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Lanza G, Salemi M, Mogavero MP, Catania V, Galeano A, Garifoli A, Lanuzza B, Morreale M, Tripodi M, Cantone M, Cappellani F, Concerto C, Rodolico A, Pennisi M, Bella R, Ferri R. Targeting the adenosinergic system in restless legs syndrome: A pilot, "proof-of-concept" placebo-controlled TMS-based protocol. PLoS One 2024; 19:e0302829. [PMID: 38728342 PMCID: PMC11086884 DOI: 10.1371/journal.pone.0302829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 04/10/2024] [Indexed: 05/12/2024] Open
Abstract
Restless Legs Syndrome (RLS) is a common sleep disorder characterized by an urge to move the legs that is responsive to movement (particularly during rest), periodic leg movements during sleep, and hyperarousal. Recent evidence suggests that the involvement of the adenosine system may establish a connection between dopamine and glutamate dysfunction in RLS. Transcranial magnetic stimulation (TMS) is a non-invasive electrophysiological technique widely applied to explore brain electrophysiology and neurochemistry under different experimental conditions. In this pilot study protocol, we aim to investigate the effects of dipyridamole (a well-known enhancer of adenosinergic transmission) and caffeine (an adenosine receptor antagonist) on measures of cortical excitation and inhibition in response to TMS in patients with primary RLS. Initially, we will assess cortical excitability using both single- and paired-pulse TMS in patients with RLS. Then, based on the measures obtained, we will explore the effects of dipyridamole and caffeine, in comparison to placebo, on various TMS parameters related to cortical excitation and inhibition. Finally, we will evaluate the psycho-cognitive performance of RLS patients to screen them for cognitive impairment and/or mood-behavioral dysfunction, thus aiming to correlate psycho-cognitive findings with TMS data. Overall, this study protocol will be the first to shed lights on the neurophysiological mechanisms of RLS involving the modulation of the adenosine system, thus potentially providing a foundation for innovative "pharmaco-TMS"-based treatments. The distinctive TMS profile observed in RLS holds indeed the potential utility for both diagnosis and treatment, as well as for patient monitoring. As such, it can be considered a target for both novel pharmacological (i.e., drug) and non-pharmacological (e.g., neuromodulatory), "TMS-guided", interventions.
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Affiliation(s)
- Giuseppe Lanza
- Oasi Research Institute-IRCCS, Troina, Italy
- Department of Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | | | - Maria P. Mogavero
- Vita-Salute San Raffaele University, Milan, Italy
- Division of Neuroscience, San Raffaele Scientific Institute, Sleep Disorders Center, Milan, Italy
| | | | | | | | | | | | | | - Mariagiovanna Cantone
- Neurology Unit, Policlinico University Hospital “G. Rodolico-San Marco”, Catania, Italy
| | - Francesco Cappellani
- Ophtalomolgy Unit, Policlinico University Hospital “G. Rodolico-San Marco”, Catania, Italy
| | - Carmen Concerto
- Psychiatry Unit, Policlinico University Hospital “G. Rodolico-San Marco”, Catania, Italy
| | - Alessandro Rodolico
- Psychiatry Unit, Policlinico University Hospital “G. Rodolico-San Marco”, Catania, Italy
| | - Manuela Pennisi
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Rita Bella
- Department of Medical and Surgical Sciences and Advanced Technologies, University of Catania, Catania, Italy
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Park BS, Heo CM, Lee YJ, Park S, Kim YW, Son S, Kwon H, Park Y, Kim Y, Lee DA, Park KM. Difference in functional connectivity between end-stage renal disease patients with and without restless legs syndrome: A prospective study. Sleep Breath 2024; 28:673-681. [PMID: 37889458 DOI: 10.1007/s11325-023-02943-9] [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: 06/26/2023] [Revised: 10/11/2023] [Accepted: 10/18/2023] [Indexed: 10/28/2023]
Abstract
PURPOSE The purpose of this study was to examine differences in functional connectivity between patients with end-stage renal disease (ESRD) with and without restless legs syndrome (RLS). In addition, the study aimed to identify any potential associations between RLS severity and functional connectivity. METHODS We enrolled patients with ESRD who had been undergoing hemodialysis. Patients with and without RLS were separated into two groups. Using functional near-infrared spectroscopy (fNIRS) and a graph theory approach, we determined the functional connectivity of patients with ESRD. The data were collected during a 300-s resting state evaluation performed in the dialysis room prior to dialysis. RESULTS Eighteen of 48 patients with ESRD were diagnosed with RLS, whereas 30 patients did not exhibit RLS symptoms. Notably, functional connectivity metrics differed significantly between patients with and without RLS. Specifically, patients with ESRD and RLS displayed higher values for mean clustering coefficient (0.474 vs. 0.352, p = 0.001), global efficiency (0.520 vs. 0.414, p = 0.001), strength (6.538 vs. 4.783, p = 0.001), and transitivity (0.714 vs. 0.521, p = 0.001), while values for diameter (5.451 vs. 7.338, p = 0.002), eccentricity (4.598 vs. 5.985, p = 0.004), and characteristic path length (2.520 vs. 3.271, p = 0.002) were lower in patients with ESRD and RLS compared to those without RLS. In addition, there were correlations between the RLS severity score and the assortative coefficient (r = 0.479, p = 0.044), the small-worldness index (r = -0.475, p = 0.046), and transitivity (r = 0.500, p = 0.034). CONCLUSIONS We demonstrated differences in functional connectivity between patients with ESRD with and without RLS, which may shed light on the pathophysiology of RLS. Notably, a number of functional connectivity metrics demonstrated strong associations with RLS severity. Our study also confirmed the applicability of fNIRS as a tool for investigating functional connectivity in patients with RLS.
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Affiliation(s)
- Bong Soo Park
- Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Chang Min Heo
- Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Yoo Jin Lee
- Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Sihyung Park
- Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Yang Wook Kim
- Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - SungHyun Son
- Department of Internal Medicine, BMS Hanseo Hospital, Busan, Korea
| | - Hyukyong Kwon
- Department of Internal Medicine, BMS Hanseo Hospital, Busan, Korea
| | - Youngchan Park
- Department of Internal Medicine, BMS Hanseo Hospital, Busan, Korea
| | - Yunmi Kim
- Department of Internal Medicine, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Dong Ah Lee
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Kang Min Park
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
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Lanza G, Mogavero MP, Lanuzza B, Tripodi M, Cantone M, Pennisi M, Bella R, Ferri R. A Topical Review on Transcranial Magnetic Stimulation in Restless Legs Syndrome. CURRENT SLEEP MEDICINE REPORTS 2024; 10:207-216. [DOI: 10.1007/s40675-024-00282-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2024] [Indexed: 07/26/2024]
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Dirks CAH, Bachmann CG. From brain to spinal cord: neuromodulation by direct current stimulation and its promising effects as a treatment option for restless legs syndrome. Front Neurol 2024; 15:1278200. [PMID: 38333606 PMCID: PMC10850250 DOI: 10.3389/fneur.2024.1278200] [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: 08/15/2023] [Accepted: 01/09/2024] [Indexed: 02/10/2024] Open
Abstract
Neuromodulation is a fast-growing field of mostly non-invasive therapies, which includes spinal cord stimulation (SCS), transcranial direct current stimulation (tDCS), vagal nerve stimulation (VNS), peripheral nerve stimulation, transcranial magnetic stimulation (TMS) and transcutaneous spinal direct current stimulation (tsDCS). This narrative review offers an overview of the therapy options, especially of tDCS and tsDCS for chronic pain and spinal cord injury. Finally, we discuss the potential of tsDCS in Restless Legs Syndrome as a promising non-invasive, alternative therapy to medication therapy.
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Lanza G, Fisicaro F, Cantone M, Pennisi M, Cosentino FII, Lanuzza B, Tripodi M, Bella R, Paulus W, Ferri R. Repetitive transcranial magnetic stimulation in primary sleep disorders. Sleep Med Rev 2023; 67:101735. [PMID: 36563570 DOI: 10.1016/j.smrv.2022.101735] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/13/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022]
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is a widely used non-invasive neuromodulatory technique. When applied in sleep medicine, the main hypothesis explaining its effects concerns the modulation of synaptic plasticity and the strength of connections between the brain areas involved in sleep disorders. Recently, there has been a significant increase in the publication of rTMS studies in primary sleep disorders. A multi-database-based search converges on the evidence that rTMS is safe and feasible in chronic insomnia, obstructive sleep apnea syndrome (OSAS), restless legs syndrome (RLS), and sleep deprivation-related cognitive deficits, whereas limited or no data are available for narcolepsy, sleep bruxism, and REM sleep behavior disorder. Regarding efficacy, the stimulation of the dorsolateral prefrontal cortex bilaterally, right parietal cortex, and dominant primary motor cortex (M1) in insomnia, as well as the stimulation of M1 leg area bilaterally, left primary somatosensory cortex, and left M1 in RLS reduced subjective symptoms and severity scale scores, with effects lasting for up to weeks; conversely, no relevant effect was observed in OSAS and narcolepsy. Nevertheless, several limitations especially regarding the stimulation protocols need to be considered. This review should be viewed as a step towards the further contribution of individually tailored neuromodulatory techniques for sleep disorders.
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Affiliation(s)
- Giuseppe Lanza
- Department of Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy; Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Troina, Italy.
| | - Francesco Fisicaro
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Mariagiovanna Cantone
- Neurology Unit, University Hospital Policlinico "G. Rodolico-San Marco", Catania, Italy; Department of Neurology, Sant'Elia Hospital, ASP Caltanissetta, Caltanissetta, Italy
| | - Manuela Pennisi
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | | | - Bartolo Lanuzza
- Department of Neurology IC and Sleep Research Centre, Oasi Research Institute-IRCCS, Troina, Italy
| | - Mariangela Tripodi
- Department of Neurology IC and Sleep Research Centre, Oasi Research Institute-IRCCS, Troina, Italy
| | - Rita Bella
- Department of Medical and Surgical Science and Advanced Technologies, University of Catania, Catania, Italy
| | - Walter Paulus
- Department of Neurology, Ludwig Maximilians University, Munich, Germany
| | - Raffaele Ferri
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Troina, Italy
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Lanza G, Cosentino FII, Lanuzza B, Tripodi M, Aricò D, Figorilli M, Puligheddu M, Fisicaro F, Bella R, Ferri R, Pennisi M. Reduced Intracortical Facilitation to TMS in Both Isolated REM Sleep Behavior Disorder (RBD) and Early Parkinson's Disease with RBD. J Clin Med 2022; 11:jcm11092291. [PMID: 35566417 PMCID: PMC9104430 DOI: 10.3390/jcm11092291] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/06/2022] [Accepted: 04/18/2022] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND a reduced intracortical facilitation (ICF), a transcranial magnetic stimulation (TMS) measure largely mediated by glutamatergic neurotransmission, was observed in subjects affected by isolated REM sleep behavior disorder (iRBD). However, direct comparison between iRBD and Parkinson's disease (PD) with RBD is currently lacking. METHODS resting motor threshold, contralateral cortical silent period, amplitude and latency of motor evoked potentials, short-interval intracortical inhibition, and intracortical facilitation (ICF) were recorded from 15 drug-naïve iRBD patients, 15 drug-naïve PD with RBD patients, and 15 healthy participants from the right First Dorsal Interosseous muscle. REM sleep atonia index (RAI), Mini Mental State Examination (MMSE), Geriatric Depression Scale (GDS), and Epworth Sleepiness Scale (ESS) were assessed. RESULTS Groups were similar for sex, age, education, and patients for RBD duration and RAI. Neurological examination, MMSE, ESS, and GDS were normal in iRBD patients and controls; ESS scored worse in PD patients, but with no difference between groups at post hoc analysis. Compared to controls, both patient groups exhibited a significantly decreased ICF, without difference between them. CONCLUSIONS iRBD and PD with RBD shared a reduced ICF, thus suggesting the involvement of glutamatergic transmission both in subjects at risk for degeneration and in those with an overt α-synucleinopathy.
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Affiliation(s)
- Giuseppe Lanza
- Department of Surgery and Medical-Surgical Specialties, University of Catania, Via Santa Sofia 78, 95123 Catania, Italy
- Clinical Neurophysiology Research Unit, Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy;
- Correspondence: ; Tel.: +39-095-3782448
| | - Filomena Irene Ilaria Cosentino
- Department of Neurology IC and Sleep Research Center, Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.I.I.C.); (B.L.); (M.T.); (D.A.)
| | - Bartolo Lanuzza
- Department of Neurology IC and Sleep Research Center, Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.I.I.C.); (B.L.); (M.T.); (D.A.)
| | - Mariangela Tripodi
- Department of Neurology IC and Sleep Research Center, Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.I.I.C.); (B.L.); (M.T.); (D.A.)
| | - Debora Aricò
- Department of Neurology IC and Sleep Research Center, Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy; (F.I.I.C.); (B.L.); (M.T.); (D.A.)
| | - Michela Figorilli
- Neurology Unit, Department of Medical Sciences and Public Health, University of Cagliari and AOU Cagliari, Asse Didattico E., SS 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy; (M.F.); (M.P.)
- Sleep Disorders Center, Department of Medical Sciences and Public Health, University of Cagliari, Asse Didattico E., SS 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Monica Puligheddu
- Neurology Unit, Department of Medical Sciences and Public Health, University of Cagliari and AOU Cagliari, Asse Didattico E., SS 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy; (M.F.); (M.P.)
- Sleep Disorders Center, Department of Medical Sciences and Public Health, University of Cagliari, Asse Didattico E., SS 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Francesco Fisicaro
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 78, 95123 Catania, Italy; (F.F.); (M.P.)
| | - Rita Bella
- Department of Medical and Surgical Science and Advanced Technologies, University of Catania, Via Santa Sofia 78, 95125 Catania, Italy;
| | - Raffaele Ferri
- Clinical Neurophysiology Research Unit, Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy;
| | - Manuela Pennisi
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 78, 95123 Catania, Italy; (F.F.); (M.P.)
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Abstract
Sleep homeostasis is a complex neurobiologic phenomenon involving a number of molecular pathways, neurotransmitter release, synaptic activity, and factors modulating neural networks. Sleep plasticity allows for homeostatic optimization of neural networks and the replay-based consolidation of specific circuits, especially important for cognition, behavior, and information processing. Furthermore, research is currently moving from an essentially brain-focused to a more comprehensive view involving other systems, such as the immune system, hormonal status, and metabolic pathways. When dysfunctional, these systems contribute to sleep loss and fragmentation as well as to sleep need. In this chapter, the implications of neural plasticity and sleep homeostasis for the diagnosis and treatment of some major sleep disorders, such as insomnia and sleep deprivation, obstructive sleep apnea syndrome, restless legs syndrome, REM sleep behavior disorder, and narcolepsy are discussed in detail with their therapeutical implications. This chapter highlights that sleep is necessary for the maintenance of an optimal brain function and is sensitive to both genetic background and environmental enrichment. Even in pathologic conditions, sleep acts as a resilient plastic state that consolidates prior information and prioritizes network activity for efficient brain functioning.
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Neurophysiological Aspects of REM Sleep Behavior Disorder (RBD): A Narrative Review. Brain Sci 2021. [PMID: 34942893 DOI: 10.3390/brainsci11121588.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
REM sleep without atonia (RSWA) is the polysomnographic (PSG) hallmark of rapid eye movement (REM) sleep behavior disorder (RBD), a feature essential for the diagnosis of this condition. Several additional neurophysiological aspects of this complex disorder have also recently been investigated in depth, which constitute the focus of this narrative review, together with RSWA. First, we describe the complex neural network underlying REM sleep and its muscle atonia, focusing on the disordered mechanisms leading to RSWA. RSWA is then described in terms of its polysomnographic features, and the methods (visual and automatic) currently available for its scoring and quantification are exposed and discussed. Subsequently, more recent and advanced neurophysiological features of RBD are described, such as electroencephalography during wakefulness and sleep, transcranial magnetic stimulation, and vestibular evoked myogenic potentials. The role of the assessment of neurophysiological features in the study of RBD is then carefully discussed, highlighting their usefulness and sensitivity in detecting neurodegeneration in the early or prodromal stages of RBD, as well as their relationship with other proposed biomarkers for the diagnosis, prognosis, and monitoring of this condition. Finally, a future research agenda is proposed to help clarify the many still unclear aspects of RBD.
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Figorilli M, Lanza G, Congiu P, Lecca R, Casaglia E, Mogavero MP, Puligheddu M, Ferri R. Neurophysiological Aspects of REM Sleep Behavior Disorder (RBD): A Narrative Review. Brain Sci 2021; 11:brainsci11121588. [PMID: 34942893 PMCID: PMC8699681 DOI: 10.3390/brainsci11121588] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 11/28/2021] [Accepted: 11/29/2021] [Indexed: 02/07/2023] Open
Abstract
REM sleep without atonia (RSWA) is the polysomnographic (PSG) hallmark of rapid eye movement (REM) sleep behavior disorder (RBD), a feature essential for the diagnosis of this condition. Several additional neurophysiological aspects of this complex disorder have also recently been investigated in depth, which constitute the focus of this narrative review, together with RSWA. First, we describe the complex neural network underlying REM sleep and its muscle atonia, focusing on the disordered mechanisms leading to RSWA. RSWA is then described in terms of its polysomnographic features, and the methods (visual and automatic) currently available for its scoring and quantification are exposed and discussed. Subsequently, more recent and advanced neurophysiological features of RBD are described, such as electroencephalography during wakefulness and sleep, transcranial magnetic stimulation, and vestibular evoked myogenic potentials. The role of the assessment of neurophysiological features in the study of RBD is then carefully discussed, highlighting their usefulness and sensitivity in detecting neurodegeneration in the early or prodromal stages of RBD, as well as their relationship with other proposed biomarkers for the diagnosis, prognosis, and monitoring of this condition. Finally, a future research agenda is proposed to help clarify the many still unclear aspects of RBD.
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Affiliation(s)
- Michela Figorilli
- Neurology Unit, Department of Medical Sciences and Public Health, University of Cagliari and AOU Cagliari, Monserrato, 09042 Cagliari, Italy; (M.F.); (P.C.); (R.L.); (E.C.); (M.P.)
- Sleep Disorders Center, Department of Medical Sciences and Public Health, University of Cagliari, Asse Didattico E., SS 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Giuseppe Lanza
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy;
- Department of Surgery and Medical-Surgical Specialties, University of Catania, Via Santa Sofia 78, 95123 Catania, Italy
| | - Patrizia Congiu
- Neurology Unit, Department of Medical Sciences and Public Health, University of Cagliari and AOU Cagliari, Monserrato, 09042 Cagliari, Italy; (M.F.); (P.C.); (R.L.); (E.C.); (M.P.)
- Sleep Disorders Center, Department of Medical Sciences and Public Health, University of Cagliari, Asse Didattico E., SS 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Rosamaria Lecca
- Neurology Unit, Department of Medical Sciences and Public Health, University of Cagliari and AOU Cagliari, Monserrato, 09042 Cagliari, Italy; (M.F.); (P.C.); (R.L.); (E.C.); (M.P.)
- Sleep Disorders Center, Department of Medical Sciences and Public Health, University of Cagliari, Asse Didattico E., SS 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Elisa Casaglia
- Neurology Unit, Department of Medical Sciences and Public Health, University of Cagliari and AOU Cagliari, Monserrato, 09042 Cagliari, Italy; (M.F.); (P.C.); (R.L.); (E.C.); (M.P.)
- Sleep Disorders Center, Department of Medical Sciences and Public Health, University of Cagliari, Asse Didattico E., SS 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Maria P. Mogavero
- Istituti Clinici Scientifici Maugeri, IRCCS, Scientific Institute of Pavia, 27100 Pavia, Italy;
| | - Monica Puligheddu
- Neurology Unit, Department of Medical Sciences and Public Health, University of Cagliari and AOU Cagliari, Monserrato, 09042 Cagliari, Italy; (M.F.); (P.C.); (R.L.); (E.C.); (M.P.)
- Sleep Disorders Center, Department of Medical Sciences and Public Health, University of Cagliari, Asse Didattico E., SS 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Raffaele Ferri
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy;
- Correspondence: ; Tel.: +39-0935-936111
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Abstract
Restless legs syndrome (RLS) is a common sensorimotor disorder characterized by an urge to move that appears during rest or is exacerbated by rest, that occurs in the evening or night and that disappears during movement or is improved by movement. Symptoms vary considerably in age at onset, frequency and severity, with severe forms affecting sleep, quality of life and mood. Patients with RLS often display periodic leg movements during sleep or resting wakefulness. RLS is considered to be a complex condition in which predisposing genetic factors, environmental factors and comorbidities contribute to the expression of the disorder. RLS occurs alone or with comorbidities, for example, iron deficiency and kidney disease, but also with cardiovascular diseases, diabetes mellitus and neurological, rheumatological and respiratory disorders. The pathophysiology is still unclear, with the involvement of brain iron deficiency, dysfunction in the dopaminergic and nociceptive systems and altered adenosine and glutamatergic pathways as hypotheses being investigated. RLS is poorly recognized by physicians and it is accordingly often incorrectly diagnosed and managed. Treatment guidelines recommend initiation of therapy with low doses of dopamine agonists or α2δ ligands in severe forms. Although dopaminergic treatment is initially highly effective, its long-term use can result in a serious worsening of symptoms known as augmentation. Other treatments include opioids and iron preparations.
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Walters AS, Paueksakon P, Adler CH, Moussouttas M, Weinstock LB, Spruyt K, Bagai K. Restless Legs Syndrome Shows Increased Silent Postmortem Cerebral Microvascular Disease With Gliosis. J Am Heart Assoc 2021; 10:e019627. [PMID: 33998250 PMCID: PMC8483539 DOI: 10.1161/jaha.120.019627] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Background Patients with restless legs syndrome (RLS) have increased silent microvascular disease by magnetic resonance imaging. However, there has been no previous autopsy confirmation of these magnetic resonance imaging findings. RLS is also frequently associated with inflammatory and immunologically mediated medical disorders. The postmortem cortex in patients with RLS was therefore evaluated for evidence of microvascular and immunological changes. Methods and Results Ten microvascular injury samples of precentral gyrus in 5 patients with RLS (3 men, 2 women; mean age, 81 years) and 9 controls (2 men, 7 women; mean age, 90 years) were studied by hematoxylin and eosin stains in a blinded fashion. None of the subjects had a history of stroke or neurologic insults. In a similar manner, the following immunohistochemistry stains were performed: (1) glial fibrillary acidic protein (representing gliosis, reactive change of glial cells in response to damage); (2) CD3 (a T‐cell marker); (3) CD19 (a B‐cell marker); (4) CD68 (a macrophage marker); and (5) CD117 (a mast cell marker). Patients with RLS had significantly greater silent microvascular disease (P=0.015) and gliosis (P=0.003). T cells were increased in RLS compared with controls (P=0.009) and tended to colocalize with microvascular disease (P=0.003). Other markers did not differ. There was no correlation between microvascular lesion load and RLS severity or duration. Conclusions Patients with RLS had statistically significantly more silent cerebral microvascular disease and gliosis than controls compatible with previous magnetic resonance imaging studies and with studies showing a link between RLS and hypertension, clinical stroke, and cardiovascular disease. T‐cell invasion may be a secondary phenomenon.
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Affiliation(s)
- Arthur S Walters
- Sleep Division Department of Neurology Vanderbilt University Medical Center Nashville TN
| | - Paisit Paueksakon
- Department of Pathology, Microbiology, and Immunology Vanderbilt University Medical Center Nashville TN
| | - Charles H Adler
- Department of Neurology Mayo Clinic College of Medicine Scottsdale AZ
| | - Michael Moussouttas
- Cerebrovascular Division Department of Neurology Rutgers Medical School New Brunswick NJ
| | | | | | - Kanika Bagai
- Sleep Division Department of Neurology Vanderbilt University Medical Center Nashville TN
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Nardone R, Sebastianelli L, Versace V, Brigo F, Golaszewski S, Pucks-Faes E, Saltuari L, Trinka E. Contribution of transcranial magnetic stimulation in restless legs syndrome: pathophysiological insights and therapeutical approaches. Sleep Med 2020; 71:124-134. [PMID: 32088150 DOI: 10.1016/j.sleep.2019.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 12/10/2019] [Accepted: 12/11/2019] [Indexed: 01/06/2023]
Abstract
Transcranial magnetic stimulation (TMS) may offer a reliable means to characterize significant pathophysiologic and neurochemical aspects of restless legs syndrome (RLS). Namely, TMS has revealed specific patterns of changes in cortical excitability and plasticity, in particular dysfunctional inhibitory mechanisms and sensorimotor integration, which are thought to be part of the pathophysiological mechanisms of RLS rather than reflect a non-specific consequence of sleep architecture alteration. If delivered repetitively, TMS is able to transiently modulate the neural activity of the stimulated and connected areas. Some studies have begun to therapeutically use repetitive TMS (rTMS) to improve sensory and motor disturbances in RLS. High-frequency rTMS applied over the primary motor cortex or the supplementary motor cortex, as well as low-frequency rTMS over the primary somatosensory cortex, seem to have transient beneficial effects. However, further studies with larger patient samples, repeated sessions, an optimized rTMS setup, and clinical follow-up are needed in order to corroborate preliminary results. Thus, we performed a systematic search of all the studies that have used TMS and rTMS techniques in patients with RLS.
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Affiliation(s)
- Raffaele Nardone
- Department of Neurology, Franz Tappeiner Hospital, Merano, Italy; Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center, Salzburg, Austria; Karl Landsteiner Institut für Neurorehabilitation und Raumfahrtneurologie, Salzburg, Austria.
| | - Luca Sebastianelli
- Department of Neurorehabilitation, Hospital of Vipiteno, Vipiteno, Italy; Research Unit for Neurorehabilitation South Tyrol, Bolzano, Italy
| | - Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno, Vipiteno, Italy; Research Unit for Neurorehabilitation South Tyrol, Bolzano, Italy
| | - Francesco Brigo
- Department of Neurology, Franz Tappeiner Hospital, Merano, Italy; Department of Neuroscience, Biomedicine and Movement Science, University of Verona, Italy
| | - Stefan Golaszewski
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria; Karl Landsteiner Institut für Neurorehabilitation und Raumfahrtneurologie, Salzburg, Austria
| | | | - Leopold Saltuari
- Department of Neurorehabilitation, Hospital of Vipiteno, Vipiteno, Italy; Research Unit for Neurorehabilitation South Tyrol, Bolzano, Italy; Department of Neurology, Hochzirl Hospital, Zirl, Austria
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria; Centre for Cognitive Neurosciences Salzburg, Salzburg, Austria; University for Medical Informatics and Health Technology, UMIT, Hall in Tirol, Austria
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Affiliation(s)
- Giuseppe Lanza
- Department of Surgery and Medical-Surgical Specialties, University of Catania, Via Santa Sofia, 78, 95125, Catania, Italy; Department of Neurology IC, Oasi Research Institute - IRCCS, Via Conte Ruggero, 73, 94018, Troina, Italy.
| | - Anna Scalise
- Clinical Neurology Unit, Department of Neurosciences, University Hospital of Udine, P.le Santa Maria della Misericordia, 15, 33100, Udine, Italy.
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de Paiva JPQ, Magalhães SC, Moura LM, Sato JR, Amaro E, Sterr A, Schlaffke L, Eckeli AL, do Prado GF, Conforto AB. Sensorimotor white matter projections and disease severity in primary Restless Legs Syndrome/Willis-Ekbom disease: a multimodal DTI analysis. Sleep Med 2020; 73:106-116. [PMID: 32805477 DOI: 10.1016/j.sleep.2020.05.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/22/2020] [Accepted: 05/26/2020] [Indexed: 01/18/2023]
Abstract
BACKGROUND Restless Legs Syndrome, a potentially disabling sleep disorder, also known as Willis-Ekbom disease (RLS/WED), may be caused by loss of inhibitory modulation of descending central motor pathways, structural changes in the somatosensory cortex, abnormal connectivity between motor and sensory areas, as well as by subtle abnormalities in white matter micro-organization. OBJECTIVE To compare diffusion-tensor imaging (DTI) metrics in areas associated with sensory or motor function, as well as sensorimotor integration, between subjects with primary mild-to-severe RLS/WED and controls. METHODS DTI metrics were assessed in 38 subjects with RLS/WED (14 mild to moderate, 24 severe to very severe) and 24 healthy age-matched controls with whole-brain Tract Based Spatial Statistics (TBSS), Region-of-interest (ROI) and probabilistic tractography based analyses. The ROIs corresponded to the corticospinal tract (CST) at the level of the cerebral peduncle; the superior, middle and inferior cerebellar peduncles. Subgroup analyses were made according to the severity of RLS/WED symptoms. The corticospinal tract was evaluated with probabilistic tractography. We also explored associations between significant findings and severity of symptoms with the Spearman's correlation coefficient. RESULTS TBSS analysis revealed decreased axial diffusivity (AD) in the left posterior thalamic radiation in RLS/WED. In subjects with severe RLS/WED, AD was reduced in the left posterior corona radiata and this reduction was negatively correlated with severity of symptoms. ROI-based analysis showed that radial diffusivity (RD) was increased in the superior cerebellar peduncles of individuals with severe RLS/WED. Tractography did not show between-group or subgroup differences. CONCLUSIONS Our results are consistent with subtle white matter changes, prominently in RLS/WED subjects with more severe symptoms, in areas related to sensory or motor function, as well as to sensorimotor integration, compared to controls. These findings support the hypothesis, raised by prior pathophysiological studies, of defective integration within these networks.
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Affiliation(s)
- Joselisa Péres Queiroz de Paiva
- Brain Institute, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil; Imaging Research Center, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil.
| | - Samir Câmara Magalhães
- Brain Institute, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil; Universidade de Fortaleza (UNIFOR), Unifor, Fortaleza, CE, Brazil
| | - Luciana Monteiro Moura
- Imaging Research Center, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil
| | - João Ricardo Sato
- Center for Mathematics, Computing and Cognition, Universidade Federal do ABC (UFABC), São Bernardo do Campo, SP, Brazil
| | - Edson Amaro
- Brain Institute, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil; Imaging Research Center, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil; Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
| | - Annette Sterr
- School of Psychology, University of Surrey, Guildford, UK
| | - Lara Schlaffke
- Department of Neurology, BG University Clinic Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Alan Luiz Eckeli
- Department of Neurosciences and Behavioral Sciences, Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | | | - Adriana Bastos Conforto
- Brain Institute, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil; Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
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Türkoglu ŞA, Bolac ES, Yildiz S, Kalaycioglu O, Yildiz N. Presynaptic inhibition in restless legs syndrome. Int J Neurosci 2020; 131:213-219. [PMID: 32108535 DOI: 10.1080/00207454.2020.1737048] [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] [Indexed: 10/24/2022]
Abstract
Introduction: Restless legs syndrome (RLS) is a condition that particularly urges at night in resting and causes the need to move the legs. Although the pathophysiology has not yet been clarified, dopamine and iron metabolism and spinal cord pathologies are blamed for causing the condition. There are few studies on spinal reflex mechanisms on RLS. In the present study, we aimed to investigate the role of presynaptic inhibition (PreI) in the spinal cord in RLS.Methods: Fourteen patients with RLS and 14 controls with similar demographic characteristics were included in the study. Soleus muscle H-reflex (Ht) investigation was performed for subjects whose electrophysiologic investigation was normal. The Ht response was conditioned to the stimulation of the common peroneal nerve (CPN) (Hc). The test and conditioned stimulation intervals were kept between 10 ms, 20 ms, 30 ms, 40 ms, 50 ms, 75 ms, 100 ms, 150 ms and 200 ms. In each inter-stimulus interval, nonparametric repeat measurement evaluations were conducted with the percentage value of Hc/Ht. The Hc/Ht values of the study and control groups in the same intervals were compared separately.Results: A significant decrease was detected in Hc values in the control group in the repeat measurement values at 20 ms and 100 ms inter-stimulus intervals; however, there was not decrease in any intervals in the patient's group.Conclusion: The absence of any decrease in Hc reflexes for 20-100 ms intervals revealed that discernible PreI was vanished in RLS patients.
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Affiliation(s)
- Şule Aydin Türkoglu
- Department of Neurology, Abant İzzet Baysal University Faculty of Medicine, Bolu, Turkey
| | - Elif Sultan Bolac
- Department of Neurology, Abant İzzet Baysal University Faculty of Medicine, Bolu, Turkey
| | - Serpil Yildiz
- Department of Neurology, Abant İzzet Baysal University Faculty of Medicine, Bolu, Turkey
| | - Oya Kalaycioglu
- Biostatistics Unit, Abant İzzet Baysal University Faculty of Medicine, Bolu, Turkey
| | - Nebil Yildiz
- Department of Neurology, Abant İzzet Baysal University Faculty of Medicine, Bolu, Turkey
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Magalhães SC, Queiroz de Paiva JP, Kaelin-Lang A, Sterr A, Eckeli AL, Winkler AM, Fernandes do Prado G, Amaro E, Conforto AB. Short-interval intracortical inhibition is decreased in restless legs syndrome across a range of severity. Sleep Med 2019; 62:34-42. [PMID: 31539846 DOI: 10.1016/j.sleep.2019.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/10/2019] [Accepted: 03/12/2019] [Indexed: 01/18/2023]
Abstract
BACKGROUND Decreased short-interval intracortical inhibition (SICI) to transcranial magnetic stimulation (TMS) of the primary motor cortex was described in subjects with restless legs syndrome/Willis-Ekbom disease (RLS/WED). It remained to be determined whether the magnitude of SICI decrease would be similar across levels of RLS/WED severity. Moreover, it was unknown whether, in addition to decreases in SICI, changes in cortical thickness or area could be detected in subjects with RLS/WED compared to controls. The objective of this study was to compare SICI, cortical thickness, and cortical area in subjects with idiopathic mild to moderate RLS/WED, severe to very severe RLS/WED, and controls. METHODS The severity of RLS/WED was assessed by the International Restless Legs Syndrome Severity Scale (IRLSS). SICI and 3T magnetic resonance imaging (MRI) data of subjects with RLS/WED and controls were compared. A receiver operating characteristic curve for SICI was designed for discrimination of participants with RLS/WED from controls. Cortical thickness and area were assessed by automated surface-based analysis. RESULTS SICI was significantly reduced in patients with mild to moderate and severe to very severe RLS/WED, compared to controls (one-way analysis of variance: F = 9.62, p < 0.001). Receiver operating characteristic curve analysis predicted RLS/WED when SICI was above 35% (area under the curve = 0.79, 95% CI 0.67-0.91, p < 0.001). Analyses of the whole brain and of regions of interest did not reveal differences in gray matter thickness or area between controls and subjects with RLS/WED. CONCLUSION SICI is an accurate cortical biomarker that can support the diagnosis of RLS/WED even in subjects with mild symptoms, but cortical thickness and area were not useful for discriminating subjects with this condition from controls.
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Affiliation(s)
- Samir Câmara Magalhães
- Hospital Israelita Albert Einstein, São Paulo, SP, Brazil; Universidade de Fortaleza, Unifor, Fortaleza, CE, Brazil.
| | | | | | - Annette Sterr
- Department of Psychology, University of Surrey, Guildford, Surrey, UK
| | - Alan Luiz Eckeli
- Departamento de Neurociências e Ciências do Comportamento, Divisão de Neurologia, Hospital das Clínicas da Faculdade de Medicina da USP-Ribeirão Preto, Ribeirão Preto, SP, Brazil
| | | | | | - Edson Amaro
- Hospital Israelita Albert Einstein, São Paulo, SP, Brazil; Departamento de Radiologia, Hospital das Clínicas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Adriana Bastos Conforto
- Hospital Israelita Albert Einstein, São Paulo, SP, Brazil; Departamento de Neurologia, Hospital das Clínicas, Universidade de São Paulo, São Paulo, SP, Brazil
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Röhrle O, Yavuz UŞ, Klotz T, Negro F, Heidlauf T. Multiscale modeling of the neuromuscular system: Coupling neurophysiology and skeletal muscle mechanics. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2019; 11:e1457. [PMID: 31237041 DOI: 10.1002/wsbm.1457] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 01/10/2023]
Abstract
Mathematical models and computer simulations have the great potential to substantially increase our understanding of the biophysical behavior of the neuromuscular system. This, however, requires detailed multiscale, and multiphysics models. Once validated, such models allow systematic in silico investigations that are not necessarily feasible within experiments and, therefore, have the ability to provide valuable insights into the complex interrelations within the healthy system and for pathological conditions. Most of the existing models focus on individual parts of the neuromuscular system and do not consider the neuromuscular system as an integrated physiological system. Hence, the aim of this advanced review is to facilitate the prospective development of detailed biophysical models of the entire neuromuscular system. For this purpose, this review is subdivided into three parts. The first part introduces the key anatomical and physiological aspects of the healthy neuromuscular system necessary for modeling the neuromuscular system. The second part provides an overview on state-of-the-art modeling approaches representing all major components of the neuromuscular system on different time and length scales. Within the last part, a specific multiscale neuromuscular system model is introduced. The integrated system model combines existing models of the motor neuron pool, of the sensory system and of a multiscale model describing the mechanical behavior of skeletal muscles. Since many sub-models are based on strictly biophysical modeling approaches, it closely represents the underlying physiological system and thus could be employed as starting point for further improvements and future developments. This article is categorized under: Physiology > Mammalian Physiology in Health and Disease Analytical and Computational Methods > Computational Methods Models of Systems Properties and Processes > Organ, Tissue, and Physiological Models.
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Affiliation(s)
- Oliver Röhrle
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany.,Stuttgart Center for Simulation Sciences (SC SimTech), University of Stuttgart, Stuttgart, Germany
| | - Utku Ş Yavuz
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany.,Biomedical Signals and Systems, Universiteit Twente, Enschede, The Netherlands
| | - Thomas Klotz
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany.,Stuttgart Center for Simulation Sciences (SC SimTech), University of Stuttgart, Stuttgart, Germany
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, Universià degli Studi di Brescia, Brescia, Italy
| | - Thomas Heidlauf
- EPS5 - Simulation and System Analysis, Hofer pdc GmbH, Stuttgart, Germany
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Feng J, Zhang Q, Zhang C, Wen Z, Zhou X. The Effect of sequential bilateral low-frequency rTMS over dorsolateral prefrontal cortex on serum level of BDNF and GABA in patients with primary insomnia. Brain Behav 2019; 9:e01206. [PMID: 30609300 PMCID: PMC6379591 DOI: 10.1002/brb3.1206] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 12/06/2018] [Accepted: 12/09/2018] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVE This study aimed to investigate the effect of sequential bilateral low-frequency repetitive transcranial magnetic stimulation (rTMS) over dorsolateral prefrontal cortex (DLPFC) on patients with primary insomnia (PI). METHODS A total of 32 eligible right-handed participants diagnosed by PI according to International classification of sleep disorders (ICD-3) were recruited into this study. Participants received 10 daily sessions of sequential bilateral 1 Hz rTMS over DLPFC. Before and after the whole procedure of rTMS, patients were assessed by Pittsburgh Sleep Quality Index (PSQI) for the severity of sleep disturbance. Meanwhile, serum concentration of brain-derived neurotrophic factor (BDNF) and gamma-aminobutyric acid (GABA) in patients was measured by ELISA and UPLC, respectively. Moreover, the amplitude of MEPs reflecting the right cortical excitability was examined. Finally, Pearson correlation analysis was performed to evaluate the correlation among the change of these variables. RESULTS After rTMS treatment, the PSQI score was markedly decreased as compared to pre-rTMS; the concentrations of serum BDNF and GABA were significantly higher; the amplitude of MEPs was markedly reduced. Pearson correlation analysis revealed that the change of PSQI score was negatively associated with the alteration of serum BDNF level and serum GABA level, and positively associated with the change of MEPs amplitude; the change of MEPs amplitude was negatively associated with fold change in the serum BDNF level and the serum GABA level; the increase in serum GABA level was positively associated with the serum BDNF level. CONCLUSIONS A sequential bilateral low-frequency rTMS over DLPFC significantly improves primary insomnia probably by increasing the level of BDNF and GABA in the brain and reducing cortical excitability.
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Affiliation(s)
- Jie Feng
- Department of NeurologyThe Second Affiliated Hospital of Soochow UniversitySuzhouChina
| | - Qing Zhang
- Laboratory of Neurological, Department of Neurology, Changzhou No.2 People’s HospitalThe Affiliated Hospital of Nanjing Medical UniversityChangzhouChina
| | - Chengliang Zhang
- Laboratory of Neurological, Department of Neurology, Changzhou No.2 People’s HospitalThe Affiliated Hospital of Nanjing Medical UniversityChangzhouChina
| | - Zhongmin Wen
- Department of NeurologyThe Second Affiliated Hospital of Soochow UniversitySuzhouChina
| | - Xianju Zhou
- Laboratory of Neurological, Department of Neurology, Changzhou No.2 People’s HospitalThe Affiliated Hospital of Nanjing Medical UniversityChangzhouChina
- Department of Neurology, Integrated Hospital of Traditional Chinese MedicineSouthern Medical UniversityGuangzhouChina
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Serranová T, Slovák M, Kemlink D, Šonka K, Hallett M, Růžička E. Prevalence of restless legs syndrome in functional movement disorders: a case-control study from the Czech Republic. BMJ Open 2019; 9:e024236. [PMID: 30670516 PMCID: PMC6347872 DOI: 10.1136/bmjopen-2018-024236] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES The prevalence of restless legs syndrome (RLS) in functional movement disorders (FMD) is not known. Patients with FMD often present with multiple motor and sensory symptoms. Some of these symptoms might be due to comorbid RLS. Therefore, our objective was to evaluate possible association between FMD and RLS. DESIGN Case-control study. SETTING Movement Disorders Center, 1st Faculty of Medicine and General University Hospital in Prague, Czech Republic. PARTICIPANTS 96 consecutive patients with clinically established FMD (80 females, mean age (SD) 45.0 (13) years), and 76 matched controls. PRIMARY AND SECONDARY OUTCOME MEASURES The primary outcome measure was prevalence of RLS based on updated International RLS Study Group criteria. Secondary outcome measures included prevalence of periodic limb movements (PLM) using actigraphy; pain, motor and sensory symptoms in lower limbs; organic comorbidities and medication affecting RLS. RESULTS RLS criteria were fulfilled in 43.8% of patients (95% CI 34 to 54) and in 7.9% of controls (95% CI 3 to 17, p<0.00001). Both RLS and PLM indices (PLMi) ≥22.5/hour were found in 21.2% of patients with FMD and 2.6% of controls. Patients with FMD with RLS had a higher mean PLMi (p<0.001) and a higher proportion of PLMi ≥22.5/hour (p<0.01) than RLS-negative patients. Patients with RLS had higher prevalence of pain and sensory symptoms in lower limbs, no difference was found in medication and prevalence of organic comorbidities in patients with FMD with and without RLS. CONCLUSIONS We found an increased prevalence of RLS in patients with FMD. Clinical diagnosis of RLS was supported by actigraphic measurement of clinically relevant PLM in a significant proportion of patients with FMD. Although functional motor and sensory symptoms may mimic RLS, RLS may be unrecognised in patients with FMD. This finding may have clinical implications in management of FMD, and it raises the possibility of common pathophysiological mechanisms of FMD and RLS/PLM.
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Affiliation(s)
- Tereza Serranová
- Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Matěj Slovák
- Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - David Kemlink
- Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Karel Šonka
- Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Mark Hallett
- Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Evžen Růžička
- Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
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Lanza G, Ferri R. The neurophysiology of hyperarousal in restless legs syndrome: Hints for a role of glutamate/GABA. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2019; 84:101-119. [PMID: 31229167 DOI: 10.1016/bs.apha.2018.12.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Restless legs syndrome (RLS) is a common sensory-motor circadian disorder, whose basic components include urge to move the legs, unpleasant sensory experience, and periodic leg movements during sleep, all associated with an enhancement of the individual's arousal state. Brain iron deficiency (BID) is considered to be a key initial pathobiological factor, based on alterations of iron acquisition by the brain, also moderated by genetic factors. In addition to the well-known dopaminergic involvement in RLS, previous studies pointed out that BID brings also a hyperglutamatergic state that influences a dysfunctional cortico-striatal-thalamic-cortical circuit in genetically vulnerable individuals. However, the enhancement of arousal mechanisms in RLS may also be explained by functional changes of the ascending arousal systems and by deficitary GABA-mediated inhibitory control. Very recently, it was also suggested that BID induces a hypoadenosinergic state in RLS, thus possibly providing a link for a putative unified pathophysiological mechanism accounting for both hyperarousal and sensory-motor signs. Consequently, RLS might be viewed as a multitransmitter neurochemical disorder, globally resulting in enhanced excitability and decreased inhibition. In this framework, understanding the complex interaction of different neuronal circuits in generating the symptoms of RLS is mandatory both for a better diagnostic refinement and for an innovative therapeutic support. Notably, multiple neurotransmission dysfunction, either primary or triggered by BID, may also bridge the gap between RLS and other chronic pain disorders. This chapter summarizes the current experimental and clinical findings into a heuristic model of the electrophysiology and neurochemistry underlying RLS.
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Czesnik D, Howells J, Bartl M, Veiz E, Ketzler R, Kemmet O, Walters AS, Trenkwalder C, Burke D, Paulus W. I h contributes to increased motoneuron excitability in restless legs syndrome. J Physiol 2018; 597:599-609. [PMID: 30430565 DOI: 10.1113/jp275341] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/18/2018] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Restless legs patients complain about sensory and motor symptoms leading to sleep disturbances. Symptoms include painful sensations, an urge to move and involuntary leg movements. The responsible mechanisms of restless legs syndrome are still not known, although current studies indicate an increased neuronal network excitability. Reflex studies indicate the involvement of spinal structures. Peripheral mechanisms have not been investigated so far. In the present study, we provide evidence of increased hyperpolarization-activated cyclic nucleotide-gated (HCN) channel-mediated inward rectification in motor axons. The excitability of sensory axons was not changed. We conclude that, in restless legs syndrome, an increased HCN current in motoneurons may play a pathophysiological role, such that these channels could represent a valuable target for pharmaceutical intervention. ABSTRACT Restless legs syndrome is a sensorimotor network disorder. So far, the responsible pathophysiological mechanisms are poorly understood. In the present study, we provide evidence that the excitability of peripheral motoneurons contributes to the pathophysiology of restless legs syndrome. In vivo excitability studies on motor and sensory axons of the median nerve were performed on patients with idiopathic restless legs syndrome (iRLS) who were not currently on treatment. The iRLS patients had greater accommodation in motor but not sensory axons to long-lasting hyperpolarization compared to age-matched healthy subjects, indicating greater inward rectification in iRLS. The most reasonable explanation is that hyperpolarization-activated cyclic nucleotide-gated (HCN) channels open at less hyperpolarized membrane potentials, a view supported by mathematical modelling. The half-activation potential for HCN channels (Bq) was the single best parameter that accounted for the difference between normal controls and iRLS data. A 6 mV depolarization of Bq reduced the discrepancy between the normal control model and the iRLS data by 92.1%. Taken together, our results suggest an increase in the excitability of motor units in iRLS that could enhance the likelihood of leg movements. The abnormal axonal properties are consistent with other findings indicating that the peripheral system is part of the network involved in iRLS.
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Affiliation(s)
- Dirk Czesnik
- Department of Clinical Neurophysiology, Medical School Göttingen, University of Göttingen, Göttingen, Germany
| | - James Howells
- Brain & Mind Centre, The University of Sydney, Sydney, NSW, Australia
| | - Michael Bartl
- Department of Clinical Neurophysiology, Medical School Göttingen, University of Göttingen, Göttingen, Germany
| | - Elisabeth Veiz
- Department of Clinical Neurophysiology, Medical School Göttingen, University of Göttingen, Göttingen, Germany
| | - Rebecca Ketzler
- Department of Clinical Neurophysiology, Medical School Göttingen, University of Göttingen, Göttingen, Germany
| | - Olga Kemmet
- Department of Clinical Neurophysiology, Medical School Göttingen, University of Göttingen, Göttingen, Germany
| | - Arthur S Walters
- Division of Sleep Medicine, School of Medicine, Medical Center North, Vanderbilt University, Nashville, TN, USA
| | - Claudia Trenkwalder
- Clinic of Neurosurgery, University Medical Center, Paracelsus Klinik Kassel, Göttingen, Germany
| | - David Burke
- Royal Prince Alfred Hospital and The University of Sydney, Sydney, NSW, Australia
| | - Walter Paulus
- Department of Clinical Neurophysiology, Medical School Göttingen, University of Göttingen, Göttingen, Germany
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Connecting clinical aspects to corticomotor excitability in restless legs syndrome: a TMS study. Sleep Med 2018; 49:105-112. [DOI: 10.1016/j.sleep.2018.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/27/2018] [Accepted: 05/04/2018] [Indexed: 01/07/2023]
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Ferré S, García-Borreguero D, Allen RP, Earley CJ. New Insights into the Neurobiology of Restless Legs Syndrome. Neuroscientist 2018; 25:113-125. [PMID: 30047288 DOI: 10.1177/1073858418791763] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Restless legs syndrome (RLS) is a common sensorimotor disorder, whose basic components include a sensory experience, akathisia, and a sleep-related motor sign, periodic leg movements during sleep (PLMS), both associated with an enhancement of the individual's arousal state. The present review attempts to integrate the major clinical and experimental neurobiological findings into a heuristic pathogenetic model. The model also integrates the recent findings on RLS genetics indicating that RLS has aspects of a genetically moderated neurodevelopmental disorder involving mainly the cortico-striatal-thalamic-cortical circuits. Brain iron deficiency (BID) remains the key initial pathobiological factor and relates to alterations of iron acquisition by the brain, also moderated by genetic factors. Experimental evidence indicates that BID leads to a hyperdopaminergic and hyperglutamatergic states that determine the dysfunction of cortico-striatal-thalamic-cortical circuits in genetically vulnerable individuals. However, the enhanced arousal mechanisms critical to RLS are better explained by functional changes of the ascending arousal systems. Recent experimental and clinical studies suggest that a BID-induced hypoadenosinergic state provides the link for a putative unified pathophysiological mechanism for sensorimotor signs of RLS and the enhanced arousal state.
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Affiliation(s)
- Sergi Ferré
- 1 National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | | | - Richard P Allen
- 3 Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
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Lanza G, Cantone M, Aricò D, Lanuzza B, Cosentino FII, Paci D, Papotto M, Pennisi M, Bella R, Pennisi G, Paulus W, Ferri R. Clinical and electrophysiological impact of repetitive low-frequency transcranial magnetic stimulation on the sensory-motor network in patients with restless legs syndrome. Ther Adv Neurol Disord 2018. [PMID: 29511386 DOI: 10.1177/1756285618759973.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Background Based on the hyperexcitability and disinhibition observed in patients with restless legs syndrome (RLS) following transcranial magnetic stimulation (TMS), we conducted a study with low-frequency repetitive TMS (rTMS) over the primary motor (M1) and somatosensory cortical areas (S1) in patients with RLS. Methods A total of 13 right-handed patients and 10 age-matched controls were studied using clinical scales and TMS. Measurements included resting motor threshold (rMT), motor-evoked potentials (MEPs), cortical silent period (CSP), and central motor conduction time (CMCT). A single evening session of rTMS (1 Hz, 20 trains, 50 stimuli each) was administered over the left M1, left S1, and sham stimulation over M1 in a random order. Clinical and TMS measures were repeated after each stimulation modality. Results Baseline CSP was shorter in patients than in controls and remained shorter in patients for both motor and somatosensory stimulation. The patients reported a subjective improvement of both initiating and maintaining sleep the night after the rTMS over S1. Patients exhibited a decrease in rMT after rTMS of S1 only, although the effect was smaller than in controls. MEP latency and CMCT changed only in controls after stimulation. Sham stimulation was without effect on the observed variables. Conclusions rTMS on S1-M1 connectivity alleviated the sensory-motor complaints of RLS patients. The TMS indexes of excitation and inhibition indicate an intracortical and corticospinal imbalance, mainly involving gamma-aminobutyric acid (GABA)ergic and glutamatergic circuitries, as well as an impairment of the short-term mechanisms of cortical plasticity. The rTMS-induced activation of the dorsal striatum with the consequent increase of dopamine release may have contributed to the clinical and neurophysiological outcome.
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Affiliation(s)
- Giuseppe Lanza
- Oasi Research Institute - IRCCS Via Conte Ruggero, 73 - 94018, Troina, Italy
| | | | | | | | | | | | | | | | - Rita Bella
- Department of Medical and Surgical Sciences and Advanced Technologies 'GF Ingrassia', Azienda Ospedaliero Universitaria Policlinico Vittorio Emanuele Catania, Catania, Italy
| | - Giovanni Pennisi
- Department of Surgery and Medical-Surgical Specialties, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele, Catania, Italy
| | - Walter Paulus
- Department of Clinical Neurophysiology, Georg August University Göttingen, Göttingen, Germany
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Lanza G, Cantone M, Aricò D, Lanuzza B, Cosentino FII, Paci D, Papotto M, Pennisi M, Bella R, Pennisi G, Paulus W, Ferri R. Clinical and electrophysiological impact of repetitive low-frequency transcranial magnetic stimulation on the sensory-motor network in patients with restless legs syndrome. Ther Adv Neurol Disord 2018; 11:1756286418759973. [PMID: 29511386 PMCID: PMC5833163 DOI: 10.1177/1756286418759973] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 12/22/2017] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Based on the hyperexcitability and disinhibition observed in patients with restless legs syndrome (RLS) following transcranial magnetic stimulation (TMS), we conducted a study with low-frequency repetitive TMS (rTMS) over the primary motor (M1) and somatosensory cortical areas (S1) in patients with RLS. METHODS A total of 13 right-handed patients and 10 age-matched controls were studied using clinical scales and TMS. Measurements included resting motor threshold (rMT), motor-evoked potentials (MEPs), cortical silent period (CSP), and central motor conduction time (CMCT). A single evening session of rTMS (1 Hz, 20 trains, 50 stimuli each) was administered over the left M1, left S1, and sham stimulation over M1 in a random order. Clinical and TMS measures were repeated after each stimulation modality. RESULTS Baseline CSP was shorter in patients than in controls and remained shorter in patients for both motor and somatosensory stimulation. The patients reported a subjective improvement of both initiating and maintaining sleep the night after the rTMS over S1. Patients exhibited a decrease in rMT after rTMS of S1 only, although the effect was smaller than in controls. MEP latency and CMCT changed only in controls after stimulation. Sham stimulation was without effect on the observed variables. CONCLUSIONS rTMS on S1-M1 connectivity alleviated the sensory-motor complaints of RLS patients. The TMS indexes of excitation and inhibition indicate an intracortical and corticospinal imbalance, mainly involving gamma-aminobutyric acid (GABA)ergic and glutamatergic circuitries, as well as an impairment of the short-term mechanisms of cortical plasticity. The rTMS-induced activation of the dorsal striatum with the consequent increase of dopamine release may have contributed to the clinical and neurophysiological outcome.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Rita Bella
- Department of Medical and Surgical Sciences and Advanced Technologies ‘GF Ingrassia’, Azienda Ospedaliero Universitaria Policlinico Vittorio Emanuele Catania, Catania, Italy
| | - Giovanni Pennisi
- Department of Surgery and Medical–Surgical Specialties, Azienda Ospedaliero Universitaria Policlinico-Vittorio Emanuele, Catania, Italy
| | - Walter Paulus
- Department of Clinical Neurophysiology, Georg August University Göttingen, Göttingen, Germany
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Cha KS, Choi JW, Jung KY, Kim KH. Frontal dysfunction in patients with restless legs syndrome performing a visual oddball task: an event-related potential source imaging study. Sleep Med 2017; 36:48-54. [DOI: 10.1016/j.sleep.2017.04.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 04/03/2017] [Accepted: 04/22/2017] [Indexed: 01/18/2023]
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de Paiva JPQ, Magalhães SC, do Prado GF, Eckeli AL, Kaelin-Lang A, Conforto AB. The duration of the cortical silent period is not abnormal in Restless Legs Syndrome/Willis-Ekbom Disease. J Neurol Sci 2017; 375:35-42. [PMID: 28320166 DOI: 10.1016/j.jns.2016.12.066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/28/2016] [Accepted: 12/28/2016] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To compare the duration of the cortical silent period (CSP) measured in a hand muscle in subjects with primary Restless Legs Syndrome (RLS/WED) and controls, using four different methods of analysis. METHODS The CSP to transcranial magnetic stimulation of the dominant motor cortex was assessed in the abductor digiti minimi of 33 subjects with RLS/WED and 24 controls. CSP duration was measured by an automated and three visually-guided methods. RESULTS There were significant differences between absolute values of CSP duration according to the method of analysis. However, irrespectively of the method used for CSP assessment, no differences were found between measurements performed in subjects with RLS/WED and subjects from the control group. CONCLUSIONS Absolute values of CSP durations analyzed by different methods should not be directly compared, because significantly different results can be obtained from the same data set. SIGNIFICANCE The CSP assessed from a hand muscle is unlikely to be a biomarker of primary RLS/WED. Our results highlight the importance of standardizing the definition of CSP onset and offset, as well as of describing in detail the methodology chosen to record and measure CSP duration, in order to enable comparisons between studies.
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Affiliation(s)
- Joselisa Péres Queiroz de Paiva
- Hospital Israelita Albert Einstein, Edifício Josef Féher (Bloco A), 2° subsolo, Av. Albert Einstein, 627/701, São Paulo, SP, Brazil CEP: 05652-900.
| | - Samir Câmara Magalhães
- Hospital Israelita Albert Einstein, Edifício Josef Féher (Bloco A), 2° subsolo, Av. Albert Einstein, 627/701, São Paulo, SP, Brazil CEP: 05652-900.
| | - Gilmar Fernandes do Prado
- Universidade Federal de São Paulo, Departamento de Neurologia e Neurocirurgia, Rua Claúdio Rossi, 394, São Paulo, SP, Brazil CEP: 01547-000.
| | - Alan Luiz Eckeli
- Hospital das Clínicas da Faculdade de Medicina, Departamento de Neurociências e Ciências do Comportamento, Divisão de Neurologia, Hospital das Clinicas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil CEP: 14.048-900.
| | - Alain Kaelin-Lang
- Neurocenter of Southern Switzerland, LBN - Laboratory for Biomedical Neurosciences, 6900 Lugano, Switzerland.
| | - Adriana Bastos Conforto
- Hospital Israelita Albert Einstein, Edifício Josef Féher (Bloco A), 2° subsolo, Av. Albert Einstein, 627/701, São Paulo, SP, Brazil CEP: 05652-900; Hospital das Clínicas da Faculdade de Medicina, Departamento de Neurologia e Núcleo de Apoio à Pesquisa em Neurociência Aplicada (NAPNA), Universidade de São Paulo, São Paulo, SP, Brazil CEP: 05403-010.
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Lanza G, Bachmann CG, Ghorayeb I, Wang Y, Ferri R, Paulus W. Central and peripheral nervous system excitability in restless legs syndrome. Sleep Med 2017; 31:49-60. [PMID: 27745789 DOI: 10.1016/j.sleep.2016.05.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 05/24/2016] [Accepted: 05/30/2016] [Indexed: 02/07/2023]
Abstract
Neurophysiological techniques have been applied in restless legs syndrome (RLS) to obtain direct and indirect measures of central and peripheral nervous system excitability, as well as to probe different neurotransmission pathways. Data converge on the hypothesis that, from a pure electrophysiological perspective, RLS should be regarded as a complex sensorimotor disorder in which cortical, subcortical, spinal cord, and peripheral nerve generators are all involved in a network disorder, resulting in an enhanced excitability and/or decreased inhibition. Although the spinal component may have dominated in neurophysiological assessment, possibly because of better accessibility compared to the brainstem or cerebral components of a hypothetical dysfunction of the diencephalic A11 area, multiple mechanisms, such as reduced central inhibition and abnormal peripheral nerve function, contribute to the pathogenesis of RLS similarly to some chronic pain conditions. Dopamine transmission dysfunction, either primary or triggered by low iron and ferritin concentrations, may also bridge the gap between RLS and chronic pain entities. Further support of disturbed central and peripheral excitability in RLS is provided by the effectiveness of nonpharmacological tools, such as repetitive transcranial magnetic stimulation and transcutaneous spinal direct current stimulation, in transiently modulating neural excitability, thereby extending the therapeutic repertoire. Understanding the complex interaction of central and peripheral neuronal circuits in generating the symptoms of RLS is mandatory for a better refinement of its therapeutic support.
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Affiliation(s)
- Giuseppe Lanza
- Sleep Research Center, I.R.C.C.S. "Oasi Maria SS.", Troina, Italy.
| | | | - Imad Ghorayeb
- Department of Clinical Neurophysiology, CHU de Bordeaux, Bordeaux, France; CNRS, INCIA, CNRS UMR 5287, Université de Bordeaux, Bordeaux, France
| | - Yuping Wang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Raffale Ferri
- Sleep Research Center, I.R.C.C.S. "Oasi Maria SS.", Troina, Italy
| | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Center, Georg August University Göttingen, Göttingen, Germany
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Özsimsek A, Koyuncuoglu HR. Electrophysiological findings of Turkish patients with restless legs syndrome. Neuropsychiatr Dis Treat 2017; 13:2005-2010. [PMID: 28794635 PMCID: PMC5538691 DOI: 10.2147/ndt.s132903] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
We aimed to investigate changes in electrophysiological findings in Turkish patients with restless legs syndrome (RLS), including F-wave latency (FWL), peripheral silent period (PSP), and Hoffmann reflex. The study took place in a university hospital in Turkey and involved 30 newly diagnosed RLS patients and 30 healthy controls who were matched for age and gender. Participant's demographics (age, gender, weight, and height), laboratory findings, and electrophysiological test outcomes were gathered and analyzed. There was no significant difference in the FWL of the median and ulnar nerves, whereas the H-wave maximum amplitude and H/M ratio were significantly higher in the RLS patients than in the controls at rest. All of the PSP parameters were similar between patients and controls for the abductor pollicis brevis and gastrocnemius muscles. However, for the tibialis anterior muscle, all the PSP duration parameters were shorter in the RLS patients, whereas the PSP latency parameters were similar. The data suggest that there may be a reduction in spinal segmental inhibition at the L4-L5-S1 level, but the mechanisms of inhibition at the L4-L5 and S1 levels may be different; furthermore, there may be no pathology in the peripheral nerves. Further prospective studies with larger cohorts are now needed to evaluate the pathophysiology of RLS with different neurophysiological assessment tools.
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Koo BB, Bagai K, Walters AS. Restless Legs Syndrome: Current Concepts about Disease Pathophysiology. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2016; 6:401. [PMID: 27536462 PMCID: PMC4961894 DOI: 10.7916/d83j3d2g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/07/2016] [Indexed: 01/31/2023]
Abstract
Background In the past few decades, much has been learned about the pathophysiology of restless legs syndrome (RLS). Investigators have studied neuropathology, imaging, electrophysiology, and genetics of RLS, identifying brain regions and biological systems affected in RLS. This manuscript will review RLS pathophysiology literature, examining the RLS state through consideration of the neuroanatomy, then the biological, organ, and genetic systems. Methods Pubmed (1966 to April 2016) was searched for the term “restless legs syndrome” cross-referenced with “pathophysiology,” “pathogenesis,” “pathology,” or “imaging.” English language papers were reviewed. Studies that focused on RLS in relation to another disease were not reviewed. Results Although there are no gross structural brain abnormalities in RLS, widespread brain areas are activated, including the pre- and post-central gyri, cingulate cortex, thalamus, and cerebellum. Pathologically, the most consistent finding is striatal iron deficiency in RLS patients. A host of other biological systems are also altered in RLS, including the dopaminergic, oxygen-sensing, opioid, glutamatergic, and serotonergic systems. Polymorphisms in genes including BTBD9 and MEIS1 are associated with RLS. Discussion RLS is a neurologic sensorimotor disorder that involves pathology, most notably iron deficiency, in motor and sensory brain areas. Brain areas not subserving movement or sensation such as the cingulate cortex and cerebellum are also involved. Other biological systems including the dopaminergic, oxygen-sensing, opioid, glutamatergic, and serotonergic systems are involved. Further research is needed to determine which of these anatomic locations or biological systems are affected primarily, and which are affected in a secondary response.
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Affiliation(s)
- Brian B Koo
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA; Department of Neurology, Connecticut Veterans Affairs Health System, West Haven, CT, USA; Yale Center for Neuroepidemiology & Clinical Neurological Research, New Haven, CT, USA
| | - Kanika Bagai
- Department of Neurology, Vanderbilt University, Nashville, TN, USA
| | - Arthur S Walters
- Department of Neurology, Vanderbilt University, Nashville, TN, USA
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