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Rossi S, Cinti A, Viberti F, Benelli A, Neri F, De Monte D, Giannotta A, Romanella S, Smeralda C, Donniacuo A, Prattichizzo D, Pasqualetti P, Santarnecchi E, Mandalà M. Frequency-dependent tuning of the human vestibular "sixth sense" by transcranial oscillatory currents. Clin Neurophysiol 2023; 153:123-132. [PMID: 37481873 DOI: 10.1016/j.clinph.2023.06.013] [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: 01/22/2023] [Revised: 05/04/2023] [Accepted: 06/12/2023] [Indexed: 07/25/2023]
Abstract
OBJECTIVE The vestibular cortex is a multisensory associative region that, in neuroimaging investigations, is activated by slow-frequency (1-2 Hz) galvanic stimulation of peripheral receptors. We aimed to directly activate the vestibular cortex with biophysically modeled transcranial oscillatory current stimulation (tACS) in the same frequency range. METHODS Thirty healthy subjects and one rare patient with chronic bilateral vestibular deafferentation underwent, in a randomized, double-blind, controlled trial, to tACS at slow (1 or 2 Hz) or higher (10 Hz) frequency and sham stimulations, over the Parieto-Insular Vestibular Cortex (PIVC), while standing on a stabilometric platform. Subjective symptoms of motion sickness were scored by Simulator Sickness Questionnaire and subjects' postural sways were monitored on the platform. RESULTS tACS at 1 and 2 Hz induced symptoms of motion sickness, oscillopsia and postural instability, that were supported by posturographic sway recordings. Both 10 Hz-tACS and sham stimulation on the vestibular cortex did not affect vestibular function. As these effects persisted in a rare patient with bilateral peripheral vestibular areflexia documented by the absence of the Vestibular-Ocular Reflex, the possibility of a current spread toward peripheral afferents is unlikely. Conversely, the 10 Hz-tACS significantly reduced his chronic vestibular symptoms in this patient. CONCLUSIONS Weak electrical oscillations in a frequency range corresponding to the physiological cortical activity of the vestibular system may generate motion sickness and postural sways, both in healthy subjects and in the case of bilateral vestibular deafferentation. SIGNIFICANCE This should be taken into account as a new side effect of tACS in future studies addressing cognitive functions. Higher frequencies of stimulation applied to the vestibular cortex may represent a new interventional option to reduce motion sickness in different scenarios.
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Affiliation(s)
- Simone Rossi
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Unit of Neurology and Clinical Neurophysiology, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy; Oto-Neuro-Tech Conjoined Lab, Policlinico Le Scotte, University of Siena, Italy.
| | - Alessandra Cinti
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Unit of Neurology and Clinical Neurophysiology, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy
| | - Francesca Viberti
- Otolaryngology, Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy
| | - Alberto Benelli
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Unit of Neurology and Clinical Neurophysiology, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy
| | - Francesco Neri
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Unit of Neurology and Clinical Neurophysiology, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy; Oto-Neuro-Tech Conjoined Lab, Policlinico Le Scotte, University of Siena, Italy
| | - David De Monte
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Unit of Neurology and Clinical Neurophysiology, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy
| | - Alessandro Giannotta
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Unit of Neurology and Clinical Neurophysiology, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy
| | - Sara Romanella
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Unit of Neurology and Clinical Neurophysiology, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy
| | - Carmelo Smeralda
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Unit of Neurology and Clinical Neurophysiology, Department of Medicine, Surgery and Neuroscience, University of Siena, Italy
| | - Aniello Donniacuo
- Otolaryngology, Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy
| | - Domenico Prattichizzo
- Oto-Neuro-Tech Conjoined Lab, Policlinico Le Scotte, University of Siena, Italy; Siena Robotics and Systems (SiRS) Lab, Department of Information Engineering and Mathematics, University of Siena, Siena, Italy
| | | | - Emiliano Santarnecchi
- Gordon Center for Medical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Marco Mandalà
- Oto-Neuro-Tech Conjoined Lab, Policlinico Le Scotte, University of Siena, Italy; Otolaryngology, Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy
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2
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Paci M, Macchioni G, Ferrarello F. Treatment approaches for pusher behaviour: a scoping review. Top Stroke Rehabil 2023; 30:119-136. [PMID: 35156566 DOI: 10.1080/10749357.2021.2016098] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Some individuals with hemiplegia show a postural disorder called pusher behavior. Various underlying theoretical mechanisms have been proposed, thus leading to various treatment approaches. OBJECTIVES The aim of this scoping review is to identify and analyze the available evidence on the treatment approaches for pusher behavior. METHODS Two independent reviewers conducted a literature search for original studies reporting on treatments for pusher behavior. Studies were searched in PubMed, Scopus, Web of Science, CINAHL and PEDro from their inception to December 2020. Treatment approaches were grouped in homogeneous areas based on the supposed underlying mechanism. To assess the reporting of the interventions, the Template for Intervention Description and Replication (TIDieR) was used. RESULTS Thirty-one papers describing 45 interventions were included in the review. Most of the studies were case reports (i.e. including 1 person) (n = 16), followed by randomized controlled trials (n = 5), single subject design trials (n = 5), non-randomized controlled trials (n = 3), and case series (i.e. including more than 1 person) (n = 2). Treatment approaches were grouped into five categories: visual feedback, somatosensory cues, visual-somatosensory integration, brain stimulation, and other nonspecific treatments. The median number of TIDIeR items reported was 7 (range 4 to 10). CONCLUSION Pusher behavior is still little-known. Five main categories of treatment approaches based on the alleged etiological underlying mechanisms have been identified. Most of studies are case reports; controlled trials should be further conducted. Intervention reporting should be improved to allow treatment replication in larger trials.
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Affiliation(s)
- Matteo Paci
- Department of Allied Health Professions, Unit of Functional Rehabilitation, Azienda Usl Toscana Centro, Florence, Italy
| | | | - Francesco Ferrarello
- Department of Allied Health Professions, Unit of Functional Rehabilitation, Azienda Usl Toscana Centro, Prato, Italy
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3
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Tarnutzer AA, Ward BK, Shaikh AG. Novel ways to modulate the vestibular system: Magnetic vestibular stimulation, deep brain stimulation and transcranial magnetic stimulation / transcranial direct current stimulation. J Neurol Sci 2023; 445:120544. [PMID: 36621040 DOI: 10.1016/j.jns.2023.120544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 12/07/2022] [Accepted: 01/02/2023] [Indexed: 01/06/2023]
Abstract
BACKGROUND Advances in neurotechnologies are revolutionizing our understanding of complex neural circuits and enabling new treatments for disorders of the human brain. In the vestibular system, electromagnetic stimuli can now modulate vestibular reflexes and sensations of self-motion by artificially stimulating the labyrinth, cerebellum, cerebral cortex, and their connections. OBJECTIVE In this narrative review, we describe evolving neuromodulatory techniques including magnetic vestibular stimulation (MVS), deep brain stimulation (DBS), transcranial magnetic stimulation (TMS), and transcranial direct-current stimulation (tDCS) and discuss current and potential future application in the field of neuro-otology. RESULTS MVS triggers both vestibular nystagmic (persistent) and perceptual (lasting ∼1 min) responses that may serve as a model to study central adaptational mechanisms and pathomechanisms of hemispatial neglect. By systematically mapping DBS electrodes, targeted stimulation of central vestibular pathways allowed modulating eye movements, vestibular heading perception, spatial attention and graviception, resulting in reduced anti-saccade error rates and hypometria, improved heading discrimination, shifts in verticality perception and transiently decreased spatial attention. For TMS/tDCS treatment trials have demonstrated amelioration of vestibular symptoms in various neuro-otological conditions, including chronic vestibular insufficiency, Mal-de-Debarquement and cerebellar ataxia. CONCLUSION Neuromodulation has a bright future as a potential treatment of vestibular dysfunction. MVS, DBS and TMS may provide new and sophisticated, customizable, and specific treatment options of vestibular symptoms in humans. While promising treatment responses have been reported for TMS/tDCS, treatment trials for vestibular disorders using MVS or DBS have yet to be defined and performed.
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Affiliation(s)
- A A Tarnutzer
- Neurology, Cantonal Hospital of Baden, Baden, Switzerland; Faculty of Medicine, University of Zurich, Zurich, Switzerland.
| | - B K Ward
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - A G Shaikh
- Department of Neurology, University Hospitals and Cleveland VA Medical Center, Case Western Reserve University, Cleveland, OH, USA
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Sinha P, Shreekantiah U, Goyal N, Sreeraj VS, Arumugham SS, Samantaray S, Jammigumpula A, Nanjundaiah GKK, Venkataramaiah S, Thennarasu K, Roy C, Purohith AN, Shenoy S, Kumar CN, Shivakumar V, Udupa K, Muralidharan K, Venkatasubramanian G, Thirthalli J, Praharaj SK, Mehta UM. Study protocol for evaluating the clinical efficacy and neurobiological correlates of sequential treatment with tDCS primed iTBS and ECT in treatment-resistant depression. Wellcome Open Res 2022. [DOI: 10.12688/wellcomeopenres.18192.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Treatment-resistant depression is a burdensome condition. Intermittent theta burst stimulation (iTBS) of the left dorsolateral prefrontal cortex is considered a treatment option in early course of resistance with a proportion of such patients responding to it. Preliminary evidence suggests a role of priming iTBS stimulation with preconditioning using cathodal transcranial direct current stimulation (tDCS). This protocol describes a double-blind randomized sham-controlled study to evaluate the clinical efficacy and tolerability of tDCS-primed iTBS in the treatment of resistant depression. Non-responders to this trial will be offered open-label electroconvulsive therapy. All participants will undergo neurobiological investigations that will enable the identification of potential response predictors and mechanisms. Methods: Three hundred and fifty consenting patients with treatment resistant depression will be randomly assigned to receive 20–30 daily sessions of true-tDCS or sham-tDCS primed iTBS over left dorsolateral prefrontal cortex at three study centers. After this blinded sham-controlled trial, non-responders to the intervention will be offered open-label true ECT. Clinical assessments, neurocognitive assessments and multimodal investigations (magnetic resonance imaging, electroencephalography, heart rate variability, investigative transcranial magnetic stimulation-transcranial direct current stimulation, gene polymorphisms) will be conducted at baseline and repeated after the end of the trial, as well as open-label ECT course. The trial will evaluate the improvement in depressive symptoms (Hamilton depression rating scale) between the two groups as the primary outcome measure.
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High Definition tDCS Effect on Postural Control in Healthy Individuals: Entropy Analysis of a Crossover Clinical Trial. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12052703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Objective: Converging evidence supporting an effect of transcranial direct current stimulation (tDCS) on postural control and human verticality perception highlights this strategy as promising for post-stroke rehabilitation. We have previously demonstrated polarity-dependent effects of high-definition tDCS (HD-tDCS) on weight-bearing asymmetry. However, there is no investigation regarding the time-course of effects on postural control induced by HD-tDCS protocols. Thus, we performed a nonlinear time series analysis focusing on the entropy of the ground reaction force as a secondary investigation of our randomized, double-blind, placebo-controlled, crossover clinical trial. Materials and Methods: Twenty healthy right-handed young adults received the following conditions (random order, separate days); anode center HD-tDCS, cathode center HD-tDCS or sham HD-tDCS at 1, 2, and 3 mA over the right temporo-parietal junction (TPJ). Using summarized time series of transfer entropy, we evaluated the exchanging information (causal direction) between both force plates and compared the dose-response across the healthy subjects with a Generalized Linear Hierarchical/Mixed Model (GLMM). Results: We found significant variation during the dynamic information flow (p < 0.001) among the dominant bodyside (and across time). A greater force transfer entropy was observed from the right to the left side during the cathode-center HD-tDCS up to 2 mA, with a causal relationship in the information flow (equilibrium force transfer) from right to left that decreased over time. Conclusions: HD-tDCS intervention induced a dynamic influence over time on postural control entropy. Right hemisphere TPJ stimulation using cathode-center HD-tDCS can induce an asymmetry of body weight distribution towards the ipsilateral side of stimulation. These results support the clinical potential of HD-tDCS for post-stroke rehabilitation.
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6
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Nascimento DC, Pinto-Orellana MA, Leite JP, Edwards DJ, Louzada F, Santos TEG. BrainWave Nets: Are Sparse Dynamic Models Susceptible to Brain Manipulation Experimentation? Front Syst Neurosci 2020; 14:527757. [PMID: 33324178 PMCID: PMC7726475 DOI: 10.3389/fnsys.2020.527757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 08/19/2020] [Indexed: 11/15/2022] Open
Abstract
Sparse time series models have shown promise in estimating contemporaneous and ongoing brain connectivity. This paper was motivated by a neuroscience experiment using EEG signals as the outcome of our established interventional protocol, a new method in neurorehabilitation toward developing a treatment for visual verticality disorder in post-stroke patients. To analyze the [complex outcome measure (EEG)] that reflects neural-network functioning and processing in more specific ways regarding traditional analyses, we make a comparison among sparse time series models (classic VAR, GLASSO, TSCGM, and TSCGM-modified with non-linear and iterative optimizations) combined with a graphical approach, such as a Dynamic Chain Graph Model (DCGM). These dynamic graphical models were useful in assessing the role of estimating the brain network structure and describing its causal relationship. In addition, the class of DCGM was able to visualize and compare experimental conditions and brain frequency domains [using finite impulse response (FIR) filter]. Moreover, using multilayer networks, the results corroborate with the susceptibility of sparse dynamic models, bypassing the false positives problem in estimation algorithms. We conclude that applying sparse dynamic models to EEG data may be useful for describing intervention-relocated changes in brain connectivity.
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Affiliation(s)
- Diego C Nascimento
- Institute of Mathematical Science and Computing, University of São Paulo, Sao Carlos, Brazil.,Departamento de Matemática, Universidad de Atacama de Chile, Copiapo, Chile
| | | | - Joao P Leite
- Ribeirao Preto Medical School, University of São Paulo, Ribeirao Preto, Brazil
| | - Dylan J Edwards
- Moss Rehabilitation Research Institute, Elkins Park, PA, United States.,School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | - Francisco Louzada
- Institute of Mathematical Science and Computing, University of São Paulo, Sao Carlos, Brazil
| | - Taiza E G Santos
- Ribeirao Preto Medical School, University of São Paulo, Ribeirao Preto, Brazil
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7
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8
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Egocentric processing in the roll plane and dorsal parietal cortex: A TMS-ERP study of the subjective visual vertical. Neuropsychologia 2019; 127:113-122. [DOI: 10.1016/j.neuropsychologia.2019.02.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 01/29/2019] [Accepted: 02/28/2019] [Indexed: 11/18/2022]
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9
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Babyar S, Santos T, Will-Lemos T, Mazin S, Edwards D, Reding M. Sinusoidal Transcranial Direct Current Versus Galvanic Vestibular Stimulation for Treatment of Lateropulsion Poststroke. J Stroke Cerebrovasc Dis 2018; 27:3621-3625. [DOI: 10.1016/j.jstrokecerebrovasdis.2018.08.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/14/2018] [Accepted: 08/20/2018] [Indexed: 10/28/2022] Open
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10
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Santos TEG, Favoretto DB, Toostani IG, Nascimento DC, Rimoli BP, Bergonzoni E, Lemos TW, Truong DQ, Delbem ACB, Makkiabadi B, Moraes R, Louzada F, Bikson M, Leite JP, Edwards DJ. Manipulation of Human Verticality Using High-Definition Transcranial Direct Current Stimulation. Front Neurol 2018; 9:825. [PMID: 30459697 PMCID: PMC6232937 DOI: 10.3389/fneur.2018.00825] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 09/12/2018] [Indexed: 01/27/2023] Open
Abstract
Background: Using conventional tDCS over the temporo-parietal junction (TPJ) we previously reported that it is possible to manipulate subjective visual vertical (SVV) and postural control. We also demonstrated that high-definition tDCS (HD-tDCS) can achieve substantially greater cortical stimulation focality than conventional tDCS. However, it is critical to establish dose-response effects using well-defined protocols with relevance to clinically meaningful applications. Objective: To conduct three pilot studies investigating polarity and intensity-dependent effects of HD-tDCS over the right TPJ on behavioral and physiological outcome measures in healthy subjects. We additionally aimed to establish the feasibility, safety, and tolerability of this stimulation protocol. Methods: We designed three separate randomized, double-blind, crossover phase I clinical trials in different cohorts of healthy adults using the same stimulation protocol. The primary outcome measure for trial 1 was SVV; trial 2, weight-bearing asymmetry (WBA); and trial 3, electroencephalography power spectral density (EEG-PSD). The HD-tDCS montage comprised a single central, and 3 surround electrodes (HD-tDCS3x1) over the right TPJ. For each study, we tested 3x2 min HD-tDCS3x1 at 1, 2 and 3 mA; with anode center, cathode center, or sham stimulation, in random order across days. Results: We found significant SVV deviation relative to baseline, specific to the cathode center condition, with consistent direction and increasing with stimulation intensity. We further showed significant WBA with direction governed by stimulation polarity (cathode center, left asymmetry; anode center, right asymmetry). EEG-PSD in the gamma band was significantly increased at 3 mA under the cathode. Conclusions: The present series of studies provide converging evidence for focal neuromodulation that can modify physiology and have behavioral consequences with clinical potential.
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Affiliation(s)
- Taiza E G Santos
- Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School University of Sao Paulo, Ribeirão Preto, Brazil
| | - Diandra B Favoretto
- Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School University of Sao Paulo, Ribeirão Preto, Brazil
| | - Iman Ghodratti Toostani
- Neurocognitive Engineering Laboratory, Center of Engineering Applied to Health University of São Paulo, São Carlos, Brazil.,Reconfigurable Computing Laboratory, Institute of Mathematics and Computer Sciences University of São Paulo, São Carlos, Brazil
| | - Diego C Nascimento
- Department of Applied Mathematics and Statistics, Institute of Mathematics and Computer Sciences University of São Paulo, São Carlos, Brazil
| | - Brunna P Rimoli
- Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School University of Sao Paulo, Ribeirão Preto, Brazil
| | - Eduardo Bergonzoni
- Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School University of Sao Paulo, Ribeirão Preto, Brazil
| | - Tenysson Will Lemos
- School of Physical Education and Sport of Ribeirao Preto University of São Paulo, Ribeirao Preto, Brazil
| | - Dennis Q Truong
- Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York, City University of New York New York, NY, United States
| | - Alexandre C B Delbem
- Neurocognitive Engineering Laboratory, Center of Engineering Applied to Health University of São Paulo, São Carlos, Brazil.,Reconfigurable Computing Laboratory, Institute of Mathematics and Computer Sciences University of São Paulo, São Carlos, Brazil
| | - Bahador Makkiabadi
- Department of Medical Physics and Biomedical Engineering, School of Medicine Tehran University of Medical Sciences (TUMS), Tehran, Iran.,Research Center for Biomedical Technology and Robotics (RCBTR), Institute of Advanced Medical Technologies (IAMT) Tehran University of Medical Sciences, Tehran, Iran
| | - Renato Moraes
- School of Physical Education and Sport of Ribeirao Preto University of São Paulo, Ribeirao Preto, Brazil
| | - Francisco Louzada
- Department of Applied Mathematics and Statistics, Institute of Mathematics and Computer Sciences University of São Paulo, São Carlos, Brazil
| | - Marom Bikson
- Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York, City University of New York New York, NY, United States
| | - Joao P Leite
- Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School University of Sao Paulo, Ribeirão Preto, Brazil
| | - Dylan J Edwards
- Moss Rehabilitation Research Institute Elkins Park, PA, United States.,School of Medical and Health Sciences, Edith Cowan University Joondalup, WA, Australia
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11
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Takeuchi N, Mori T, Suzukamo Y, Izumi SI. Modulation of Excitability in the Temporoparietal Junction Relieves Virtual Reality Sickness. CYBERPSYCHOLOGY BEHAVIOR AND SOCIAL NETWORKING 2018; 21:381-387. [PMID: 29792509 DOI: 10.1089/cyber.2017.0499] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Virtual reality (VR) immersion often provokes subjective discomfort and postural instability, so called VR sickness. The neural mechanism of VR sickness is speculated to be related to visual-vestibular information mismatch and/or postural instability. However, the approaches proposed to relieve VR sickness through modulation of brain activity are poorly understood. Using transcranial direct current stimulation (tDCS), we aimed to investigate whether VR sickness could be relieved by the modulation of cortical excitability in the temporoparietal junction (TPJ), which is known to be involved in processing of both vestibular and visual information. Twenty healthy subjects received tDCS over right TPJ before VR immersion. The order of the three types of tDCS (anodal, cathodal, and sham) was counterbalanced across subjects. We evaluated the subjective symptoms, heart rate, and center of pressure at baseline, after tDCS, and after VR immersion. VR immersion using head-mounted displays provoked subjective discomfort and postural instability. However, anodal tDCS over right TPJ ameliorated subjective disorientation symptoms and postural instability induced by VR immersion compared with sham condition. The amelioration of VR sickness by anodal tDCS over the right TPJ might result from relief of the sensory conflict and/or facilitation of vestibular function. Our result not only has potential clinical implications for the neuromodulation approach of VR sickness but also implies a causal role of the TPJ in VR sickness.
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Affiliation(s)
- Naoyuki Takeuchi
- 1 Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine , Sendai, Japan
| | - Takayuki Mori
- 1 Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine , Sendai, Japan
| | - Yoshimi Suzukamo
- 1 Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine , Sendai, Japan
| | - Shin-Ichi Izumi
- 1 Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine , Sendai, Japan
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12
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Alberts BBGT, Selen LPJ, Verhagen WIM, Pennings RJE, Medendorp WP. Bayesian quantification of sensory reweighting in a familial bilateral vestibular disorder (DFNA9). J Neurophysiol 2017; 119:1209-1221. [PMID: 29357473 DOI: 10.1152/jn.00082.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
DFNA9 is a rare progressive autosomal dominantly inherited vestibulo-cochlear disorder, resulting in a homogeneous group of patients with hearing impairment and bilateral vestibular function loss. These patients suffer from a deteriorated sense of spatial orientation, leading to balance problems in darkness, especially on irregular surfaces. Both behavioral and functional imaging studies suggest that the remaining sensory cues could compensate for the loss of vestibular information. A thorough model-based quantification of this reweighting in individual patients is, however, missing. Here we psychometrically examined the individual patient's sensory reweighting of these cues after complete vestibular loss. We asked a group of DFNA9 patients and healthy control subjects to judge the orientation (clockwise or counterclockwise relative to gravity) of a rod presented within an oriented square frame (rod-in-frame task) in three different head-on-body tilt conditions. Our results show a cyclical frame-induced bias in perceived gravity direction across a 90° range of frame orientations. The magnitude of this bias was significantly increased in the patients compared with the healthy control subjects. Response variability, which increased with head-on-body tilt, was also larger for the patients. Reverse engineering of the underlying signal properties, using Bayesian inference principles, suggests a reweighting of sensory signals, with an increase in visual weight of 20-40% in the patients. Our approach of combining psychophysics and Bayesian reverse engineering is the first to quantify the weights associated with the different sensory modalities at an individual patient level, which could make it possible to develop personal rehabilitation programs based on the patient's sensory weight distribution. NEW & NOTEWORTHY It has been suggested that patients with vestibular deficits can compensate for this loss by increasing reliance on other sensory cues, although an actual quantification of this reweighting is lacking. We combine experimental psychophysics with a reverse engineering approach based on Bayesian inference principles to quantify sensory reweighting in individual vestibular patients. We discuss the suitability of this approach for developing personal rehabilitation programs based on the patient's sensory weight distribution.
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Affiliation(s)
- Bart B G T Alberts
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen , Nijmegen , The Netherlands
| | - Luc P J Selen
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen , Nijmegen , The Netherlands
| | - Wim I M Verhagen
- Neurology, Canisius Wilhelmina Hospital , Nijmegen , The Netherlands
| | - Ronald J E Pennings
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen , Nijmegen , The Netherlands.,Department of Otorhinolaryngology, Radboud University Medical Centre , Nijmegen , The Netherlands
| | - W Pieter Medendorp
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen , Nijmegen , The Netherlands
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13
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Kheradmand A, Winnick A. Perception of Upright: Multisensory Convergence and the Role of Temporo-Parietal Cortex. Front Neurol 2017; 8:552. [PMID: 29118736 PMCID: PMC5660972 DOI: 10.3389/fneur.2017.00552] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 09/28/2017] [Indexed: 12/18/2022] Open
Abstract
We inherently maintain a stable perception of the world despite frequent changes in the head, eye, and body positions. Such "orientation constancy" is a prerequisite for coherent spatial perception and sensorimotor planning. As a multimodal sensory reference, perception of upright represents neural processes that subserve orientation constancy through integration of sensory information encoding the eye, head, and body positions. Although perception of upright is distinct from perception of body orientation, they share similar neural substrates within the cerebral cortical networks involved in perception of spatial orientation. These cortical networks, mainly within the temporo-parietal junction, are crucial for multisensory processing and integration that generate sensory reference frames for coherent perception of self-position and extrapersonal space transformations. In this review, we focus on these neural mechanisms and discuss (i) neurobehavioral aspects of orientation constancy, (ii) sensory models that address the neurophysiology underlying perception of upright, and (iii) the current evidence for the role of cerebral cortex in perception of upright and orientation constancy, including findings from the neurological disorders that affect cortical function.
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Affiliation(s)
- Amir Kheradmand
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Otolaryngology – Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Ariel Winnick
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
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14
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Babyar S, Santos-Pontelli T, Will-Lemos T, Mazin S, Bikson M, Truong DQ, Edwards D, Reding M. Center of Pressure Speed Changes with tDCS Versus GVS in Patients with Lateropulsion after Stroke. Brain Stimul 2016; 9:796-798. [DOI: 10.1016/j.brs.2016.06.053] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 06/18/2016] [Indexed: 11/17/2022] Open
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