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11
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Restless Legs Syndrome: Known Knowns and Known Unknowns. Brain Sci 2022; 12:brainsci12010118. [PMID: 35053861 PMCID: PMC8773543 DOI: 10.3390/brainsci12010118] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/09/2022] [Accepted: 01/12/2022] [Indexed: 02/06/2023] Open
Abstract
Although restless legs syndrome (RLS) is a common neurological disorder, it remains poorly understood from both clinical and pathophysiological perspectives. RLS is classified among sleep-related movement disorders, namely, conditions characterized by simple, often stereotyped movements occurring during sleep. However, several clinical, neurophysiological and neuroimaging observations question this view. The aim of the present review is to summarize and query some of the current concepts (known knowns) and to identify open questions (known unknowns) on RLS pathophysiology. Based on several lines of evidence, we propose that RLS should be viewed as a disorder of sensorimotor interaction with a typical circadian pattern of occurrence, possibly arising from neurochemical dysfunction and abnormal excitability in different brain structures.
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12
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Kim R, Witelski TP. Uncovering the dynamics of a circadian-dopamine model influenced by the light-dark cycle. Math Biosci 2021; 344:108764. [PMID: 34952036 DOI: 10.1016/j.mbs.2021.108764] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 11/09/2021] [Accepted: 11/26/2021] [Indexed: 10/19/2022]
Abstract
The neurotransmitter dopamine (DA) is known to be influenced by the circadian timekeeping system in the mammalian brain. We have previously created a single-cell differential equations model to understand the mechanisms behind circadian rhythms of extracellular DA. In this paper, we investigate the dynamics in our model and study different behaviors such as entrainment to the 24-hour light-dark cycle and robust periodicity versus decoupling, quasiperiodicity, and chaos. Imbalances in DA are often accompanied by disrupted circadian rhythms, such as in Parkinson's disease, hyperactivity, and mood disorders. Our model provides new insights into the links between the circadian clock and DA. We show that the daily rhythmicity of DA can be disrupted by decoupling between interlocked loops of the clock circuitry or by quasiperiodic clock behaviors caused by misalignment with the light-dark cycle. The model can be used to further study how the circadian clock affects the dopaminergic system, and to help develop therapeutic strategies for disrupted DA rhythms. .
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Affiliation(s)
- Ruby Kim
- Department of Mathematics, Duke University, Durham, NC, USA.
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13
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Moderie C, Carrier J, Dang-Vu TT. [Sleep disorders in patients with a neurocognitive disorder]. Encephale 2021; 48:325-334. [PMID: 34916075 DOI: 10.1016/j.encep.2021.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/24/2021] [Accepted: 08/29/2021] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Sleep disorders are prevalent in patients with a neurocognitive disorder, and diagnosis and treatment in these patients remain challenging in clinical practice. METHODS This narrative review offers a systematic approach to diagnose and treat sleep disorders in neurocognitive disorders. RESULTS Alzheimer's disease is often associated with circadian rhythm disorders, chronic insomnia, and sleep apnea-hypopnea syndrome. Alpha-synucleinopathies (e.g., Parkinson's disease and Lewy body dementia) are often associated with a rapid eye movement sleep behavior disorder, restless legs syndrome, chronic insomnia, and sleep apnea-hypopnea syndrome. A focused history allows to diagnose most sleep disorders. Clinicians should ensure to gather the following information in all patients with a neurocognitive disorder: (1) the presence of difficulties falling asleep or staying asleep, (2) the impact of sleep disturbances on daily functioning (fatigue, sleepiness and other daytime consequences), and (3) abnormal movements in sleep. Sleep diaries and questionnaires can assist clinicians in screening for specific sleep disorders. Polysomnography is recommended if a rapid eye movement sleep behavior disorder or a sleep apnea-hypopnea syndrome are suspected. Sleep complaints should prompt clinicians to ensure that comorbidities interfering with sleep are properly managed. The main treatment for moderate to severe obstructive sleep apnea-hypopnea syndrome remains continuous positive airway pressure, as its efficacy has been demonstrated in patients with neurocognitive disorders. Medications should also be reviewed, and time of administration should be optimized (diuretics and stimulating medications in the morning, sedating medications in the evening). Importantly, cholinesterase inhibitors (especially donepezil) may trigger insomnia. Switching to morning dosing or to an alternative drug may help. Cognitive-behavioral therapy for insomnia is indicated to treat chronic insomnia in neurocognitive disorders. False beliefs regarding sleep should be addressed with the patient and their caregiver. The sleep environment should be optimized (decrease light exposure at night, minimize noise, avoid taking vital signs, etc.). Sleep restriction can be considered as patients with a neurocognitive disorder often spend too much time in bed. The need for naps should be assessed case by case as naps may contribute to insomnia in some patients but allow others to complete their diurnal activities. Trazodone (50mg) may also be used under certain circumstances in chronic insomnia. Recent evidence does not support a role for exogenous melatonin in patients with a neucognitive disorder and insomnia. Patients in long-term care facilities are often deprived of an adequate diurnal exposure to light. Increasing daytime exposure to light may improve sleep and mood. Patients with circadian rhythm disorders can also benefit from light therapy (morning bright light therapy in case of phase delay and evening bright light therapy in case of phase advance). Rapid eye movement sleep behavior disorder can lead to violent behaviors, and the sleeping environment should be secured (e.g., mattress on the floor, remove surrounding objects). Medication exacerbating this disorder should be stopped if possible. High dose melatonin (6 to 18mg) or low dose clonazepam (0.125-0.25mg) at bedtime may be used to reduce symptoms. Melatonin is preferred in first-line as it is generally well tolerated with few side effects. Patients with restless legs syndrome should be investigated for iron deficiency. Medication decreasing dopaminergic activity should be reduced or stopped if possible. Behavioral strategies such as exercise and leg massages may be beneficial. Low-dose dopamine agonists (such as pramipexole 0.125mg two hours before bedtime) can be used to treat the condition, but a prolonged treatment may paradoxically worsen the symptoms. Alpha-2-delta calcium channel ligands can also be used while monitoring for the risk of falls. CONCLUSION Multiple and sustained nonpharmacological approaches are recommended for the treatment of sleep disturbances in patients with neurocognitive disorder. Pharmacological indications remain limited, and further randomized clinical trials integrating a multimodal approach are warranted to evaluate the treatment of sleep disorders in specific neurocognitive disorders.
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Affiliation(s)
- C Moderie
- Département de psychiatrie, université McGill, Montréal, Québec, Canada
| | - J Carrier
- Centre de recherche de l'institut universitaire de gériatrie de Montréal, Montréal, Québec, Canada; Département de psychologie, université de Montréal, Montréal, Québec, Canada; Centre d'études avancées en médecine du sommeil, Montréal, Québec, Canada
| | - T T Dang-Vu
- Centre de recherche de l'institut universitaire de gériatrie de Montréal, Montréal, Québec, Canada; Département de psychologie, université de Montréal, Montréal, Québec, Canada; Département de santé, kinésiologie et physiologie appliquée, centre d'études en neurobiologie comportementale et centre PERFORM, université Concordia, Montréal, Québec, Canada.
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14
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Restless legs syndrome affecting the head region: "restless head syndrome". Neurol Sci 2021; 43:2565-2570. [PMID: 34661784 DOI: 10.1007/s10072-021-05667-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 10/14/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Restless legs syndrome (RLS) is a well-established disease that has recently been shown to have variants affecting the arms, face, abdomen, and genital area. To our knowledge, there has been no study reporting on the RLS variant affecting the head region. METHODS The retrospective study reviewed a total of 460 patients who presented to Fırat University Medical School and were diagnosed as having RLS based on the International Restless Legs Syndrome Study Group (IRLSSG) criteria between June 2017 and January 2020. Of these, 18 patients that presented with head-related RLS symptoms (in addition to legs or arms) and four cases that presented with isolated head involvement were included in the study. RESULTS In 15 out of 18 (81.8%) patients, the restless head syndrome was accompanied by restless arm syndrome (RAS). In the remaining four (18.2%) patients, the disease involved the head region alone. The disease initially emerged in a single region in the body and gradually spread to one or multiple other regions in most patients and the symptoms were relieved by head rubbing. Serum iron level was low in 8 (36.4%) patients and normal in 14 (63.6%) patients. All the patients had normal cranial imaging and the symptoms were eliminated after dopaminergic therapy. CONCLUSIONS Although RLS typically involves the legs alone, it may also affect other body parts such as upper extremities, abdomen, face, and genital area. We propose that the novel RLS variant described in the present study could be termed "restless head syndrome."
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Cubo E, Collazo Riobo C, Gallego-Nieto C, Elizari-Roncal M, Barroso-Pérez T, Calvo S, Echavarria A, Marras C. Survival in Restless Legs Syndrome: An 11-Year Surveillance, Community-Based Population Study. Neuroepidemiology 2020; 54:375-382. [DOI: 10.1159/000508855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 05/20/2020] [Indexed: 11/19/2022] Open
Abstract
<b><i>Background:</i></b> A growing body of evidence relates restless legs syndrome (RLS) to an increased risk of mortality attributable to both cerebrovascular and cardiovascular events. The aim was to investigate survival in patients with RLS. <b><i>Methods:</i></b> This was an observational, retrospective longitudinal study of a cohort of patients followed up for 11 years. RLS was diagnosed by a physician using the International RLS Study Group criteria. Mortality was analyzed using age-standardized mortality ratios (SMR: observed/expected deaths) and Cox regression analysis. <b><i>Results:</i></b> Vital status was studied in a cohort of 232 patients: 181 women (78%), 96 with RLS (41.4%) with a mean age at baseline of 49.8 ± 15.0 years and a mean RLS duration of 14.1 ± 1.9 years, and 136 non-RLS (58.6%) with a mean age of 51.3 ± 14.9 years. This RLS cohort was followed up for a period of 10.4 ± 2.0 years. As of September 2019, 17 (7.3%) patients died (6 with RLS, 6.3%), and the most frequent cause was oncological (66.7%). A total of 944 person-years of observations were available for survival analysis. RLS was not associated with increased mortality in adjusted Cox regression analysis (HR = 1.12, 95% CI: 0.40–3.15), and survival was similar to that expected for the general population (SMR = 0.61, 95% CI: 0.27–1.36). <b><i>Conclusions:</i></b> RLS seems not to be associated with increased mortality compared to the general population. Still, studies with prospective data collection with large samples are needed to study the long-term mortality risk factors in RLS cohorts.
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16
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Ahmed N, Kandil M, Elfil M, Jamal A, Koo BB. Hypothyroidism in restless legs syndrome. J Sleep Res 2020; 30:e13091. [PMID: 32483857 DOI: 10.1111/jsr.13091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/14/2020] [Accepted: 05/04/2020] [Indexed: 01/17/2023]
Abstract
The diurnal nature of restless legs syndrome (RLS) and its response to dopamine hint that hormones are central in RLS pathophysiology. Hypothyroidism has been linked to RLS, but studies are limited. This study's objective is to determine whether RLS is more prevalent in persons with hypothyroidism and whether hypothyroidism is more prevalent in RLS sufferers. Persons with hypothyroidism and controls were recruited through an on-line registry of potential research participants. RLS was assessed using the Cambridge-Hopkins questionnaire. RLS persons and controls were recruited through RLS Foundation and on-line registry advertisements and assessed for hypothyroidism by self-report. The International RLS Study Group Severity Scale assessed RLS severity; 266 hypothyroid subjects and 321 controls were comparable in age (52.3 ± 13.4 versus 53.9 ± 11.7 years; p = .14) and gender (91.7% versus 91.3% women; p = .85), as were 354 RLS and 313 controls (59.1 ± 13.2 versus 58.2 ± 13.6 years; p = .41; 80.8% versus 78.3% women; p = .42). Hypothyroid participants versus controls had a significantly higher prevalence of RLS (14.3% versus 8.1%; p = .02). RLS participants versus controls had a significantly higher prevalence of hypothyroidism (22.3% versus. 13.8%; p = .005). RLS severity was similar in persons with and without hypothyroidism. Among 73 persons with RLS and hypothyroidism, 14 previously were hyperthyroid versus 0 of 37 persons with hypothyroidism alone (p = .004). RLS prevalence is increased in individuals with hypothyroidism; hypothyroidism prevalence is increased in individuals with RLS. Persons with hypothyroidism and RLS are significantly more likely than those with hypothyroidism alone to have had hyperthyroidism prior to hypothyroidism. Associations between RLS and thyroid disease may shed light on complex biological mechanisms underlying RLS.
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Affiliation(s)
- Nada Ahmed
- Department of Neurology, Yale University, New Haven, Connecticut, USA
| | - Mohamed Kandil
- Department of Neurology, Yale University, New Haven, Connecticut, USA
| | - Mohamed Elfil
- Department of Neurology, Yale University, New Haven, Connecticut, USA
| | - Abdalla Jamal
- Department of Neurology, Yale University, New Haven, Connecticut, USA
| | - Brian B Koo
- Department of Neurology, Yale University, New Haven, Connecticut, USA.,Center for Neuroepidemiology and Clinical Neurologic Research, New Haven, Connecticut, USA
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17
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Lyu S, Doroodchi A, Xing H, Sheng Y, DeAndrade MP, Yang Y, Johnson TL, Clemens S, Yokoi F, Miller MA, Xiao R, Li Y. BTBD9 and dopaminergic dysfunction in the pathogenesis of restless legs syndrome. Brain Struct Funct 2020; 225:1743-1760. [PMID: 32468214 DOI: 10.1007/s00429-020-02090-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 05/13/2020] [Indexed: 01/17/2023]
Abstract
Restless legs syndrome (RLS) is characterized by an urge to move legs, usually accompanied by uncomfortable sensations. RLS symptoms generally happen at night and can be relieved by movements. Genetic studies have linked polymorphisms in BTBD9 to a higher risk of RLS. Knockout of BTBD9 homolog in mice (Btbd9) and fly results in RLS-like phenotypes. A dysfunctional dopaminergic system is associated with RLS. However, the function of BTBD9 in the dopaminergic system and RLS is not clear. Here, we made use of the simple Caenorhabditis elegans nervous system. Loss of hpo-9, the worm homolog of BTBD9, resulted in hyperactive egg-laying behavior. Analysis of genetic interactions between hpo-9 and genes for dopamine receptors (dop-1, dop-3) indicated that hpo-9 and dop-1 worked similarly. Reporter assays of dop-1 and dop-3 revealed that hpo-9 knockout led to a significant increase of DOP-3 expression. This appears to be evolutionarily conserved in mice with an increased D2 receptor (D2R) mRNA in the striatum of the Btbd9 knockout mice. Furthermore, the striatal D2R protein was significantly decreased and Dynamin I was increased. Overall, activities of DA neurons in the substantia nigra were not altered, but the peripheral D1R pathway was potentiated in the Btbd9 knockout mice. Finally, we generated and characterized the dopamine neuron-specific Btbd9 knockout mice and detected an active-phase sleepiness, suggesting that dopamine neuron-specific loss of Btbd9 is sufficient to disturb the sleep. Our results suggest that increased activities in the D1R pathway, decreased activities in the D2R pathway, or both may contribute to RLS.
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Affiliation(s)
- Shangru Lyu
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Atbin Doroodchi
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Hong Xing
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Yi Sheng
- Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Mark P DeAndrade
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Youfeng Yang
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Tracy L Johnson
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Fumiaki Yokoi
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Michael A Miller
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Rui Xiao
- Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Yuqing Li
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA.
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18
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Lyu S, DeAndrade MP, Unger EL, Mueller S, Oksche A, Walters AS, Li Y. Mu opioid receptor knockout mouse: Phenotypes with implications on restless legs syndrome. J Neurosci Res 2020; 98:1532-1548. [PMID: 32424971 DOI: 10.1002/jnr.24637] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 04/12/2020] [Accepted: 04/17/2020] [Indexed: 12/19/2022]
Abstract
Restless legs syndrome (RLS) is characterized by an irresistible need to move the legs while sitting or lying at night with insomnia as a frequent consequence. Human RLS has been associated with abnormalities in the endogenous opioid system, the dopaminergic system, the iron regulatory system, anemia, and inflammatory and auto-immune disorders. Our previous work indicates that mice lacking all three subtypes of opioid receptors have a phenotype similar to that of human RLS. To study the roles of each opioid receptor subtype in RLS, we first used mu opioid receptor knockout (MOR KO) mice based on our earlier studies using postmortem brain and cell culture. The KO mice showed decreased hemoglobin, hematocrit, and red blood cells (RBCs), with an appearance of microcytic RBCs indicating anemia. Together with decreased serum iron and transferrin, but increased ferritin levels, the anemia is similar to that seen with chronic inflammation in humans. A decreased serum iron level was also observed in the wildtype mice treated with an MOR antagonist. Iron was increased in the liver and spleen of the KO mice. Normal circadian variations in the dopaminergic and serotoninergic systems were absent in the KO mice. The KO mice showed hyperactivity and increased thermal sensitivity in wakefulness primarily during what would normally be the sleep phase similar to that seen in human RLS. Deficits in endogenous opioid system transmission could predispose to anemia of inflammation and loss of circadian variations in dopaminergic or serotonergic systems, thereby contributing to an RLS-like phenotype.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Mark P DeAndrade
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Erica L Unger
- Department of Biology, Lebanon Valley College, Annville, PA, USA
| | | | - Alexander Oksche
- Mundipharma Research Limited, Cambridge, UK.,Rudolf-Buchheim-Institut für Pharmakologie, University of Giessen, Giessen, Germany
| | - Arthur S Walters
- Division of Sleep Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
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19
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Le syndrome des jambes sans repos. Rev Med Interne 2020; 41:258-264. [DOI: 10.1016/j.revmed.2020.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 12/31/2019] [Accepted: 01/06/2020] [Indexed: 12/14/2022]
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20
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Lyu S, DeAndrade MP, Mueller S, Oksche A, Walters AS, Li Y. Hyperactivity, dopaminergic abnormalities, iron deficiency and anemia in an in vivo opioid receptors knockout mouse: Implications for the restless legs syndrome. Behav Brain Res 2019; 374:112123. [PMID: 31376441 DOI: 10.1016/j.bbr.2019.112123] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/24/2019] [Accepted: 07/30/2019] [Indexed: 12/13/2022]
Abstract
Previous studies have uncovered a potential role of the opioid system in iron hemostasis and dopamine metabolism. Abnormalities in both of these systems have been noted in human RLS. Autopsy studies of human RLS have shown an endogenous opioid deficiency in the thalamus. Opioids, particularly prolonged-release oxycodone/naloxone, have been approved in Europe to be a second-line therapy for severe restless legs syndrome (RLS). To study the role of opioid receptors in the pathogenesis of RLS, we used a triple knockout (KO) mouse strain that lack mu, delta, and kappa opioid receptors and explored the behavioral and biochemical parameters relevant to RLS. The triple KO mice showed hyperactivity and a trend of increased probability of waking during the rest period (day) akin to that in human RLS (night). Surprisingly, triple KO mice also exhibit decreased serum iron concentration, evidence of anemia, a significant dysfunction in dopamine metabolism akin to that noted in human RLS, as well as an increased latency in response to thermal stimuli. To our knowledge, this is the first study to demonstrate that the endogenous opioid system may play a role in iron metabolism and subsequently in the pathogenesis of anemia. It is also the first study showing that opioid receptors are involved in the production of motor restlessness with a circadian predominance. Our findings support the role of endogenous opioids in the pathogenesis of RLS, and the triple KO mice can be used to understand the relationship between iron deficiency, anemia, dopaminergic dysfunction, and RLS.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Mark P DeAndrade
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Stefan Mueller
- Mundipharma Research GmbH & Co. KG, Höhenstraße 10, Limburg, Germany
| | - Alexander Oksche
- Mundipharma Research Limited, Cambridge, UK; Rudolf-Buchheim-Institut für Pharmakologie, University of Giessen, Giessen, Germany
| | - Arthur S Walters
- Division of Sleep Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.
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Cubo E, Gallego-Nieto C, Elizari-Roncal M, Barroso-Pérez T, Collazo C, Calvo S, Delgado-López PD. Is Restless Legs Syndrome Associated with an Increased Risk of Mortality? A Meta-Analysis of Cohort Studies. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2019; 9:650. [PMID: 31413895 PMCID: PMC6691746 DOI: 10.7916/tohm.v0.650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 04/06/2019] [Indexed: 12/01/2022]
Abstract
Background Restless legs syndrome (RLS) is a common sleep disorder,. although controversial, growing evidence relates the presence of RLS to an increased risk of mortality, mainly due to cardiovascular events. The aim of this article was to review the role of RLS as a risk factor of mortality according to independent cohort studies. Methods We performed a literature review via PubMed database for articles relating RLS and mortality. We used the random-effects model to calculate the pooled effect estimates on mortality. Heterogeneity between studies was assessed using quantitative and qualitative analysis. Results Out of 100 articles identified, 13 were finally included. Although studies were heterogeneous (p = 0.001), no significant publication bias was found. When all cohort studies were considered, the random-effects model yielded a significantly increased risk of mortality in RLS versus non-RLS patients (13 studies, hazard ratio [HR] = 1.52, 95% confidence interval [CI] 1.28-1.80). However, this association was not statistically significant when only cohort studies using the international RLS diagnostic criteria were considered (5 studies, HR = 1.63, 95% CI 0.94-2.81). Discussion The results of this meta-analysis suggest that RLS seems to be a risk factor of mortality, although this association is conditioned by the diagnostic criteria used in the studies. Future long-term follow-up standardized mortality studies are needed to address this important question that carries potential impact on population global health.
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Affiliation(s)
- Esther Cubo
- Neurology Department, Hospital Universitario Burgos, ES.,Health Science Department, University of Burgos, ES
| | | | | | | | | | - Sara Calvo
- Research Unit, Hospital Universitario Burgos, ES
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23
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Chiaro G, Manconi M. Restless legs syndrome, periodic limb movements during sleep and cardiovascular risk. Auton Neurosci 2019; 220:102554. [PMID: 31331694 DOI: 10.1016/j.autneu.2019.102554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/20/2019] [Accepted: 05/28/2019] [Indexed: 12/16/2022]
Abstract
Multiple mechanisms may modulate an association between restless legs syndrome/Willis-Ekbom disease (RLS/WED) and cardiovascular disease (CVD), including chronic sleep deprivation, intermittent, periodic limb movements in sleep (PLMS)-related autonomic fluctuations and possible autonomic dysfunction intrinsically associated with RLS per se. The purpose of this paper is to review the existing RLS/WED literature focusing on the pathophysiologic evidence for possible associations between RLS/WED and PLMS with CVD and events (CVE). Specific intrinsic dysautonomic aspects of the disease, which may contribute to generating CVD, are separately discussed. The association between RLS/WED and both CV risk factors and CVD still remains elusive. Although several shared pathophysiological causes could explain these possible relationships, the emerging body of literature focusing on these disorders remains controversial. Not only longitudinal population-based studies and meta-analyses, but also more animal models and therapeutic interventions are needed in order to build a sufficiently robust body of evidence on this topic.
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Affiliation(s)
- Giacomo Chiaro
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital of Lugano, Lugano, Switzerland; Department of Biomedical and Neuromotor Sciences, Bellaria Hospital, University of Bologna, Bologna, Italy
| | - Mauro Manconi
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital of Lugano, Lugano, Switzerland; Department of Neurology, Bern University Hospital, Bern, Switzerland.
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24
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Adil SM, Han JL, Parente BA, Hickey P, Lad SP. Spinal Cord Stimulation for Restless Legs Syndrome: Case Series and Mechanistic Hypothesis. Stereotact Funct Neurosurg 2019; 97:31-36. [PMID: 30947223 DOI: 10.1159/000494737] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 10/07/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND Spinal cord stimulation (SCS) is a well-established therapy for chronic pain syndromes, with growing applicability to other conditions. Restless legs syndrome (RLS) is a widespread, chronic movement disorder managed primarily and incompletely by medication, and its etiology can be classified as idiopathic or secondary. METHODS Three patients underwent SCS implantation for chronic back and/or leg pain with concomitant targeting of RLS: (1) a 34-year-old man with sporadic RLS symptoms that strongly intensified after military-related spinal fractures, (2) a 54-year-old man with RLS likely secondary to meralgia paresthetica, and (3) a 42-year-old man with low back and right lower extremity pain after a military motor vehicle accident. RESULTS Continuing through 40-month, 2-month, and 28-month follow-ups, respectively, the patients experienced exemplary relief of their RLS symptoms. Notably in the case of patient 1, this benefit appears separate from his pain relief, as during the 5-month period directly after surgery but before adjusted targeting, he only experienced pain alleviation. CONCLUSIONS To our knowledge, this is the first reported case of using SCS as a potentially long-lasting, safe, and highly effective therapy for RLS of mixed etiology. Additionally, 2 patients with RLS possibly secondary to chronic pain also benefited from the therapy. This success may be due to increased inhibition from hypothalamic cells controlling dopaminergic input to the spine.
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Affiliation(s)
- Syed M Adil
- Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA
| | - Jing L Han
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Beth A Parente
- Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA
| | - Patrick Hickey
- Department of Neurology, Duke University Medical Center, Durham, North Carolina, USA
| | - Shivanand P Lad
- Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA,
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Ferini-Strambi L, Carli G, Casoni F, Galbiati A. Restless Legs Syndrome and Parkinson Disease: A Causal Relationship Between the Two Disorders? Front Neurol 2018; 9:551. [PMID: 30087647 PMCID: PMC6066514 DOI: 10.3389/fneur.2018.00551] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/19/2018] [Indexed: 11/13/2022] Open
Abstract
Restless Legs Syndrome/Willis-Ekbom Disease (RLS/WED) is a common sleep related movement disorder that can be idiopathic or occurs in comorbidity with other medical conditions such as polyneuropathy, iron deficiency anemia, multiple sclerosis, hypertension and cardiovascular diseases. In recent years, a growing body of literature investigated the association between RLS/WED and Parkinson's Disease (PD). Several questions regarding the comorbidity between these two disorders are still unanswered. If the insurgence of RLS/WED may precede the onset of PD, or if RLS/WED could represent a secondary condition of PD and if impaired dopaminergic pathway may represent a bridge between these two conditions are still debatable issues. In this review, we critically discuss the relationship between RLS/WED and PD by reviewing cross sectional and longitudinal studies, as well as the role of dopamine in these disorders. A twofold interpretation have to be taken into account: dopaminergic therapy may have a crucial role in the development of RLS/WED in PD patients or RLS/WED can be conceived as an early manifestation of PD rather than a risk factor. Several studies showed a high prevalence of RLS/WED in PD patients and several findings related to dopaminergic and iron alterations in both disorders, however up to now it is difficult to find a point of agreement between studies. A greater number of systematic and strongly controlled longitudinal studies as well as basic pathophysiological investigations particularly in RLS/WED are needed to clarify this complex relationship.
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Affiliation(s)
- Luigi Ferini-Strambi
- Department of Clinical Neurosciences, IRCCS San Raffaele Scientific Institute, Neurology - Sleep Disorders Center, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
| | - Giulia Carli
- Department of Clinical Neurosciences, IRCCS San Raffaele Scientific Institute, Neurology - Sleep Disorders Center, Milan, Italy
| | - Francesca Casoni
- Department of Clinical Neurosciences, IRCCS San Raffaele Scientific Institute, Neurology - Sleep Disorders Center, Milan, Italy
| | - Andrea Galbiati
- Department of Clinical Neurosciences, IRCCS San Raffaele Scientific Institute, Neurology - Sleep Disorders Center, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
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Zhang R, Schrempf W, Brandt MD, Mückschel M, Beste C, Stock AK. RLS patients show better nocturnal performance in the Simon task due to diminished visuo-motor priming. Clin Neurophysiol 2017; 129:112-121. [PMID: 29172115 DOI: 10.1016/j.clinph.2017.10.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/03/2017] [Accepted: 10/18/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVE The restless legs syndrome (RLS) is characterized by sensory-motor symptoms which usually occur predominantly at rest in the evening and at night. It is assumed that this circadian rhythm is caused by low dopamine levels in the evening. Yet, it has never been investigated whether RLS patients show diurnal variations in cognitive functions modulated by dopamine and what neurophysiological and functional neuroanatomical processes underlie such modulations. METHODS We used a Simon task combined with EEG and source localization to investigate whether top-down response selection and/or automatic visuo-motor priming are subject to diurnal changes in RLS patients, as compared to matched healthy controls. RESULTS We found that RLS patients showed better task performance due to reduced visuo-motor priming in the evening, as reflected by smaller early lateralized readiness potential (e-LRP) amplitudes and decreased activation of the superior parietal cortex and premotor cortex. Top-down response selection and early attentional processing were unaffected by RLS. CONCLUSIONS Counterintuitively, RLS patients show enhanced task performance in the evening, i.e. when experiencing dopaminergic deficiency. Yet, this may be explained by deficits in visuo-motor priming that lead to reduced false response tendencies. SIGNIFICANCE This study reveals a counterintuitive circadian variation of cognitive functions in RLS patients.
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Affiliation(s)
- Rui Zhang
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Schubertstr. 42, 01307 Dresden, Germany.
| | - Wiebke Schrempf
- Department of Neurology, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Moritz D Brandt
- Department of Neurology, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany; German Center for Neurodegenerative Diseases (DZNE) Dresden, Arnoldstraße 18, 01307 Dresden, Germany
| | - Moritz Mückschel
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Schubertstr. 42, 01307 Dresden, Germany; MS Centre Dresden, Faculty of Medicine of the TU Dresden, Blasewitzer Str. 43, 01307 Dresden, Germany
| | - Christian Beste
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Schubertstr. 42, 01307 Dresden, Germany; Experimental Neurobiology, National Institute of Mental Health, Topolová 748, 25067 Klecany, Czech Republic
| | - Ann-Kathrin Stock
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Schubertstr. 42, 01307 Dresden, Germany
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Zhang R, Brandt MD, Schrempf W, Beste C, Stock AK. Neurophysiological mechanisms of circadian cognitive control in RLS patients - an EEG source localization study. NEUROIMAGE-CLINICAL 2017; 15:644-652. [PMID: 28664035 PMCID: PMC5480014 DOI: 10.1016/j.nicl.2017.06.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/09/2017] [Accepted: 06/10/2017] [Indexed: 01/18/2023]
Abstract
The circadian variation of sensory and motor symptoms with increasing severity in the evening and at night is a key diagnostic feature/symptom of the restless legs syndrome (RLS). Even though many neurological diseases have shown a strong nexus between motor and cognitive symptoms, it has remained unclear whether cognitive performance of RLS patients declines in the evening and which neurophysiological mechanisms are affected by the circadian variation. In the current study, we examined daytime effects (morning vs. evening) on cognitive performance in RLS patients (n = 33) compared to healthy controls (n = 29) by analyzing flanker interference effects in combination with EEG and source localization techniques. RLS patients showed larger flanker interference effects in the evening than in the morning (p = .023), while healthy controls did not display a comparable circadian variation. In line with this, the neurophysiological data showed smaller N1 amplitudes in RLS patients compared to controls in the interfering task condition in the evening (p = .042), but not in the morning. The results demonstrate diurnal cognitive changes in RLS patients with intensified impairments in the evening. It seems that not all dopamine-regulated cognitive processes are altered in RLS and thus show daytime-dependent impairments. Instead, the daytime-related cognitive impairment emerges from attentional selection processes within the extra-striate visual cortex, but not from later cognitive processes such as conflict monitoring and response selection. RLS patients have larger flanker interference effect in the evening. RLS patients have enhanced impairment of attentional selection in the evening. Nocturnal attentional impairment relies on the extra-striate visual cortex. Conflict monitoring and response selection are not affected by RLS.
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Affiliation(s)
- Rui Zhang
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Schubertstr. 42, 01307 Dresden, Germany.
| | - Moritz D Brandt
- Department of Neurology, Carl Gustav Carus University Hospital Dresden, Fetscherstraße 74, 01307 Dresden, Germany; German Center for Neurodegenerative Diseases (DZNE) Dresden, 01307 Dresden, Germany
| | - Wiebke Schrempf
- Department of Neurology, Carl Gustav Carus University Hospital Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Christian Beste
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Schubertstr. 42, 01307 Dresden, Germany; Experimental Neurobiology, National Institute of Mental Health, Topolová 748, 250 67 Klecany, Czech Republic
| | - Ann-Kathrin Stock
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Schubertstr. 42, 01307 Dresden, Germany
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Khan FH, Ahlberg CD, Chow CA, Shah DR, Koo BB. Iron, dopamine, genetics, and hormones in the pathophysiology of restless legs syndrome. J Neurol 2017; 264:1634-1641. [PMID: 28236139 DOI: 10.1007/s00415-017-8431-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/16/2017] [Accepted: 02/18/2017] [Indexed: 12/16/2022]
Abstract
Restless legs syndrome (RLS) is a common, chronic neurologic condition, which causes a persistent urge to move the legs in the evening that interferes with sleep. Human and animal studies have been used to study the pathophysiologic state of RLS and much has been learned about the iron and dopamine systems in relation to RLS. Human neuropathologic and imaging studies have consistently shown decreased iron in different brain regions including substantia nigra and thalamus. These same areas also demonstrate a state of relative dopamine excess. While it is not known how these changes in dopamine or iron produce the symptoms of RLS, genetic and hormone studies of RLS have identified other biologic systems or genes, such as the endogenous opioid and melanocortin systems and BTBD9 and MEIS1, that may explain some of the iron or dopamine changes in relation to RLS. This manuscript will review what is known about the pathophysiology of RLS, especially as it relates to changes in iron, dopamine, genetics, and hormonal systems.
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Affiliation(s)
- Farhan H Khan
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Caitlyn D Ahlberg
- Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Christopher A Chow
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Divya R Shah
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Brian B Koo
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA.
- Connecticut Veterans Affairs Medical Center, 950 Campbell Avenue, West Haven, CT, 06516, USA.
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Cho YW, Kang MS, Kim KT, Do SY, Lim JG, Lee SY, Motamedi GK. Quantitative sensory test for primary restless legs syndrome/Willis–Ekbom disease using the current perception threshold test. Sleep Med 2017; 30:19-23. [DOI: 10.1016/j.sleep.2016.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 02/02/2016] [Accepted: 03/01/2016] [Indexed: 10/22/2022]
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Connectome and molecular pharmacological differences in the dopaminergic system in restless legs syndrome (RLS): plastic changes and neuroadaptations that may contribute to augmentation. Sleep Med 2016; 31:71-77. [PMID: 27539027 DOI: 10.1016/j.sleep.2016.06.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/21/2016] [Accepted: 06/04/2016] [Indexed: 01/08/2023]
Abstract
Restless legs syndrome (RLS) is primarily treated with levodopa and dopaminergics that target the inhibitory dopamine receptor subtypes D3 and D2. The initial success of this therapy led to the idea of a hypodopaminergic state as the mechanism underlying RLS. However, multiple lines of evidence suggest that this simplified concept of a reduced dopamine function as the basis of RLS is incomplete. Moreover, long-term medication with the D2/D3 agonists leads to a reversal of the initial benefits of dopamine agonists and augmentation, which is a worsening of symptoms under therapy. The recent findings on the state of the dopamine system in RLS that support the notion that a dysfunction in the dopamine system may in fact induce a hyperdopaminergic state are summarized. On the basis of these data, the concept of a dynamic nature of the dopamine effects in a circadian context is presented. The possible interactions of cell adhesion molecules expressed by the dopaminergic systems and their possible effects on RLS and augmentation are discussed. Genome-wide association studies (GWAS) indicate a significantly increased risk for RLS in populations with genomic variants of the cell adhesion molecule receptor type protein tyrosine phosphatase D (PTPRD), and PTPRD is abundantly expressed by dopamine neurons. PTPRD may play a role in the reconfiguration of neural circuits, including shaping the interplay of G protein-coupled receptor (GPCR) homomers and heteromers that mediate dopaminergic modulation. Recent animal model data support the concept that interactions between functionally distinct dopamine receptor subtypes can reshape behavioral outcomes and change with normal aging. Additionally, long-term activation of one dopamine receptor subtype can increase the receptor expression of a different receptor subtype with opposite modulatory actions. Such dopamine receptor interactions at both spinal and supraspinal levels appear to play important roles in RLS. In addition, these interactions can extend to the adenosine A1 and A2A receptors, which are also prominently expressed in the striatum. Interactions between adenosine and dopamine receptors and dopaminergic cell adhesion molecules, including PTPRD, may provide new pharmacological targets for treating RLS. In summary, new treatment options for RLS that include recovery from augmentation will have to consider dynamic changes in the dopamine system that occur during the circadian cycle, plastic changes that can develop as a function of treatment or with aging, changes in the connectome based on alterations in cell adhesion molecules, and receptor interactions that may extend beyond the dopamine system itself.
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Romigi A, Vitrani G, D'Aniello A, Di Gennaro G. Amelioration of untreated restless legs syndrome by tadalafil in a patient with erectile dysfunction. Clin Neuropharmacol 2015; 38:62. [PMID: 25768855 DOI: 10.1097/wnf.0000000000000070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Andrea Romigi
- *Sleep Medicine Center, IRCCS Neuromed Istituto Neurologico Mediterraneo, Pozzilli (IS); and †Department of Neurophysiopathology, Sleep and Epilepsy Center, Università di Roma Tor Vergata, Rome, Italy
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Sharon D. Nonpharmacologic Management of Restless Legs Syndrome (Willis-Ekbom Disease). Sleep Med Clin 2015; 10:263-78, xiii. [DOI: 10.1016/j.jsmc.2015.05.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Chen PK, Fuh JL, Wang SJ. Bidirectional triggering association between migraine and restless legs syndrome: A diary study. Cephalalgia 2015. [PMID: 26195587 DOI: 10.1177/0333102415596444] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
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.
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Affiliation(s)
- Ping-Kun Chen
- Department of Neurology, Lin-Shin Hospital, Taiwan Department of Neurology, China Medical University Hospital, Taiwan School of Medicine, China Medical University, Taiwan
| | - Jong-Ling Fuh
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taiwan Faculty of Medicine, National Yang-Ming University School of Medicine, Taiwan
| | - Shuu-Jiun Wang
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taiwan Faculty of Medicine, National Yang-Ming University School of Medicine, Taiwan Brain Research Center, National Yang-Ming University School of Medicine, Taiwan
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Earley CJ, Connor J, Garcia-Borreguero D, Jenner P, Winkelman J, Zee PC, Allen R. Altered brain iron homeostasis and dopaminergic function in Restless Legs Syndrome (Willis-Ekbom Disease). Sleep Med 2014; 15:1288-301. [PMID: 25201131 DOI: 10.1016/j.sleep.2014.05.009] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 05/15/2014] [Accepted: 05/27/2014] [Indexed: 12/31/2022]
Abstract
Restless legs syndrome (RLS), also known as Willis-Ekbom Disease (WED), is a sensorimotor disorder for which the exact pathophysiology remains unclear. Brain iron insufficiency and altered dopaminergic function appear to play important roles in the etiology of the disorder. This concept is based partly on extensive research studies using cerebrospinal fluid (CSF), autopsy material, and brain imaging indicating reduced regional brain iron and on the clinical efficacy of dopamine receptor agonists for alleviating RLS symptoms. Finding causal relations, linking low brain iron to altered dopaminergic function in RLS, has required however the use of animal models. These models have provided insights into how alterations in brain iron homeostasis and dopaminergic system may be involved in RLS. The results of animal models of RLS and biochemical, postmortem, and imaging studies in patients with the disease suggest that disruptions in brain iron trafficking lead to disturbances in striatal dopamine neurotransmission for at least some patients with RLS. This review examines the data supporting an iron deficiency-dopamine metabolic theory of RLS by relating the results from animal model investigations of the influence of brain iron deficiency on dopaminergic systems to data from clinical studies in patients with RLS.
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Affiliation(s)
- Christopher J Earley
- Department of Neurology, The Johns Hopkins Bayview Medical Center, Baltimore, MD, USA.
| | - James Connor
- Department of Neurosurgery, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | | | - Peter Jenner
- Neurodegenerative Diseases Research Group, Institute of Pharmaceutical Science, School of Biomedical Sciences, King's College, London, UK
| | - John Winkelman
- Brigham and Women's Hospital Sleep Health Center, Brighton, MA, USA
| | - Phyllis C Zee
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Richard Allen
- Department of Neurology, The Johns Hopkins Bayview Medical Center, Baltimore, MD, USA
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Jung JS, Lee HJ, Cho CH, Kang SG, Yoon HK, Park YM, Moon JH, Yang HJ, Song HM, Kim L. Association between restless legs syndrome and CLOCK and NPAS2 gene polymorphisms in schizophrenia. Chronobiol Int 2014; 31:838-44. [PMID: 24824748 DOI: 10.3109/07420528.2014.914034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Previous studies have suggested that there is a genetic basis to restless legs syndrome (RLS) development. Occurrence of antipsychotic-induced RLS could also be due to differences in genetic susceptibility. We investigated whether CLOCK and NPAS2 gene polymorphisms are associated with RLS in schizophrenic patients on antipsychotics because RLS symptoms usually manifest during the evening and night. We assessed symptoms of RLS in 190 Korean schizophrenic patients on antipsychotics and divided the subjects into two groups according to the International Restless Legs Syndrome Study Group diagnostic criteria: (i) subjects who met all the criteria and (ii) the remaining subjects who did not meet all the criteria. We found a significant difference in the number of subjects with different genotype and allele carrier frequencies for the CLOCK gene (rs2412646) between the two groups (p = 0.031 and 0.010, respectively). Distribution of CLOCK haplotypes (rs2412646-rs1801260) was significantly different between schizophrenic patients with and without RLS (p = 0.021). However, the distributions of allelic, genotypic, and haplotypic variants of NPAS2 (rs2305160 and rs6725296) were not significantly different between the two groups. Our results suggest that CLOCK polymorphisms are associated with increased susceptibility of schizophrenic patients to RLS. We hypothesize that RLS in schizophrenia patients treated with antipsychotics may be a very mild akathisia that manifests during the night and is under control of circadian oscillation.
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Affiliation(s)
- Jin-Sook Jung
- Department of Psychiatry, College of Medicine, Korea University , Seoul , South Korea
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Sawanyawisuth K, Palinkas LA, Ancoli-Israel S, Dimsdale JE, Loredo JS. Ethnic differences in the prevalence and predictors of restless legs syndrome between Hispanics of Mexican descent and non-Hispanic Whites in San Diego county: a population-based study. J Clin Sleep Med 2013; 9:47-53. [PMID: 23319904 DOI: 10.5664/jcsm.2338] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
STUDY OBJECTIVES To investigate the prevalence and predictors of RLS in Hispanics of Mexican descent (HMD) and non-Hispanic whites (NHW). DESIGN A population-based random digit dialing telephone questionnaire. SETTING San Diego County California PARTICIPANTS 1,754 HMD and 1,913 NHW adults ≥ 18 years of age able to participate in a telephone interview in English or Spanish. INTERVENTIONS None. MEASUREMENTS AND RESULTS RLS was defined by the presence of all 4 criteria of the International Restless Legs Study Group. Sleepiness was measured by the Epworth Sleepiness Scale. Acculturation was evaluated using the Short Acculturation Scale for Hispanics. Risk factors for RLS were by self-report. The survey was conducted in the subject's language of choice. RLS prevalence was significantly lower in HMD than in NHW (14.4% vs.18.3%, p = 0.002). High acculturation HMD had a significantly greater RLS prevalence than the low acculturation group (17.4% vs. 12.8%, p = 0.008). Predictors of RLS varied between HMD and NHW. Female gender (OR 1.40, 95% CI 1.04, 1.90, p = 0.027), smoking (OR 1.82, 95% CI 1.27, 2.61, p = 0.001), and acculturation (OR 1.47, 95% CI 1.10, 1.97, p = 0.009) were independent predictors of RLS in HMD, while only older age (OR 1.01, 95% CI 1.0, 1.02) was an independent predictor of RLS for NHW. CONCLUSION The prevalence of RLS was significantly lower in HMD than in NHW, and significantly greater in high acculturation HMD. Our data suggest that risk factors for RLS vary by race/ethnicity and acculturation is an independent risk for RLS in HMD.
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Earley CJ, Kuwabara H, Wong DF, Gamaldo C, Salas RE, Brašić JR, Ravert HT, Dannals RF, Allen RP. Increased synaptic dopamine in the putamen in restless legs syndrome. Sleep 2013; 36:51-7. [PMID: 23288971 DOI: 10.5665/sleep.2300] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Prior studies using positron emission tomography (PET) or single-photon emission computed tomography techniques have reported inconsistent findings regarding differences between patients with restless legs syndrome (RLS) and control patients in the striatal dopamine-2 receptor (D2R) binding potentials (BP). D2R-BP does reflect receptor-ligand interactions such as receptor affinity (K(d)) and density (β(max)) or neurotransmitter synaptic concentrations. Thus, differences in D2R-BP reflect changes in these primary factors. PET techniques are currently available to estimate D2R β(max) and K(d). DESIGN Separate morning and evening PET scans were performed. The D2R-BP were measured in basal ganglia using [(11)C]raclopride. SETTING Academic medical center. PATIENTS OR PARTICIPANTS Thirty-one patients with primary RLS and 36 age- and sex-matched control patients completed the study. MEASURES AND RESULTS Patients with RLS had lower D2R-BP in putamen and caudate but not the ventral striatum. A subgroups analysis of those RLS patients who had not previously taken dopaminergic medications continued to show a significantly lower D2R-BP in the posterior putamen. D2R-BP did not differ between night and day for either group. D2R β(max) and K(d) did not differ significantly between patients with RLS and control patients but did show a strong and significant increase at night in the ventral striatum. Primary and secondary clinical measures of disease status failed to show any relation to D2R in any brain region. CONCLUSIONS Given the lack of any difference in either β(max) or K(d) and the prior studies supporting an increase in presynaptic dopaminergic activity, the current changes found in D2R-BP likely reflect an increase in synaptic dopamine.
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Garcia-Borreguero D, Ferini-Strambi L, Kohnen R, O'Keeffe S, Trenkwalder C, Högl B, Benes H, Jennum P, Partinen M, Fer D, Montagna P, Bassetti CL, Iranzo A, Sonka K, Williams AM. European guidelines on management of restless legs syndrome: report of a joint task force by the European Federation of Neurological Societies, the European Neurological Society and the European Sleep Research Society. Eur J Neurol 2012; 19:1385-96. [DOI: 10.1111/j.1468-1331.2012.03853.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 07/12/2012] [Indexed: 11/27/2022]
Affiliation(s)
| | | | - Ralf Kohnen
- RPS Research Germany and Psychology Department; University Erlangen-Nuremberg; Nuremberg Germany
| | - Shaun O'Keeffe
- Department of Geriatric Medicine; Galway University Hospitals; Galway Ireland
| | - Claudia Trenkwalder
- Paracelsus-Elena Klinik; Center of Parkinsonism and Movement Disorders; Kassel Germany
- Department of Clinical Neurophysiology; University of Goettingen; Kassel Germany
| | - Birgit Högl
- Department of Neurology; Innsbruck Medical University; Innsbruck Austria
| | - Heike Benes
- Somni Bene Institute for Medical Research and Sleep Medicine, and Neurology Department; University of Rostock; Schwerin Germany
| | - Poul Jennum
- Danish Center for Sleep Medicine; Glostrup Hospital, and Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - Markku Partinen
- Helsinki Sleep Clinic; Vitalmed Research Centre; Helsinki Finland
| | | | - Pasquale Montagna
- Department of Neurological Sciences; University of Bologna; Bologna Italy
| | - Claudio L. Bassetti
- Department of Neurology; University Hospital (Inselspital), Bern, and Neurocenter of Southern Switzerland; Lugano Switzerland
| | - Alex Iranzo
- Neurology Service and Multidisciplinary Sleep Unit; Hospital Clinic; Barcelona Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED); Barcelona Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Barcelona Spain
| | - Karel Sonka
- Department of Neurology; First Faculty of Medicine, Charles University; Prague Czech Republic
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DeAndrade MP, Johnson RL, Unger EL, Zhang L, van Groen T, Gamble KL, Li Y. Motor restlessness, sleep disturbances, thermal sensory alterations and elevated serum iron levels in Btbd9 mutant mice. Hum Mol Genet 2012; 21:3984-92. [PMID: 22678064 DOI: 10.1093/hmg/dds221] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Restless legs syndrome (RLS), also known as Willis-Ekbom disease, is a sensory-motor neurological disorder with a circadian component. RLS is characterized by uncomfortable sensations in the extremities, generally at night or during sleep, which often leads to an uncontrollable urge to move them for relief. Recently, genomic studies identified single-nucleotide polymorphisms in BTBD9, along with three other genes, as being associated with a higher risk of RLS. Little is known about the function of BTBD9 or its potential role in the pathophysiology of RLS. We therefore examined a line of Btbd9 mutant mice we recently generated for phenotypes similar to symptoms found in RLS patients. We observed that the Btbd9 mutant mice had motor restlessness, sensory alterations likely limited to the rest phase, and decreased sleep and increased wake times during the rest phase. Additionally, the Btbd9 mutant mice had altered serum iron levels and monoamine neurotransmitter systems. Furthermore, the sensory alterations in the Btbd9 mutant mice were relieved using ropinirole, a dopaminergic agonist widely used for RLS treatment. These results, taken together, suggest that the Btbd9 mutant mice model several characteristics similar to RLS and would therefore be the first genotypic mouse model of RLS. Furthermore, our data provide further evidence that BTBD9 is involved in RLS, and future studies of the Btbd9 mutant mice will help shine light on its role in the pathophysiology of RLS. Finally, our data argue for the utility of Btbd9 mutant mice to discover and screen novel therapeutics for RLS.
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Affiliation(s)
- Mark P DeAndrade
- Interdisciplinary Program in Biomedical Sciences and Department of Neurology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
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Aras G, Kadakal F, Purisa S, Kanmaz D, Aynaci A, Isik E. Are we aware of restless legs syndrome in COPD patients who are in an exacerbation period? Frequency and probable factors related to underlying mechanism. COPD 2012; 8:437-43. [PMID: 22149404 DOI: 10.3109/15412555.2011.623737] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A few previous studies have reported that the patients with chronic obstructive pulmonary disease (COPD) have a 29.1% to 36.8% frequency of restless legs syndrome (RLS). In this study, we observed RLS symptoms in patients experiencing COPD exacerbation to better understand the relationship between the many clinical parameters of COPD and the presence of RLS and to attract the attention of specialists on the association between the two conditions. Twenty-two male patients in COPD exacerbation; 17 healthy individuals were evaluated in this study. The patients were evaluated using the 2003 RLS symptom criteria outlined by the International Restless Legs Syndrome Study Groups (IRLSSG). The Pittsburgh Sleep Quality Index and Epworth daytime sleepiness scale were used to assess the sleep quality of patients. The RLS symptoms were correlated with blood levels of laboratory and clinical parameters. Statistical analyses were performed using SPSS 17.0 statistical software packet. The Pittsburgh Sleep Quality Index and Epworth daytime sleepiness scale scores were increased in COPD patients and correlated significantly with RLS symptoms. It was found that 54.5% of COPD patients with acute exacerbations were observed to have RLS symptoms. The Pittsburgh Sleep Quality Index was significantly higher in COPD patients with RLS symptoms compared to COPD patients without RLS symptoms (p < 0.05). We did not observe any significant difference in the previously reported metabolic and clinical parameters associated with RLS in COPD patients with and without RLS. RLS symptoms increase during COPD exacerbation and lead to decreased sleep quality.
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Affiliation(s)
- Gulfidan Aras
- Yedikule Chest Disease and Surgery Education and Research Hospital, Istanbul, Turkey.
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Thorpe AJ, Clair A, Hochman S, Clemens S. Possible Sites of Therapeutic Action in Restless Legs Syndrome: Focus on Dopamine and α 2δ Ligands. Eur Neurol 2011; 66:18-29. [DOI: 10.1159/000328431] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 04/11/2011] [Indexed: 01/01/2023]
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Duffy JF, Lowe ASW, Silva EJ, Winkelman JW. Periodic limb movements in sleep exhibit a circadian rhythm that is maximal in the late evening/early night. Sleep Med 2011; 12:83-8. [PMID: 21093364 PMCID: PMC3052966 DOI: 10.1016/j.sleep.2010.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 05/07/2010] [Accepted: 06/11/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Periodic limb movements in sleep (PLMS) show a time-of-night pattern, with most movements at the beginning of the night. Our study aimed to determine whether this pattern is due to an endogenous circadian rhythm, like that in the related movement disorder Restless Legs Syndrome (RLS). METHODS Four healthy older adults with a screening PLMI>20 were studied in an inpatient forced desynchrony protocol with an imposed sleep-wake cycle of 20 h for 12 "nights," allowing separation of circadian and sleep homeostatic influences on leg movements. We recorded sleep polysomnographically throughout each scheduled episode, including left and right anterior tibialis EMG. RESULTS PLMS in Stage 2 showed both a significant time-within-sleep pattern and a significant circadian rhythm. The circadian rhythm in PLMS peaked at the circadian phases when usual sleep onset occurs, preceding the evening rise in melatonin secretion. CONCLUSIONS In our subjects, the circadian pattern of PLMs expression was very similar to that previously reported in patients with RLS. This evidence for a circadian rhythm in PLMS has implications for treatment and provides direction for future studies of the pathophysiology of this movement disorder.
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Affiliation(s)
- Jeanne F Duffy
- Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Earley CJ, Allen RP, Hening W. Restless legs syndrome and periodic leg movements in sleep. HANDBOOK OF CLINICAL NEUROLOGY 2011; 99:913-48. [PMID: 21056236 DOI: 10.1016/b978-0-444-52007-4.00015-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Abstract
Restless legs syndrome (RLS) is characterized by a compelling, often insatiable, need to move the legs, accompanied by unpleasant sensations located mainly in the ankles and calves. Because symptoms are brought on by inactivity, distress intrudes upon everyday, sedentary activities such as plane travel, car rides, and attending school, meetings, or the theatre. Symptoms show a diurnal preference for the evening and night, so disruption of sleep onset or maintenance is particularly common. RLS is associated with both lower ratings of quality of life and higher rates of cardiovascular disease. Four common genetic loci associating to RLS have recently been identified, but the molecular pathways by which they increase risk for RLS have yet to be determined. Both sensory (RLS) and motor (periodic limb movements of sleep) symptoms are responsive to dopaminergic medications, yet clear delineation of dopaminergic pathology has not emerged. Brain iron is reduced in many, but not all, patients with RLS. First-line treatment for RLS includes agents acting at D(2) and D(3) dopamine receptors.
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Restless legs syndrome and periodic limb movements disorder in the pediatric population. Curr Opin Pulm Med 2010; 16:559-67. [DOI: 10.1097/mcp.0b013e32833f11ae] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Trenkwalder C, Paulus W. Restless legs syndrome: pathophysiology, clinical presentation and management. Nat Rev Neurol 2010; 6:337-46. [PMID: 20531433 DOI: 10.1038/nrneurol.2010.55] [Citation(s) in RCA: 200] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Facheris MF, Hicks AA, Pramstaller PP, Pichler I. Update on the management of restless legs syndrome: existing and emerging treatment options. Nat Sci Sleep 2010; 2:199-212. [PMID: 23616710 PMCID: PMC3630948 DOI: 10.2147/nss.s6946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
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.
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Affiliation(s)
- Maurizio F Facheris
- Institute of Genetic Medicine, European Academy Bozen/Bolzano (EURAC), Bolzano, Italy (Affiliated institute of the University of Lübeck, Lübeck, Germany) ; Department of Neurology, Central Hospital, Bolzano, Italy
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Schlesinger I, Erikh I, Avizohar O, Sprecher E, Yarnitsky D. Cardiovascular risk factors in restless legs syndrome. Mov Disord 2009; 24:1587-92. [DOI: 10.1002/mds.22486] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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