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Chen J, Sprigg J, Castle N, Matson C, Hedjoudje A, Dai C. A Virtual Inner Ear Model Selects Ramped Pulse Shapes for Vestibular Afferent Stimulation. Bioengineering (Basel) 2023; 10:1436. [PMID: 38136027 PMCID: PMC10740892 DOI: 10.3390/bioengineering10121436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/03/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Bilateral vestibular deficiency (BVD) results in chronic dizziness, blurry vision when moving the head, and postural instability. Vestibular prostheses (VPs) show promise as a treatment, but the VP-restored vestibulo-ocular reflex (VOR) gain in human trials falls short of expectations. We hypothesize that the slope of the rising ramp in stimulation pulses plays an important role in the recruitment of vestibular afferent units. To test this hypothesis, we utilized customized programming to generate ramped pulses with different slopes, testing their efficacy in inducing electrically evoked compound action potentials (eCAPs) and current spread via bench tests and simulations in a virtual inner model created in this study. The results confirmed that the slope of the ramping pulses influenced the recruitment of vestibular afferent units. Subsequently, an optimized stimulation pulse train was identified using model simulations, exhibiting improved modulation of vestibular afferent activity. This optimized slope not only reduced the excitation spread within the semicircular canals (SCCs) but also expanded the neural dynamic range. While the model simulations exhibited promising results, in vitro and in vivo experiments are warranted to validate the findings of this study in future investigations.
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Affiliation(s)
- Joseph Chen
- Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
- School of Medicine and Biomedical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Jayden Sprigg
- Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Nicholas Castle
- Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Cayman Matson
- School of Medicine and Biomedical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | | | - Chenkai Dai
- Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
- School of Medicine and Biomedical Engineering, University of Oklahoma, Norman, OK 73019, USA
- Biomedical Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA
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Kojima Y, Ling L, Phillips JO. Compensatory saccade in the vestibular impaired monkey. Front Neurol 2023; 14:1198274. [PMID: 37780695 PMCID: PMC10538121 DOI: 10.3389/fneur.2023.1198274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 08/11/2023] [Indexed: 10/03/2023] Open
Abstract
Introduction Loss of the vestibulo-ocular reflex (VOR) affects visual acuity during head movements. Patients with unilateral and bilateral vestibular deficits often use saccadic eye movements to compensate for an inadequate VOR. Two types of compensatory saccades have been distinguished, covert saccades and overt saccades. Covert saccades occur during head rotation, whereas overt saccades occur after the head has stopped moving. The generation of covert saccades is part of a central vestibular compensation process that improves visual acuity and suppresses oscillopsia. Understanding the covert saccade mechanism may facilitate vestibular rehabilitation strategies that can improve the patient's quality of life. To understand the brain mechanisms underlying covert saccades at the neural level, studies in an animal model are necessary. In this study, we employed non-human primates whose vestibular end organs are injured. Methods We examined eye movement during the head-impulse test, which is a clinical test to evaluate the vestibulo-ocular reflex. During this test, the monkeys are required to fixate on a target and the head is rapidly and unexpectedly rotated to stimulate the horizontal semi-circular canals. Results Similar to human subjects, monkeys made compensatory saccades. We compared these saccades with catch-up saccades following a moving target that simulates the visual conditions during the head impulse test. The shortest latency of the catch-up saccades was 250 ms, which indicates that it requires at least 250 ms to induce saccades by a visual signal. The latency of some compensatory saccades is shorter than 250 ms during the head impulse test, suggesting that such short latency compensatory saccades were not induced visually. The peak velocity of the short latency saccades was significantly lower than that of longer latency saccades. The peak velocity of these longer latency saccades was closer to that of visually guided saccades induced by a stepping target. Conclusion These results are consistent with studies in human patients. Thus, this study demonstrates, for the first time, compensatory covert saccades in vestibular impaired monkeys.
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Affiliation(s)
- Yoshiko Kojima
- Department of Otolaryngology-HNS, University of Washington, Seattle, WA, United States
- National Primate Research Center, Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA, United States
| | - Leo Ling
- National Primate Research Center, Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA, United States
| | - James O. Phillips
- Department of Otolaryngology-HNS, University of Washington, Seattle, WA, United States
- National Primate Research Center, Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA, United States
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Stultiens JJA, Lewis RF, Phillips JO, Boutabla A, Della Santina CC, Glueckert R, van de Berg R. The Next Challenges of Vestibular Implantation in Humans. J Assoc Res Otolaryngol 2023; 24:401-412. [PMID: 37516679 PMCID: PMC10504197 DOI: 10.1007/s10162-023-00906-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Accepted: 06/29/2023] [Indexed: 07/31/2023] Open
Abstract
Patients with bilateral vestibulopathy suffer from a variety of complaints, leading to a high individual and social burden. Available treatments aim to alleviate the impact of this loss and improve compensatory strategies. Early experiments with electrical stimulation of the vestibular nerve in combination with knowledge gained by cochlear implant research, have inspired the development of a vestibular neuroprosthesis that can provide the missing vestibular input. The feasibility of this concept was first demonstrated in animals and later in humans. Currently, several research groups around the world are investigating prototype vestibular implants, in the form of vestibular implants as well as combined cochlear and vestibular implants. The aim of this review is to convey the presentations and discussions from the identically named symposium that was held during the 2021 MidWinter Meeting of the Association for Research in Otolaryngology, with researchers involved in the development of vestibular implants targeting the ampullary nerves. Substantial advancements in the development have been made. Yet, research and development processes face several challenges to improve this neuroprosthesis. These include, but are not limited to, optimization of the electrical stimulation profile, refining the surgical implantation procedure, preserving residual labyrinthine functions including hearing, as well as gaining regulatory approval and establishing a clinical care infrastructure similar to what exists for cochlear implants. It is believed by the authors that overcoming these challenges will accelerate the development and increase the impact of a clinically applicable vestibular implant.
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Affiliation(s)
- Joost Johannes Antonius Stultiens
- Department of Otorhinolaryngology & Head and Neck Surgery, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, 6202 AZ, The Netherlands.
| | - Richard F Lewis
- Department of Otolaryngology and Neurology, Harvard Medical School, Boston, MA, USA
| | - James O Phillips
- Department of Otolaryngology, University of Washington, Seattle, WA, USA
| | - Anissa Boutabla
- Department of Otorhinolaryngology & Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Charles C Della Santina
- Department of Biomedical Engineering and Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Rudolf Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Raymond van de Berg
- Department of Otorhinolaryngology & Head and Neck Surgery, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, 6202 AZ, The Netherlands
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4
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Soto E, Pliego A, Vega R. Vestibular prosthesis: from basic research to clinics. Front Integr Neurosci 2023; 17:1161860. [PMID: 37265514 PMCID: PMC10230114 DOI: 10.3389/fnint.2023.1161860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 04/26/2023] [Indexed: 06/03/2023] Open
Abstract
Balance disorders are highly prevalent worldwide, causing substantial disability with high personal and socioeconomic impact. The prognosis in many of these patients is poor, and rehabilitation programs provide little help in many cases. This medical problem can be addressed using microelectronics by combining the highly successful cochlear implant experience to produce a vestibular prosthesis, using the technical advances in micro gyroscopes and micro accelerometers, which are the electronic equivalents of the semicircular canals (SCC) and the otolithic organs. Reaching this technological milestone fostered the possibility of using these electronic devices to substitute the vestibular function, mainly for visual stability and posture, in case of damage to the vestibular endorgans. The development of implantable and non-implantable devices showed diverse outcomes when considering the integrity of the vestibular pathways, the device parameters (current intensity, impedance, and waveform), and the targeted physiological function (balance and gaze). In this review, we will examine the development and testing of various prototypes of the vestibular implant (VI). The insight raised by examining the state-of-the-art vestibular prosthesis will facilitate the development of new device-development strategies and discuss the feasibility of complex combinations of implantable devices for disorders that directly affect balance and motor performance.
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Affiliation(s)
- Enrique Soto
- Benemérita Universidad Autónoma de Puebla, Instituto de Fisiología, Puebla, Mexico
| | - Adriana Pliego
- Benemérita Universidad Autónoma de Puebla, Instituto de Fisiología, Puebla, Mexico
- Universidad Autónoma del Estado de México (UAEMéx), Facultad de Medicina, Toluca, Mexico
| | - Rosario Vega
- Benemérita Universidad Autónoma de Puebla, Instituto de Fisiología, Puebla, Mexico
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Chow MR, Fernandez Brillet C, Hageman KN, Roberts DC, Ayiotis AI, Haque RM, Della Santina CC. Binocular 3-D otolith-ocular reflexes: responses of chinchillas to natural and prosthetic stimulation after ototoxic injury and vestibular implantation. J Neurophysiol 2023; 129:1157-1176. [PMID: 37018758 PMCID: PMC10151050 DOI: 10.1152/jn.00445.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 03/29/2023] [Accepted: 03/29/2023] [Indexed: 04/07/2023] Open
Abstract
The otolith end organs inform the brain about gravitational and linear accelerations, driving the otolith-ocular reflex (OOR) to stabilize the eyes during translational motion (e.g., moving forward without rotating) and head tilt with respect to gravity. We previously characterized OOR responses of normal chinchillas to whole body tilt and translation and to prosthetic electrical stimulation targeting the utricle and saccule via electrodes implanted in otherwise normal ears. Here we extend that work to examine OOR responses to tilt and translation stimuli after unilateral intratympanic gentamicin injection and to natural/mechanical and prosthetic/electrical stimulation delivered separately or in combination to animals with bilateral vestibular hypofunction after right ear intratympanic gentamicin injection followed by surgical disruption of the left labyrinth at the time of electrode implantation. Unilateral intratympanic gentamicin injection decreased natural OOR response magnitude to about half of normal, without markedly changing OOR response direction or symmetry. Subsequent surgical disruption of the contralateral labyrinth at the time of electrode implantation surgery further decreased OOR magnitude during natural stimulation, consistent with bimodal-bilateral otolith end organ hypofunction (ototoxic on the right ear, surgical on the left ear). Delivery of pulse frequency- or pulse amplitude-modulated prosthetic/electrical stimulation targeting the left utricle and saccule in phase with whole body tilt and translation motion stimuli yielded responses closer to normal than the deficient OOR responses of those same animals in response to head tilt and translation alone.NEW & NOTEWORTHY Previous studies to expand the scope of prosthetic stimulation of the otolith end organs showed that selective stimulation of the utricle and saccule is possible. This article further defines those possibilities by characterizing a diseased animal model and subsequently studying its responses to electrical stimulation alone and in combination with mechanical motion. We show that we can partially restore responses to tilt and translation in animals with unilateral gentamicin ototoxic injury and contralateral surgical disruption.
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Affiliation(s)
- Margaret R Chow
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Celia Fernandez Brillet
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Kristin N Hageman
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Dale C Roberts
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Andrianna I Ayiotis
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Razi M Haque
- Lawrence Livermore National Laboratory, Livermore, California, United States
| | - Charles C Della Santina
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
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D’Alessandro S, Handler M, Saba R, Garnham C, Baumgarten D. Computer Simulation of the Electrical Stimulation of the Human Vestibular System: Effects of the Reactive Component of Impedance on Voltage Waveform and Nerve Selectivity. J Assoc Res Otolaryngol 2022; 23:815-833. [PMID: 36050508 PMCID: PMC9789245 DOI: 10.1007/s10162-022-00868-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 08/13/2022] [Indexed: 01/06/2023] Open
Abstract
The vestibular system is responsible for our sense of balance and spatial orientation. Recent studies have shown the possibility of partially restoring the function of this system using vestibular implants. Electrical modeling is a valuable tool in assisting the development of these implants by analyzing stimulation effects. However, previous modeling approaches of the vestibular system assumed quasi-static conditions. In this work, an extended modeling approach is presented that considers the reactive component of impedance and the electrode-tissue interface and their effects are investigated in a 3D human vestibular computer model. The Fourier finite element method was employed considering the frequency-dependent electrical properties of the different tissues. The electrode-tissue interface was integrated by an instrumental electrode model. A neuron model of myelinated fibers was employed to predict the nerve responses to the electrical stimulus. Morphological changes of the predicted voltage waveforms considering the dielectric tissue properties were found compared to quasi-static simulations, particularly during monopolar electrode configuration. Introducing the polarization capacitance and the scar tissue around the electrode in combination with a power limitation leads to a considerable current reduction applied through the active electrode and, consequently, to reduced voltage amplitudes of the stimulus waveforms. The reactive component of impedance resulted in better selectivity for the excitation of target nerves compared to the quasi-static simulation at the expense of slightly increased stimulus current amplitudes. We conclude that tissue permittivity and effects of the electrode-tissue interface should be considered to improve the accuracy of the simulations.
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Affiliation(s)
- Simone D’Alessandro
- Institute of Electrical and Biomedical Engineering, UMIT - Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Michael Handler
- Institute of Electrical and Biomedical Engineering, UMIT - Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | | | | | - Daniel Baumgarten
- Institute of Electrical and Biomedical Engineering, UMIT - Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
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Deng J, Zhu Q, Zhang K, Xie D, Wu W. Vestibular function in children with cochlear implant: Impact and evaluation. Front Neurol 2022; 13:938751. [PMID: 36090862 PMCID: PMC9449973 DOI: 10.3389/fneur.2022.938751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 08/04/2022] [Indexed: 11/13/2022] Open
Abstract
Over the last 30 years, cochlear implant (CI) has been dedicated to improving the rehabilitation of hearing impairments. However, CI has shown potential detrimental effects on vestibular function. For children, due to atypical symptoms and difficulty in cooperating with vestibular function tests, systematic and objective assessments of vestibular function with CI have been conducted sparsely. This review focuses on the impact of vestibular function in children with CI and summarized the evaluation of vestibular function in children. In addition, some recommended strategies are summarized and proposed.
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Maudoux A, Vitry S, El-Amraoui A. Vestibular Deficits in Deafness: Clinical Presentation, Animal Modeling, and Treatment Solutions. Front Neurol 2022; 13:816534. [PMID: 35444606 PMCID: PMC9013928 DOI: 10.3389/fneur.2022.816534] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/23/2022] [Indexed: 11/13/2022] Open
Abstract
The inner ear is responsible for both hearing and balance. These functions are dependent on the correct functioning of mechanosensitive hair cells, which convert sound- and motion-induced stimuli into electrical signals conveyed to the brain. During evolution of the inner ear, the major changes occurred in the hearing organ, whereas the structure of the vestibular organs remained constant in all vertebrates over the same period. Vestibular deficits are highly prevalent in humans, due to multiple intersecting causes: genetics, environmental factors, ototoxic drugs, infections and aging. Studies of deafness genes associated with balance deficits and their corresponding animal models have shed light on the development and function of these two sensory systems. Bilateral vestibular deficits often impair individual postural control, gaze stabilization, locomotion and spatial orientation. The resulting dizziness, vertigo, and/or falls (frequent in elderly populations) greatly affect patient quality of life. In the absence of treatment, prosthetic devices, such as vestibular implants, providing information about the direction, amplitude and velocity of body movements, are being developed and have given promising results in animal models and humans. Novel methods and techniques have led to major progress in gene therapies targeting the inner ear (gene supplementation and gene editing), 3D inner ear organoids and reprograming protocols for generating hair cell-like cells. These rapid advances in multiscale approaches covering basic research, clinical diagnostics and therapies are fostering interdisciplinary research to develop personalized treatments for vestibular disorders.
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Affiliation(s)
- Audrey Maudoux
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France
- Center for Balance Evaluation in Children (EFEE), Otolaryngology Department, Assistance Publique des Hôpitaux de Paris, Robert-Debré University Hospital, Paris, France
| | - Sandrine Vitry
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France
| | - Aziz El-Amraoui
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France
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Sosna-Duranowska M, Tacikowska G, Gos E, Krupa A, Skarzynski PH, Skarzynski H. Vestibular Function After Cochlear Implantation in Partial Deafness Treatment. Front Neurol 2021; 12:667055. [PMID: 34093414 PMCID: PMC8175845 DOI: 10.3389/fneur.2021.667055] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/14/2021] [Indexed: 11/18/2022] Open
Abstract
Introduction: Cochlear implantation is a fully accepted method of treating individuals with profound hearing loss. Since the indications for cochlear implantation have broadened and include patients with low-frequency residual hearing, single-sided deafness, or an already implanted ear (meaning bilateral cochlear implantation), the emphasis now needs to be on vestibular protection. Materials and Methods: The research group was made up of 107 patients operated on in the otorhinolaryngosurgery department: 59 females and 48 males, aged 10.4–80.2 years (M = 44.4; SD = 18.4) with hearing loss lasting from 1.4 to 56 years (M = 22.7; SD = 13.5). The patients underwent cVEMP, oVEMP, a caloric test, and vHIT assessment preoperatively, and, postoperatively, cVEMP and oVEMP at 1–3 months and a caloric test and vHIT at 4–6 months. Results: After cochlear implantation, there was postoperative loss of cVEMP in 19.2% of the patients, oVEMP in 17.4%, reduction of caloric response in 11.6%, and postoperative destruction of the lateral, anterior, and posterior semicircular canal as measured with vHIT in 7.1, 3.9, and 4% respectively. Conclusions: Hearing preservation techniques in cochlear implantation are connected with vestibular protection, but the risk of vestibular damage in never totally eliminated. The vestibular preservation is associated with hearing preservation and the relation is statistically significant. Informed consent for cochlear implantation must include information about possible vestibular damage. Since the risk of vestibular damage is appreciable, preoperative otoneurological diagnostics need to be conducted in the following situations: qualification for a second implant, after otosurgery (especially if the opposite ear is to be implanted), having a history of vestibular complaints, and when there are no strict audiological or anatomical indications on which side to operate.
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Affiliation(s)
| | | | - Elzbieta Gos
- Institute of Physiology and Pathology of Hearing, Warsaw, Poland
| | - Anna Krupa
- Institute of Physiology and Pathology of Hearing, Warsaw, Poland
| | - Piotr Henryk Skarzynski
- Institute of Physiology and Pathology of Hearing, Warsaw, Poland.,Medical University of Warsaw, Warsaw, Poland
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Fluctuations in Vestibular Afferent Excitability in Menière's Disease. Otol Neurotol 2020; 41:810-816. [PMID: 32229758 DOI: 10.1097/mao.0000000000002634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine if Menière's disease is associated with fluctuations in afferent excitability in four human subjects previously implanted with vestibular stimulators. STUDY DESIGN Longitudinal repeated measures. SETTING Tertiary referral center, human vestibular research laboratory. PATIENTS Four human subjects with previously uncontrolled Menière's disease unilaterally implanted in each semicircular canal with a vestibular stimulator. One subject had only two canals implanted. INTERVENTION(S) Repeated measures of electrically-evoked slow phase eye velocity and vestibular electrically-evoked compound action potentials (vECAP) over 2 to 4 years. MAIN OUTCOME MEASURE(S) Slow phase eye velocity and N1-P1 vECAP amplitudes as a function of time. RESULTS There were statistically significant fluctuations in electrically evoked slow phase eye velocity over time in at least one semicircular canal of each subject. vECAP N1-P1 amplitudes measured at similar time intervals and stimulus intensities seem to show somewhat correlated fluctuations. One of the subjects had a single Menière's attack during this time period. The others did not. CONCLUSIONS In these four subjects originally diagnosed with Menière's disease, there was fluctuating electrical excitability of the ampullar nerve of at least one canal in each subject. These fluctuations occurred without active symptoms of Menière's disease.
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Kim G, Lee S, Kim KS. Dominant parameter of galvanic vestibular stimulation for the non-associative learning processes. Med Biol Eng Comput 2020; 58:701-708. [PMID: 31953797 DOI: 10.1007/s11517-019-02117-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 12/28/2019] [Indexed: 12/22/2022]
Abstract
Electrical stimulus is one of the common stimulating methods, and Galvanic vestibular stimulation (GVS) is the oldest form as an electrical stimulation. Nevertheless, GVS is still considered as a secondary stimulating tool for the medical purposes. Even though some unarguable findings have made using GVS, its use has been limited because of its ambiguity as an input source. For better understanding, many previous studies mainly focused on its functional effects, like the ocular reflexes. However, its fundamental effects on the neural activities are still elusive, such as the dominant influences by different parameters of GVS. Here we compared the effects on the neuronal responses by applying two different parameters, strength and rate, of GVS. To assess the dominance on the neuronal responses to these parameters, we designed three independent stimuli. Those stimuli were multiply applied to obtain the responding slopes based on the mechanism of non-associative learning processes, and the effects on the neurons were calculated as an inner angle between two responding slopes. Out of 23 neurons, 15 (65.2%) units were affected more by the strength with a statistical significance (p = 0.047). The ranges of the inner angles also implied the strength (- 3.354°~2.063°) mainly modulated by the neuronal responses comparing with those by the rate (- 2.001°~1.975°). The dominance of the parameters was closely related with the neuronal sensitivity to stimulation (SE) (p = 0.018), while there were few relations with the neuronal regularity, directional preference (DP), and the physiological response (PR) (p > 0.059). Thus, the neural information related with the dominance was delivered by the irregular neurons, and these types of neurons should be the targets for the stimulation. Graphical abstract.
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Affiliation(s)
- Gyutae Kim
- Research Institute for Aerospace Medicine, Inha University, High-Tech center #303, 100 Inharo, Namgu, InCheon, 402-751, South Korea.
- Institute for Information and Electronics Research, Inha University, High-Tech center #716, 100 Inharo, Namgu, InCheon, 402-751, South Korea.
| | - Sangmin Lee
- Institute for Information and Electronics Research, Inha University, High-Tech center #716, 100 Inharo, Namgu, InCheon, 402-751, South Korea
- Department of Electronic Engineering, Inha University, High-Tech center #704, 100 Inharo, Namgu, InCheon, 402-751, South Korea
| | - Kyu-Sung Kim
- Research Institute for Aerospace Medicine, Inha University, High-Tech center #303, 100 Inharo, Namgu, InCheon, 402-751, South Korea
- Department of Otolaryngology Head & Neck Surg., Inha University Hospital, 27 Inhang-ro, Jung-Gu, Incheon, 400-711, South Korea
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van de Berg R, Ramos A, van Rompaey V, Bisdorff A, Perez-Fornos A, Rubinstein JT, Phillips JO, Strupp M, Della Santina CC, Guinand N. The vestibular implant: Opinion statement on implantation criteria for research. J Vestib Res 2020; 30:213-223. [PMID: 32651339 PMCID: PMC9249290 DOI: 10.3233/ves-200701] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 05/20/2020] [Indexed: 12/26/2022]
Abstract
This opinion statement proposes a set of candidacy criteria for vestibular implantation of adult patients with bilateral vestibulopathy (BVP) in a research setting. The criteria include disabling chronic symptoms like postural imbalance, unsteadiness of gait and/or head movement-induced oscillopsia, combined with objective signs of reduced or absent vestibular function in both ears. These signs include abnormal test results recorded during head impulses (video head impulse test or scleral coil technique), bithermal caloric testing and rotatory chair testing (sinusoidal stimulation of 0.1 Hz). Vestibular implant (VI) implantation criteria are not the same as diagnostic criteria for bilateral vestibulopathy. The major difference between VI-implantation criteria and the approved diagnostic criteria for BVP are that all included vestibular tests of semicircular canal function (head impulse test, caloric test, and rotatory chair test) need to show significant impairments of vestibular function in the implantation criteria. For this, a two-step paradigm was developed. First, at least one of the vestibular tests needs to fulfill stringent criteria, close to those for BVP. If this is applicable, then the other vestibular tests have to fulfill a second set of criteria which are less stringent than the original criteria for BVP. If the VI-implantation is intended to excite the utricle and/or saccule (otolith stimulation), responses to cervical and ocular vestibular evoked myogenic potentials must be absent in addition to the above mentioned abnormalities of semicircular canal function. Finally, requirements for safe and potentially effective stimulation should be met, including implanting patients with BVP of peripheral origin only, and assessing possible medical and psychiatric contraindications.
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Affiliation(s)
- Raymond van de Berg
- Department of Otorhinolaryngology and Head & Neck Surgery, Maastricht University Medical Center+, Maastricht, The Netherlands
- Faculty of Physics, Tomsk State University, Tomsk, Russian Federation
| | - Angel Ramos
- Department of Otolaryngology Head Neck Surgery. Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria. Department of Otolaryngology. Las Palmas University. (ULPGC). Psychoacoustic & Equilibrium Laboratory. Las Palmas University (ULPGC)
| | - Vincent van Rompaey
- Department of Otorhinolaryngology and Head & Neck Surgery, Antwerp University Hospital, Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium
| | - Alexandre Bisdorff
- Clinique du Vertige, Centre Hospitalier Emile Mayrisch, Esch-sur-Alzette, Luxembourg
| | - Angelica Perez-Fornos
- Division of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Jay T. Rubinstein
- Otolaryngology-HNS, Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA, USA
| | - James O. Phillips
- Otolaryngology-HNS, Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA, USA
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Ludwig Maximilians University, Munich, Germany
| | - Charles C. Della Santina
- Departments of Otolaryngology – Head & Neck Surgery and Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Nils Guinand
- Division of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
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Abstract
Monkeys are a premier model organism for neuroscience research. Activity in the central nervous systems of monkeys can be recorded and manipulated while they perform complex perceptual, motor, or cognitive tasks. Conventional techniques for manipulating neural activity in monkeys are too coarse to address many of the outstanding questions in primate neuroscience, but optogenetics holds the promise to overcome this hurdle. In this article, we review the progress that has been made in primate optogenetics over the past 5 years. We emphasize the use of gene regulatory sequences in viral vectors to target specific neuronal types, and we present data on vectors that we engineered to target parvalbumin-expressing neurons. We conclude with a discussion of the utility of optogenetics for treating sensorimotor hearing loss and Parkinson's disease, areas of translational neuroscience in which monkeys provide unique leverage for basic science and medicine.
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Ramos Macias A, Ramos de Miguel A, Rodriguez Montesdeoca I, Borkoski Barreiro S, Falcón González JC. Chronic Electrical Stimulation of the Otolith Organ: Preliminary Results in Humans with Bilateral Vestibulopathy and Sensorineural Hearing Loss. Audiol Neurootol 2019; 25:79-90. [PMID: 31801137 DOI: 10.1159/000503600] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 09/16/2019] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Bilateral vestibulopathy is an important cause of imbalance that is misdiagnosed. The clinical management of patients with bilateral vestibular loss remains difficult as there is no clear evidence for an effective treatment. In this paper, we try to analyze the effect of chronic electrical stimulation and adaptation to electrical stimulation of the vestibular system in humans when stimulating the otolith organ with a constant pulse train to mitigate imbalance due to bilateral vestibular dysfunction (BVD). METHODS We included 2 patients in our study with BVD according to Criteria Consensus of the Classification Committee of the Bárány Society. Both cases were implanted by using a full-band straight electrode to stimulate the otoliths organs and simultaneously for the cochlear stimulation we use a perimodiolar electrode. RESULTS In both cases Vestibular and clinical test (video head impulse test, videonistagmography cervical vestibular evoked myogenic potentials, cVEMP and oVEMP), subjective visual vertical test, computerized dynamic posturography, dynamic gait index, Time UP and Go test and dizziness handicap index) were performed. Posture and gait metrics reveal important improvement if compare with preoperartive situation. Oscillopsia, unsteadiness, independence and quality of life improved to almost normal situation. DISCUSSION/CONCLUSION Prosthetic implantation of the otolith organ in humans is technically feasible. Electrical stimulation might have potential effects on balance and this is stable after 1 year follow-up. This research provides new possibilities for the development of vestibular implants to improve gravito-inertial acceleration sensation, in this case by the otoliths stimulation.
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Affiliation(s)
- Angel Ramos Macias
- Department of Otolaryngology, Faculty of Medicine, University of Las Palmas de Gran Canaria, Las Palmas, Spain,
| | - Angel Ramos de Miguel
- Hearing and Balance Laboratory, University of Las Palmas de Gran Canaria, Las Palmas, Spain
| | - Isaura Rodriguez Montesdeoca
- Department of Otolaryngology, and Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, Las Palmas, Spain
| | - Silvia Borkoski Barreiro
- Department of Otolaryngology, and Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, Las Palmas, Spain
| | - Juan Carlos Falcón González
- Department of Otolaryngology, and Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, Las Palmas, Spain
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15
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Stultiens JJA, Postma AA, Guinand N, Pérez Fornos A, Kingma H, van de Berg R. Vestibular Implantation and the Feasibility of Fluoroscopy-Guided Electrode Insertion. Otolaryngol Clin North Am 2019; 53:115-126. [PMID: 31677739 DOI: 10.1016/j.otc.2019.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recent research has shown promising results for the development of a clinically feasible vestibular implant in the near future. However, correct electrode placement remains a challenge. It was shown that fluoroscopy was able to visualize the semicircular canal ampullae and electrodes, and guide electrode insertion in real time. Ninety-four percent of the 18 electrodes were implanted correctly (<1.5 mm distance to target). The median distances were 0.60 mm, 0.85 mm, and 0.65 mm for the superior, lateral, and posterior semicircular canal, respectively. These findings suggest that fluoroscopy can significantly improve electrode placement during vestibular implantation.
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Affiliation(s)
- Joost Johannes Antonius Stultiens
- Department of Otorhinolaryngology-Head and Neck Surgery, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, P.O. box 5800, 6202 AZ, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Alida Annechien Postma
- Department of Radiology and Nuclear Medicine, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, P.O. box 5800, 6202 AZ, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Nils Guinand
- Division of Otorhinolaryngology-Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Rue Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland
| | - Angélica Pérez Fornos
- Division of Otorhinolaryngology-Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Rue Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland
| | - Hermanus Kingma
- Department of Otorhinolaryngology-Head and Neck Surgery, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, P.O. box 5800, 6202 AZ, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Raymond van de Berg
- Department of Otorhinolaryngology-Head and Neck Surgery, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, P.O. box 5800, 6202 AZ, Maastricht University Medical Center, Maastricht, The Netherlands.
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16
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Vestibular implant: does it really work? A systematic review. Braz J Otorhinolaryngol 2019; 85:788-798. [PMID: 31606334 PMCID: PMC9443005 DOI: 10.1016/j.bjorl.2019.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 07/11/2019] [Accepted: 07/29/2019] [Indexed: 11/25/2022] Open
Abstract
Introduction People with vestibular loss present a deficit in the vestibular system, which is primarily responsible for promoting postural control, gaze stabilization, and spatial orientation while the head moves. There is no effective treatment for a bilateral loss of vestibular function. Recently, a vestibular implant was developed for people with bilateral loss of vestibular function to improve this function and, consequently, the quality of life of these patients. Objective To identify in the scientific literature evidence that vestibular implants in people with vestibular deficit improves vestibular function. Methods One hundred and forty six articles were found from five databases and 323 articles from the gray literature mentioning the relationship between vestibular implant and vestibular function in humans. The PICOS strategy (Population, Intervention, Comparison and Outcome) was used to define the eligibility criteria. The studies that met the inclusion criteria for this second step were included in a qualitative synthesis, and each type of study was analyzed according to the bias risk assessment of the Joanna Briggs Institute through the critical assessment checklist Joanna Briggs institute for quasi-experimental studies and the Joanna Briggs institute critical assessment checklist for case reports. Results Of the 21 articles included in reading the full text, 10 studies were selected for the qualitative analysis in the present systematic review. All ten articles analyzed through the critical assessment checklist Joanna Briggs institute showed a low risk of bias. The total number of samples in the evaluated articles was 18 patients with vestibular implants. Conclusions Taken together, these findings support the feasibility of vestibular implant for restoration of the vestibulo-ocular reflex in a broad frequency range and illustrate new challenges for the development of this technology.
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17
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Sluydts M, Curthoys I, Vanspauwen R, Papsin BC, Cushing SL, Ramos A, Ramos de Miguel A, Borkoski Barreiro S, Barbara M, Manrique M, Zarowski A. Electrical Vestibular Stimulation in Humans: A Narrative Review. Audiol Neurootol 2019; 25:6-24. [PMID: 31533097 DOI: 10.1159/000502407] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/29/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND In patients with bilateral vestibulopathy, the regular treatment options, such as medication, surgery, and/or vestibular rehabilitation, do not always suffice. Therefore, the focus in this field of vestibular research shifted to electrical vestibular stimulation (EVS) and the development of a system capable of artificially restoring the vestibular function. Key Message: Currently, three approaches are being investigated: vestibular co-stimulation with a cochlear implant (CI), EVS with a vestibular implant (VI), and galvanic vestibular stimulation (GVS). All three applications show promising results but due to conceptual differences and the experimental state, a consensus on which application is the most ideal for which type of patient is still missing. SUMMARY Vestibular co-stimulation with a CI is based on "spread of excitation," which is a phenomenon that occurs when the currents from the CI spread to the surrounding structures and stimulate them. It has been shown that CI activation can indeed result in stimulation of the vestibular structures. Therefore, the question was raised whether vestibular co-stimulation can be functionally used in patients with bilateral vestibulopathy. A more direct vestibular stimulation method can be accomplished by implantation and activation of a VI. The concept of the VI is based on the technology and principles of the CI. Different VI prototypes are currently being evaluated regarding feasibility and functionality. So far, all of them were capable of activating different types of vestibular reflexes. A third stimulation method is GVS, which requires the use of surface electrodes instead of an implanted electrode array. However, as the currents are sent through the skull from one mastoid to the other, GVS is rather unspecific. It should be mentioned though, that the reported spread of excitation in both CI and VI use also seems to induce a more unspecific stimulation. Although all three applications of EVS were shown to be effective, it has yet to be defined which option is more desirable based on applicability and efficiency. It is possible and even likely that there is a place for all three approaches, given the diversity of the patient population who serves to gain from such technologies.
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Affiliation(s)
- Morgana Sluydts
- European Institute for Otorhinolaryngology, GZA Hospitals Antwerp, Wilrijk, Belgium,
| | - Ian Curthoys
- Vestibular Research Laboratory, University of Sydney, Sydney, New South Wales, Australia
| | - Robby Vanspauwen
- European Institute for Otorhinolaryngology, GZA Hospitals Antwerp, Wilrijk, Belgium
| | - Blake Croll Papsin
- Department of Otolaryngology - Head and Neck Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sharon Lynn Cushing
- Department of Otolaryngology - Head and Neck Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Angel Ramos
- Hearing Loss Unit, Otorhinolaryngology, Head and Neck Department, Complejo Hospitalario Universitario Insular Materno Infantil, Las Palmas of Gran Canaria, Spain
| | - Angel Ramos de Miguel
- Hearing Loss Unit, Otorhinolaryngology, Head and Neck Department, Complejo Hospitalario Universitario Insular Materno Infantil, Las Palmas of Gran Canaria, Spain
| | - Silvia Borkoski Barreiro
- Hearing Loss Unit, Otorhinolaryngology, Head and Neck Department, Complejo Hospitalario Universitario Insular Materno Infantil, Las Palmas of Gran Canaria, Spain
| | | | - Manuel Manrique
- Otorhinolaryngology Department, Clinica Universidad de Navarra, Pamplona, Spain
| | - Andrzej Zarowski
- European Institute for Otorhinolaryngology, GZA Hospitals Antwerp, Wilrijk, Belgium
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18
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Abstract
Purpose of review Bilateral vestibular deficits exist and their prevalence is more important than believed by the medical community. Their severe impact has inspired several teams to develop technical solutions in an attempt to rehabilitate patients. A particularly promising pathway is the vestibular implant. This article describes the main milestones in this field, mainly focusing on work conducted in human patients. Recent findings There have been substantial research efforts, first in animals and more recently in humans, toward the development of vestibular implants. Humans have demonstrated surprising adaptation capabilities to the artificial vestibular signal. Today, the possibility of restoring vestibular reflexes, particularly the vestibulo-ocular reflex, and even achieving useful function in close-to-reality tasks (i.e. improving visual abilities while walking) have been demonstrated in humans. Summary The vestibular implant opens new perspectives, not only as an effective therapeutic tool, but also pushes us to go beyond current knowledge and well-established clinical concepts.
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19
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Abstract
The advances in technology leading to rapid developments in implantable auditory devices are constantly evolving. Devices are becoming smaller, less visible, and more efficient. The ability to preserve hearing outcomes with cochlear implantation will continue to evolve as surgical techniques improve with the use of continuous feedback during the procedure as well as with intraoperative delivery of drugs and robot assistance. As engineering methods improve, there may one day be a totally implantable aid that is self-sustaining in hearing-impaired patients making them indistinguishable from patients without hearing loss.
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Affiliation(s)
- Robert M Rhodes
- The Department of Otolaryngology Head and Neck Surgery, The University of Oklahoma Health Sciences Center, 800 Stanton L Young Boulevard, Suite 1400, Oklahoma City, OK 73104, USA
| | - Betty S Tsai Do
- The Department of Otolaryngology Head and Neck Surgery, The University of Oklahoma Health Sciences Center, 800 Stanton L Young Boulevard, Suite 1400, Oklahoma City, OK 73104, USA.
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20
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Schier P, Handler M, Johnson Chacko L, Schrott-Fischer A, Fritscher K, Saba R, Baumgartner C, Baumgarten D. Model-Based Vestibular Afferent Stimulation: Evaluating Selective Electrode Locations and Stimulation Waveform Shapes. Front Neurosci 2018; 12:588. [PMID: 30214391 PMCID: PMC6125370 DOI: 10.3389/fnins.2018.00588] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 08/06/2018] [Indexed: 12/02/2022] Open
Abstract
A dysfunctional vestibular system can be a severe detriment to the quality of life of a patient. Recent studies have shown the feasibility for a vestibular implant to restore rotational sensation via electrical stimulation of vestibular ampullary nerves. However, the optimal stimulation site for selective elicitation of the desired nerve is still unknown. We realized a finite element model on the basis of μCT scans of a human inner ear and incorporated naturally distributed, artificial neural trajectories. A well-validated neuron model of myelinated fibers was incorporated to predict nerve responses to electrical stimulation. Several virtual electrodes were placed in locations of interest inside the bony labyrinth (intra-labyrinthine) and inside the temporal bone, near the target nerves (extra-labyrinthine), to determine preferred stimulation sites and electrode insertion depths. We investigated various monopolar and bipolar electrode configurations as well as different pulse waveform shapes for their ability to selectively stimulate the target nerve and for their energy consumption. The selectivity was evaluated with an objective measure of the fiber recruitment. Considerable differences of required energy and achievable selectivity between the configurations were observed. Bipolar, intra-labyrinthine electrodes provided the best selectivities but also consumed the highest amount of energy. Bipolar, extra-labyrinthine configurations did not offer any advantages compared to the monopolar approach. No selective stimulation could be performed with the monopolar, intra-labyrinthine approach. The monopolar, extra-labyrinthine electrodes required the least energy for satisfactory selectivities, making it the most promising approach for functional vestibular implants. Different pulse waveform shapes did not affect the achieved selectivity considerably but shorter pulse durations showed consistently a more selective activation of the target nerves. A cathodic, centered triangular waveform shape was identified as the most energy-efficient of the tested shapes. Based on these simulations we are able to recommend the monopolar, extra-labyrinthine stimulation approach with cathodic, centered triangular pulses as good trade-off between selectivity and energy consumption. Future implant designs could benefit from the findings presented here.
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Affiliation(s)
- Peter Schier
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, UMIT-Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Michael Handler
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, UMIT-Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Lejo Johnson Chacko
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Karl Fritscher
- Department for Biomedical Computer Science and Mechatronics, Institute of Biomedical Image Analysis, UMIT-Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | | | - Christian Baumgartner
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, UMIT-Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria.,Faculty of Computer Science and Biomedical Engineering, Institute of Health Care Engineering, Graz University of Technology, Graz, Austria
| | - Daniel Baumgarten
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, UMIT-Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria.,Department of Computer Science and Automation, Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
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21
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Phillips JO, Ling L, Nowack AL, Phillips CM, Nie K, Rubinstein JT. The Dynamics of Prosthetically Elicited Vestibulo-Ocular Reflex Function Across Frequency and Context in the Rhesus Monkey. Front Neurosci 2018; 12:88. [PMID: 29867306 PMCID: PMC5962652 DOI: 10.3389/fnins.2018.00088] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 02/02/2018] [Indexed: 12/25/2022] Open
Abstract
Electrical vestibular neurostimulation may be a viable tool for modulating vestibular afferent input to restore vestibular function following injury or disease. To do this, such stimulators must provide afferent input that can be readily interpreted by the central nervous system to accurately represent head motion to drive reflexive behavior. Since vestibular afferents have different galvanic sensitivity, and different natural sensitivities to head rotational velocity and acceleration, and electrical stimulation produces aphysiological synchronous activation of multiple afferents, it is difficult to assign a priori an appropriate transformation between head velocity and acceleration and the properties of the electrical stimulus used to drive vestibular reflex function, i.e., biphasic pulse rate or pulse current amplitude. In order to empirically explore the nature of the transformation between vestibular prosthetic stimulation and vestibular reflex behavior, in Rhesus macaque monkeys we parametrically varied the pulse rate and current amplitude of constant rate and current amplitude pulse trains, and the modulation frequency of sinusoidally modulated pulse trains that were pulse frequency modulated (FM) or current amplitude modulated (AM). In addition, we examined the effects of differential eye position and head position on the observed eye movement responses. We conclude that there is a strong and idiosyncratic, from canal to canal, effect of modulation frequency on the observed eye velocities that are elicited by stimulation. In addition, there is a strong effect of initial eye position and initial head position on the observed responses. These are superimposed on the relationships between pulse frequency or current amplitude and eye velocity that have been shown previously.
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Affiliation(s)
- James O Phillips
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States.,Virginia Merril Bloedel Hearing Research Center, University of Washington, Seattle, WA, United States
| | - Leo Ling
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States
| | - Amy L Nowack
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States
| | - Christopher M Phillips
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States.,Epidemiology, University of Washington, Seattle, WA, United States
| | - Kaibao Nie
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Virginia Merril Bloedel Hearing Research Center, University of Washington, Seattle, WA, United States.,Bioengineering, University of Washington, Seattle, WA, United States
| | - Jay T Rubinstein
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States.,Virginia Merril Bloedel Hearing Research Center, University of Washington, Seattle, WA, United States.,Bioengineering, University of Washington, Seattle, WA, United States
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22
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Crane BT, Schubert MC. An adaptive vestibular rehabilitation technique. Laryngoscope 2018; 128:713-718. [PMID: 28543062 PMCID: PMC5700867 DOI: 10.1002/lary.26661] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/05/2017] [Accepted: 04/11/2017] [Indexed: 12/22/2022]
Abstract
OBJECTIVES/HYPOTHESIS There is a large variation in vestibular rehabilitation (VR) results depending on type of therapy, adherence, and the appropriateness for the patient's level of function. A novel adaptive vestibular rehabilitation (AVR) program was developed and evaluated. STUDY DESIGN Technology and procedure development, and prospective multicenter trial. METHODS Those with complete unilateral vestibular hypofunction and symptomatic at least 3 months with a Dizziness Handicap Inventory (DHI) >30 were eligible. Patients were given a device to use with their own computer. They were instructed to use the program daily, with each session lasting about 10 minutes. The task consisted of reporting orientation of the letter C, which appeared when their angular head velocity exceeded a threshold. The letter size and head velocity required were adjusted based on prior performance. Performance on the task was remotely collected by the investigator as well as a weekly DHI score. RESULTS Four patients aged 31 to 74 years (mean = 51 years) were enrolled in this feasibility study to demonstrate efficacy. Two had treated vestibular schwannomas and two had vestibular neuritis. Starting DHI was 32 to 56 (mean = 42), which was reduced to 0 to 16 (mean = 11.5) after a month of therapy, a clinically and statistically significant (P < .05) improvement. The three who continued therapy an additional month improved to a DHI of 4. CONCLUSIONS This AVR method has advantages over traditional VR in terms of cost and customization for patient ability and obtained a major improvement in symptoms. This study demonstrated a clinically and statistically significant decrease in symptoms after 4 weeks of therapy. LEVEL OF EVIDENCE 2b. Laryngoscope, 128:713-718, 2018.
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Affiliation(s)
- Benjamin T. Crane
- Department of Otolaryngology, University of Rochester
- Department of Neuroscience, University of Rochester
- Department of Bioengineering, University of Rochester
| | - Michael C. Schubert
- Department of Otolaryngology, Johns Hopkins University
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University
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23
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Johnson Chacko L, Schmidbauer DT, Handschuh S, Reka A, Fritscher KD, Raudaschl P, Saba R, Handler M, Schier PP, Baumgarten D, Fischer N, Pechriggl EJ, Brenner E, Hoermann R, Glueckert R, Schrott-Fischer A. Analysis of Vestibular Labyrinthine Geometry and Variation in the Human Temporal Bone. Front Neurosci 2018. [PMID: 29535601 PMCID: PMC5834493 DOI: 10.3389/fnins.2018.00107] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Stable posture and body movement in humans is dictated by the precise functioning of the ampulla organs in the semi-circular canals. Statistical analysis of the interrelationship between bony and membranous compartments within the semi-circular canals is dependent on the visualization of soft tissue structures. Thirty-one human inner ears were prepared, post-fixed with osmium tetroxide and decalcified for soft tissue contrast enhancement. High resolution X-ray microtomography images at 15 μm voxel-size were manually segmented. This data served as templates for centerline generation and cross-sectional area extraction. Our estimates demonstrate the variability of individual specimens from averaged centerlines of both bony and membranous labyrinth. Centerline lengths and cross-sectional areas along these lines were identified from segmented data. Using centerlines weighted by the inverse squares of the cross-sectional areas, plane angles could be quantified. The fit planes indicate that the bony labyrinth resembles a Cartesian coordinate system more closely than the membranous labyrinth. A widening in the membranous labyrinth of the lateral semi-circular canal was observed in some of the specimens. Likewise, the cross-sectional areas in the perilymphatic spaces of the lateral canal differed from the other canals. For the first time we could precisely describe the geometry of the human membranous labyrinth based on a large sample size. Awareness of the variations in the canal geometry of the membranous and bony labyrinth would be a helpful reference in designing electrodes for future vestibular prosthesis and simulating fluid dynamics more precisely.
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Affiliation(s)
- Lejo Johnson Chacko
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Dominik T Schmidbauer
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria.,Department of Biotechnology & Food Engineering, Management Center Innsbruck, Innsbruck, Austria
| | - Stephan Handschuh
- VetImaging, VetCore Facility for Research, University of Veterinary Medicine, Vienna, Austria
| | - Alen Reka
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Karl D Fritscher
- Institute of Biomedical Image Analysis, UMIT, Hall in Tirol, Austria
| | - Patrik Raudaschl
- Institute of Biomedical Image Analysis, UMIT, Hall in Tirol, Austria
| | | | - Michael Handler
- Institute of Electrical and Biomedical Engineering, UMIT, Hall in Tirol, Austria
| | - Peter P Schier
- Institute of Electrical and Biomedical Engineering, UMIT, Hall in Tirol, Austria
| | - Daniel Baumgarten
- Institute of Electrical and Biomedical Engineering, UMIT, Hall in Tirol, Austria.,Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Natalie Fischer
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Elisabeth J Pechriggl
- Division of Clinical and Functional Anatomy, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | - Erich Brenner
- Division of Clinical and Functional Anatomy, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | - Romed Hoermann
- Division of Clinical and Functional Anatomy, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | - Rudolf Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria.,University Clinics Innsbruck, Tirol Kliniken, Innsbruck, Austria
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24
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Handler M, Schier PP, Fritscher KD, Raudaschl P, Johnson Chacko L, Glueckert R, Saba R, Schubert R, Baumgarten D, Baumgartner C. Model-based Vestibular Afferent Stimulation: Modular Workflow for Analyzing Stimulation Scenarios in Patient Specific and Statistical Vestibular Anatomy. Front Neurosci 2017; 11:713. [PMID: 29311790 PMCID: PMC5742128 DOI: 10.3389/fnins.2017.00713] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 12/05/2017] [Indexed: 12/12/2022] Open
Abstract
Our sense of balance and spatial orientation strongly depends on the correct functionality of our vestibular system. Vestibular dysfunction can lead to blurred vision and impaired balance and spatial orientation, causing a significant decrease in quality of life. Recent studies have shown that vestibular implants offer a possible treatment for patients with vestibular dysfunction. The close proximity of the vestibular nerve bundles, the facial nerve and the cochlear nerve poses a major challenge to targeted stimulation of the vestibular system. Modeling the electrical stimulation of the vestibular system allows for an efficient analysis of stimulation scenarios previous to time and cost intensive in vivo experiments. Current models are based on animal data or CAD models of human anatomy. In this work, a (semi-)automatic modular workflow is presented for the stepwise transformation of segmented vestibular anatomy data of human vestibular specimens to an electrical model and subsequently analyzed. The steps of this workflow include (i) the transformation of labeled datasets to a tetrahedra mesh, (ii) nerve fiber anisotropy and fiber computation as a basis for neuron models, (iii) inclusion of arbitrary electrode designs, (iv) simulation of quasistationary potential distributions, and (v) analysis of stimulus waveforms on the stimulation outcome. Results obtained by the workflow based on human datasets and the average shape of a statistical model revealed a high qualitative agreement and a quantitatively comparable range compared to data from literature, respectively. Based on our workflow, a detailed analysis of intra- and extra-labyrinthine electrode configurations with various stimulation waveforms and electrode designs can be performed on patient specific anatomy, making this framework a valuable tool for current optimization questions concerning vestibular implants in humans.
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Affiliation(s)
- Michael Handler
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Peter P Schier
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Karl D Fritscher
- Department for Biomedical Computer Science and Mechatronics, Institute of Biomedical Image Analysis, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Patrik Raudaschl
- Department for Biomedical Computer Science and Mechatronics, Institute of Biomedical Image Analysis, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Lejo Johnson Chacko
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Rudolf Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria.,Department of Otolaryngology Tirol Kliniken, University Clinics Innsbruck, Innsbruck, Austria
| | | | - Rainer Schubert
- Department for Biomedical Computer Science and Mechatronics, Institute of Biomedical Image Analysis, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Daniel Baumgarten
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria.,Department of Computer Science and Automation, Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Christian Baumgartner
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria.,Faculty of Computer Science and Biomedical Engineering, Institute of Health Care Engineering, Graz University of Technology, Graz, Austria
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25
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Volkenstein S, Dazert S. Recent surgical options for vestibular vertigo. GMS CURRENT TOPICS IN OTORHINOLARYNGOLOGY, HEAD AND NECK SURGERY 2017; 16:Doc01. [PMID: 29279721 PMCID: PMC5738932 DOI: 10.3205/cto000140] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vertigo is not a well-defined disease but a symptom that can occur in heterogeneous entities diagnosed and treated mainly by otolaryngologists, neurologists, internal medicine, and primary care physicians. Most vertigo syndromes have a good prognosis and management is predominantly conservative, whereas the need for surgical therapy is rare, but for a subset of patients often the only remaining option. In this paper, we describe and discuss different surgical therapy options for hydropic inner ear diseases, Menière's disease, dehiscence syndromes, perilymph fistulas, and benign paroxysmal positional vertigo. At the end, we shortly introduce the most recent developments in regard to vestibular implants. Surgical therapy is still indicated for vestibular disease in selected patients nowadays when conservative options did not reduce symptoms and patients are still suffering. Success depends on the correct diagnosis and choosing among different procedures the ones going along with an adequate patient selection. With regard to the invasiveness and the possible risks due to surgery, in depth individual counseling is absolutely necessary. Ablative and destructive surgical procedures usually achieve a successful vertigo control, but are associated with a high risk for hearing loss. Therefore, residual hearing has to be included in the decision making process for surgical therapy.
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Affiliation(s)
- Stefan Volkenstein
- Department of Otolaryngology, Head & Neck Surgery, Ruhr-University of Bochum at the St. Elisabeth Hospital of Bochum, Germany
| | - Stefan Dazert
- Department of Otolaryngology, Head & Neck Surgery, Ruhr-University of Bochum at the St. Elisabeth Hospital of Bochum, Germany
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26
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van de Berg R, Guinand N, Ranieri M, Cavuscens S, Khoa Nguyen TA, Guyot JP, Lucieer F, Starkov D, Kingma H, van Hoof M, Perez-Fornos A. The Vestibular Implant Input Interacts with Residual Natural Function. Front Neurol 2017; 8:644. [PMID: 29312107 PMCID: PMC5735071 DOI: 10.3389/fneur.2017.00644] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/16/2017] [Indexed: 12/12/2022] Open
Abstract
Objective Patients with bilateral vestibulopathy (BV) can still have residual “natural” function. This might interact with “artificial” vestibular implant input (VI-input). When fluctuating, it could lead to vertigo attacks. Main objective was to investigate how “artificial” VI-input is integrated with residual “natural” input by the central vestibular system. This, to explore (1) whether misalignment in the response of “artificial” VI-input is sufficiently counteracted by well-aligned residual “natural” input and (2) whether “artificial” VI-input is able to influence and counteract the response to residual “natural” input, to show feasibility of a “vestibular pacemaker.” Materials and methods Five vestibular electrodes in four BV patients implanted with a VI were available. This involved electrodes with a predominantly horizontal response and electrodes with a predominantly vertical response. Responses to predominantly horizontal residual “natural” input and predominantly horizontal and vertical “artificial” VI-input were separately measured first. Then, inputs were combined in conditions where both would hypothetically collaborate or counteract. In each condition, subjects were subjected to 60 cycles of sinusoidal stimulation presented at 1 Hz. Gain, asymmetry, phase and angle of eye responses were calculated. Signal averaging was performed. Results Combining residual “natural” input and “artificial” VI-input resulted in an interaction in which characteristics of the resulting eye movement responses could significantly differ from those observed when responses were measured for each input separately (p < 0.0013). In the total eye response, inputs with a stronger vector magnitude seemed to have stronger weights than inputs with a lower vector magnitude, in a non-linear combination. Misalignment in the response of “artificial” VI-input was not sufficiently counteracted by well-aligned residual “natural” input. “Artificial” VI-input was able to significantly influence and counteract the response to residual “natural” input. Conclusion In the acute phase of VI-activation, residual “natural” input and “artificial” VI-input interact to generate eye movement responses in a non-linear fashion. This implies that different stimulation paradigms and more complex signal processing strategies will be required unless the brain is able to optimally combine both sources of information after adaptation during chronic use. Next to this, these findings could pave the way for using the VI as “vestibular pacemaker.”
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Affiliation(s)
- Raymond van de Berg
- Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, Department of Otorhinolaryngology and Head and Neck Surgery, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Nils Guinand
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Maurizio Ranieri
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Samuel Cavuscens
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - T A Khoa Nguyen
- Translational Neural Engineering Lab, Center for Neuroprosthetics, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jean-Philippe Guyot
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Florence Lucieer
- Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, Department of Otorhinolaryngology and Head and Neck Surgery, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, Netherlands
| | | | - Herman Kingma
- Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, Department of Otorhinolaryngology and Head and Neck Surgery, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Marc van Hoof
- Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, Department of Otorhinolaryngology and Head and Neck Surgery, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Angelica Perez-Fornos
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
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27
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Interfacing with the nervous system: a review of current bioelectric technologies. Neurosurg Rev 2017; 42:227-241. [PMID: 29063229 DOI: 10.1007/s10143-017-0920-2] [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] [Received: 07/13/2017] [Revised: 09/15/2017] [Accepted: 10/09/2017] [Indexed: 02/07/2023]
Abstract
The aim of this study is to discuss the state of the art with regard to established or promising bioelectric therapies meant to alter or control neurologic function. We present recent reports on bioelectric technologies that interface with the nervous system at three potential sites-(1) the end organ, (2) the peripheral nervous system, and (3) the central nervous system-while exploring practical and clinical considerations. A literature search was executed on PubMed, IEEE, and Web of Science databases. A review of the current literature was conducted to examine functional and histomorphological effects of neuroprosthetic interfaces with a focus on end-organ, peripheral, and central nervous system interfaces. Innovations in bioelectric technologies are providing increasing selectivity in stimulating distinct nerve fiber populations in order to activate discrete muscles. Significant advances in electrode array design focus on increasing selectivity, stability, and functionality of implantable neuroprosthetics. The application of neuroprosthetics to paretic nerves or even directly stimulating or recording from the central nervous system holds great potential in advancing the field of nerve and tissue bioelectric engineering and contributing to clinical care. Although current physiotherapeutic and surgical treatments seek to restore function, structure, or comfort, they bear significant limitations in enabling cosmetic or functional recovery. Instead, the introduction of bioelectric technology may play a role in the restoration of function in patients with neurologic deficits.
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28
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van de Berg R, Lucieer F, Guinand N, van Tongeren J, George E, Guyot JP, Kingma H, van Hoof M, Temel Y, van Overbeeke J, Perez-Fornos A, Stokroos R. The Vestibular Implant: Hearing Preservation during Intralabyrinthine Electrode Insertion-A Case Report. Front Neurol 2017; 8:137. [PMID: 28443060 PMCID: PMC5385458 DOI: 10.3389/fneur.2017.00137] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/24/2017] [Indexed: 11/30/2022] Open
Abstract
Objective The vestibular implant seems feasible as a clinically useful device in the near future. However, hearing preservation during intralabyrinthine implantation remains a challenge. It should be preserved to be able to treat patients with bilateral vestibulopathy and (partially) intact hearing. This case study investigated the feasibility of hearing preservation during the acute phase after electrode insertion in the semicircular canals. Methods A 40-year-old woman with normal hearing underwent a translabyrinthine approach for a vestibular schwannoma Koos Grade IV. Hearing was monitored using auditory brainstem response audiometry (ABR). ABR signals were recorded synchronously to video recordings of the surgery. Following the principles of soft surgery, a conventional dummy electrode was inserted in the lateral semicircular canal for several minutes and subsequently removed. The same procedure was then applied for the posterior canal. Finally, the labyrinthectomy was completed, and the schwannoma was removed. Results Surgery was performed without complications. No leakage of endolymph and no significant reduction of ABR response were observed during insertion and after removal of the electrodes from the semicircular canals, indicting no damage to the peripheral auditory function. The ABR response significantly changed when the semicircular canals were completely opened during the labyrinthectomy. This was indicated by a change in the morphology and latency of peak V of the ABR signal. Conclusion Electrode insertion in the semicircular canals is possible without acutely damaging the peripheral auditory function measured with ABR, as shown in this proof-of-principle clinical investigation.
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Affiliation(s)
- Raymond van de Berg
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Florence Lucieer
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Nils Guinand
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Joost van Tongeren
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Erwin George
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Jean-Philippe Guyot
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Herman Kingma
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Marc van Hoof
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Yasin Temel
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Jacobus van Overbeeke
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Angelica Perez-Fornos
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Robert Stokroos
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands
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29
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Perez Fornos A, Cavuscens S, Ranieri M, van de Berg R, Stokroos R, Kingma H, Guyot JP, Guinand N. The vestibular implant: A probe in orbit around the human balance system. J Vestib Res 2017; 27:51-61. [DOI: 10.3233/ves-170604] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Angelica Perez Fornos
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Samuel Cavuscens
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Maurizio Ranieri
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Raymond van de Berg
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, The Netherlands
- Faculty of Physics, Tomsk State University, Russian Federation
| | - Robert Stokroos
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Herman Kingma
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, The Netherlands
- Faculty of Physics, Tomsk State University, Russian Federation
| | - Jean-Philippe Guyot
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Nils Guinand
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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30
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Naples JG, Eisen MD. The History and Evolution of Surgery on the Vestibular Labyrinth. Otolaryngol Head Neck Surg 2016; 155:816-819. [PMID: 27554515 DOI: 10.1177/0194599816665807] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 08/03/2016] [Indexed: 11/17/2022]
Abstract
The history of surgery on the vestibular labyrinth is rich but sparsely documented in the literature. The story begins over a century ago with the labyrinthectomy in an era that consisted exclusively of ablative surgery for infection or vertigo. Improved understanding of vestibular physiology and pathology produced an era of selective ablation and hearing preservation that includes semicircular canal occlusion for benign paroxysmal positional vertigo. An era of restoration began with a discovery of superior semicircular canal dehiscence and its repair. The final era of vestibular replacement is upon us as the possibility of successful prosthetic vestibular implantation becomes reality.
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Affiliation(s)
- James G Naples
- University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Marc D Eisen
- University of Connecticut Health Center, Farmington, Connecticut, USA
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31
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Hageman KN, Kalayjian ZK, Tejada F, Chiang B, Rahman MA, Fridman GY, Dai C, Pouliquen PO, Georgiou J, Della Santina CC, Andreou AG. A CMOS Neural Interface for a Multichannel Vestibular Prosthesis. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2016; 10:269-79. [PMID: 25974945 PMCID: PMC4641830 DOI: 10.1109/tbcas.2015.2409797] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We present a high-voltage CMOS neural-interface chip for a multichannel vestibular prosthesis (MVP) that measures head motion and modulates vestibular nerve activity to restore vision- and posture-stabilizing reflexes. This application specific integrated circuit neural interface (ASIC-NI) chip was designed to work with a commercially available microcontroller, which controls the ASIC-NI via a fast parallel interface to deliver biphasic stimulation pulses with 9-bit programmable current amplitude via 16 stimulation channels. The chip was fabricated in the ONSemi C5 0.5 micron, high-voltage CMOS process and can accommodate compliance voltages up to 12 V, stimulating vestibular nerve branches using biphasic current pulses up to 1.45±0.06 mA with durations as short as 10 μs/phase. The ASIC-NI includes a dedicated digital-to-analog converter for each channel, enabling it to perform complex multipolar stimulation. The ASIC-NI replaces discrete components that cover nearly half of the 2nd generation MVP (MVP2) printed circuit board, reducing the MVP system size by 48% and power consumption by 17%. Physiological tests of the ASIC-based MVP system (MVP2A) in a rhesus monkey produced reflexive eye movement responses to prosthetic stimulation similar to those observed when using the MVP2. Sinusoidal modulation of stimulus pulse rate from 68-130 pulses per second at frequencies from 0.1 to 5 Hz elicited appropriately-directed slow phase eye velocities ranging in amplitude from 1.9-16.7 °/s for the MVP2 and 2.0-14.2 °/s for the MVP2A. The eye velocities evoked by MVP2 and MVP2A showed no significant difference ( t-test, p=0.34), suggesting that the MVP2A achieves performance at least as good as the larger MVP2.
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Affiliation(s)
- Kristin N. Hageman
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Zaven K. Kalayjian
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Francisco Tejada
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Bryce Chiang
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Mehdi A. Rahman
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Gene Y. Fridman
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Chenkai Dai
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Philippe O. Pouliquen
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Julio Georgiou
- Department of Electrical and Computer Engineering, University of Cyprus, 1678 Nicosa, Cyprus
| | - Charles C. Della Santina
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Andreas G. Andreou
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
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32
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Sun DQ, Ward BK, Semenov YR, Carey JP, Della Santina CC. Bilateral Vestibular Deficiency: Quality of Life and Economic Implications. JAMA Otolaryngol Head Neck Surg 2015; 140:527-34. [PMID: 24763518 DOI: 10.1001/jamaoto.2014.490] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
IMPORTANCE Bilateral vestibular deficiency (BVD) causes chronic imbalance and unsteady vision and greatly increases the risk of falls; however, its effects on quality of life and economic impact are not well defined. OBJECTIVE To quantify disease-specific and health-related quality of life, health care utilization, and economic impact on individuals with BVD in comparison with those with unilateral vestibular deficiency (UVD). DESIGN, SETTING, AND PARTICIPANTS Cross-sectional survey study of patients with BVD or UVD and healthy controls at an academic medical center. Vestibular dysfunction was diagnosed by means of caloric nystagmography. INTERVENTIONS Survey questionnaire. MAIN OUTCOMES AND MEASURES Health status was measured using the Dizziness Handicap Index (DHI) and Health Utility Index Mark 3 (HUI3). Economic burden was estimated using participant responses to questions on disease-specific health care utilization and lost productivity. RESULTS Fifteen patients with BVD, 22 with UVD, and 23 healthy controls participated. In comparison with patients with UVD and controls, patients with BVD had significantly worse DHI (P < .001) and HUI3 scores. Statistically significant between-group differences were observed for overall HUI3 score (P < .001) and for specific attributes including vision, hearing, ambulation, emotion, and pain (P < .001 for all). Generalized linear model analysis of clinical variables associated with HUI3 scores after adjustment for other variables (including sex, race, education, age, and frequency of dizziness-related outpatient clinic visits) showed that the presence of UVD (P < .001) or BVD (P < .001), increased dizziness-related emergency room visits (P = .002), and increased dizziness-related missed work days (P < .001) were independently associated with worse HUI3 scores. Patients with BVD and UVD incurred estimated mean (range) annual economic burdens of $13,019 ($0-$48,830) and $3531 ($0-$48,442) per patient, respectively. CONCLUSIONS AND RELEVANCE Bilateral vestibular deficiency significantly decreases quality of life and imposes substantial economic burdens on individuals and society. These results underscore the limits of adaptation and compensation in BVD. Furthermore, they quantify the potential benefits of prosthetic restoration of vestibular function both to these individuals and to society.
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Affiliation(s)
- Daniel Q Sun
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Bryan K Ward
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yevgeniy R Semenov
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - John P Carey
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Charles C Della Santina
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland2Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland
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33
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Loss of Afferent Vestibular Input Produces Central Adaptation and Increased Gain of Vestibular Prosthetic Stimulation. J Assoc Res Otolaryngol 2015; 17:19-35. [PMID: 26438271 DOI: 10.1007/s10162-015-0544-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 09/14/2015] [Indexed: 11/29/2022] Open
Abstract
Implanted vestibular neurostimulators are effective in driving slow phase eye movements in monkeys and humans. Furthermore, increases in slow phase velocity and electrically evoked compound action potential (vECAP) amplitudes occur with increasing current amplitude of electrical stimulation. In intact monkeys, protracted intermittent stimulation continues to produce robust behavioral responses and preserved vECAPs. In lesioned monkeys, shorter duration studies show preserved but with somewhat lower or higher velocity behavioral responses. It has been proposed that such changes are due to central adaptive changes in the electrically elicited vestibulo-ocular reflex (VOR). It is equally possible that these differences are due to changes in the vestibular periphery in response to activation of the vestibular efferent system. In order to investigate the site of adaptive change in response to electrical stimulation, we performed transtympanic gentamicin perfusions to induce rapid changes in vestibular input in monkeys with long-standing stably functioning vestibular neurostimulators, disambiguating the effects of implantation from the effects of ototoxic lesion. Gentamicin injection was effective in producing a large reduction in natural VOR only when it was performed in the non-implanted ear, suggesting that the implanted ear contributed little to the natural rotational response before injection. Injection of the implanted ear produced a reduction in the vECAP responses in that ear, suggesting that the intact hair cells in the non-functional ipsilateral ear were successfully lesioned by gentamicin, reducing the efficacy of stimulation in that ear. Despite this, injection of both ears produced central plastic changes that resulted in a dramatically increased slow phase velocity nystagmus elicited by electrical stimulation. These results suggest that loss of vestibular afferent activity, and a concurrent loss of electrically elicited vestibular input, produces an increase in the efficacy of a vestibular neurostimulator by eliciting centrally adapted behavioral responses without concurrent adaptive increase of galvanic afferent activation in the periphery.
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34
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Guinand N, van de Berg R, Cavuscens S, Stokroos RJ, Ranieri M, Pelizzone M, Kingma H, Guyot JP, Perez-Fornos A. Vestibular Implants: 8 Years of Experience with Electrical Stimulation of the Vestibular Nerve in 11 Patients with Bilateral Vestibular Loss. ORL J Otorhinolaryngol Relat Spec 2015; 77:227-240. [PMID: 26367113 DOI: 10.1159/000433554] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND The concept of the vestibular implant is primarily to artificially restore the vestibular function in patients with a bilateral vestibular loss (BVL) by providing the central nervous system with motion information using electrical stimulation of the vestibular nerve. Our group initiated human trials about 10 years ago. METHODS Between 2007 and 2013, 11 patients with a BVL received a vestibular implant prototype providing electrodes to stimulate the ampullary branches of the vestibular nerve. Eye movements were recorded and analyzed to assess the effects of the electrical stimulation. Perception induced by electrical stimulation was documented. RESULTS Smooth, controlled eye movements were obtained in all patients showing that electrical stimulation successfully activated the vestibulo-ocular pathway. However, both the electrical dynamic range and the amplitude of the eye movements were variable from patient to patient. The axis of the response was consistent with the stimulated nerve branch in 17 out of the 24 tested electrodes. Furthermore, in at least 1 case, the elicited eye movements showed characteristics similar to those of compensatory eye movements observed during natural activities such as walking. Finally, diverse percepts were reported upon electrical stimulation (i.e., rotatory sensations, sound, tickling or pressure) with intensity increasing as the stimulation current increased. CONCLUSIONS These results demonstrate that electrical stimulation is a safe and effective means to activate the vestibular system, even in a heterogeneous patient population with very different etiologies and disease durations. Successful tuning of this information could turn this vestibular implant prototype into a successful artificial balance organ.
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Marianelli P, Capogrosso M, Bassi Luciani L, Panarese A, Micera S. A Computational Framework for Electrical Stimulation of Vestibular Nerve. IEEE Trans Neural Syst Rehabil Eng 2015; 23:897-909. [DOI: 10.1109/tnsre.2015.2407861] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sun DQ, Lehar M, Dai C, Swarthout L, Lauer AM, Carey JP, Mitchell DE, Cullen KE, Santina CCD. Histopathologic Changes of the Inner ear in Rhesus Monkeys After Intratympanic Gentamicin Injection and Vestibular Prosthesis Electrode Array Implantation. J Assoc Res Otolaryngol 2015; 16:373-87. [PMID: 25790951 PMCID: PMC4417088 DOI: 10.1007/s10162-015-0515-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/02/2015] [Indexed: 11/29/2022] Open
Abstract
Bilateral vestibular deficiency (BVD) due to gentamicin ototoxicity can significantly impact quality of life and result in large socioeconomic burdens. Restoring sensation of head rotation using an implantable multichannel vestibular prosthesis (MVP) is a promising treatment approach that has been tested in animals and humans. However, uncertainty remains regarding the histopathologic effects of gentamicin ototoxicity alone or in combination with electrode implantation. Understanding these histological changes is important because selective MVP-driven stimulation of semicircular canals (SCCs) depends on persistence of primary afferent innervation in each SCC crista despite both the primary cause of BVD (e.g., ototoxic injury) and surgical trauma associated with MVP implantation. Retraction of primary afferents out of the cristae and back toward Scarpa's ganglion would render spatially selective stimulation difficult to achieve and could limit utility of an MVP that relies on electrodes implanted in the lumen of each ampulla. We investigated histopathologic changes of the inner ear associated with intratympanic gentamicin (ITG) injection and/or MVP electrode array implantation in 11 temporal bones from six rhesus macaque monkeys. Hematoxylin and eosin-stained 10-μm temporal bone sections were examined under light microscopy for four treatment groups: normal (three ears), ITG-only (two ears), MVP-only (two ears), and ITG + MVP (four ears). We estimated vestibular hair cell (HC) surface densities for each sensory neuroepithelium and compared findings across end organs and treatment groups. In ITG-only, MVP-only, and ITG + MVP ears, we observed decreased but persistent ampullary nerve fibers of SCC cristae despite ITG treatment and/or MVP electrode implantation. ITG-only and ITG + MVP ears exhibited neuroepithelial thinning and loss of type I HCs in the cristae but little effect on the maculae. MVP-only and ITG + MVP ears exhibited no signs of trauma to the cochlea or otolith end organs except in a single case of saccular injury due to over-insertion of the posterior SCC electrode. While implanted electrodes reached to within 50-760 μm of the target cristae and were usually ensheathed in a thin fibrotic capsule, dense fibrotic reaction and osteoneogenesis were each observed in only one of six electrode tracts examined. Consistent with physiologic studies that have demonstrated directionally appropriate vestibulo-ocular reflex responses to MVP electrical stimulation years after implantation in these animals, histologic findings in the present study indicate that although intralabyrinthine MVP implantation causes some inner ear trauma, it can be accomplished without destroying the distal afferent fibers an MVP is designed to excite.
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Affiliation(s)
- Daniel Q. Sun
- />Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD USA
- />Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins Outpatient Center, 6th floor, 601 North Caroline Street, Baltimore, MD 21287 USA
| | - Mohamed Lehar
- />Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Chenkai Dai
- />Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Lani Swarthout
- />Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Amanda M. Lauer
- />Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - John P. Carey
- />Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | | | | | - Charles C. Della Santina
- />Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD USA
- />Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD USA
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Phillips C, Ling L, Oxford T, Nowack A, Nie K, Rubinstein JT, Phillips JO. Longitudinal performance of an implantable vestibular prosthesis. Hear Res 2015; 322:200-11. [PMID: 25245586 PMCID: PMC4369472 DOI: 10.1016/j.heares.2014.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 08/20/2014] [Accepted: 09/08/2014] [Indexed: 11/30/2022]
Abstract
Loss of vestibular function may be treatable with an implantable vestibular prosthesis that stimulates semicircular canal afferents with biphasic pulse trains. Several studies have demonstrated short-term activation of the vestibulo-ocular reflex (VOR) with electrical stimulation. Fewer long-term studies have been restricted to small numbers of animals and stimulation designed to produce adaptive changes in the electrically elicited response. This study is the first large consecutive series of implanted rhesus macaque to be studied longitudinally using brief stimuli designed to limit adaptive changes in response, so that the efficacy of electrical activation can be studied over time, across surgeries, canals and animals. The implantation of a vestibular prosthesis in animals with intact vestibular end organs produces variable responses to electrical stimulation across canals and animals, which change in threshold for electrical activation of eye movements and in elicited slow phase velocities over time. These thresholds are consistently lower, and the slow phase velocities higher, than those obtained in human subjects. The changes do not appear to be correlated with changes in electrode impedance. The variability in response suggests that empirically derived transfer functions may be required to optimize the response of individual canals to a vestibular prosthesis, and that this function may need to be remapped over time. This article is part of a Special Issue entitled .
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Affiliation(s)
| | - Leo Ling
- Otolaryngology - HNS, University of Washington, Seattle, WA, USA; Washington National Primate Research Center, University of Washington, Seattle, WA, USA
| | - Trey Oxford
- Washington National Primate Research Center, University of Washington, Seattle, WA, USA
| | - Amy Nowack
- Washington National Primate Research Center, University of Washington, Seattle, WA, USA
| | - Kaibao Nie
- Otolaryngology - HNS, University of Washington, Seattle, WA, USA; Electrical Engineering, University of Washington, Seattle, WA, USA
| | - Jay T Rubinstein
- Otolaryngology - HNS, University of Washington, Seattle, WA, USA; Bioengineering, University of Washington, Seattle, WA, USA
| | - James O Phillips
- Otolaryngology - HNS, University of Washington, Seattle, WA, USA; Washington National Primate Research Center, University of Washington, Seattle, WA, USA.
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Phillips JO, Ling L, Nie K, Jameyson E, Phillips CM, Nowack AL, Golub JS, Rubinstein JT. Vestibular implantation and longitudinal electrical stimulation of the semicircular canal afferents in human subjects. J Neurophysiol 2015; 113:3866-92. [PMID: 25652917 DOI: 10.1152/jn.00171.2013] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 02/02/2015] [Indexed: 11/22/2022] Open
Abstract
Animal experiments and limited data in humans suggest that electrical stimulation of the vestibular end organs could be used to treat loss of vestibular function. In this paper we demonstrate that canal-specific two-dimensionally (2D) measured eye velocities are elicited from intermittent brief 2 s biphasic pulse electrical stimulation in four human subjects implanted with a vestibular prosthesis. The 2D measured direction of the slow phase eye movements changed with the canal stimulated. Increasing pulse current over a 0-400 μA range typically produced a monotonic increase in slow phase eye velocity. The responses decremented or in some cases fluctuated over time in most implanted canals but could be partially restored by changing the return path of the stimulation current. Implantation of the device in Meniere's patients produced hearing and vestibular loss in the implanted ear. Electrical stimulation was well tolerated, producing no sensation of pain, nausea, or auditory percept with stimulation that elicited robust eye movements. There were changes in slow phase eye velocity with current and over time, and changes in electrically evoked compound action potentials produced by stimulation and recorded with the implanted device. Perceived rotation in subjects was consistent with the slow phase eye movements in direction and scaled with stimulation current in magnitude. These results suggest that electrical stimulation of the vestibular end organ in human subjects provided controlled vestibular inputs over time, but in Meniere's patients this apparently came at the cost of hearing and vestibular function in the implanted ear.
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Affiliation(s)
- James O Phillips
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; National Primate Research Center, University of Washington, Seattle, Washington; and Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington
| | - Leo Ling
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; National Primate Research Center, University of Washington, Seattle, Washington; and
| | - Kaibao Nie
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington
| | - Elyse Jameyson
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington
| | - Christopher M Phillips
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; National Primate Research Center, University of Washington, Seattle, Washington; and
| | - Amy L Nowack
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; National Primate Research Center, University of Washington, Seattle, Washington; and
| | - Justin S Golub
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington
| | - Jay T Rubinstein
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; Department of Bioengineering, University of Washington, Seattle, Washington; National Primate Research Center, University of Washington, Seattle, Washington; and Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington
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van de Berg R, Guinand N, Nguyen TAK, Ranieri M, Cavuscens S, Guyot JP, Stokroos R, Kingma H, Perez-Fornos A. The vestibular implant: frequency-dependency of the electrically evoked vestibulo-ocular reflex in humans. Front Syst Neurosci 2015; 8:255. [PMID: 25653601 PMCID: PMC4299437 DOI: 10.3389/fnsys.2014.00255] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 12/29/2014] [Indexed: 12/05/2022] Open
Abstract
The vestibulo-ocular reflex (VOR) shows frequency-dependent behavior. This study investigated whether the characteristics of the electrically evoked VOR (eVOR) elicited by a vestibular implant, showed the same frequency-dependency. Twelve vestibular electrodes implanted in seven patients with bilateral vestibular hypofunction (BVH) were tested. Stimuli consisted of amplitude-modulated electrical stimulation with a sinusoidal profile at frequencies of 0.5, 1, and 2 Hz. The main characteristics of the eVOR were evaluated and compared to the “natural” VOR characteristics measured in a group of age-matched healthy volunteers who were subjected to horizontal whole body rotations with equivalent sinusoidal velocity profiles at the same frequencies. A strong and significant effect of frequency was observed in the total peak eye velocity of the eVOR. This effect was similar to that observed in the “natural” VOR. Other characteristics of the (e)VOR (angle, habituation-index, and asymmetry) showed no significant frequency-dependent effect. In conclusion, this study demonstrates that, at least at the specific (limited) frequency range tested, responses elicited by a vestibular implant closely mimic the frequency-dependency of the “normal” vestibular system.
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Affiliation(s)
- Raymond van de Berg
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center Maastricht, Netherlands ; Faculty of Physics, Tomsk State University Tomsk, Russia
| | - Nils Guinand
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals Geneva, Switzerland
| | - T A Khoa Nguyen
- Translational Neural Engineering Lab, Center for Neuroprosthetics, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland
| | - Maurizio Ranieri
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals Geneva, Switzerland
| | - Samuel Cavuscens
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals Geneva, Switzerland
| | - Jean-Philippe Guyot
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals Geneva, Switzerland
| | - Robert Stokroos
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center Maastricht, Netherlands
| | - Herman Kingma
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center Maastricht, Netherlands ; Faculty of Physics, Tomsk State University Tomsk, Russia
| | - Angelica Perez-Fornos
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals Geneva, Switzerland
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Abstract
HYPOTHESIS A functional vestibular prosthesis can be implanted in human such that electrical stimulation of each semicircular canal produces canal-specific eye movements while preserving vestibular and auditory function. BACKGROUND A number of vestibular disorders could be treated with prosthetic stimulation of the vestibular end organs. We have previously demonstrated in rhesus monkeys that a vestibular neurostimulator, based on the Nucleus Freedom cochlear implant, can produce canal-specific electrically evoked eye movements while preserving auditory and vestibular function. An investigational device exemption has been obtained from the FDA to study the feasibility of treating uncontrolled Ménière's disease with the device. METHODS The UW/Nucleus vestibular implant was implanted in the perilymphatic space adjacent to the three semicircular canal ampullae of a human subject with uncontrolled Ménière's disease. Preoperative and postoperative vestibular and auditory function was assessed. Electrically evoked eye movements were measured at 2 time points postoperatively. RESULTS Implantation of all semicircular canals was technically feasible. Horizontal canal and auditory function were largely, but not totally, lost. Electrode stimulation in 2 of 3 canals resulted in canal-appropriate eye movements. Over time, stimulation thresholds increased. CONCLUSION Prosthetic implantation of the semicircular canals in humans is technically feasible. Electrical stimulation resulted in canal-specific eye movements, although thresholds increased over time. Preservation of native auditory and vestibular function, previously observed in animals, was not demonstrated in a single subject with advanced Ménière's disease.
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Nguyen TAK, Ranieri M, DiGiovanna J, Peter O, Genovese V, Perez Fornos A, Micera S. A real-time research platform to study vestibular implants with gyroscopic inputs in vestibular deficient subjects. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2014; 8:474-484. [PMID: 25073124 DOI: 10.1109/tbcas.2013.2290089] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Researchers have succeeded in partly restoring damaged vestibular functionality in several animal models. Recently, acute interventions have also been demonstrated in human patients. Our previous work on a vestibular implant for humans used predefined stimulation patterns; here we present a research tool that facilitates motion-modulated stimulation. This requires a system that can process gyroscope measurements and send stimulation parameters to a hybrid vestibular-cochlear implant in real-time. To match natural vestibular latencies, the time from sensor input to stimulation output should not exceed 6.5 ms. We describe a system based on National Instrument's CompactRIO platform that can meet this requirement and also offers floating point precision for advanced transfer functions. It is designed for acute clinical interventions, and is sufficiently powerful and flexible to serve as a development platform for evaluating prosthetic control strategies. Amplitude and pulse frequency modulation to predetermined functions or sensor inputs have been validated. The system has been connected to human patients, who each have received a modified MED-EL cochlear implant for vestibular stimulation, and patient tests are ongoing.
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Perez Fornos A, Guinand N, van de Berg R, Stokroos R, Micera S, Kingma H, Pelizzone M, Guyot JP. Artificial balance: restoration of the vestibulo-ocular reflex in humans with a prototype vestibular neuroprosthesis. Front Neurol 2014; 5:66. [PMID: 24808890 PMCID: PMC4010770 DOI: 10.3389/fneur.2014.00066] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Accepted: 04/16/2014] [Indexed: 12/05/2022] Open
Abstract
The vestibular system plays a crucial role in the multisensory control of balance. When vestibular function is lost, essential tasks such as postural control, gaze stabilization, and spatial orientation are limited and the quality of life of patients is significantly impaired. Currently, there is no effective treatment for bilateral vestibular deficits. Research efforts both in animals and humans during the last decade set a solid background to the concept of using electrical stimulation to restore vestibular function. Still, the potential clinical benefit of a vestibular neuroprosthesis has to be demonstrated to pave the way for a translation into clinical trials. An important parameter for the assessment of vestibular function is the vestibulo-ocular reflex (VOR), the primary mechanism responsible for maintaining the perception of a stable visual environment while moving. Here we show that the VOR can be artificially restored in humans using motion-controlled, amplitude modulated electrical stimulation of the ampullary branches of the vestibular nerve. Three patients received a vestibular neuroprosthesis prototype, consisting of a modified cochlear implant providing vestibular electrodes. Significantly higher VOR responses were observed when the prototype was turned ON. Furthermore, VOR responses increased significantly as the intensity of the stimulation increased, reaching on average 79% of those measured in healthy volunteers in the same experimental conditions. These results constitute a fundamental milestone and allow us to envision for the first time clinically useful rehabilitation of patients with bilateral vestibular loss.
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Affiliation(s)
- Angelica Perez Fornos
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals , Geneva , Switzerland
| | - Nils Guinand
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals , Geneva , Switzerland
| | - Raymond van de Berg
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center , Maastricht , Netherlands
| | - Robert Stokroos
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center , Maastricht , Netherlands
| | - Silvestro Micera
- Translational Neural Engineering Laboratory, Center for Neuroprosthetics, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland ; The BioRobotics Institute, Scuola Superiore Sant'Anna , Pisa , Italy
| | - Herman Kingma
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center , Maastricht , Netherlands
| | - Marco Pelizzone
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals , Geneva , Switzerland
| | - Jean-Philippe Guyot
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals , Geneva , Switzerland
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Newlands SD, Wei M. Responses of central vestibular neurons to sinusoidal yaw rotation in compensated macaques after unilateral labyrinthectomy. J Neurophysiol 2013; 110:1822-36. [PMID: 23864379 DOI: 10.1152/jn.00365.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
After vestibular labyrinth injury, behavioral measures of vestibular function partially recover through the process of vestibular compensation. The present study was performed to improve our understanding of the physiology of macaque vestibular nucleus neurons in the compensated state (>6 wk) after unilateral labyrinthectomy (UL). The responses of neurons to sinusoidal yaw rotation at a series of frequencies (0.1-2.0 Hz) and peak velocities (7.5-210°/s) were examined to determine how the behavior of these cells differed from those in animals with intact labyrinths. The sensitivity of neurons responding to ipsilateral rotation (type I) did not differ between the intact and injured sides after UL, although this sensitivity was lower bilaterally after lesion than before lesion. The sensitivity of neurons that increase firing with contralateral rotation (type II) was higher ipsilateral to the UL than before lesion or in the nucleus contralateral to the UL. UL did not increase asymmetry in the responses of individual type I or II neurons to ipsilateral vs. contralateral rotation, nor does it change the power law relationship between neuronal firing and level of stimulation. Increased sensitivities of contralesional type I neurons to the remaining vestibular nerve input and increased efficacy of inhibitory vestibular commissures projecting to the ipsilesional vestibular nucleus appear to be responsible for recovery of dynamic function of central vestibular neurons in compensated animals. The portion of type I neurons on the ipsilesional side is reduced in compensated animals, which likely accounts for the asymmetries in vestibular reflexes and perception that characterize vestibular function after UL.
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Affiliation(s)
- Shawn D Newlands
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas
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Postural responses to electrical stimulation of the vestibular end organs in human subjects. Exp Brain Res 2013; 229:181-95. [PMID: 23771587 DOI: 10.1007/s00221-013-3604-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 05/29/2013] [Indexed: 10/26/2022]
Abstract
A multichannel vestibular prosthesis that delivers electrical stimulation to the perilymph of individual semicircular canals is a potential new treatment modality for patients with vestibular deficiencies. Most research in this field has evaluated the efficacy of this approach by its ability to reproduce eye movements in response to head rotations. Our group has developed such a device and implanted it in four human subjects with intractable unilateral Meniere's disease. This allows us to evaluate individual semicircular canal contribution to the control of balance and posture in human subjects. In this report, we demonstrate that electrical stimulation trains delivered to the perilymph of individual semicircular canals elicit postural responses specific to the particular canal stimulated, with some current spread to adjacent end organs. Modulation of stimulation current modulates the amplitude of the postural response. However, eye movements elicited by the same electrical stimuli were not consistent with postural responses in magnitude or direction in all subjects. Taken together, these findings support the feasibility of a vestibular prosthesis for the control of balance and illustrate new challenges for the development of this technology.
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Vestibular loss as a contributor to Alzheimer's disease. Med Hypotheses 2013; 80:360-7. [PMID: 23375669 DOI: 10.1016/j.mehy.2012.12.023] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 12/06/2012] [Accepted: 12/25/2012] [Indexed: 01/29/2023]
Abstract
Alzheimer's disease is a complex disorder whose etiology is still controversial. It is proposed that vestibular loss may contribute to the onset of Alzheimer's disease, which initially involves degeneration of cholinergic systems in the posterior parietal-temporal, medial-temporal, and posterior-cingulate regions. A major projection to this system emanates from the semicircular canals of the vestibular labyrinth, with vestibular damage leading to severe degeneration of the medial-temporal region. The vestibular loss hypothesis is further supported by the vestibular symptoms found in Alzheimer's patients as well as in various diseases that are major risk factors for Alzheimer's disease.
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Abstract
PURPOSE OF REVIEW To summarize the recent progress in the development of vestibular implants. The review is timely because of the recent advances in the field and because MED-EL has recently announced that they are developing a vestibular implant for clinical applications. RECENT FINDINGS The handicap experienced by patients suffering from bilateral vestibulopathy has a strong negative impact on physical and social functioning that appears to justify a surgical intervention. Two different surgical approaches to insert electrodes to stimulate ampullary neurons have been shown to be viable. The three-dimensional vestibulo-ocular reflex in rhesus monkeys produced with a three-dimensional vestibular implant showed gains that were relatively normal during acute stimulation. Rotation cues provided by an implant interact with otolith cues in a qualitatively normal manner. The brain appears to adapt plastically to the cues provided via artificial electrical stimulation. SUMMARY Research to date includes just a few human studies, but available data from both humans and animals support the technological and physiological feasibility of vestibular implants. Although vestibular implant users should not expect normal vestibular function - any more than cochlear implant users should expect normal hearing - data suggest that significant functional improvements are possible.
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Davidovics NS, Rahman MA, Dai C, Ahn J, Fridman GY, Della Santina CC. Multichannel vestibular prosthesis employing modulation of pulse rate and current with alignment precompensation elicits improved VOR performance in monkeys. J Assoc Res Otolaryngol 2013; 14:233-48. [PMID: 23355001 DOI: 10.1007/s10162-013-0370-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 01/02/2013] [Indexed: 11/30/2022] Open
Abstract
An implantable prosthesis that stimulates vestibular nerve branches to restore the sensation of head rotation and the three-dimensional (3D) vestibular ocular reflex (VOR) could benefit individuals disabled by bilateral loss of vestibular sensation. Our group has developed a vestibular prosthesis that partly restores normal function in animals by delivering biphasic current pulses via electrodes implanted in semicircular canals. Despite otherwise promising results, this approach has been limited by insufficient velocity of VOR response to head movements that should inhibit the implanted labyrinth and by misalignment between direction of head motion and prosthetically elicited VOR. We report that significantly larger VOR eye velocities in the inhibitory direction can be elicited by adapting a monkey to elevated baseline stimulation rate and current prior to stimulus modulation and then concurrently modulating ("co-modulating") both rate and current below baseline levels to encode inhibitory angular head velocity. Co-modulation of pulse rate and current amplitude above baseline can also elicit larger VOR eye responses in the excitatory direction than do either pulse rate modulation or current modulation alone. Combining these stimulation strategies with a precompensatory 3D coordinate transformation improves alignment and magnitude of evoked VOR eye responses. By demonstrating that a combination of co-modulation and precompensatory transformation strategies achieves a robust VOR response in all directions with significantly improved alignment in an animal model that closely resembles humans with vestibular loss, these findings provide a solid preclinical foundation for application of vestibular stimulation in humans.
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Affiliation(s)
- Natan S Davidovics
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
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Nie K, Ling L, Bierer SM, Kaneko CRS, Fuchs AF, Oxford T, Rubinstein JT, Phillips JO. An experimental vestibular neural prosthesis: design and preliminary results with rhesus monkeys stimulated with modulated pulses. IEEE Trans Biomed Eng 2013; 60:1685-92. [PMID: 23358943 DOI: 10.1109/tbme.2013.2241433] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A vestibular neural prosthesis was designed on the basis of a cochlear implant for treatment of Meniere's disease and other vestibular disorders. Computer control software was developed to generate patterned pulse stimuli for exploring optimal parameters to activate the vestibular nerve. Two rhesus monkeys were implanted with the prototype vestibular prosthesis and they were behaviorally evaluated post implantation surgery. Horizontal and vertical eye movement responses to patterned electrical pulse stimulations were collected on both monkeys. Pulse amplitude modulated (PAM) and pulse rate modulated (PRM) trains were applied to the lateral canal of each implanted animal. Robust slow-phase nystagmus responses following the PAM or PRM modulation pattern were observed in both implanted monkeys in the direction consistent with the activation of the implanted canal. Both PAM and PRM pulse trains can elicit a significant amount of in-phase modulated eye velocity changes and they could potentially be used for efficiently coding head rotational signals in future vestibular neural prostheses.
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Affiliation(s)
- Kaibao Nie
- Department of Otolaryngology, Department of Electrical Engineering, and Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA 98195, USA.
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Abstract
Animal studies on inner ear development, repair and regeneration provide understanding of molecular pathways that can be harnessed for treating inner ear disease. Use of transgenic mouse technology, in particular, has contributed knowledge of genes that regulate development of hair cells and innervation, and of molecular players that can induce regeneration, but this technology is not applicable for human treatment, for practical and ethical reasons. Therefore other means for influencing gene expression in the inner ear are needed. We describe several gene vectors useful for inner ear gene therapy and the practical aspects of introducing these vectors into the ear. We then review the progress toward using gene transfer for therapies in both auditory and balance systems, and discuss the technological milestones needed to advance to clinical application of these methods.
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Affiliation(s)
- Hideto Fukui
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, 1150 West Medical Center Dr., Ann Arbor, MI 48109-5648, USA
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