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Antelmi E, Mogavero MP, Lanza G, Cartella SM, Ferini-Strambi L, Plazzi G, Ferri R, Tinazzi M. Sensory aspects of restless legs syndrome: Clinical, neurophysiological and neuroimaging prospectives. Sleep Med Rev 2024; 76:101949. [PMID: 38749362 DOI: 10.1016/j.smrv.2024.101949] [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: 07/06/2023] [Revised: 11/20/2023] [Accepted: 04/29/2024] [Indexed: 07/26/2024]
Abstract
Restless Legs Syndrome (RLS) is a complex sensorimotor disorder, classified among the sleep-related movement disorders. Although sensory symptoms appear as key features of the disorder, they are still poorly characterized from a clinical perspective and conceptualized from a pathophysiological point of view. In this review, we aim to describe the clinical and functional substrates of RLS, focusing mainly on its sensory symptoms and on their neurophysiological and anatomical correlates. Knowledge of both subjective sensory symptoms and objective sensory signs are still controversial. Current data also indicate that the sensory component of RLS seems to be subserved by anomalies of sensorimotor integration and by mechanism of central sensitization. Overall, electrophysiological findings highlight the involvement of multiple generators in the pathogenesis of RLS, eventually resulting in an increased nervous system excitability and/or alterations in inhibition within the somatosensory and nociceptive pathways. Structural and functional neuroimaging data show the involvement of several crucial areas and circuits, among which the thalamus appears to play a pivotal role. A holistic approach looking at brain connectivity, structural or functional abnormalities, and their interplay with molecular vulnerability and neurotransmitter alterations is warranted to disentangle the complex framework of RLS.
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Affiliation(s)
- Elena Antelmi
- Neurology Unit, Parkinson Disease and Movement Disorders Division, DIMI Department of Engineering and Medicine of Innovation, University of Verona, Italy.
| | - Maria P Mogavero
- Vita-Salute San Raffaele University, Milan, Italy; San Raffaele Scientific Institute, Division of Neuroscience, Sleep Disorders Center, Milan, Italy
| | - Giuseppe Lanza
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Troina, Italy; University of Catania, Department of Surgery and Medical-Surgical Specialties, Catania, Italy
| | - Sandy M Cartella
- Movement Disorders Centre, Department of Neurology, Policlinico "Madonna Della Consolazione", Reggio Calabria, Italy
| | - Luigi Ferini-Strambi
- Vita-Salute San Raffaele University, Milan, Italy; San Raffaele Scientific Institute, Division of Neuroscience, Sleep Disorders Center, Milan, Italy
| | - Giuseppe Plazzi
- IRCCS, Istituto Delle Scienze Neurologiche di Bologna, Bologna, Italy; Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Raffaele Ferri
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Troina, Italy
| | - Michele Tinazzi
- Neurology Unit, Parkinson Disease and Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Italy
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Antelmi E, Mingolla GP, Mogavero MP, Ferri R, Lanza G, Morgante F, Bonetto C, Conte A, Ferini-Strambi L, Plazzi G, Berardelli A, Tinazzi M. A survey-based approach on restless legs syndrome: practices and perspectives among Italian neurologists. J Neurol 2024; 271:4227-4236. [PMID: 38607430 DOI: 10.1007/s00415-024-12356-7] [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: 02/19/2024] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/13/2024]
Abstract
INTRODUCTION Restless Legs Syndrome (RLS) is a widely prevalent and complex neurological disorder. Despite notable advancements in managing RLS, the disorder continues to face challenges related to its recognition and management. OBJECTIVE This study seeks to gain comprehensive insights into the knowledge and clinical practices among Italian neurologists regarding RLS diagnosis, management, and treatment, comparing approaches among general neurologists, movement disorder specialists, and sleep experts. METHODS Members of the Italian Society of Neurology, the Italian Society of Parkinson and Movement Disorders, and the Italian Association of Sleep Medicine were invited to participate in a 19-question online survey. RESULTS Among the 343 surveyed neurologists, 60% categorized RLS as a "sleep-related movement disorder." Forty% indicated managing 5-15 RLS patients annually, with sleep specialists handling the highest patient volume. Of note, only 34% adhered strictly to all five essential diagnostic criteria. The majority (69%) favored low-dosage dopamine agonists as their first-line treatment, with movement disorder specialists predominantly endorsing this approach, while sleep experts preferred iron supplementation. Regular screening for iron levels was widespread (91%), with supplementation typically guided by serum iron alterations. In cases of ineffective initial treatments, escalating dopamine agonist dosage was the preferred strategy (40%). CONCLUSIONS These findings underscore a lack of a clear conceptualization of RLS, with a widespread misconception of the disorder as solely a movement disorder significantly influencing treatment approaches. Disparities in RLS understanding across neurology subspecialties underscore the necessity for improved diagnostic accuracy, targeted educational initiatives, and management guidelines to ensure consistent and effective RLS management.
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Affiliation(s)
- Elena Antelmi
- Neurology Unit, Parkinson Disease and Movement Disorders Division, AOUI, Verona, Italy.
- DIMI Department of Engineering and Medicine of Innovation, University of Verona, Verona, Italy.
| | - Gloria Pompea Mingolla
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Maria Paola Mogavero
- Vita-Salute San Raffaele University, Milan, Italy
- Division of Neuroscience, Sleep Disorders Center, San Raffaele Scientific Institute, Milan, Italy
| | - Raffaele Ferri
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Troina, Italy
| | - Giuseppe Lanza
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Troina, Italy
- Department of Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Francesca Morgante
- Neuroscience and Cell Biology Institute, Neuromodulation and Motor Control Section, St George's University of London, London, UK
| | - Chiara Bonetto
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Antonella Conte
- Department of Human Neurosciences, Sapienza, University of Rome, Rome, Italy
- IRCCS Neuromed, Pozzilli, Italy
| | - Luigi Ferini-Strambi
- Vita-Salute San Raffaele University, Milan, Italy
- Division of Neuroscience, Sleep Disorders Center, San Raffaele Scientific Institute, Milan, Italy
| | - Giuseppe Plazzi
- IRCCS Istituto Delle Scienze Neurologiche Di Bologna (ISNB), Bologna, Italy
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Alfredo Berardelli
- Department of Human Neurosciences, Sapienza, University of Rome, Rome, Italy
- IRCCS Neuromed, Pozzilli, Italy
| | - Michele Tinazzi
- Neurology Unit, Parkinson Disease and Movement Disorders Division, AOUI, Verona, Italy
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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Antelmi E, Squintani GM, Sandri A, Lippolis M, Segatti A, Tinazzi M. Defect of the Endogenous Inhibitory Pain System in Idiopathic Restless Legs Syndrome: A Laser Evoked Potentials Study. Mov Disord 2023; 38:1688-1696. [PMID: 37314385 DOI: 10.1002/mds.29509] [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: 03/20/2023] [Revised: 05/24/2023] [Accepted: 05/30/2023] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND Restless legs syndrome (RLS) is a complex sensorimotor disorder. Symptoms worsen toward evening and at rest and are temporarily relieved by movement. Symptoms are perceived as painful in up to 45% of cases, and nociception system may be involved. OBJECTIVES To assess the descending diffuse noxious inhibitory control in RLS patients. METHODS Twenty-one RLS patients and twenty age and sex-matched healthy controls (HC) underwent a conditioned pain modulation protocol. Cutaneous heat stimuli were delivered via laser evoked potentials (LEPs) on the dorsum of the right hand (UL) and foot (LL). N2 and P2 latencies, N2/P2 amplitude and pain ratings (NRS) were recorded before (baseline), during, and after a heterotopic noxious conditioning stimulation (HNCS) application. The baseline/HNCS ratio was calculated for both UL and LL. RESULTS N2 and P2 latencies did not vary between groups at each condition and limbs. Both groups showed a physiological N2/P2 amplitude and NRS reduction during the HNCS condition in UL and LL in comparison to baseline and post conditions (all, P < 0.003). Between-groups comparisons revealed a significant lower amplitude reduction in RLS at the N2/P2 amplitude during the HNCS condition only for LL (RLS, 13.6 μV; HC, 10.1 μV; P = 0.004). Such result was confirmed by the significant difference at the ratio (RLS, 69%, HC, 52.5%; P = 0.038). CONCLUSIONS The lower physiological reduction during the HNCS condition at LL in RLS patients suggests a defect in the endogenous inhibitory pain system. Further studies should clarify the causal link of this finding, also investigating the circadian modulation of this paradigm. © 2023 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Elena Antelmi
- Neurology Unit, Parkinson Disease and Movement Disorders Division, DIMI Department of Engineering and Medicine of Innovation, University of Verona, Verona, Italy
| | | | - Angela Sandri
- Neurology Unit, Parkinson Disease and Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | | | - Alessia Segatti
- UOC Neurology A, Department of Neurosciences, AOUI, Verona, Italy
| | - Michele Tinazzi
- Neurology Unit, Parkinson Disease and Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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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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Ku J, Lee YS, Kim KT, Chang H, Cho YW. Alterations in Salience Network Functional Connectivity in Individuals with Restless Legs Syndrome. Sci Rep 2020; 10:7643. [PMID: 32377013 PMCID: PMC7203171 DOI: 10.1038/s41598-020-64641-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 04/20/2020] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Restless legs syndrome (RLS) is a neurological disorder which is most commonly identified by an urge to move the legs. It often shows alterations in sensory processing which implies the salience network (SN) is experiencing changes. This study investigates the functional connectivity (FC) between the SN and other areas of the brain in RLS patients during the resting state period. METHODS Thirty patients with drug naïve idiopathic RLS and 30 healthy age and gender matched controls were included in this study. Resting state fMRIs were performed in the morning during the asymptomatic period. The SN comparisons were conducted between the two groups. RESULTS The RLS group showed a reduction in SN FC in the right pyramis, and an increase in SN FC in the bilateral orbitofrontal gyri and right postcentral gyrus. CONCLUSIONS The results of this study give reason to believe that SN FC in RLS patients is altered during asymptomatic periods. This could have an influence on the processing of the saliency of information, particularly sensory information processing and inhibition mechanisms.
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Affiliation(s)
- Jeonghun Ku
- Department of Biomedical Engineering, Keimyung University School of Medicine, Dongsan Medical Center, Daegu, South Korea
| | - Yeong Seon Lee
- Department of Neurology, Keimyung University School of Medicine, Dongsan Medical Center, Daegu, South Korea
| | - Keun Tae Kim
- Department of Neurology, Keimyung University School of Medicine, Dongsan Medical Center, Daegu, South Korea
| | - HyukWon Chang
- Department of Radiology, Keimyung University School of Medicine, Dongsan Medical Center, Daegu, South Korea
| | - Yong Won Cho
- Department of Neurology, Keimyung University School of Medicine, Dongsan Medical Center, Daegu, South Korea.
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