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Cheng I, Sasegbon A, Hamdy S. Evaluating the Therapeutic Application of Neuromodulation in the Human Swallowing System. Dysphagia 2023; 38:1005-1024. [PMID: 36239821 PMCID: PMC10326109 DOI: 10.1007/s00455-022-10528-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 09/30/2022] [Indexed: 11/03/2022]
Abstract
In the last two decades, the focus of neurogenic dysphagia management has moved from passive compensatory strategies to evidence-based rehabilitative approaches. Advances in technology have enabled the development of novel treatment approaches such as neuromodulation techniques, which target the promotion of neurological reorganization for functional recovery of swallowing. Given the rapid pace of development in the field, this review aims to summarize the current findings on the effects of neuromodulation techniques on the human swallowing system and evaluate their therapeutic potential for neurogenic dysphagia. Implications for future clinical research and practical considerations for using neuromodulation in clinical practice will also be discussed.
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Affiliation(s)
- Ivy Cheng
- Centre for Gastrointestinal Sciences, Division of Diabetes, Endocrinology and Gastroenterology, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Ayodele Sasegbon
- Centre for Gastrointestinal Sciences, Division of Diabetes, Endocrinology and Gastroenterology, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Shaheen Hamdy
- Centre for Gastrointestinal Sciences, Division of Diabetes, Endocrinology and Gastroenterology, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
- Centre for Gastrointestinal Sciences, University of Manchester, Clinical Sciences Building, Salford Royal Foundation Trust, Eccles Old Road, Salford, M6 8HD, UK.
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2
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Todd G, Rae CD, Taylor JL, Rogasch NC, Butler JE, Hayes M, Wilcox RA, Gandevia SC, Aoun K, Esterman A, Lewis SJG, Hall JM, Matar E, Godau J, Berg D, Plewnia C, von Thaler A, Chiang C, Double KL. Motor cortical excitability and pre-supplementary motor area neurochemistry in healthy adults with substantia nigra hyperechogenicity. J Neurosci Res 2023; 101:263-277. [PMID: 36353842 PMCID: PMC10952673 DOI: 10.1002/jnr.25145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 10/08/2022] [Accepted: 10/26/2022] [Indexed: 11/12/2022]
Abstract
Substantia nigra (SN) hyperechogenicity, viewed with transcranial ultrasound, is a risk marker for Parkinson's disease. We hypothesized that SN hyperechogenicity in healthy adults aged 50-70 years is associated with reduced short-interval intracortical inhibition in primary motor cortex, and that the reduced intracortical inhibition is associated with neurochemical markers of activity in the pre-supplementary motor area (pre-SMA). Short-interval intracortical inhibition and intracortical facilitation in primary motor cortex was assessed with paired-pulse transcranial magnetic stimulation in 23 healthy adults with normal (n = 14; 61 ± 7 yrs) or abnormally enlarged (hyperechogenic; n = 9; 60 ± 6 yrs) area of SN echogenicity. Thirteen of these participants (7 SN- and 6 SN+) also underwent brain magnetic resonance spectroscopy to investigate pre-SMA neurochemistry. There was no relationship between area of SN echogenicity and short-interval intracortical inhibition in the ipsilateral primary motor cortex. There was a significant positive relationship, however, between area of echogenicity in the right SN and the magnitude of intracortical facilitation in the right (ipsilateral) primary motor cortex (p = .005; multivariate regression), evidenced by the amplitude of the conditioned motor evoked potential (MEP) at the 10-12 ms interstimulus interval. This relationship was not present on the left side. Pre-SMA glutamate did not predict primary motor cortex inhibition or facilitation. The results suggest that SN hyperechogenicity in healthy older adults may be associated with changes in excitability of motor cortical circuitry. The results advance understanding of brain changes in healthy older adults at risk of Parkinson's disease.
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Affiliation(s)
- Gabrielle Todd
- UniSA Clinical & Health Sciences and Alliance for Research in Exercise, Nutrition and Activity (ARENA)University of South AustraliaAdelaideSouth AustraliaAustralia
| | - Caroline D. Rae
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- Faculty of MedicineUniversity of New South WalesKensingtonNew South WalesAustralia
| | - Janet L. Taylor
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- Faculty of MedicineUniversity of New South WalesKensingtonNew South WalesAustralia
- School of Medical and Health SciencesEdith Cowan UniversityJoondalupWestern AustraliaAustralia
| | - Nigel C. Rogasch
- Hopwood Centre for NeurobiologySouth Australian Health and Medical Research InstituteAdelaideSouth AustraliaAustralia
- Faculty of Health and Medical SciencesThe University of AdelaideAdelaideSouth AustraliaAustralia
- School of Psychological Sciences and Turner Institute for Brain and Mental HealthMonash UniversityMelbourneVictoriaAustralia
| | - Jane E. Butler
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- Faculty of MedicineUniversity of New South WalesKensingtonNew South WalesAustralia
| | - Michael Hayes
- Department of NeurologyConcord Repatriation General HospitalConcordNew South WalesAustralia
| | - Robert A. Wilcox
- UniSA Clinical & Health Sciences and Alliance for Research in Exercise, Nutrition and Activity (ARENA)University of South AustraliaAdelaideSouth AustraliaAustralia
- Department of NeurologyFlinders Medical CentreBedford ParkSouth AustraliaAustralia
- College of Medicine and Public HealthFlinders UniversityBedford ParkSouth AustraliaAustralia
| | - Simon C. Gandevia
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- Faculty of MedicineUniversity of New South WalesKensingtonNew South WalesAustralia
| | - Karl Aoun
- Brain and Mind Centre and School of Medical Sciences (Neuroscience)The University of SydneySydneyNew South WalesAustralia
| | - Adrian Esterman
- UniSA Clinical & Health Sciences and Alliance for Research in Exercise, Nutrition and Activity (ARENA)University of South AustraliaAdelaideSouth AustraliaAustralia
| | - Simon J. G. Lewis
- ForeFront Parkinson's Disease Research Clinic, Brain and Mind Centre, Faculty of Medicine and HealthThe University of SydneyCamperdownNew South WalesAustralia
| | - Julie M. Hall
- Department of Experimental PsychologyGhent UniversityGhentBelgium
| | - Elie Matar
- ForeFront Parkinson's Disease Research Clinic, Brain and Mind Centre, Faculty of Medicine and HealthThe University of SydneyCamperdownNew South WalesAustralia
| | - Jana Godau
- Department of NeurologyKlinikum Kassel GmbHKasselGermany
| | - Daniela Berg
- Department of Neurology, UKSH, Campus KielChristian‐Albrechts‐UniversityKielGermany
| | - Christian Plewnia
- Department of Psychiatry and Psychotherapy, Neurophysiology & Interventional NeuropsychiatryUniversity of TübingenTübingenGermany
| | | | - Clarence Chiang
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- Faculty of MedicineUniversity of New South WalesKensingtonNew South WalesAustralia
| | - Kay L. Double
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- Brain and Mind Centre and School of Medical Sciences (Neuroscience)The University of SydneySydneyNew South WalesAustralia
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3
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Fang WJ, Zheng F, Zhang LZ, Wang WH, Yu CC, Shao J, Wu YJ. Research progress of clinical intervention and nursing for patients with post-stroke dysphagia. Neurol Sci 2022; 43:5875-5884. [PMID: 35661279 PMCID: PMC9166186 DOI: 10.1007/s10072-022-06191-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 05/31/2022] [Indexed: 11/29/2022]
Abstract
Post-stroke dysphagia (PSD) is a common and costly complication of stroke and is associated with increased mortality, morbidity, and hospitalization. Although most patients can spontaneously resume swallowing, there are still many patients who do not recover and even die. Despite multiple advances in the acute treatment and secondary prevention of stroke, the effective treatment of PSD remains a neglected area. Studies have shown that repair mechanisms of neurostimulation techniques and increased cortical activity play an important role in the treatment of PSD. In addition, nutritional interventions are also crucial for the treatment of malnutrition in PSD patients. Therefore, this article reviews the effects of the current main clinical treatment methods and nutritional interventions on the treatment and rehabilitation of PSD patients. It also emphasized the necessity of developing an individualized care plan for PSD patients, which is of great significance to promote the clinical treatment, nutritional status, prognosis, and quality of life of PSD patients.
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Affiliation(s)
- Wen-Juan Fang
- Department of Neurology, The Second People's Hospital of Hefei, Heifei Hospital Affiliated to Anhui Medical University, Hefei, Anhui, 230011, China
| | - Fei Zheng
- Department of Neurology, The Second People's Hospital of Hefei, Heifei Hospital Affiliated to Anhui Medical University, Hefei, Anhui, 230011, China
| | - Lin-Zhi Zhang
- Department of Neurology, The Second People's Hospital of Hefei, Heifei Hospital Affiliated to Anhui Medical University, Hefei, Anhui, 230011, China
| | - Wen-Hui Wang
- Department of Neurology, The Second People's Hospital of Hefei, Heifei Hospital Affiliated to Anhui Medical University, Hefei, Anhui, 230011, China
| | - Cheng-Chen Yu
- Department of Neurology, The Second People's Hospital of Hefei, Heifei Hospital Affiliated to Anhui Medical University, Hefei, Anhui, 230011, China
| | - Juan Shao
- Department of Neurology, The Second People's Hospital of Hefei, Heifei Hospital Affiliated to Anhui Medical University, Hefei, Anhui, 230011, China
| | - Yi-Jin Wu
- The Second Affiliated Hospital of Wannan Medical College, Wuhu, 241000, Anhui, China.
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4
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Nicolini C, Fahnestock M, Gibala MJ, Nelson AJ. Understanding the Neurophysiological and Molecular Mechanisms of Exercise-Induced Neuroplasticity in Cortical and Descending Motor Pathways: Where Do We Stand? Neuroscience 2020; 457:259-282. [PMID: 33359477 DOI: 10.1016/j.neuroscience.2020.12.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023]
Abstract
Exercise is a promising, cost-effective intervention to augment successful aging and neurorehabilitation. Decline of gray and white matter accompanies physiological aging and contributes to motor deficits in older adults. Exercise is believed to reduce atrophy within the motor system and induce neuroplasticity which, in turn, helps preserve motor function during aging and promote re-learning of motor skills, for example after stroke. To fully exploit the benefits of exercise, it is crucial to gain a greater understanding of the neurophysiological and molecular mechanisms underlying exercise-induced brain changes that prime neuroplasticity and thus contribute to postponing, slowing, and ameliorating age- and disease-related impairments in motor function. This knowledge will allow us to develop more effective, personalized exercise protocols that meet individual needs, thereby increasing the utility of exercise strategies in clinical and non-clinical settings. Here, we review findings from studies that investigated neurophysiological and molecular changes associated with acute or long-term exercise in healthy, young adults and in healthy, postmenopausal women.
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Affiliation(s)
- Chiara Nicolini
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Margaret Fahnestock
- Department of Psychiatry & Behavioral Neurosciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Martin J Gibala
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Aimee J Nelson
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.
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5
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Jones CA, Colletti CM, Ding MC. Post-stroke Dysphagia: Recent Insights and Unanswered Questions. Curr Neurol Neurosci Rep 2020; 20:61. [PMID: 33136216 PMCID: PMC7604228 DOI: 10.1007/s11910-020-01081-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2020] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW We explored themes in recent post-stroke dysphagia literature, focusing on the following questions: (1) What does post-stroke dysphagia look like?; (2) Who gets post-stroke dysphagia?; (3) What are the consequences of post-stroke dysphagia?; and (4) How can we improve treatment of post-stroke dysphagia? RECENT FINDINGS There have been several improvements in quantitative descriptions of swallowing physiology using standard and new evaluation techniques. These descriptions have been correlated with lesion locations, and several factors can predict development of post-stroke dysphagia and its sequelae. Novel treatment paradigms have leveraged post-stroke neuroplastic improvements using neurostimulation and biofeedback techniques. Despite recent findings, the field is limited by lack of standardization and unanswered questions on rehabilitation variables. Our improved understanding of post-stroke dysphagia will enhance our ability to prevent, identify, and treat it. Future work should be grounded in swallowing physiology and continue refining treatments, particularly in the acute stage.
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Affiliation(s)
- Corinne A Jones
- Neurology; Dell Medical School, The University of Texas, 1601 Trinity St. Bldg. B, Stop Z0700, Austin, TX, 78712, USA. .,Speech, Language, & Hearing Sciences; Moody College of Communication, The University of Texas, Austin, TX, USA.
| | - Christina M Colletti
- Neurology; Dell Medical School, The University of Texas, 1601 Trinity St. Bldg. B, Stop Z0700, Austin, TX, 78712, USA
| | - Ming-Chieh Ding
- Neurology; Dell Medical School, The University of Texas, 1601 Trinity St. Bldg. B, Stop Z0700, Austin, TX, 78712, USA
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Cuypers K, Marsman A. Transcranial magnetic stimulation and magnetic resonance spectroscopy: Opportunities for a bimodal approach in human neuroscience. Neuroimage 2020; 224:117394. [PMID: 32987106 DOI: 10.1016/j.neuroimage.2020.117394] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 08/18/2020] [Accepted: 09/17/2020] [Indexed: 12/19/2022] Open
Abstract
Over the last decade, there has been an increasing number of studies combining transcranial magnetic stimulation (TMS) and magnetic resonance spectroscopy (MRS). MRS provides a manner to non-invasively investigate molecular concentrations in the living brain and thus identify metabolites involved in physiological and pathological processes. Particularly the MRS-detectable metabolites glutamate, the major excitatory neurotransmitter, and gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter, are of interest when combining TMS and MRS. TMS is a non-invasive brain stimulation technique that can be applied either as a neuromodulation or neurostimulation tool, specifically targeting glutamatergic and GABAergic mechanisms. The combination of TMS and MRS can be used to evaluate alterations in brain metabolite levels following an interventional TMS protocol such as repetitive TMS (rTMS) or paired associative stimulation (PAS). MRS can also be combined with a variety of non-interventional TMS protocols to identify the interplay between brain metabolite levels and measures of excitability or receptor-mediated inhibition and facilitation. In this review, we provide an overview of studies performed in healthy and patient populations combining MRS and TMS, both as a measurement tool and as an intervention. TMS and MRS may reveal complementary and comprehensive information on glutamatergic and GABAergic neurotransmission. Potentially, connectivity changes and dedicated network interactions can be probed using the combined TMS-MRS approach. Considering the ongoing technical developments in both fields, combined studies hold future promise for investigations of brain network interactions and neurotransmission.
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Affiliation(s)
- Koen Cuypers
- Department of Movement Sciences, Group Biomedical Sciences, Movement Control & Neuroplasticity Research Group, KU Leuven, 3001 Heverlee, Belgium; REVAL Research Institute, Hasselt University, Agoralaan, Building A, 3590 Diepenbeek, Belgium
| | - Anouk Marsman
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Section 714, Kettegård Allé 30, 26500 Hvidovre, Denmark.
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7
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Zhang G, Gao C, Ruan X, Liu Y, Li Y, Li E, Jiang L, Liu L, Chen X, Jiang X, Xu G, Lan Y, Wei X. Intermittent Theta-Burst Stimulation Over the Suprahyoid Muscles Motor Cortex Facilitates Increased Degree Centrality in Healthy Subjects. Front Hum Neurosci 2020; 14:200. [PMID: 32612517 PMCID: PMC7309184 DOI: 10.3389/fnhum.2020.00200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 05/05/2020] [Indexed: 11/21/2022] Open
Abstract
Theta-burst stimulation (TBS), a variant of repetitive transcranial magnetic stimulation (rTMS), can potentially benefit the treatment of swallowing disorders. However, the after-effects of TBS on the swallowing motor cortex remain uncertain. The newly developed graph-based analysis of the centrality approach has been increasingly used to explore brain networks. The purpose of this study was to identify degree centrality (DC) alterations in the brain network after different TBS protocols were performed over the suprahyoid muscles motor cortex in healthy subjects. A total of 40 right-handed healthy subjects (mean age: 23.73 ± 2.57 years, range: 21–30, 20 females) were included in this study and randomly assigned to two groups, including the continuous TBS (cTBS) group and the intermittent TBS (iTBS) group. All of the subjects underwent resting-state functional magnetic resonance imaging (rs-fMRI) scanning before and after TBS implementation. Compared to the baseline, cTBS resulted in increased DC values in the left inferior frontal gyrus (P < 0.01). In the iTBS group, decreased DC was observed in the left cerebellum and left medial frontal gyrus; However, increased DC was observed in several brain areas including the right superior temporal gyrus, right superior frontal gyrus, right postcentral gyri and left paracentral lobule (P < 0.01). These results indicated that cTBS mainly results in increasing DC in the ipsilateral. However, iTBS is capable of facilitating the excitability of the swallowing motor cortex and increasing the connectivity of multiple brain regions, including the bilateral sensorimotor network, and might have therapeutic potential in the treatment of swallowing disorders.
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Affiliation(s)
- Guoqin Zhang
- Department of Radiology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Cuihua Gao
- Department of Radiology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Xiuhang Ruan
- Department of Radiology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Yanli Liu
- Department of Radiology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Yuting Li
- The Second Affiliated Hospital, South China University of Technology, Guangzhou, China
| | - E Li
- Department of Radiology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Lisheng Jiang
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Lingling Liu
- Department of Radiology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Xin Chen
- Department of Radiology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China.,The Second Affiliated Hospital, South China University of Technology, Guangzhou, China
| | - Xinqing Jiang
- Department of Radiology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China.,The Second Affiliated Hospital, South China University of Technology, Guangzhou, China
| | - Guangqing Xu
- Department of Rehabilitation Medicine, Beijing Tiantan Hospital, The Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Yue Lan
- The Second Affiliated Hospital, South China University of Technology, Guangzhou, China.,Department of Rehabilitation Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Xinhua Wei
- Department of Radiology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China.,The Second Affiliated Hospital, South China University of Technology, Guangzhou, China
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8
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Cysique LA, Jugé L, Gates T, Tobia M, Moffat K, Brew BJ, Rae C. Covertly active and progressing neurochemical abnormalities in suppressed HIV infection. NEUROLOGY-NEUROIMMUNOLOGY & NEUROINFLAMMATION 2018; 5:e430. [PMID: 29312999 PMCID: PMC5754644 DOI: 10.1212/nxi.0000000000000430] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 10/10/2017] [Indexed: 11/15/2022]
Abstract
Objective To assess whether HIV-related brain injury is progressive in persons with suppressed HIV infection. Methods Seventy-three HIV+ virally suppressed men and 35 HIV- men, screened for psychiatric and alcohol/drug use disorders, underwent neuropsychological evaluation and proton magnetic resonance spectroscopy (1H-MRS) at baseline and after and 23 ± 5 months. 1H-MRS included brain regions known to be vulnerable to HIV and aging: frontal white matter (FWM), posterior cingulate cortex (PCC), and caudate area (CA). Major brain metabolites such as creatine (Cr: marker of cellular energy), N-acetyl aspartate (NAA: marker of neuronal integrity), choline (marker of cellular membrane turnover), glutamate/glutamine (excitatory/inhibitory neurotransmitter), and myo-Inositol (mI: marker of neuroinflammation) were calculated with reference to water signal. Neurocognitive decline was corrected for practice effect and baseline HIV-associated neurocognitive disorder (HAND) status. Results Across the study period, 44% had intact cognition, 42% stable HAND (including the single case that improved), 10% progressing HAND, and 4% incident HAND. When analyzing the neurochemical data per neurocognitive trajectories, we found decreasing PCC Cr in all subgroups compared with controls (p < 0.002). In addition, relative to the HIV- group, stable HAND showed decreasing FWM Cr, incident HAND showed steep FWM Cr reduction, whereas progressing HAND had a sharply decreasing PCC NAA and reduced but stable CA NAA. When analyzing the neurochemical data at the group level (HIV+ vs HIV- groups), we found stable abnormal metabolite concentrations over the study period: decreased FWM and PCC Cr (both p < 0.001), decreased PCC NAA and CA NAA (both p < 0.05) and PCC mI increase (p < 0.05). HIV duration and historical HAND had modest effects on metabolite changes. Conclusions Our study reveals covertly active or progressing HIV-related brain injury in the majority of this virally suppressed cohort, reflecting ongoing neuropathogenic processes that are only partially worsened by historical HAND and HIV duration. Longer-term studies will be important for determining the prognosis of these slowly evolving neurochemical abnormalities.
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Affiliation(s)
- Lucette A Cysique
- School of Medical Sciences (L.A.C., L.J., M.T., C.R.), Faculty of Medicine, UNSW Australia, Sydney; Neuroscience Research Australia (L.A.C., L.J., C.R.), Randwick; Peter Duncan Neuroscience Research Unit (L.A.C., T.G., B.J.B.), St. Vincent's Applied Medical Research Center, Darlinghurst; and St. Vincent's Hospital Sydney (L.A.C., T.G., K.M., B.J.B.), Darlinghurst, New South Wales, Australia
| | - Lauriane Jugé
- School of Medical Sciences (L.A.C., L.J., M.T., C.R.), Faculty of Medicine, UNSW Australia, Sydney; Neuroscience Research Australia (L.A.C., L.J., C.R.), Randwick; Peter Duncan Neuroscience Research Unit (L.A.C., T.G., B.J.B.), St. Vincent's Applied Medical Research Center, Darlinghurst; and St. Vincent's Hospital Sydney (L.A.C., T.G., K.M., B.J.B.), Darlinghurst, New South Wales, Australia
| | - Thomas Gates
- School of Medical Sciences (L.A.C., L.J., M.T., C.R.), Faculty of Medicine, UNSW Australia, Sydney; Neuroscience Research Australia (L.A.C., L.J., C.R.), Randwick; Peter Duncan Neuroscience Research Unit (L.A.C., T.G., B.J.B.), St. Vincent's Applied Medical Research Center, Darlinghurst; and St. Vincent's Hospital Sydney (L.A.C., T.G., K.M., B.J.B.), Darlinghurst, New South Wales, Australia
| | - Michael Tobia
- School of Medical Sciences (L.A.C., L.J., M.T., C.R.), Faculty of Medicine, UNSW Australia, Sydney; Neuroscience Research Australia (L.A.C., L.J., C.R.), Randwick; Peter Duncan Neuroscience Research Unit (L.A.C., T.G., B.J.B.), St. Vincent's Applied Medical Research Center, Darlinghurst; and St. Vincent's Hospital Sydney (L.A.C., T.G., K.M., B.J.B.), Darlinghurst, New South Wales, Australia
| | - Kirsten Moffat
- School of Medical Sciences (L.A.C., L.J., M.T., C.R.), Faculty of Medicine, UNSW Australia, Sydney; Neuroscience Research Australia (L.A.C., L.J., C.R.), Randwick; Peter Duncan Neuroscience Research Unit (L.A.C., T.G., B.J.B.), St. Vincent's Applied Medical Research Center, Darlinghurst; and St. Vincent's Hospital Sydney (L.A.C., T.G., K.M., B.J.B.), Darlinghurst, New South Wales, Australia
| | - Bruce J Brew
- School of Medical Sciences (L.A.C., L.J., M.T., C.R.), Faculty of Medicine, UNSW Australia, Sydney; Neuroscience Research Australia (L.A.C., L.J., C.R.), Randwick; Peter Duncan Neuroscience Research Unit (L.A.C., T.G., B.J.B.), St. Vincent's Applied Medical Research Center, Darlinghurst; and St. Vincent's Hospital Sydney (L.A.C., T.G., K.M., B.J.B.), Darlinghurst, New South Wales, Australia
| | - Caroline Rae
- School of Medical Sciences (L.A.C., L.J., M.T., C.R.), Faculty of Medicine, UNSW Australia, Sydney; Neuroscience Research Australia (L.A.C., L.J., C.R.), Randwick; Peter Duncan Neuroscience Research Unit (L.A.C., T.G., B.J.B.), St. Vincent's Applied Medical Research Center, Darlinghurst; and St. Vincent's Hospital Sydney (L.A.C., T.G., K.M., B.J.B.), Darlinghurst, New South Wales, Australia
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9
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Direct and Indirect Therapy: Neurostimulation for the Treatment of Dysphagia After Stroke. Dysphagia 2018. [DOI: 10.1007/174_2017_147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Application of noninvasive brain stimulation for post-stroke dysphagia rehabilitation. Kaohsiung J Med Sci 2017; 33:55-61. [DOI: 10.1016/j.kjms.2016.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 09/20/2016] [Accepted: 11/09/2016] [Indexed: 11/15/2022] Open
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11
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Lin T, Jiang L, Dou Z, Wu C, Liu F, Xu G, Lan Y. Effects of Theta Burst Stimulation on Suprahyoid Motor Cortex Excitability in Healthy Subjects. Brain Stimul 2016; 10:91-98. [PMID: 27692927 DOI: 10.1016/j.brs.2016.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 08/16/2016] [Accepted: 08/19/2016] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND Continuous theta burst stimulation (cTBS) and intermittent TBS (iTBS) are powerful patterns of repetitive transcranial magnetic stimulation (rTMS), with substantial potential for motor function rehabilitation post-stroke. However, TBS of suprahyoid motor cortex excitability has not been investigated. This study investigated TBS effects on suprahyoid motor cortex excitability and its potential mechanisms in healthy subjects. METHODS Thirty-five healthy subjects (23 females; mean age = 21.66 ± 1.66 years) completed three TBS protocols on separate days, separated by at least one week. A stereotaxic neuronavigation system facilitated accurate TMS positioning. Left and right suprahyoid motor evoked potentials (SMEP) were recorded using single-pulse TMS from the contralateral suprahyoid motor cortex before stimulation (baseline) and 0, 15, and 30 min after stimulation. The SMEP latency and amplitude were analyzed via repeated measures analysis of variance. RESULTS cTBS suppressed ipsilateral suprahyoid motor cortex excitability and activated the contralateral suprahyoid motor cortex. iTBS facilitated ipsilateral suprahyoid motor cortex excitability; however, it did not affect the contralateral excitability. iTBS eliminated the inhibitory effect caused by cTBS applied to the contralateral suprahyoid motor cortex. TBS had no significant effect on the latencies of bilateral SMEP. TBS effects on suprahyoid motor cortex excitability lasted a minimum of 30 min. CONCLUSIONS TBS effectively regulates suprahyoid motor cortex excitability. Suppression of excitability in one hemisphere leads to further activation of the corresponding contralateral motor cortex. iTBS reverses the inhibitory effect induced by cTBS of the contralateral suprahyoid motor cortex.
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Affiliation(s)
- Tuo Lin
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Lisheng Jiang
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Zulin Dou
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Cheng Wu
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Feng Liu
- Department of Geriatrics, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Guangqing Xu
- Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
| | - Yue Lan
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China.
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Pisegna JM, Kaneoka A, Pearson WG, Kumar S, Langmore SE. Effects of non-invasive brain stimulation on post-stroke dysphagia: A systematic review and meta-analysis of randomized controlled trials. Clin Neurophysiol 2016; 127:956-968. [PMID: 26070517 PMCID: PMC5326549 DOI: 10.1016/j.clinph.2015.04.069] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 03/19/2015] [Accepted: 04/25/2015] [Indexed: 01/07/2023]
Abstract
OBJECTIVE The primary aim of this review is to evaluate the effects of non-invasive brain stimulation on post-stroke dysphagia. METHODS Thirteen databases were systematically searched through July 2014. Studies had to meet pre-specified inclusion and exclusion criteria. Each study's methodological quality was examined. Effect sizes were calculated from extracted data and combined for an overall summary statistic. RESULTS Eight randomized controlled trials were included. These trials revealed a significant, moderate pooled effect size (0.55; 95% CI=0.17, 0.93; p=0.004). Studies stimulating the affected hemisphere had a combined effect size of 0.46 (95% CI=-0.18, 1.11; p=0.16); studies stimulating the unaffected hemisphere had a combined effect size of 0.65 (95% CI=0.14, 1.16; p=0.01). At long-term follow up, three studies demonstrated a large but non-significant pooled effect size (0.81, p=0.11). CONCLUSIONS This review found evidence for the efficacy of non-invasive brain stimulation on post-stroke dysphagia. A significant effect size resulted when stimulating the unaffected rather than the affected hemisphere. This finding is in agreement with previous studies implicating the plasticity of cortical neurons in the unaffected hemisphere. SIGNIFICANCE Non-invasive brain stimulation appears to assist cortical reorganization in post-stroke dysphagia but emerging factors highlight the need for more data.
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Affiliation(s)
- Jessica M Pisegna
- Boston University Medical Center, FGH Building 820 Harrison Ave., Boston, MA 02118, United States; Boston University, Sargent College, 635 Commonwealth Ave., Boston, MA 02215, United States.
| | - Asako Kaneoka
- Boston University Medical Center, FGH Building 820 Harrison Ave., Boston, MA 02118, United States; Boston University, Sargent College, 635 Commonwealth Ave., Boston, MA 02215, United States.
| | - William G Pearson
- Georgia Regents University, 1120 15th St., Augusta, GA 30912, United States.
| | - Sandeep Kumar
- Beth Israel Deaconess Medical Center, 330 Brookline Ave., Boston, MA 02215, United States.
| | - Susan E Langmore
- Boston University Medical Center, FGH Building 820 Harrison Ave., Boston, MA 02118, United States; Boston University, Sargent College, 635 Commonwealth Ave., Boston, MA 02215, United States.
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Elshukri O, Michou E, Mentz H, Hamdy S. Brain and behavioral effects of swallowing carbonated water on the human pharyngeal motor system. J Appl Physiol (1985) 2015; 120:408-15. [PMID: 26607248 DOI: 10.1152/japplphysiol.00653.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 11/20/2015] [Indexed: 11/22/2022] Open
Abstract
Chemical stimulation of the swallowing network with carbonation and citric acid has been investigated, showing potential benefits on swallowing of dysphagic patients. Despite this, the underlying mechanisms for these effects are not fully understood. Here we investigated the effects of 5 ml liquid bolus swallows of carbonated, citric acid, and still water on a swallowing reaction-time tasks paradigm in 16 healthy adults (8 male, mean age 33 ± 3.7 yr, protocol 1). We then investigated the net effects of "sensory bolus interventions" (40 repeated swallows every 15 s) of the three different liquid boluses on corticobulbar excitability, as examined with single-pulse transcranial magnetic stimulation (TMS) in 16 participants (8 female, mean age 33 ± 3.7 yr, protocol 2). The findings showed that a larger number of correctly timed swallows (within a predetermined time window) was accomplished mainly with carbonated liquids (z = -2.04, P = 0.04 vs. still water, protocol 1). Both carbonated and citric acid liquid interventions with 40 swallows increased corticobulbar excitability of the stronger pharyngeal projection, suggesting a similar modulatory pathway for the effects on swallowing. However, carbonation showed superiority (P = 0.04, F = 4.75, 2-way ANOVA), with the changes lasting up to 60 min following the intervention. These results hold significance for future further and in-depth physiological investigations of the differences between different stimuli on swallowing neural network.
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Affiliation(s)
- Omsaad Elshukri
- Gastrointestinal Centre, Institute of Inflammation and Repair, Manchester Academic Health Sciences Centre (MAHSC), University of Manchester, Salford Royal NHS Foundation Trust, Salford, United Kingdom; and
| | - Emilia Michou
- Gastrointestinal Centre, Institute of Inflammation and Repair, Manchester Academic Health Sciences Centre (MAHSC), University of Manchester, Salford Royal NHS Foundation Trust, Salford, United Kingdom; and
| | - Hannah Mentz
- Gastrointestinal Centre, Institute of Inflammation and Repair, Manchester Academic Health Sciences Centre (MAHSC), University of Manchester, Salford Royal NHS Foundation Trust, Salford, United Kingdom; and Department Pädagogik und Rehabilitation, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Shaheen Hamdy
- Gastrointestinal Centre, Institute of Inflammation and Repair, Manchester Academic Health Sciences Centre (MAHSC), University of Manchester, Salford Royal NHS Foundation Trust, Salford, United Kingdom; and
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Michou E, Williams S, Vidyasagar R, Downey D, Mistry S, Edden RAE, Hamdy S. fMRI and MRS measures of neuroplasticity in the pharyngeal motor cortex. Neuroimage 2015; 117:1-10. [PMID: 25976926 DOI: 10.1016/j.neuroimage.2015.05.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 04/22/2015] [Accepted: 05/04/2015] [Indexed: 02/08/2023] Open
Abstract
INTRODUCTION Paired associative stimulation (PAS), is a novel non-invasive technique where two neural substrates are employed in a temporally coordinated manner in order to modulate cortico-motor excitability within the motor cortex (M1). In swallowing, combined pharyngeal electrical and transcranial-magnetic-stimulation induced beneficial neurophysiological and behavioural effects in healthy subjects and dysphagic stroke patients. Here, we aimed to investigate the whole-brain changes in neural activation during swallowing using functional magnetic resonance imaging (fMRI) following PAS application and in parallel assess associated GABA changes with magnetic resonance spectroscopy (MRS). METHODS Healthy adults (n=11, 38±9years old) were randomised to receive real and sham PAS to the 'stronger' motor cortex pharyngeal representation, on 2 separate visits. Following PAS, event-related fMRI was performed to assess changes in brain activation in response to water and saliva swallowing and during rest. Data were analysed (SPM8) at P<.001. MRS data were acquired using MEGA-PRESS before and after the fMRI acquisitions on both visits and GABA concentrations were measured (AMARES, jMRUI). RESULTS Following real PAS, BOLD signal changes (group analyses) increased at the site of stimulation during water and saliva swallowing, compared to sham PAS. It is also evident that PAS induced significant increases in BOLD signal to contralateral (to stimulation) hemispheric areas that are of importance to the swallowing neural network. Following real PAS, GABA:creatine ratio showed a trend to increase contralateral to PAS. CONCLUSION Targeted PAS applied to the human pharyngeal motor cortex induces local and remote changes in both primary and non-primary areas for water and saliva tasks. There is a possibility that changes of the inhibitory neurotransmitter, GABA, may play a role in the changes in BOLD signal. These findings provide evidence for the mechanisms underlying the beneficial effects of PAS on the brain swallowing network.
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Affiliation(s)
- Emilia Michou
- Centre for Gastrointestinal Sciences, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester, Clinical Sciences Building, Salford Royal Hospital (part of the Manchester Academic Health Sciences Centre (MAHSC)), Eccles Old Road, Salford M6 8HD, UK.
| | - Steve Williams
- Centre for Imaging Science, Manchester Academic Health Sciences Centre, University of Manchester, Oxford Road, M13 9PT, UK
| | - Rishma Vidyasagar
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Melbourne, Victoria, Australia; Department of Anatomy and Neuroscience, Melbourne University, Melbourne, Victoria, Australia
| | - Darragh Downey
- Neuroscience and Psychiatry Unit, Manchester Academic Health Sciences Centre, University of Manchester, Oxford Road, M13 9PT, UK
| | - Satish Mistry
- Centre for Gastrointestinal Sciences, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester, Clinical Sciences Building, Salford Royal Hospital (part of the Manchester Academic Health Sciences Centre (MAHSC)), Eccles Old Road, Salford M6 8HD, UK
| | - Richard A E Edden
- FM Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shaheen Hamdy
- Centre for Gastrointestinal Sciences, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester, Clinical Sciences Building, Salford Royal Hospital (part of the Manchester Academic Health Sciences Centre (MAHSC)), Eccles Old Road, Salford M6 8HD, UK
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Macrae PR, Jones RD, Huckabee ML. The effect of swallowing treatments on corticobulbar excitability: a review of transcranial magnetic stimulation induced motor evoked potentials. J Neurosci Methods 2014; 233:89-98. [PMID: 24932964 DOI: 10.1016/j.jneumeth.2014.06.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 06/07/2014] [Accepted: 06/09/2014] [Indexed: 10/25/2022]
Abstract
Transcranial magnetic stimulation (TMS) has been used extensively as a method of investigating the corticomotor physiology of many motor tasks, including healthy and disordered swallowing. Changes in excitability of cortical projections to various swallowing muscles have been documented in response to treatments with TMS induced motor evoked potentials (MEPs). These studies have provided valuable insight into CNS response to swallowing impairment, and more importantly, the adaptations associated with functional recovery. However, unique obstacles are presented when investigating corticobulbar neurophysiology associated with the complex task of swallowing. Stringent methodological control and supplementary outcome measures are required to ensure robust and clinically applicable findings. This article offers a tutorial for the researcher who may be considering the use of TMS for investigating changes in cortical excitability associated with various swallowing paradigms. Included is a review of the mechanisms of TMS and what can be measured with this technique, a summary of existing research using MEPs to investigate swallowing, a review of methodological factors that may influence outcomes, and proposed directions for new areas of research.
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Affiliation(s)
- Phoebe R Macrae
- New Zealand Brain Research Institute, 66 Stewart Street, Christchurch, New Zealand; Department of Communication Disorders, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
| | - Richard D Jones
- New Zealand Brain Research Institute, 66 Stewart Street, Christchurch, New Zealand; Department of Communication Disorders, University of Canterbury, Private Bag 4800, Christchurch, New Zealand; Department of Medicine, University of Otago, Private Bag 4710, Christchurch, New Zealand; Department of Medical Physics and Bioengineering, Canterbury District Health Board, Private Bag 4710, Christchurch, New Zealand.
| | - Maggie-Lee Huckabee
- New Zealand Brain Research Institute, 66 Stewart Street, Christchurch, New Zealand; Department of Communication Disorders, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
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Vasant DH, Mistry S, Michou E, Jefferson S, Rothwell JC, Hamdy S. Transcranial direct current stimulation reverses neurophysiological and behavioural effects of focal inhibition of human pharyngeal motor cortex on swallowing. J Physiol 2013; 592:695-709. [PMID: 24247983 PMCID: PMC3934709 DOI: 10.1113/jphysiol.2013.263475] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The human cortical swallowing system exhibits bilateral but functionally asymmetric representation in health and disease as evidenced by both focal cortical inhibition (pre-conditioning with 1 Hz repetitive transcranial magnetic stimulation; rTMS) and unilateral stroke, where disruption of the stronger (dominant) pharyngeal projection alters swallowing neurophysiology and behaviour. Moreover, excitatory neurostimulation protocols capable of reversing the disruptive effects of focal cortical inhibition have demonstrated therapeutic promise in post-stroke dysphagia when applied contralaterally. In healthy participants (n = 15, 8 males, mean age (±SEM) 35 ± 9 years), optimal parameters of transcranial direct current stimulation (tDCS) (anodal, 1.5 mA, 10 min) were applied contralaterally after 1 Hz rTMS pre-conditioning to the strongest pharyngeal projection. Swallowing neurophysiology was assessed in both hemispheres by intraluminal recordings of pharyngeal motor-evoked responses (PMEPs) to single-pulse TMS as a measure of cortical excitability. Swallowing behaviour was examined using a pressure-based reaction time protocol. Measurements were made before and for up to 60 min post intervention. Subjects were randomised to active or sham tDCS after 1 Hz rTMS on separate days and data were compared using repeated measures ANOVA. Active tDCS increased PMEPs bilaterally (F1,14 = 7.4, P = 0.017) reversing the inhibitory effects of 1 Hz rTMS in the pre-conditioned hemisphere (F1,14 = 10.1, P = 0.007). Active tDCS also enhanced swallowing behaviour, increasing the number of correctly timed challenge swallows compared to sham (F1,14 = 6.3, P = 0.025). Thus, tDCS to the contralateral pharyngeal motor cortex reverses the neurophysiological and behavioural effects of focal cortical inhibition on swallowing in healthy individuals and has therapeutic potential for dysphagia rehabilitation.
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Affiliation(s)
- Dipesh H Vasant
- Gastrointestinal Centre, Institute of Inflammation and Repair, University of Manchester, Manchester Academic Health Sciences Centre (MAHSC), Salford Royal NHS Foundation Trust, Salford M6 8HD, UK.
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Michou E, Mistry S, Jefferson S, Tyrrell P, Hamdy S. Characterizing the mechanisms of central and peripheral forms of neurostimulation in chronic dysphagic stroke patients. Brain Stimul 2013; 7:66-73. [PMID: 24314909 PMCID: PMC3893483 DOI: 10.1016/j.brs.2013.09.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/12/2013] [Accepted: 09/17/2013] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Swallowing problems following stroke may result in increased risk of aspiration pneumonia, malnutrition, and dehydration. OBJECTIVE/HYPOTHESIS Our hypothesis was that three neurostimulation techniques would produce beneficial effects on chronic dysphagia following stroke through a common brain mechanism that would predict behavioral response. METHODS In 18 dysphagic stroke patients (mean age: 66 ± 3 years, 3 female, time-post-stroke: 63 ± 15 weeks [±SD]), pharyngeal electromyographic responses were recorded after single-pulse transcranial magnetic stimulation (TMS) over the pharyngeal motor cortex, to measure corticobulbar excitability before, immediately, and 30 min, after real and sham applications of neurostimulation. Patients were randomized to a single session of either: pharyngeal electrical stimulation (PES), paired associative stimulation (PAS) or repetitive TMS (rTMS). Penetration-aspiration scores and bolus transfer timings were assessed before and after both real and sham interventions using videofluoroscopy. RESULTS Corticobulbar excitability of pharyngeal motor cortex was beneficially modulated by PES, PAS and to a lesser extent by rTMS, with functionally relevant changes in the unaffected hemisphere. Following combining the results of real neurostimulation, an overall increase in corticobulbar excitability in the unaffected hemisphere (P = .005, F1,17 = 10.6, ANOVA) with an associated 15% reduction in aspiration (P = .005, z = -2.79) was observed compared to sham. CONCLUSIONS In this mechanistic study, an increase in corticobulbar excitability the unaffected projection was correlated with the improvement in swallowing safety (P = .001, rho = -.732), but modality-specific differences were observed. Paradigms providing peripheral input favored change in neurophysiological and behavioral outcome measures in chronic dysphagia patients. Further larger cohort studies of neurostimulation in chronic dysphagic stroke are imperative.
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Affiliation(s)
- Emilia Michou
- Gastrointestinal Centre, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester (Part of the Manchester Academic Health Sciences Centre [MAHSC]), Salford Royal Hospital, Clinical Sciences Building, Salford M6 8HD, UK
| | - Satish Mistry
- Gastrointestinal Centre, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester (Part of the Manchester Academic Health Sciences Centre [MAHSC]), Salford Royal Hospital, Clinical Sciences Building, Salford M6 8HD, UK
| | - Samantha Jefferson
- Gastrointestinal Centre, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester (Part of the Manchester Academic Health Sciences Centre [MAHSC]), Salford Royal Hospital, Clinical Sciences Building, Salford M6 8HD, UK
| | - Pippa Tyrrell
- Stroke Medicine, Institute of Cardiovascular Sciences, University of Manchester (Part of the Manchester Academic Health Sciences Centre [MAHSC]), Salford Royal Hospital Foundation Trust, Salford M6 8HD, UK
| | - Shaheen Hamdy
- Gastrointestinal Centre, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester (Part of the Manchester Academic Health Sciences Centre [MAHSC]), Salford Royal Hospital, Clinical Sciences Building, Salford M6 8HD, UK.
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Neurostimulation as an Approach to Dysphagia Rehabilitation: Current Evidence. CURRENT PHYSICAL MEDICINE AND REHABILITATION REPORTS 2013. [DOI: 10.1007/s40141-013-0034-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Michou E, Mistry S, Rothwell J, Hamdy S. Priming pharyngeal motor cortex by repeated paired associative stimulation: implications for dysphagia neurorehabilitation. Neurorehabil Neural Repair 2013; 27:355-62. [PMID: 23300211 PMCID: PMC4108291 DOI: 10.1177/1545968312469837] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Several stimulation parameters can influence the neurophysiological and behavioral effects of paired associative stimulation (PAS), a neurostimulation paradigm that repeatedly pairs a peripheral electrical with a central cortical (transcranial magnetic stimulation [TMS]) stimulus. This also appears to be the case when PAS is applied to the pharyngeal motor cortex (MI), with some variability in excitatory responses, questioning its translation into a useful therapy for patients with brain injury. OBJECTIVE To investigate whether repeated PAS in both "responders" and "nonresponders" could enhance cortical excitability in pharyngeal MI more robustly. METHODS Based on their responses after single PAS, healthy participants were stratified into 2 groups of "responders" and "nonresponders" and underwent 2 periods (60 minutes inter-PAS interval) of active and sham PAS in a randomized order. Neurophysiological measurements with single TMS pulses from pharyngeal motor representation were collected up to 90 minutes after the second PAS period. RESULTS Repeated PAS increased cortical excitability up to 95% at 60 minutes following the second PAS in both the "responders" and "nonresponders." Moreover, cortical excitability in the "nonresponders" was significantly different after repeated PAS compared with single and sham application (P = .02; z = -2.2). CONCLUSIONS Double dose PAS switched "nonresponders" to "responders." These results are important for PAS application to dysphagic stroke patients who do not initially respond to a single application.
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Affiliation(s)
| | | | - John Rothwell
- Institute of Neurology, University College London, London, UK
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Mistry S, Michou E, Rothwell J, Hamdy S. Remote effects of intermittent theta burst stimulation of the human pharyngeal motor system. Eur J Neurosci 2012; 36:2493-9. [PMID: 22640033 PMCID: PMC4300514 DOI: 10.1111/j.1460-9568.2012.08157.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intermittent theta burst stimulation (iTBS) is a novel, non-invasive form of brain stimulation capable of facilitating excitability of the human primary motor cortex with therapeutic potential in the treatment of neurological conditions, such as multiple sclerosis. The objectives of this study were to evaluate the effects of iTBS on cortical properties in the human pharyngeal motor system. Transcranial magnetic stimulation (TMS)-evoked pharyngeal motor responses were recorded via a swallowed intra-luminal catheter and used to assess motor cortical pathways to the pharynx in both hemispheres before and for up to 90 min after iTBS in 15 healthy adults (nine male/six female, 22-59 years old). Active/sham iTBS comprised 600 intermittent repetitive TMS pulses, delivered in a double-blind pseudo-randomised order over each hemisphere on separate days at least 1 week apart. Abductor pollicis brevis (APB) recordings were used as control. Hemispheric interventional data were compared with sham using repeated-measures anova. iTBS was delivered at an average intensity of 43±1% of stimulator output. Compared with sham, iTBS to the hemisphere with stronger pharyngeal projections induced increased responses only in the contralateral weaker projection 60-90 min post-iTBS (maximum 54±19%, P≤0.007), with no change in stronger hemisphere responses. By contrast, iTBS to weaker projections had no significant effects (P=0.39) on either hemisphere. APB responses similarly did not change significantly (P=0.78) across all study arms. We conclude that iTBS can induce remote changes in corticobulbar excitability. While further studies will clarify the extent of these changes, iTBS holds promise as a potential treatment for dysphagia after unilateral brain damage.
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Affiliation(s)
- Satish Mistry
- Inflammation Sciences Research Group, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - Emilia Michou
- Inflammation Sciences Research Group, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - John Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK
| | - Shaheen Hamdy
- Inflammation Sciences Research Group, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
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Batouli SAH, Sachdev PS, Wen W, Wright MJ, Suo C, Ames D, Trollor JN. The heritability of brain metabolites on proton magnetic resonance spectroscopy in older individuals. Neuroimage 2012; 62:281-9. [PMID: 22561359 DOI: 10.1016/j.neuroimage.2012.04.043] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 04/18/2012] [Accepted: 04/22/2012] [Indexed: 11/16/2022] Open
Abstract
Twin studies have shown that many aspects of brain structure are heritable, suggesting a strong genetic contribution to brain structure. Less is known about functional aspects of the brain, in particular biologically relevant metabolites in the brain such as those measured by proton magnetic resonance spectroscopy (((1))H MRS), N-acetyl-aspartate (NAA), creatine (Cr), choline (Cho) and myoinositol (ml), which have been suggested as possible markers of brain aging and early dementia. We examined 296 (56 male/108 female monozygotic and 43 male/89 female dizygotic) older twins (mean age 72.2 ± 5.5 years, range 65-88), for the levels of these metabolites relative to the H(2)O signal in the posterior cingulate cortex using ((1))H MRS. All metabolites showed substantial heritability, which was greatest for the neuronal integrity marker NAA (72%), and less so for the others - Cr (51%), Cho (33%) and ml (55%). The heritability of these markers did not change significantly with age or sex. The genetic determination of NAA, along with the evidence that NAA levels change in aging and neurodegenerative diseases suggest that it is a potential endophenotype of brain aging and dementia.
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Affiliation(s)
- Seyed Amir Hossein Batouli
- School of Psychiatry, University of New South Wales, 22-32 King Street, Building R1F, Randwick Campus, UNSW, Randwick, 2052, Sydney, Australia.
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Doeltgen SH, Huckabee ML. Swallowing Neurorehabilitation: From the Research Laboratory to Routine Clinical Application. Arch Phys Med Rehabil 2012; 93:207-13. [DOI: 10.1016/j.apmr.2011.08.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 08/18/2011] [Accepted: 08/25/2011] [Indexed: 10/14/2022]
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Michou E, Mistry S, Jefferson S, Singh S, Rothwell J, Hamdy S. Targeting unlesioned pharyngeal motor cortex improves swallowing in healthy individuals and after dysphagic stroke. Gastroenterology 2012; 142:29-38. [PMID: 21963761 PMCID: PMC4300844 DOI: 10.1053/j.gastro.2011.09.040] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 09/08/2011] [Accepted: 09/20/2011] [Indexed: 01/22/2023]
Abstract
BACKGROUND & AIMS Patients with stroke experience swallowing problems (dysphagia); increased risk of aspiration pneumonia, malnutrition, and dehydration; and have increased mortality. We investigated the behavioral and neurophysiological effects of a new neurostimulation technique (paired associative stimulation [PAS]), applied to the pharyngeal motor cortex, on swallowing function in healthy individuals and patients with dysphagia from stroke. METHODS We examined the optimal parameters of PAS to promote plasticity by combining peripheral pharyngeal (electrical) with cortical stimulation. A virtual lesion was used as an experimental model of stroke, created with 1-Hz repetitive transcranial magnetic stimulation over the pharyngeal cortex in 12 healthy individuals. We tested whether hemispheric targeting of PAS altered swallowing performance before applying the technique to 6 patients with severe, chronic dysphagia from stroke (mean of 38.8 ± 24.4 weeks poststroke). RESULTS Ten minutes of PAS to the unlesioned pharyngeal cortex reversed (bilaterally) the cortical suppression induced by virtual lesion (lesioned: F(1,9) = 21.347, P = .001; contralesional: F(1,9) = 9.648, P = .013; repeated-measures analysis of variance) compared with sham PAS. It promoted changes in behavior responses measured with a swallowing reaction time task (F(1,7) = 21.02, P = .003; repeated-measures analysis of variance). In patients with chronic dysphagia, real PAS induced short-term bilateral changes in the brain; the unaffected pharyngeal cortex had increased excitability (P = .001; 95% confidence interval, 0.21-0.05; post hoc paired t test) with reduced penetration-aspiration scores and changes in swallowing biomechanics determined by videofluoroscopy. CONCLUSIONS The beneficial neurophysiological and behavioral properties of PAS, when applied to unlesioned brain, provide the foundation for further investigation into the use of neurostimulation as a rehabilitative approach for patients with dysphagia from stroke.
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Affiliation(s)
- Emilia Michou
- School of Translational Medicine - Inflammation Sciences, University of Manchester (part of the Manchester Academic Health Sciences Centre), Salford Royal Hospital, Salford, England
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Jayasekeran V, Pendleton N, Holland G, Payton A, Jefferson S, Michou E, Vasant D, Ollier B, Horan M, Rothwell J, Hamdy S. Val66Met in brain-derived neurotrophic factor affects stimulus-induced plasticity in the human pharyngeal motor cortex. Gastroenterology 2011; 141:827-836.e1-3. [PMID: 21699787 DOI: 10.1053/j.gastro.2011.05.047] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 05/03/2011] [Accepted: 05/26/2011] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Polymorphisms in brain-derived neurotrophic factor (BDNF) can affect brain and behavioral responses. However, little is known about the effects of a single nucleotide polymorphism (SNP) in BDNF, at codon 66 (the Val-Met substitution, detected in approximately 33% of the Caucasian population) on stimulation-induced plasticity in the cortico-bulbar system. We examined whether this SNP influenced outcomes of different forms of neurostimulation applied to the pharyngeal motor cortex. METHODS Thirty-eight healthy volunteers were assessed for corticobulbar excitability after single-pulse, transcranial magnetic stimulation of induced pharyngeal electromyographic responses, recorded from a swallowed intraluminal catheter. Thereafter, volunteers were conditioned with pharyngeal electrical stimulation, or 2 forms of repetitive (1 and 5 Hz) transcranial magnetic stimulation (rTMS). Repeated measurements of pharyngeal motor-evoked potentials were assessed with transcranial magnetic stimulation for as long as 1 hour after the 3 forms of neurostimulation and correlated with SNPs at codon 66 of BDNF (encoding Val or Met). RESULTS Pharyngeal electrical stimulation significantly increased the amplitude of motor-evoked potentials in individuals with the SNP that encoded Val66, compared to those that encoded Met66, with a strong GENOTYPE*TIME interaction (F₈,₁₁₂ = 2.4; P = .018). By contrast, there was a significant reduction in latencies of subjects with the SNP that encoded Met66 after 5-Hz rTMS (F₃,₆₀ = 4.9; P = .04). In addition, the expected inhibitory effect of 1-Hz rTMS on amplitude was not observed in subjects with the SNP that encoded Met66 in BDNF (F₇,₁₄₀ = 2.23; P = .035). CONCLUSIONS An SNP in human BDNF at codon 66 affects plasticity of the pharyngeal cortex to different forms of neurostimulation. Genetic analysis might help select specific forms of neurostimulation as therapeutics for patients with disorders such as dysphagic stroke.
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Affiliation(s)
- Vanoo Jayasekeran
- Inflammation Sciences Research Group, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
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Mistry S, Michou E, Vasant DH, Hamdy S. Direct and Indirect Therapy: Neurostimulation for the Treatment of Dysphagia After Stroke. Dysphagia 2011. [DOI: 10.1007/174_2011_416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Chow AM, Zhou IY, Fan SJ, Chan KW, Chan KC, Wu EX. Metabolic changes in visual cortex of neonatal monocular enucleated rat: a proton magnetic resonance spectroscopy study. Int J Dev Neurosci 2010; 29:25-30. [DOI: 10.1016/j.ijdevneu.2010.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2010] [Revised: 08/30/2010] [Accepted: 10/01/2010] [Indexed: 01/14/2023] Open
Affiliation(s)
- April M. Chow
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
| | - Iris Y. Zhou
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
| | - Shu Juan Fan
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
| | - Kannie W.Y. Chan
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
| | - Kevin C. Chan
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
| | - Ed X. Wu
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
- Department of AnatomyThe University of Hong KongPokfulamHong Kong SARChina
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27
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Jacobs GE, der Grond JV, Teeuwisse WM, Langeveld TJC, van Pelt J, Verhagen JCM, de Kam ML, Cohen AF, Zitman FG, van Gerven JMA. Hypothalamic glutamate levels following serotonergic stimulation: a pilot study using 7-Tesla magnetic resonance spectroscopy in healthy volunteers. Prog Neuropsychopharmacol Biol Psychiatry 2010; 34:486-91. [PMID: 20138102 DOI: 10.1016/j.pnpbp.2010.01.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 01/10/2010] [Accepted: 01/27/2010] [Indexed: 01/10/2023]
Abstract
INTRODUCTION AND PURPOSE Functional proton magnetic resonance spectroscopy (MRS) can be applied to measure pharmacodynamic effects of central nervous system (CNS)-active drugs. The serotonin precursor 5-hydroxytryptophan (5-HTP), administered together with carbidopa and granisetron to improve kinetics and reduce adverse effects, acutely enhances central serotonergic neurotransmission and induces hypothalamus-pituitary-adrenal-(HPA) axis activation. We studied the hypothalamic levels of glutamate/glutamine (Glx), choline (Chol), N-acetyl-aspartate (NAA) and creatine using 7-Tesla (7T) MRS, and adrenocorticotropic hormone (ACTH) and cortisol in peripheral blood, after the administration of the 5-HTP function test in healthy volunteers. METHODS A randomized, double blind, placebo-controlled, two-way cross-over study was performed in 12 healthy males with a 7day wash-out period. After administration of the oral 5-HTP function test, ACTH and cortisol were measured over 4h and MRS scans at 7T were performed every 30min over 3h measuring Glx:Creatine, Chol:Creatine and NAA:Creatine ratios. RESULTS In the hypothalamus, the administration of 5-HTP had no effect on the average Glx, Chol or NAA levels over 180min but induced a significant decrease of Glx at 60min on post-hoc analysis. 5-HTP-induced significant ACTH release reaching an E(max) of 60.2ng/L at 80min followed by cortisol with an E(max) of 246.4ng/mL at 110min. CONCLUSIONS The reduction in hypothalamic Glx levels after serotonergic stimulation is compatible with activation of excitatory neurons in this region, which is expected to cause depletion of local glutamate stores. The hypothalamic MRS-response reached its maximum prior to subsequent increases of ACTH and cortisol, which support the functional relevance of hypothalamic Glx-depletion for activation of the HPA-axis. This exploratory study shows that MRS is capable of detecting neuronal activation following functional stimulation of a targeted brain area.
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Affiliation(s)
- G E Jacobs
- Centre for Human Drug Research, Leiden, The Netherlands.
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28
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Hamdy S. Role of Neurostimulation and Neuroplasticity in the Rehabilitation of Dysphagia After Stroke. ACTA ACUST UNITED AC 2010. [DOI: 10.1044/sasd19.1.3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Abstract
Swallowing problems are common after brain injury, and can affect as many as 50% of patients in the period immediately after stroke. In some cases this can lead to serious morbidity, in particular malnutrition and pulmonary aspiration. Despite this, swallowing therapies remain controversial, with limited evidence base and little in the way of objective scientific criteria. Moreover, swallowing can recover in some patients to a safe level within weeks, making it an interesting model for understanding brain recovery and cortical plasticity. A better understanding of these adaptive processes as seen in spontaneous recovery therefore may help in developing therapeutic interventions that can drive plasticity and so encourage the recovery process. In this article, I will examine present knowledge about the recovery mechanisms for swallowing after brain injury, particularly from investigations with Transcranial Magnetic Stimulation, and explore what aspects are important for compensating for recovery after damage. In addition, I will describe novel approaches to swallowing therapy, based on objective neurophysiological models that may be useful in speeding up the process of recovery and encouraging cortical plasticity that may form the basis for future clinical trials of dysphagia after brain injury.
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Affiliation(s)
- Shaheen Hamdy
- GI Sciences, School of Translational Medicine, Faculty of Medical and Health Sciences, University of Manchester, Salford Royal HospitalSalford, UK
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Jefferson S, Mistry S, Singh S, Rothwell J, Hamdy S. Characterizing the application of transcranial direct current stimulation in human pharyngeal motor cortex. Am J Physiol Gastrointest Liver Physiol 2009; 297:G1035-40. [PMID: 19815630 PMCID: PMC2850087 DOI: 10.1152/ajpgi.00294.2009] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Transcranial direct current stimulation (tDCS) is a novel intervention that can modulate brain excitability in health and disease; however, little is known about its effects on bilaterally innervated systems such as pharyngeal motor cortex. Here, we assess the effects of differing doses of tDCS on the physiology of healthy human pharyngeal motor cortex as a prelude to designing a therapeutic intervention in dysphagic patients. Healthy subjects (n = 17) underwent seven regimens of tDCS (anodal 10 min 1 mA, cathodal 10 min 1 mA, anodal 10 min 1.5 mA, cathodal 10 min 1.5 mA, anodal 20 min 1 mA, cathodal 20 min 1 mA, Sham) on separate days, in a double blind randomized order. Bihemispheric motor evoked potential (MEP) responses to single-pulse transcranial magnetic stimulation (TMS) as well as intracortical facilitation (ICF) and inhibition (ICI) were recorded using a swallowed pharyngeal catheter before and up to 60 min following the tDCS. Compared with sham, both 10 min 1.5 mA and 20 min 1 mA anodal stimulation induced increases in cortical excitability in the stimulated hemisphere (+44 +/- 17% and +59 +/- 16%, respectively; P < 0.005) whereas only 10 min 1.5 mA cathodal stimulation induced inhibition (-26 +/- 4%, P = 0.02). There were neither contralateral hemisphere changes nor any evidence for ICI or ICF in driving the ipsilateral effects. In conclusion, anodal tDCS can alter pharyngeal motor cortex excitability in an intensity-dependent manner, with little evidence for transcallosal spread. Anodal stimulation may therefore provide a useful means of stimulating pharyngeal cortex and promoting recovery in dysphagic patients.
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Affiliation(s)
- Samantha Jefferson
- 1Department of Gastrointestinal Sciences, Salford Royal Foundation Trust, University of Manchester, Manchester; and
| | - Satish Mistry
- 1Department of Gastrointestinal Sciences, Salford Royal Foundation Trust, University of Manchester, Manchester; and
| | - Salil Singh
- 1Department of Gastrointestinal Sciences, Salford Royal Foundation Trust, University of Manchester, Manchester; and
| | - John Rothwell
- 2Sobell Department of Neurophysiology, Institute of Neurology, University College London, London, United Kingdom
| | - Shaheen Hamdy
- 1Department of Gastrointestinal Sciences, Salford Royal Foundation Trust, University of Manchester, Manchester; and
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Jefferson S, Mistry S, Michou E, Singh S, Rothwell JC, Hamdy S. Reversal of a virtual lesion in human pharyngeal motor cortex by high frequency contralesional brain stimulation. Gastroenterology 2009; 137:841-9, 849.e1. [PMID: 19427312 DOI: 10.1053/j.gastro.2009.04.056] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 04/22/2009] [Accepted: 04/27/2009] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Excitatory brain stimulation with repetitive transcranial magnetic stimulation (rTMS) has been proposed as a treatment for dysphagia after stroke. Moreover, 1-Hz rTMS can induce a "virtual lesion" in the human pharyngeal motor cortex that suppresses brain activity and temporarily disrupts swallowing. We thus examined if rTMS could reverse the disrupted brain and swallowing functions following a unilateral virtual lesion in the pharyngeal motor cortex, such that rTMS might be developed as a therapy. METHODS Healthy subjects (n = 23) were given varying conditions of 5-Hz rTMS over the pharyngeal motor cortex to determine the most effective excitatory parameters. Thereafter, a unilateral virtual lesion was made in the pharyngeal motor cortex using 1-Hz rTMS, followed by contralateral active or sham 5-Hz rTMS. Motor evoked potentials and serial swallowing reaction times were recorded before and for 60 minutes postlesion to assess reversibility of the disruption to the brain and swallowing. RESULTS The greatest increase in pharyngeal motor cortex excitability was seen following 250 pulses of 5-Hz rTMS (F(1,11) = 10.3, P = .008), an effect that lasted over 2 hours. In contrast to sham rTMS, active contralateral 5-Hz rTMS completely abolished the cortical suppression induced by the virtual lesion, with effects occurring for up to 50 minutes in both unlesioned (F(1,11) = 6, P = .03) and lesioned (F(1,11) = 67, P < .001) hemispheres. Active rTMS also reversed the changes in swallowing behavior (F(1,8) = 9, P = .018), restoring function to prelesional levels. CONCLUSIONS Contralesional-targeted neurostimulation modulates brain activity and swallowing motor behavior after experimental disruption and might be usefully applied in stroke-affected patients as a therapy for dysphagia.
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Affiliation(s)
- Samantha Jefferson
- School of Translational Medicine-GI Sciences, Salford Royal Hospital, University of Manchester, Salford, England
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