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Park SY, Park YM, Kim YR. A Comparative Investigation of Functional Connectivity Utilizing Electroencephalography in Insomnia Patients with and without Restless Leg Syndrome. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE : THE OFFICIAL SCIENTIFIC JOURNAL OF THE KOREAN COLLEGE OF NEUROPSYCHOPHARMACOLOGY 2024; 22:314-321. [PMID: 38627078 PMCID: PMC11024702 DOI: 10.9758/cpn.23.1117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/30/2023] [Accepted: 09/04/2023] [Indexed: 04/19/2024]
Abstract
Objective The current study aimed to identify distinctive functional brain connectivity characteristics that differentiate patients with restless legs syndrome (RLS) from those with primary insomnia. Methods Quantitative electroencephalography (QEEG) was employed to analyze connectivity matrices using the phaselocking value technique. A total of 107 patients with RLS (RLS group) and 17 patients with insomnia without RLS (primary insomnia group) were included in the study. Demographic variables were compared using t tests and chi-square tests, while differences in connectivity were examined through multiple analyses of covariance. Correlation analysis was conducted to explore the relationship between connectivity and the severity of RLS. Results The results indicated significant differences in the primary somatosensory cortex (F = 4.377, r = 0.039), primary visual cortex (F = 4.215, r = 0.042), and anterior prefrontal cortex (F = 5.439, r = 0.021) between the RLS and primary insomnia groups. Furthermore, the connectivity of the sensory cortex, including the primary somatosensory cortex (r = -0.247, p = 0.014), sensory association cortex (r = -0.238, p = 0.028), retrosplenial region (r = -0.302, p = 0.002), angular gyrus (r = -0.258, p = 0.008), supramarginal gyrus (r = -0.230, p = 0.020), primary visual cortex (r = -0.275, p = 0.005) and secondary visual cortex (r = -0.226, p = 0.025) exhibited an inverse association with RLS symptom severity. Conclusion The prefrontal cortex, primary somatosensory cortex, and visual cortex showed potential as diagnostic biomarkers for distinguishing RLS from primary insomnia. These findings indicate that QEEG-based functional connectivity analysis shows promise as a valuable diagnostic tool for RLS and provides insights into its underlying mechanisms. Further research is needed to explore this aspect further.
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Affiliation(s)
- Seo-Young Park
- Department of Psychiatry, Inje University College of Medicine, Goyang, Korea
| | - Young-Min Park
- Psychiatric Clinic in Your Brain and Mind, Goyang, Korea
| | - Yang Rae Kim
- Kim’s Hue Neuropsychiatric Clinic, Bucheon, Korea
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Park KM, Kim KT, Lee DA, Motamedi GK, Cho YW. Structural and functional multilayer network analysis in restless legs syndrome patients. J Sleep Res 2024; 33:e14104. [PMID: 37963544 DOI: 10.1111/jsr.14104] [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: 07/13/2023] [Revised: 10/15/2023] [Accepted: 10/27/2023] [Indexed: 11/16/2023]
Abstract
The combination of brain structural and functional connectivity offers complementary insights into its organisation. Multilayer network analysis explores various relationships across different layers within a single system. We aimed to investigate changes in the structural and functional multilayer network in 69 patients with primary restless legs syndrome (RLS) compared with 50 healthy controls. Participants underwent diffusion tensor imaging (DTI) and resting state-functional magnetic resonance imaging (rs-fMRI) using a three-tesla MRI scanner. We constructed a structural connectivity matrix derived from DTI using a DSI program and made a functional connectivity matrix based on rs-fMRI using an SPM program and CONN toolbox. A multilayer network analysis, using BRAPH program, was then conducted to assess the connectivity patterns in both groups. At the global level, significant differences there were between the patients with RLS and healthy controls. The average multiplex participation was lower in patients with RLS than in healthy controls (0.804 vs. 0.821, p = 0.042). Additionally, several regions showed significant differences in the nodal level in multiplex participation between patients with RLS and healthy controls, particularly the frontal and temporal lobes. The regions affected included the inferior frontal gyrus, medial orbital gyrus, precentral gyrus, rectus gyrus, insula, superior and inferior temporal gyrus, medial and lateral occipitotemporal gyrus, and temporal pole. These results represent evidence of diversity in interactions between structural and functional connectivity in patients with RLS, providing a more comprehensive understanding of the brain network in RLS. This may contribute to a precise diagnosis of RLS, and aid the development of a biomarker to track treatment effectiveness.
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Affiliation(s)
- Kang Min Park
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Keun Tae Kim
- Department of Neurology, Keimyung University School of Medicine, Daegu, Korea
| | - Dong Ah Lee
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Gholam K Motamedi
- Department of Neurology, Georgetown University Hospital, Washington, District of Columbia, USA
| | - Yong Won Cho
- Department of Neurology, Keimyung University School of Medicine, Daegu, Korea
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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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Zhang J, Zhang J, Sun H, Yang J, Ma Y, Chen K, Su J, Yu X, Yang F, Zhang Z, Zhao T, Hu X, Zhai Y, Liu Q, Wang J, Liu C, Wang Z. Cerebellum drives functional dysfunctions in restless leg syndrome. Sleep Med 2023; 110:172-178. [PMID: 37595434 DOI: 10.1016/j.sleep.2023.08.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/04/2023] [Accepted: 08/14/2023] [Indexed: 08/20/2023]
Abstract
OBJECTIVE Restless legs syndrome (RLS) has serious effects on patients' sleep quality, physical and mental health. However, the pathophysiological mechanisms of RLS remain unclear. This study utilized both static and dynamic functional activity and connectivity analyses approaches as well as effective connectivity analysis to reveal the neurophysiological basis of RLS. METHODS The resting-state functional MRI (rs-fMRI) data from 32 patients with RLS and 33 age-, and gender-matched healthy control (HC) were collected. Dynamic and static amplitude of low frequency fluctuation (ALFF), functional connectivity (FC), and Granger causality analysis (GCA) were employed to reveal the abnormal functional activities and couplings in patients with RLS. RESULTS RLS patients showed over-activities in left parahippocampus and right cerebellum, hyper-connectivities of right cerebellum with left basal ganglia, left postcentral gyrus and right precentral gyrus, and enhanced effective connectivity from right cerebellum to left postcentral gyrus compared to HC. CONCLUSIONS Abnormal cerebellum-basal ganglia-sensorimotor cortex circuit may be the underlying neuropathological basis of RLS. Our findings highlight the important role of right cerebellum in the onset of RLS and suggest right cerebellum may be a potential target for precision therapy.
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Affiliation(s)
- Jiang Zhang
- College of Electrical Engineering, Sichuan University, Chengdu, China; Med-X Center for Informatics, Sichuan University, Chengdu, China
| | - Jingyue Zhang
- College of Electrical Engineering, Sichuan University, Chengdu, China
| | - Hui Sun
- College of Electrical Engineering, Sichuan University, Chengdu, China
| | - Jia Yang
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
| | - Yingzi Ma
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
| | - Kexuan Chen
- Medical School, Kunming University of Science and Technology, Kunming, China
| | - Jing Su
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
| | - Xiaohui Yu
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
| | - Futing Yang
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
| | - Zhiwei Zhang
- College of Electrical Engineering, Sichuan University, Chengdu, China
| | - Tianyu Zhao
- College of Electrical Engineering, Sichuan University, Chengdu, China
| | - Xiuying Hu
- Med-X Center for Informatics, Sichuan University, Chengdu, China; Innovation Center of Nursing Research, Nursing Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, China
| | - Yiran Zhai
- College of Electrical Engineering, Sichuan University, Chengdu, China; Med-X Center for Informatics, Sichuan University, Chengdu, China
| | - Qihong Liu
- College of Biomedical Engineering, Sichuan University, Chengdu, China
| | - Jiaojian Wang
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China.
| | - Chunyan Liu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Key Laboratory of Neuromodulation, Beijing, China.
| | - Zhengbo Wang
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China.
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Sandri A, Mingolla GP, Camonita G, Lippolis M, Tinazzi M, Antelmi E. Reduced Interoception Abilities in Patients with Restless Legs Syndrome. Mov Disord Clin Pract 2023; 10:1126-1130. [PMID: 37476313 PMCID: PMC10354597 DOI: 10.1002/mdc3.13759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/15/2023] [Accepted: 04/18/2023] [Indexed: 07/22/2023] Open
Abstract
Background Restless legs syndrome (RLS) is a complex sensorimotor disorder occurring with a typical circadian fashion. Association with additional features, like alexithymia and nocturnal compulsive behaviors further complicates the framework. Objectives To assess interoception in RLS. Methods A total of 25 RLS patients and 28 controls underwent the heartbeat tracking task (interoceptive accuracy [IAC]). RLS symptoms' frequency, disturbance and duration, nocturnal behaviors, interoceptive awareness (IAW), alexithymia, depressive and anxiety symptoms were also collected. Results RLS patients showed significant lower IAC (P = 0.0003) and IAW (P = 0.012), and reported more nocturnal eating behaviors (P < 0.001). IAC positively correlated with IAW (R = 0.32), and negatively correlated with age (R = -0.58). Nocturnal eating behavior negatively correlated with IAC (R = -0.44) and IAW (R = -0.50). Conclusions RLS patients presented reduced interoceptive abilities correlating with higher nocturnal eating behaviors. Future studies are needed to explore the role of interoception in RLS pathophysiology, also in relation to other sensorimotor aspects.
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Affiliation(s)
- Angela Sandri
- Neurology Unit, Parkinson Disease and Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement SciencesUniversity of VeronaVeronaItaly
| | - Gloria Pompea Mingolla
- Neurology Unit, Parkinson Disease and Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement SciencesUniversity of VeronaVeronaItaly
| | - Giorgia Camonita
- Neurology Unit, Parkinson Disease and Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement SciencesUniversity of VeronaVeronaItaly
| | | | - Michele Tinazzi
- Neurology Unit, Parkinson Disease and Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement SciencesUniversity of VeronaVeronaItaly
| | - Elena Antelmi
- Neurology Unit, Parkinson Disease and Movement Disorders Division, Department of Neurosciences, Biomedicine and Movement SciencesUniversity of VeronaVeronaItaly
- DIMI Department of Engineering and Medicine of InnovationUniversity of VeronaVeronaItaly
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Heidbreder A, Trenkwalder C, Bachmann CG, Bartl M, Fulda S, Habersack L, Maihöfner C, Mathis J, Muntean L, Schneider B, Stefani A, Paulus J, Young P. Restless Legs Syndrom. SOMNOLOGIE 2023. [DOI: 10.1007/s11818-023-00399-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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7
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Liu Z, Guan R, Pan L. Exploration of restless legs syndrome under the new concept: A review. Medicine (Baltimore) 2022; 101:e32324. [PMID: 36550837 PMCID: PMC9771278 DOI: 10.1097/md.0000000000032324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Restless leg syndrome (Restless legs syndrome, RLS) is a common neurological disorder. The pathogenesis of RLS remains unknown, and recent pathophysiological developments have shown the contribution of various genetic markers, neurotransmitter dysfunction, and iron deficiency to the disease, as well as other unidentified contributing mechanisms, particularly chronic renal dysfunction. RLS enhancement syndrome is frequently observed in patients with RLS who have received long-term dopamine agonist therapy, manifesting as a worsening of RLS symptoms, usually associated with an increase in the dose of dopamine agonist. Some patients with RLS can adequately control their symptoms with non-pharmacological measures such as massage and warm baths. First-line treatment options include iron supplementation for those with evidence of reduced iron stores, or gabapentin or pregabalin, as well as dopamine agonists, such as pramipexole. Second-line therapies include opioids such as tramadol. RLS seriously affects the quality of life of patients, and because its pathogenesis is unclear, more biological evidence and treatment methods need to be explored.
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Affiliation(s)
- Zhao Liu
- Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province
- *Correspondence: Zhao Liu, Heilongjiang University of Traditional Chinese Medicine, 24 Heping Road, Harbin 150006, Heilongjiang Province (e-mail: )
| | - Ruiqian Guan
- Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province
- Second Affiliated Hospital of Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province
| | - Limin Pan
- Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province
- First Affiliated Hospital of Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province
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van der Veen S, Caviness JN, Dreissen YE, Ganos C, Ibrahim A, Koelman JH, Stefani A, Tijssen MA. Myoclonus and other jerky movement disorders. Clin Neurophysiol Pract 2022; 7:285-316. [PMID: 36324989 PMCID: PMC9619152 DOI: 10.1016/j.cnp.2022.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 08/29/2022] [Accepted: 09/11/2022] [Indexed: 11/27/2022] Open
Abstract
Myoclonus and other jerky movements form a large heterogeneous group of disorders. Clinical neurophysiology studies can have an important contribution to support diagnosis but also to gain insight in the pathophysiology of different kind of jerks. This review focuses on myoclonus, tics, startle disorders, restless legs syndrome, and periodic leg movements during sleep. Myoclonus is defined as brief, shock-like movements, and subtypes can be classified based the anatomical origin. Both the clinical phenotype and the neurophysiological tests support this classification: cortical, cortical-subcortical, subcortical/non-segmental, segmental, peripheral, and functional jerks. The most important techniques used are polymyography and the combination of electromyography-electroencephalography focused on jerk-locked back-averaging, cortico-muscular coherence, and the Bereitschaftspotential. Clinically, the differential diagnosis of myoclonus includes tics, and this diagnosis is mainly based on the history with premonitory urges and the ability to suppress the tic. Electrophysiological tests are mainly applied in a research setting and include the Bereitschaftspotential, local field potentials, transcranial magnetic stimulation, and pre-pulse inhibition. Jerks due to a startling stimulus form the group of startle syndromes. This group includes disorders with an exaggerated startle reflex, such as hyperekplexia and stiff person syndrome, but also neuropsychiatric and stimulus-induced disorders. For these disorders polymyography combined with a startling stimulus can be useful to determine the pattern of muscle activation and thus the diagnosis. Assessment of symptoms in restless legs syndrome and periodic leg movements during sleep can be performed with different validated scoring criteria with the help of electromyography.
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Affiliation(s)
- Sterre van der Veen
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands,Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
| | - John N. Caviness
- Department of Neurology, Mayo Clinic Arizona, Movement Neurophysiology Laboratory, Scottsdale, AZ, USA
| | - Yasmine E.M. Dreissen
- Department of Neurosurgery, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Christos Ganos
- Movement Disorders and Neuromodulation Unit, Department of Neurology, Charité University Medicine Berlin, Berlin, Germany
| | - Abubaker Ibrahim
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Johannes H.T.M. Koelman
- Department of Neurology and Clinical Neurophysiology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Ambra Stefani
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Marina A.J. Tijssen
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands,Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands,Corresponding author at: Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), PO Box 30.001, 9700 RB Groningen, The Netherlands.
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9
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Geng C, Yang Z, Zhang T, Xu P, Zhang H. Polysomnographic nighttime features of Restless Legs Syndrome: A systematic review and meta-analysis. Front Neurol 2022; 13:961136. [PMID: 36090852 PMCID: PMC9452633 DOI: 10.3389/fneur.2022.961136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 07/29/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundRestless Legs Syndrome (RLS) is a common sleep disorder. Polysomnographic (PSG) studies have been used to explore the night sleep characteristics of RLS, but their relationship with RLS has not been fully analyzed and researched.MethodsWe searched the Cochrane Library electronic literature, PubMed, and EMBASE databases to identify research literature comparing the differences in polysomnography between patients with RLS and healthy controls (HCs).ResultsThis review identified 26 studies for meta-analysis. Our research found that the rapid eye movement sleep (REM)%, sleep efficiency (SE)%, total sleep time (TST) min, and N2 were significantly decreased in patients with RLS compared with HCs, while sleep latency (SL) min, stage shifts (SS), awakenings number (AWN), wake time after sleep onset (WASO) min, N1%, rapid eye movement sleep latency (REML), and arousal index (AI) were significantly increased. Additionally, there was no significant difference among N3%, slow wave sleep (SWS)%, and apnea-hypopnea index (AHI).ConclusionOur findings demonstrated that architecture and sleep continuity had been disturbed in patients with RLS, which further illustrates the changes in sleep structure in patients with RLS. In addition, further attention to the underlying pathophysiological mechanisms of RLS and its association with neurodegenerative diseases is needed in future studies.
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Affiliation(s)
- Chaofan Geng
- Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Zhenzhen Yang
- Fuwai Central China Cardiovascular Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Tingting Zhang
- Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Pengfei Xu
- Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Hongju Zhang
- Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
- Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
- *Correspondence: Hongju Zhang
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Zang QL, Zheng JH, Ma JJ, Zhang Q, Huang PP, Shen NN, Miao W. Neuroanatomy and Functional Connectivity in Patients with Parkinson's Disease with or without Restless Legs Syndrome. Neurol Ther 2022; 11:1625-1636. [PMID: 35999489 DOI: 10.1007/s40120-022-00397-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/08/2022] [Indexed: 11/30/2022] Open
Abstract
INTRODUCTION Restless legs syndrome (RLS) is a common non-motor symptom in Parkinson's disease (PD), but its pathogenesis remains unclear. This study aimed to explore the potential neural substrates of RLS in a large sample of patients with PD. METHODS A total of 42 patients with PD with RLS and 124 patients with PD without RLS were prospectively recruited at our hospital between February 2019 and October 2020 and underwent structural and resting-state functional magnetic resonance imaging. Differences between the two patient groups were assessed using voxel-based morphometry and functional connectivity analysis. PD duration, Part III of the Movement Disorder Society's Unified Parkinson's Disease Rating Scale (MDS-UPDRS-III) score, and levodopa equivalent daily dose were treated as covariates. RESULTS Patients with PD with RLS had significantly larger gray matter volume in the bilateral posterior cingulate cortex than patients with PD without RLS (FDR-adjusted P < 0.05). Compared to patients without RLS, those with RLS had significantly lower functional connectivity between the left central opercular cortex and the bilateral precentral gyri and postcentral gyri (FDR-adjusted P < 0.001). CONCLUSION Our study provides the first evidence that in patients with PD, RLS is associated with significantly larger gray matter volume in the posterior cingulate cortex and lower resting-state functional connectivity within the sensorimotor network. Our results may help clarify the pathophysiology of RLS in PD and identify possible therapeutic targets.
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Affiliation(s)
- Qiu Ling Zang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, 1 Jian She East Road, Zhengzhou, 450007, Henan Province, People's Republic of China
| | - Jin Hua Zheng
- Department of Neurology, Henan Provincial People's Hospital, No. 7, Weiwu Road, Zhengzhou, 450003, Henan Province, People's Republic of China
| | - Jian Jun Ma
- Department of Neurology, Henan Provincial People's Hospital, No. 7, Weiwu Road, Zhengzhou, 450003, Henan Province, People's Republic of China.
| | - Qi Zhang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, 1 Jian She East Road, Zhengzhou, 450007, Henan Province, People's Republic of China
| | - Pei Pei Huang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, 1 Jian She East Road, Zhengzhou, 450007, Henan Province, People's Republic of China
| | - Nan Nan Shen
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, 1 Jian She East Road, Zhengzhou, 450007, Henan Province, People's Republic of China
| | - Wang Miao
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, 1 Jian She East Road, Zhengzhou, 450007, Henan Province, People's Republic of China.
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Park KM, Kim KT, Lee DA, Cho YW. Structural brain connectivity in patients with restless legs syndrome: a diffusion tensor imaging study. Sleep 2022; 45:6575835. [PMID: 35485481 DOI: 10.1093/sleep/zsac099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/07/2022] [Indexed: 11/13/2022] Open
Abstract
STUDY OBJECTIVES To evaluate alterations of global and local structural brain connectivity in patients with restless legs syndrome (RLS). METHODS Patients with primary RLS and healthy controls were recruited at a sleep center where they underwent diffusion tensor imaging (DTI) of the brain. We calculated the network measures of global and local structural brain connectivity based on the DTI in both groups using DSI studio program and a graph theory. RESULTS A total of 69 patients with primary RLS and 51 healthy controls were included in the study. We found a significant difference in the global structural connectivity between the groups. The transitivity in the patients with RLS was lower than that in healthy controls (0.031 vs. 0.033, p = 0.035). Additionally, there were significant differences in the local structural connectivity between the groups. The characteristic path length (r = 0.283, p = 0.018), radius of graph (r = 0.260, p = 0.030), and diameter of graph (r = 0.280, p = 0.019) were all positively correlated with RLS severity, whereas the mean clustering coefficient (r = -0.327, p = 0.006), global efficiency (r = -0.272, p = 0.023), small-worldness index (r = -0.325, p = 0.006), and transitivity (r = -0.351, p = 0.003) were negatively correlated with RLS severity. CONCLUSION We identified changes in the global structural connectivity of patients with RLS using graph theory based on DTI, which showed decreased segregation in the brain network compared to healthy controls. These changes are well correlated with RLS severity. We also found changes in local structural connectivity, especially in regions involved in sensorimotor function, which suggests that these areas play a pivotal role in RLS. These findings contribute to a better understanding of the pathophysiology of RLS symptoms.
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Affiliation(s)
- Kang Min Park
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, South Korea
| | - Keun Tae Kim
- Department of Neurology, Keimyung University School of Medicine, Daegu, South Korea
| | - Dong Ah Lee
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, South Korea
| | - Yong Won Cho
- Department of Neurology, Keimyung University School of Medicine, Daegu, South Korea
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Kassubek J. Advanced network neuroimaging as an approach to unravel the pathophysiology of restless legs syndrome. Sleep 2022; 45:6601536. [PMID: 35666236 PMCID: PMC9272244 DOI: 10.1093/sleep/zsac125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Affiliation(s)
- Jan Kassubek
- Department of Neurology, University of Ulm, Ulm, Germany
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Khachatryan SG, Ferri R, Fulda S, Garcia-Borreguero D, Manconi M, Muntean ML, Stefani A. Restless legs syndrome: Over 50 years of European contribution. J Sleep Res 2022; 31:e13632. [PMID: 35808955 PMCID: PMC9542244 DOI: 10.1111/jsr.13632] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 11/28/2022]
Abstract
Restless legs syndrome (RLS) is a sensorimotor neurological disorder characterised by an urge to move the limbs with a circadian pattern (occurring in the evening/at night), more prominent at rest, and relieved with movements. RLS is one of the most prevalent sleep disorders, occurring in 5%-10% of the European population. Thomas Willis first described RLS clinical cases already in the 17th century, and Karl-Axel Ekbom described the disease as a modern clinical entity in the 20th century. Despite variable severity, RLS can markedly affect sleep (partly through the presence of periodic leg movements) and quality of life, with a relevant socio-economic impact. Thus, its recognition and treatment are essential. However, screening methods present limitations and should be improved. Moreover, available RLS treatment options albeit providing sustained relief to many patients are limited in number. Additionally, the development of augmentation with dopamine agonists represents a major treatment problem. A better understanding of RLS pathomechanisms can bring to light novel treatment possibilities. With emerging new avenues of research in pharmacology, imaging, genetics, and animal models of RLS, this is an interesting and constantly growing field of research. This review will update the reader on the current state of RLS clinical practice and research, with a special focus on the contribution of European researchers.
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Affiliation(s)
- Samson G Khachatryan
- Department of Neurology and Neurosurgery, National Institute of Health, Yerevan, Armenia.,Sleep Disorders Center, Somnus Neurology Clinic, Yerevan, Armenia
| | | | - Stephany Fulda
- Sleep Medicine Unit, Neurocenter of Southern Switzerland, Ospedale Civico, Lugano, Switzerland
| | | | - Mauro Manconi
- Sleep Medicine Unit, Neurocenter of Southern Switzerland, Ospedale Civico, Lugano, Switzerland.,Department of Neurology, University Hospital, Inselspital, Bern, Switzerland
| | - Maria-Lucia Muntean
- Center for Parkinson's Disease and Movement Disorders, Paracelsus-Elena Klinik, Kassel, Germany
| | - Ambra Stefani
- Sleep Disorders Clinic, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
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Park KM, Kim KT, Kang KW, Park JA, Seo JG, Kim J, Chang H, Kim EY, Cho YW. Alterations of Functional Connectivity in Patients With Restless Legs Syndrome. J Clin Neurol 2022; 18:290-297. [PMID: 35589318 PMCID: PMC9163943 DOI: 10.3988/jcn.2022.18.3.290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/28/2022] [Accepted: 02/03/2022] [Indexed: 11/17/2022] Open
Abstract
Restless legs syndrome (RLS) is a common neurological illness marked by a strong desire to move one’s legs, usually in association with uncomfortable sensations. Recent studies have investigated brain networks and connectivity in RLS. The advent of network analysis has greatly improved our understanding of the brain and various neurological disorders. A few studies have investigated alterations in functional connectivity in patients with RLS. This article reviews functional connectivity studies of patients with RLS, which have identified significant alterations relative to healthy controls in several brain networks including thalamic, salience, default-mode, and small-world networks. In addition, network changes related to RLS treatment have been found, including to repetitive transcranial magnetic stimulation, transcutaneous spinal cord direct-current stimulation, and dopaminergic drugs. These findings suggest that the underlying pathogenesis of RLS includes alterations in the functional connectivity in the brain and that RLS is a network disorder.
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Affiliation(s)
- Kang Min Park
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Keun Tae Kim
- Department of Neurology, Keimyung University School of Medicine, Daegu, Korea
| | - Kyung Wook Kang
- Department of Neurology, Chonnam National University Hospital, Gwangju, Korea
| | - Jung A Park
- Department of Neurology, Daegu Catholic University Medical Center, Daegu, Korea
| | - Jong-Geun Seo
- Department of Neurology, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Jiyoung Kim
- Department of Neurology, Pusan National University School of Medicine, Busan, Korea
| | - Hyeyeon Chang
- Department of Neurology, Konyang University School of Medicine, Daejeon, Korea
| | - Eun Young Kim
- Department of Neurology, Chungnam National University Sejong Hospital, Sejong, Korea
| | - Yong Won Cho
- Department of Neurology, Keimyung University School of Medicine, Daegu, Korea.
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15
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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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16
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Shen J, Xu C. Analysis of Brain Activity Changes in Patients with Parkinson's Disease Based on Resting-State Functional Magnetic Resonance Imaging. JOURNAL OF HEALTHCARE ENGINEERING 2022; 2022:8561351. [PMID: 35047157 PMCID: PMC8763543 DOI: 10.1155/2022/8561351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 11/21/2021] [Accepted: 11/22/2021] [Indexed: 11/21/2022]
Abstract
This paper uses resting-state functional magnetic resonance imaging to observe the changes in local consistency of brain activity in patients with Parkinson's disease (PD). Both healthy volunteers and Parkinson's disease patients were scanned for resting brain functional imaging, and the collected raw data were processed using resting functional magnetic resonance data processing toolkit software. This study adopted the use of Regional Homogeneity (ReHo). The postprocessing method of RS-fMRI is to study the spontaneous brain activity changes of patients with Parkinson's disease and cognitive impairment and to explore the changes in the function of their brain regions in the hope of providing help for the treatment of Parkinson's disease cognitive impairment. The results showed that, compared with the normal control group, the brain regions with increased ReHo values in the PD group were the right central anterior gyrus, the right lingual gyrus, the left middle occipital gyrus, and the bilateral anterior cuneiform lobes. The results show that PD patients have abnormal brain nerve activities in the resting state, and these abnormal brain nerve activities may be related to PD cognitive and behavioral dysfunction.
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Affiliation(s)
- Juan Shen
- School of Medical, Yan'an University, Yan'an, Shaanxi 716000, China
| | - Chao Xu
- Department of Radiology, Cardiovascular and Cerebrovascular Branch, Affiliated Hospital of Yan'an University, Yan'an, Shaanxi 716000, China
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17
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Geng C, Yang Z, Kong X, Xu P, Zhang H. Correlation between vitamin D and poor sleep status in restless legs syndrome. Front Endocrinol (Lausanne) 2022; 13:994545. [PMID: 36187108 PMCID: PMC9519848 DOI: 10.3389/fendo.2022.994545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 08/29/2022] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Restless Legs Syndrome (RLS) is closely related to poorer sleep quality. Vitamin D can regulate sleep regulation, cell proliferation, and differentiation. To measure whether vitamin D has predictive value for poor sleep quality in RLS was our aim in this study. METHODS To analyze the serum levels of 25-hydroxyvitamin D [25(OH)D] in 95 RLS patients. We used the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality. Subjects had been divided into a normal and poor-sleeper groups according to the PSQI score. Using correlation and regression analysis to explore underlying etiologies that affect sleep disorder in RLS patients. RESULTS Patients in the poor-sleeper group had significantly lower vitamin D levels in comparison to the normal group. The serum vitamin D levels were negative correlate with PSQI scores after adjusting for confounding factors. In addition, regression analysis showed that vitamin D could act as a predictor for sleep disorders in RLS patients (odds ratio [OR] = 0.008, p = 0.004). The area under the curve (AUC), cut-off value, sensitivity, and specificity of serum vitamin D was 0.967 (95% CI 0.935-0.998), 16.84 ng/ml, 87.5%, and 93.7% by receiver operating characteristic (ROC) analysis. CONCLUSION Our study confirmed the relationship between poorer sleep quality and vitamin D in RLS. However, the causal relationship between vitamin D deficiency and RLS is currently inconclusive. The effect of vitamin D supplementation is needed to confirm as the therapeutic strategies for sleep disorders in RLS patients in future work.
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Affiliation(s)
- Chaofan Geng
- Henan University People’s Hospital, Henan Provincial People’s Hospital, Zhengzhou, China
| | - Zhenzhen Yang
- Fuwai Central China Cardiovascular Hospital, Henan Provincial People’s Hospital, Zhengzhou, China
| | - Xiumei Kong
- Henan University Joint National Laboratory for Antibody Drug Engineering, Kaifeng, China
| | - Pengfei Xu
- Henan Provincial Chest Hospital, Zhengzhou, China
| | - Hongju Zhang
- Henan University People’s Hospital, Henan Provincial People’s Hospital, Zhengzhou, China
- Zhengzhou University People’s Hospital, Henan Provincial People’s Hospital, Zhengzhou, China
- *Correspondence: Hongju Zhang,
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18
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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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Xu Y, Wen H, Li J, Yang J, Luo K, Chang L. The relationship between sleep disorders, anxiety, depression, and cognitive function with restless legs syndrome (RLS) in the elderly. Sleep Breath 2021; 26:1309-1318. [PMID: 34436711 DOI: 10.1007/s11325-021-02477-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 08/01/2021] [Accepted: 08/11/2021] [Indexed: 02/07/2023]
Abstract
OBJECTIVES Restless legs syndrome (RLS) has a significant effect on sleep and quality of life. Delays in diagnosis and treatment are frequent due to a lack of awareness. In this study, a clinical analysis was performed to examine the relationship between sleep, mood, and cognitive function in RLS. METHODS According to the Pittsburgh Sleep Quality Index score (PSQI), patients with RLS were divided into a sleep disorders group (SD, PSQI > 7) and non-sleep disorders group (NSD, PSQI ≤ 7). Healthy controls were selected as a control group matched for age, cultural background, and marital status. We compared differences between the three groups using the Hamilton Anxiety Scale (HAMA), Hamilton Depression (HAMD), Mini-Mental State Examination (MMSE), and Montreal Cognitive Assessment (MoCA). The SD and NSD groups were also assessed with the Restless Leg Syndrome Rating Scale (RLSRS) and the severity of RLS between the two groups was compared. The analysis used t-test, ANOVA, and Pearson correlation. RESULTS (1) Among the 54 RLS patients, 30 people in the control group, 35 patients with sleep disorders (SD, 65%), and 19 patients without sleep disorders (NSD, 35%), there were no significant differences in age, educational level, marital status, or trauma history. (2) The comparison results of the case group (SD and NSD) and the control group showed highly significant differences (P < 0.01) in the PSQI-HAMA-HAMD score but no significant differences between the NSD group, the SD group, and the control group in MMSE score. There was no difference between the NSD group and the control group in the MoCA, but a significant difference (P < 0.05) between the SD group and the control group was found. (3) The comparison between the NSD and the SD groups revealed significant differences in the RLSRS, HAMA, and HAMD scores (P < 0.05), but there were no statistical differences (P > 0.05) between two groups on MMSE and MoCA score. (4) Correlation and regression showed that there was a linear correlation between PSQI scores and RLSRS and HAMD scores in patients with RLS (P < 0.05). The regression equation was PSQI = - 2.393 + 0.494 RLSRS + 0.170 HAMD. CONCLUSIONS RLS patients were prone to sleep disorders, anxiety, and depression. Sleep disorders increased with the severity of the RLS and had some influence on the patient's cognitive function. Sleep disorders were closely related to RLSRS and HAMD.
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Affiliation(s)
- Yuan Xu
- Department of Neurology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, People's Republic of China.,Comprehensive Stroke Center, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, People's Republic of China
| | - Hongbin Wen
- Department of Neurology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, People's Republic of China.,Comprehensive Stroke Center, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, People's Republic of China
| | - Jie Li
- Department of Neurology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, People's Republic of China.,Comprehensive Stroke Center, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, People's Republic of China
| | - Jing Yang
- Department of Neurology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, People's Republic of China
| | - Kai Luo
- School of Food Science and Technology & School of Chemical Engineering, Hubei University of Arts and Science, Xiangyang, 441053, People's Republic of China.
| | - Liying Chang
- Department of Neurology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, People's Republic of China.,Comprehensive Stroke Center, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, People's Republic of China
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20
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Bergmann M, Heidbreder A, Stefani A, Raccagni C, Brandauer E, Rudzki D, Fischer MB, Rossmanith E, Pasztorek M, Löscher WN, Högl B, Wanschitz JV. Signs of sympathetic and endothelial cell activation in the skin of patients with restless legs syndrome. Sleep Med 2021; 84:227-236. [PMID: 34174707 DOI: 10.1016/j.sleep.2021.05.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/28/2021] [Accepted: 05/31/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES To evaluate skin biopsies of patients with early- and late onset restless legs syndrome (RLS) for concomitant small fiber neuropathy (SFN) and to determine cutaneous sympathetic innervation and microvascularization in comparison to healthy individuals. METHODS Density of intraepidermal nerve fibers (IENFD), adrenergic nerve fibers and dermal capillaries was analyzed by immunofluorescence for PGP9.5, tyrosine hydroxylase and endothelial markers CD31 and CD105 in skin biopsies of 11 individuals with RLS and 8 age- and sex-matched controls. RESULTS IENFD did not differ between RLS and controls, but two RLS patients with comorbid impaired glucose metabolism fulfilled morphometric criteria of SFN according to published normative values. In contrast, dermal nerve bundles of RLS patients showed an increased density of tyrosine hydroxylase+ adrenergic nerve fibers (p < 0.005). Moreover, an increased ratio between immature CD105+ and mature CD31+ endothelial cells within dermal capillaries was observed in RLS (p < 0.02). CONCLUSIONS SFN, as a potential contributing factor for RLS, should be considered in patients with predisposing comorbidities presenting with burning or shooting pain, dysesthesias and impaired sensory and temperature perception. Evidence of an increased adrenergic innervation of the skin in RLS patients is in accordance with sympathetic hyperactivity while signs of endothelial cell activation may reflect an adaptive response to tissue hypoxia.
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Affiliation(s)
- Melanie Bergmann
- Department of Neurology, Medical University of Innsbruck, Innsbruck, 6020, Austria
| | - Anna Heidbreder
- Department of Neurology, Medical University of Innsbruck, Innsbruck, 6020, Austria
| | - Ambra Stefani
- Department of Neurology, Medical University of Innsbruck, Innsbruck, 6020, Austria
| | - Cecilia Raccagni
- Department of Neurology, Medical University of Innsbruck, Innsbruck, 6020, Austria; Department of Neurology, Regional General Hospital, Bolzano, 39100, Italy
| | - Elisabeth Brandauer
- Department of Neurology, Medical University of Innsbruck, Innsbruck, 6020, Austria
| | - Dagmar Rudzki
- Department of Neurology, Medical University of Innsbruck, Innsbruck, 6020, Austria
| | - Michael B Fischer
- Department for Health Science and Biomedicine, Danube University Krems, Krems, 3500, Austria; Clinic for Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Vienna, 1090, Austria
| | - Eva Rossmanith
- Department for Health Science and Biomedicine, Danube University Krems, Krems, 3500, Austria
| | - Markus Pasztorek
- Department for Health Science and Biomedicine, Danube University Krems, Krems, 3500, Austria
| | - Wolfgang N Löscher
- Department of Neurology, Medical University of Innsbruck, Innsbruck, 6020, Austria
| | - Birgit Högl
- Department of Neurology, Medical University of Innsbruck, Innsbruck, 6020, Austria
| | - Julia V Wanschitz
- Department of Neurology, Medical University of Innsbruck, Innsbruck, 6020, Austria.
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21
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Colzato LS, Zhang W, Brandt MD, Stock AK, Beste C. Cognitive profile in Restless Legs Syndrome: A signal-to-noise ratio account. CURRENT RESEARCH IN NEUROBIOLOGY 2021; 2:100021. [PMID: 36246509 PMCID: PMC9559071 DOI: 10.1016/j.crneur.2021.100021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/05/2021] [Accepted: 07/29/2021] [Indexed: 11/19/2022] Open
Abstract
Restless legs syndrome (RLS) is a common neurological disorder characterized by a sensorimotor condition, where patients feel an uncontrollable urge to move the lower limbs in the evening and/or during the night. RLS does not only have a profound impact on quality of life due to the disturbed night-time sleep, but there is growing evidence that untreated or insufficiently managed RLS might also cause cognitive changes in patients affected by this syndrome. It has been proposed that RLS is caused by alterations in the signal-to-noise ratio (SNR) and in dopamine (DA) neurotransmission in the nervous system. Based on this evidence, we propose the “SNR-DA hypothesis” as an explanation of how RLS could affect cognitive performance. According to this hypothesis, variations/reductions in the SNR underlie RLS-associated cognitive deficits, which follow an inverted U-shaped function: In unmedicated patients, low dopamine levels worsen the SNR, which eventually impairs cognition. Pharmacological treatment enhances DA levels in medicated patients, which likely improves/normalizes the SNR in case of optimal doses, thus restoring cognition to a normal level. However, overmedication might push patients past the optimal point on the inverted U-shaped curve, where an exaggerated SNR potentially impairs cognitive performance relying on cortical noise such as cognitive flexibility. Based on these assumptions of SNR alterations, we propose to directly measure neural noise via “1/f noise” and related metrics to use transcranial random noise stimulation (tRNS), a noninvasive brain stimulation method which manipulates the SNR, as a research tool and potential treatment option for RLS. Restless legs syndrome (RLS) is a common neurological disorder. RLS is caused by alterations in the SNR ratio and in DA neurotransmission. The SNR- DA hypothesis how RLS affects cognitive performance is presented.
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Affiliation(s)
- Lorenza S. Colzato
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Germany
- Cognitive Psychology, Faculty of Psychology, Shandong Normal University, Jinan, China
- University Neuropsychology Center, Faculty of Medicine, TU Dresden, Germany
| | - Wenxin Zhang
- Cognitive Psychology, Faculty of Psychology, Shandong Normal University, Jinan, China
| | - Moritz D. Brandt
- Department of Neurology, University Hospital, Technische Universität Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Ann-Kathrin Stock
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Germany
- University Neuropsychology Center, Faculty of Medicine, TU Dresden, Germany
- Biopsychology, Faculty of Psychology, TU Dresden, Dresden, Germany
| | - Christian Beste
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Germany
- Cognitive Psychology, Faculty of Psychology, Shandong Normal University, Jinan, China
- University Neuropsychology Center, Faculty of Medicine, TU Dresden, Germany
- Corresponding author. Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Germany Schubertstrasse 42, D-01309, Dresden, Germany.
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