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Ten Hoor M, van de Berg R, Pérez Fornos A, Stultiens JJA. Electrical stimulation of the vestibular nerve: evaluating effects and potential starting points for optimization in vestibular implants. Curr Opin Otolaryngol Head Neck Surg 2024:00020840-990000000-00144. [PMID: 39171746 DOI: 10.1097/moo.0000000000001001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
PURPOSE OF REVIEW Oscillopsia and unsteadiness are common and highly debilitating symptoms in individuals with bilateral vestibulopathy. A lack of adequate treatment options encouraged the investigation of vestibular implants, which aim to restore vestibular function with motion-modulated electrical stimulation. This review aims to outline the ocular and postural responses that can be evoked with electrical prosthetic stimulation of the semicircular canals and discuss potential approaches to further optimize evoked responses. Particular focus is given to the stimulation paradigm. RECENT FINDINGS Feasibility studies in animals paved the way for vestibular implantation in human patients with bilateral vestibulopathy. Recent human trials demonstrated prosthetic electrical stimulation to partially restore vestibular reflexes, enhance dynamic visual acuity, and generate controlled postural responses. To further optimize prosthetic performance, studies predominantly targeted eye responses elicited by the vestibulo-ocular reflex, aiming to minimize misalignments and asymmetries while maximizing the response. Changes of stimulation parameters are shown to hold promise to increase prosthetic efficacy, together with surgical refinements and neuroplastic effects. SUMMARY Optimization of the stimulation paradigm, in combination with a more precise electrode placement, holds great potential to enhance the clinical benefit of vestibular implants.
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Affiliation(s)
- Marieke Ten Hoor
- Department of Otorhinolaryngology & Head and Neck Surgery, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, 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, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Angélica Pérez Fornos
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - 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, Maastricht, The Netherlands
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Steinhardt CR, Mitchell DE, Cullen KE, Fridman GY. Pulsatile electrical stimulation creates predictable, correctable disruptions in neural firing. Nat Commun 2024; 15:5861. [PMID: 38997274 PMCID: PMC11245474 DOI: 10.1038/s41467-024-49900-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 06/21/2024] [Indexed: 07/14/2024] Open
Abstract
Electrical stimulation is a key tool in neuroscience, both in brain mapping studies and in many therapeutic applications such as cochlear, vestibular, and retinal neural implants. Due to safety considerations, stimulation is restricted to short biphasic pulses. Despite decades of research and development, neural implants lead to varying restoration of function in patients. In this study, we use computational modeling to provide an explanation for how pulsatile stimulation affects axonal channels and therefore leads to variability in restoration of neural responses. The phenomenological explanation is transformed into equations that predict induced firing rate as a function of pulse rate, pulse amplitude, and spontaneous firing rate. We show that these equations predict simulated responses to pulsatile stimulation with a variety of parameters as well as several features of experimentally recorded primate vestibular afferent responses to pulsatile stimulation. We then discuss the implications of these effects for improving clinical stimulation paradigms and electrical stimulation-based experiments.
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Affiliation(s)
- Cynthia R Steinhardt
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA.
- Center for Theoretical Neuroscience, Columbia University, New York, NY, USA.
| | - Diana E Mitchell
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada
| | - Kathleen E Cullen
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Department of Otolaryngology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Gene Y Fridman
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Department of Otolaryngology, Johns Hopkins School of Medicine, Baltimore, MD, USA
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Schoo DP, Ward BK, Chow MR, Ayiotis AI, Fernández Brillet C, Boutros PJ, Lane KE, Lee CN, Morris BJ, Carey JP, Della Santina CC. Vestibular Implant Surgery. Laryngoscope 2024; 134:1842-1846. [PMID: 37767871 DOI: 10.1002/lary.31004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 07/14/2023] [Accepted: 08/16/2023] [Indexed: 09/29/2023]
Affiliation(s)
- Desi P Schoo
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
| | - Bryan K Ward
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
| | - Margaret R Chow
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
- Labyrinth Devices, LLC, Baltimore, Maryland, U.S.A
| | - Andrianna I Ayiotis
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
| | - Celia Fernández Brillet
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
| | - Peter J Boutros
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
| | - Kelly E Lane
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
| | - Claudia N Lee
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
| | - Brian J Morris
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
| | - John P Carey
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
| | - Charles C Della Santina
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A
- Labyrinth Devices, LLC, Baltimore, Maryland, U.S.A
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Vermorken BL, Volpe B, van Boxel SCJ, Stultiens JJA, van Hoof M, Marcellis R, Loos E, van Soest A, McCrum C, Meijer K, Guinand N, Pérez Fornos A, van Rompaey V, Devocht E, van de Berg R. The VertiGO! Trial protocol: A prospective, single-center, patient-blinded study to evaluate efficacy and safety of prolonged daily stimulation with a multichannel vestibulocochlear implant prototype in bilateral vestibulopathy patients. PLoS One 2024; 19:e0301032. [PMID: 38547135 PMCID: PMC10977751 DOI: 10.1371/journal.pone.0301032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 02/02/2024] [Indexed: 04/02/2024] Open
Abstract
BACKGROUND A combined vestibular (VI) and cochlear implant (CI) device, also known as the vestibulocochlear implant (VCI), was previously developed to restore both vestibular and auditory function. A new refined prototype is currently being investigated. This prototype allows for concurrent multichannel vestibular and cochlear stimulation. Although recent studies showed that VCI stimulation enables compensatory eye, body and neck movements, the constraints in these acute study designs prevent them from creating more general statements over time. Moreover, the clinical relevance of potential VI and CI interactions is not yet studied. The VertiGO! Trial aims to investigate the safety and efficacy of prolonged daily motion modulated stimulation with a multichannel VCI prototype. METHODS A single-center clinical trial will be carried out to evaluate prolonged VCI stimulation, assess general safety and explore interactions between the CI and VI. A single-blind randomized controlled crossover design will be implemented to evaluate the efficacy of three types of stimulation. Furthermore, this study will provide a proof-of-concept for a VI rehabilitation program. A total of minimum eight, with a maximum of 13, participants suffering from bilateral vestibulopathy and severe sensorineural hearing loss in the ear to implant will be included and followed over a five-year period. Efficacy will be evaluated by collecting functional (i.e. image stabilization) and more fundamental (i.e. vestibulo-ocular reflexes, self-motion perception) outcomes. Hearing performance with a VCI and patient-reported outcomes will be included as well. DISCUSSION The proposed schedule of fitting, stimulation and outcome testing allows for a comprehensive evaluation of the feasibility and long-term safety of a multichannel VCI prototype. This design will give insights into vestibular and hearing performance during VCI stimulation. Results will also provide insights into the expected daily benefit of prolonged VCI stimulation, paving the way for cost-effectiveness analyses and a more comprehensive clinical implementation of vestibulocochlear stimulation in the future. TRIAL REGISTRATION ClinicalTrials.gov: NCT04918745. Registered 28 April 2021.
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Affiliation(s)
- Bernd L. Vermorken
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Benjamin Volpe
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Stan C. J. van Boxel
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Joost J. A. Stultiens
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Marc van Hoof
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Rik Marcellis
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, Netherlands
| | - Elke Loos
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands
- Department of Neurosciences, Research Group Experimental Oto-Rhino-Laryngology (ExpORL), KU Leuven, University of Leuven, Leuven, Belgium
- Department of Otorhinolaryngology-Head and Neck Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Alexander van Soest
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Chris McCrum
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, Netherlands
| | - Kenneth Meijer
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, Netherlands
| | - Nils Guinand
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands
- Division of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Angélica Pérez Fornos
- Division of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Vincent van Rompaey
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands
- Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
- Department of Otorhinolaryngology and Head and Neck Surgery, Antwerp University Hospital, Edegem, Belgium
| | - Elke Devocht
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Raymond van de Berg
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands
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Ayiotis AI, Schoo DP, Fernandez Brillet C, Lane KE, Carey JP, Della Santina CC. Patient-Reported Outcomes After Vestibular Implantation for Bilateral Vestibular Hypofunction. JAMA Otolaryngol Head Neck Surg 2024; 150:240-248. [PMID: 38300591 PMCID: PMC10835607 DOI: 10.1001/jamaoto.2023.4475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/02/2023] [Indexed: 02/02/2024]
Abstract
Importance Standard-of-care treatment proves inadequate for many patients with bilateral vestibular hypofunction (BVH). Vestibular implantation is an emerging alternative. Objective To examine patient-reported outcomes from prosthetic vestibular stimulation. Design, Setting, and Participants The Multichannel Vestibular Implant (MVI) Early Feasibility Study is an ongoing prospective, nonrandomized, single-group, single-center cohort study conducted at Johns Hopkins Hospital that has been active since 2016 in which participants serve as their own controls. The study includes adults with severe or profound adult-onset BVH for at least 1 year and inadequate compensation despite standard-of-care treatment. As of March 2023, 12 candidates completed the eligibility screening process. Intervention The MVI system electrically stimulates semicircular canal branches of the vestibular nerve to convey head rotation. Main Outcomes and Measures Patient-reported outcome instruments assessing dizziness (Dizziness Handicap Inventory [DHI]) and vestibular-related disability (Vestibular Disorders-Activities of Daily Living [VADL]). Health-related quality of life (HRQOL) assessed using the Short Form-36 Utility (SF36U) and Health Utilities Index Mark 3 (HUI3), from which quality-adjusted life-years were computed. Results Ten individuals (5 female [50%]; mean [SD] age, 58.5 [5.0] years; range, 51-66 years) underwent unilateral implantation. A control group of 10 trial applicants (5 female [50%]; mean [SD] age, 55.1 [8.5] years; range, 42-73 years) completed 6-month follow-up surveys after the initial application. After 0.5 years of continuous MVI use, a pooled mean (95% CI) of within-participant changes showed improvements in dizziness (DHI, -36; 95% CI, -55 to -18), vestibular disability (VADL, -1.7; 95% CI, -2.6 to -0.7), and HRQOL by SF36U (0.12; 95% CI, 0.07-0.17) but not HUI3 (0.02; 95% CI, -0.22 to 0.27). Improvements exceeded minimally important differences in the direction of benefit (exceeding 18, 0.65, and 0.03, respectively, for DHI, VADL, and SF36U). The control group reported no mean change in dizziness (DHI, -4; 95% CI, -10 to 2), vestibular disability (VADL, 0.1; 95% CI, -0.9 to 1.1) or HRQOL per SF36U (0; 95% CI, -0.06 to 0.05) but an increase in HRQOL per HUI3 (0.10; 95% CI, 0.04-0.16). Lifetime HRQOL gain for MVI users was estimated to be 1.7 quality-adjusted life-years (95% CI, 0.6-2.8) using SF36U and 1.4 (95% CI, -1.2 to 4.0) using HUI3. Conclusions and Relevance This cohort study found that vestibular implant recipients report vestibular symptom improvements not reported by a control group. These patient-reported benefits support the use of vestibular implantation as a treatment for bilateral vestibular hypofunction.
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Affiliation(s)
- Andrianna I. Ayiotis
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Desi P. Schoo
- Department of Otolaryngology–Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
- Department of Otolaryngology, The Ohio State University Wexner Medical Center, Columbus
| | | | - Kelly E. Lane
- Department of Otolaryngology–Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - John P. Carey
- Department of Otolaryngology–Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Charles C. Della Santina
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
- Department of Otolaryngology–Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
- Labyrinth Devices, LLC
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Abstract
PURPOSE OF REVIEW Electrical stimulation of the peripheral and central vestibular system using noninvasive (galvanic vestibular stimulation, GVS) or invasive (intracranial electrical brain stimulation, iEBS) approaches have a long history of use in studying self-motion perception and balance control. The aim of this review is to summarize recent electrophysiological studies of the effects of GVS, and functional mapping of the central vestibular system using iEBS in awake patients. RECENT FINDINGS The use of GVS has become increasingly common in the assessment and treatment of a wide range of clinical disorders including vestibulopathy and Parkinson's disease. The results of recent single unit recording studies have provided new insight into the neural mechanisms underlying GVS-evoked improvements in perceptual and motor responses. Furthermore, the application of iEBS in patients with epilepsy or during awake brain surgery has provided causal evidence of vestibular information processing in mostly the middle cingulate cortex, posterior insula, inferior parietal lobule, amygdala, precuneus, and superior temporal gyrus. SUMMARY Recent studies have established that GVS evokes robust and parallel activation of both canal and otolith afferents that is significantly different from that evoked by natural head motion stimulation. Furthermore, there is evidence that GVS can induce beneficial neural plasticity in the central pathways of patients with vestibular loss. In addition, iEBS studies highlighted an underestimated contribution of areas in the medial part of the cerebral hemispheres to the cortical vestibular network.
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Affiliation(s)
- Christophe Lopez
- Aix Marseille Univ, CNRS, Laboratory of Cognitive Neuroscience (LNC), FR3C, Marseille, France
| | - Kathleen E. Cullen
- Department of Biomedical Engineering, Johns Hopkins University
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University
- Department of Neuroscience, Johns Hopkins University
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore 21205 MD, USA
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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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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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Brillet CF, Chow MR, Ayiotis AI, Santina CCD. VESTIBULAR IMPLANT STIMULATION PAUSE DETECTION THRESHOLDS: IMPLICATIONS FOR DESIGN OF BATTERY DEPLETION ALERTS. PROCEEDINGS OF THE ... DESIGN OF MEDICAL DEVICES CONFERENCE. DESIGN OF MEDICAL DEVICES CONFERENCE 2023; 2023:V001T08A001. [PMID: 39139149 PMCID: PMC11321489 DOI: 10.1115/dmd2023-8085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
Vestibular implants (VI) modulate the rate and amplitude of charge-balanced current pulses to encode head angular velocity or acceleration. When the battery of a VI becomes depleted, stimulation interruptions can cause vertigo. To avoid this, VIs can use alert signals such as vibration and beeping to remind the user to replace the battery. However, in distracting and noisy environments typical of activities of daily life, some patients may fail to hear or feel those alerts, so a physiological signal can be used as an alternate channel for signaling battery depletion. Pauses in the stimulation waveform can be delivered for this purpose, with the length of the pause long enough to be detected reliably by the patient but not so long as to induce dizziness or a vertigo attack. As a guide for the design of a physiologic battery depletion alert system, this study reports the ability of nine long-term, continuous VI users to detect stimulation pauses of various durations. We also show the effect of distraction on patients' detection thresholds and response latencies for detected events.
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Affiliation(s)
| | | | - Andrianna I Ayiotis
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD
| | - Charles C Della Santina
- Departments of Otolaryngology-Head & Neck Surgery and Biomedical Engineering, Johns Hopkins University, Baltimore, MD
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Schoo DP, Ayiotis AI, Brillet CF, Chow MR, Lane KE, Ward BK, Carey JP, Santina CCD. Vestibular Implantation Can Work Even After More Than 20 Years of Bilateral Vestibular Hypofunction. Otol Neurotol 2023; 44:168-171. [PMID: 36624598 PMCID: PMC9851668 DOI: 10.1097/mao.0000000000003768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE To determine whether prosthetic stimulation delivered via a vestibular implant can elicit artificial sensation of head movement despite long (23-yr) duration adult-onset ototoxic bilateral vestibular hypofunction (BVH). STUDY DESIGN Case report. SETTING Tertiary care center as part of a first-in-human clinical trial. PATIENTS One. INTERVENTIONS Unilateral vestibular implantation with an investigational multichannel vestibular implant in a 55-year-old man with a well-documented 23-year history of aminoglycoside-induced BVH. MAIN OUTCOME MEASURES Electrically evoked vestibulo-ocular reflexes (eeVOR). RESULTS Vestibular implant stimulation can drive stimulus-aligned eeVOR and elicit a vestibular percept 23 years after the onset of bilateral vestibulopathy. Prosthetic stimulation targeting individual semicircular canals elicited eye movements that approximately aligned with each targeted canal's axis. The magnitude of the eeVOR response increased with increasing stimulus current amplitude. Response alignment and magnitude were similar to those observed for implant recipients who underwent vestibular implantation less than 10 years after BVH onset. Responses were approximately stable for 18 months of continuous device use (24 h/d except during sleep). CONCLUSIONS Vestibular implantation and prosthetic electrical stimulation of semicircular canal afferent nerves can drive canal-specific eye movement responses more than 20 years after the onset of ototoxic vestibular hypofunction.
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Affiliation(s)
- Desi P. Schoo
- Johns Hopkins University School of Medicine, Department of Otolaryngology-Head and Neck Surgery
| | - Andrianna I. Ayiotis
- Johns Hopkins University School of Medicine, Department of Biomedical Engineering
| | | | - Margaret R. Chow
- Johns Hopkins University School of Medicine, Department of Biomedical Engineering
- Labyrinth Devices, LLC, Baltimore, Maryland, USA
| | - Kelly E. Lane
- Johns Hopkins University School of Medicine, Department of Biomedical Engineering
| | - Bryan K. Ward
- Johns Hopkins University School of Medicine, Department of Otolaryngology-Head and Neck Surgery
| | - John P. Carey
- Johns Hopkins University School of Medicine, Department of Otolaryngology-Head and Neck Surgery
| | - Charles C. Della Santina
- Johns Hopkins University School of Medicine, Department of Otolaryngology-Head and Neck Surgery
- Johns Hopkins University School of Medicine, Department of Biomedical Engineering
- Labyrinth Devices, LLC, Baltimore, Maryland, USA
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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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Starkov D, Pleshkov M, Guinand N, Pérez Fornos A, Ranieri M, Cavuscens S, Stultiens JJA, Devocht EMJ, Kingma H, van de Berg R. Optimized Signal Analysis to Quantify the Non-Linear Behaviour of the Electrically Evoked Vestibulo-Ocular Reflex in Patients with a Vestibular Implant. Audiol Neurootol 2022; 27:458-468. [PMID: 35817001 PMCID: PMC9808707 DOI: 10.1159/000525577] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 06/06/2022] [Indexed: 01/07/2023] Open
Abstract
INTRODUCTION Different eye movement analysis algorithms are used in vestibular implant research to quantify the electrically evoked vestibulo-ocular reflex (eVOR). Often, standard techniques are used as applied for quantification of the natural VOR in healthy subjects and patients with vestibular loss. However, in previous research, it was observed that the morphology of the VOR and eVOR may differ substantially. In this study, it was investigated if the analysis techniques for eVOR need to be adapted to optimize a truthful quantification of the eVOR (VOR gain, orientation of the VOR axis, asymmetry, and phase shift). METHODS "Natural" VOR responses were obtained in six age-matched healthy subjects, and eVOR responses were obtained in eight bilateral-vestibulopathy patients fitted with a vestibular implant. Three conditions were tested: "nVOR" 1-Hz sinusoidal whole-body rotations of healthy subjects in a rotatory chair, "eVOR" 1-Hz sinusoidal electrical vestibular implant stimulation without whole-body rotations in bilateral-vestibulopathy patients, and "dVOR" 1-Hz sinusoidal whole-body rotations in bilateral-vestibulopathy patients using the chair-mounted gyroscope output to drive the electrical vestibular implant stimulation (therefore also in sync 1 Hz sinusoidal). VOR outcomes were determined from the obtained VOR responses, using three different eye movement analysis paradigms: (1) peak eye velocity detection using the raw eye traces; (2) peak eye velocity detection using full-cycle sine fitting of eye traces; (3) peak eye velocity detection using half-cycle sine fitting of eye traces. RESULTS The type of eye movement analysis algorithm significantly influenced VOR outcomes, especially regarding the VOR gain and asymmetry of the eVOR in bilateral-vestibulopathy patients fitted with a vestibular implant. Full-cycle fitting lowered VOR gain in the eVOR condition (mean difference: 0.14 ± 0.06 95% CI, p = 0.018). Half-cycle fitting lowered VOR gain in the dVOR condition (mean difference: 0.08 ± 0.04 95% CI, p = 0.009). In the eVOR condition, half-cycle fitting was able to demonstrate the asymmetry between the excitatory and inhibitory phases of stimulation in comparison with the full-cycle fitting (mean difference: 0.19 ± 0.12 95% CI, p = 0.024). The VOR axis and phase shift did not differ significantly between eye movement analysis algorithms. In healthy subjects, no clinically significant effect of eye movement analysis algorithms on VOR outcomes was observed. CONCLUSION For the analysis of the eVOR, the excitatory and inhibitory phases of stimulation should be analysed separately due to the inherent asymmetry of the eVOR. A half-cycle fitting method can be used as a more accurate alternative for the analysis of the full-cycle traces.
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Affiliation(s)
- Dmitrii Starkov
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands,Faculty of Physics, Tomsk State Research University, Tomsk, Russian Federation,*Dmitrii Starkov,
| | - Maksim Pleshkov
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands,Faculty of Physics, Tomsk State Research University, Tomsk, Russian Federation
| | - Nils Guinand
- Department of Clinical Neurosciences, Service of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals, Geneva, Switzerland
| | - Angélica Pérez Fornos
- Department of Clinical Neurosciences, Service of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals, Geneva, Switzerland
| | - Maurizio Ranieri
- Department of Clinical Neurosciences, Service of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals, Geneva, Switzerland
| | - Samuel Cavuscens
- Department of Clinical Neurosciences, Service of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals, Geneva, Switzerland
| | - Joost Johannes Antonius Stultiens
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Elke Maria Johanna Devocht
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Herman Kingma
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands,Faculty of Physics, Tomsk State Research University, Tomsk, Russian Federation
| | - Raymond van de Berg
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands,Faculty of Physics, Tomsk State Research University, Tomsk, Russian Federation
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Abolpour Moshizi S, Pastras CJ, Sharma R, Parvez Mahmud MA, Ryan R, Razmjou A, Asadnia M. Recent advancements in bioelectronic devices to interface with the peripheral vestibular system. Biosens Bioelectron 2022; 214:114521. [PMID: 35820254 DOI: 10.1016/j.bios.2022.114521] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 06/23/2022] [Accepted: 06/27/2022] [Indexed: 11/26/2022]
Abstract
Balance disorders affect approximately 30% of the population throughout their lives and result in debilitating symptoms, such as spontaneous vertigo, nystagmus, and oscillopsia. The main cause of balance disorders is peripheral vestibular dysfunction, which may occur as a result of hair cell loss, neural dysfunction, or mechanical (and morphological) abnormality. The most common cause of vestibular dysfunction is arguably vestibular hair cell damage, which can result from an array of factors, such as ototoxicity, trauma, genetics, and ageing. One promising therapy is the vestibular prosthesis, which leverages the success of the cochlear implant, and endeavours to electrically integrate the primary vestibular afferents with the vestibular scene. Other translational approaches of interest include stem cell regeneration and gene therapies, which aim to restore or modify inner ear receptor function. However, both of these techniques are in their infancy and are currently undergoing further characterization and development in the laboratory, using animal models. Another promising translational avenue to treating vestibular hair cell dysfunction is the potential development of artificial biocompatible hair cell sensors, aiming to replicate functional hair cells and generate synthetic 'receptor potentials' for sensory coding of vestibular stimuli to the brain. Recently, artificial hair cell sensors have demonstrated significant promise, with improvements in their output, such as sensitivity and frequency selectivity. This article reviews the history and current state of bioelectronic devices to interface with the labyrinth, spanning the vestibular implant and artificial hair cell sensors.
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Affiliation(s)
| | - Christopher John Pastras
- School of Engineering, Macquarie University, Sydney, NSW, Australia; School of Medical Sciences, University of Sydney, NSW, Australia
| | - Rajni Sharma
- School of Engineering, Macquarie University, Sydney, NSW, Australia
| | - M A Parvez Mahmud
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - Rachel Ryan
- College of Public Health, The Ohio State University, Columbus, OH, 43210, United States
| | - Amir Razmjou
- School of Engineering, Macquarie University, Sydney, NSW, Australia; School of Engineering, Edith Cowan University, Joondalup, Perth, WA, 6027, Australia
| | - Mohsen Asadnia
- School of Engineering, Macquarie University, Sydney, NSW, Australia.
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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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16
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Aaron KA, Hosseini DK, Vaisbuch Y, Scheibinger M, Grillet N, Heller S, Wang T, Cheng AG. Selection Criteria Optimal for Recovery of Inner Ear Tissues From Deceased Organ Donors. Otol Neurotol 2022; 43:e507-e514. [PMID: 35120078 PMCID: PMC9527037 DOI: 10.1097/mao.0000000000003496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To identify optimal conditions for recovering viable inner ear tissues from deceased organ donors. SETTING Tertiary recovery hospitals and Donor Network West Organ Recovery Center. INTERVENTIONS Recovering bilateral inner ear tissues and immunohistological analysis. MAIN OUTCOME MEASURES Immunohistochemical analysis of utricles from human organ donors after brain death (DBD) or donors after cardiac death (DCD). RESULTS Vestibular tissues from 21 organ donors (39 ears) were recovered. Of these, 18 donors (33 utricles) were examined by immunofluorescence. The sensory epithelium was present in seven utricles (two from DBD and five from DCD). Relative to DBD utricles, DCD organs more commonly displayed dense populations of hair cells and supporting cells. Relative to DBD, DCD had significantly shorter postmortem interval time to tissue recovery (<48 h). Compared to donors with no sensory epithelium, donors with intact and viable sensory epithelium (both DCD and DBD) had significantly shorter lag time to resuscitation prior to hospital admission (6.4 ± 9.2 vs 35.6 ± 23.7 min, respectively) as well as a shorter time between pronouncements of death to organ recovery (22.6 ± 30.4 vs 64.8 ± 22.8 h, respectively). CONCLUSIONS Organ donors are a novel resource for bilateral inner ear organs. Selecting tissue donors within defined parameters can optimize the quality of recovered inner ear tissues, thereby facilitating future research investigating sensory and nonsensory cells.
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Affiliation(s)
- Ksenia A. Aaron
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Davood K. Hosseini
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
- Department of Internal Medicine, Hackensack University Medical Center, Hackensack. New Jersey, USA
| | - Yona Vaisbuch
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
- Department of Otolaryngology-Head and Neck Surgery, Rambam Medical Center, Haifa, Israel
| | - Mirko Scheibinger
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Nicolas Grillet
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Stefan Heller
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Tian Wang
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Alan G. Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
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17
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Pleshkov MO, D'Alessandro S, Svetlik M, Starkov D, Zaytsev V, Handler M, Baumgarten D, Saba R, van de Berg R, Demkin V, Kingma H. Fitting the determined impedance in the guinea pig inner ear to randles circuit using square error minimization in the range of 100 Hz to 50 kHz. Biomed Phys Eng Express 2022; 8. [PMID: 35042198 DOI: 10.1088/2057-1976/ac4c4a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 01/18/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE A number of lumped and distributed parameter models of the inner ear have been proposed in order to improve the vestibular implant stimulation. The models should account for all significant physical phenomena influencing the current propagation: electrical double layer (EDL) and medium polarization. The electrical properties of the medium are reflected in the electrical impedance, therefore the aim of this study was to measure the impedance in the guinea pig inner ear and construct its equivalent circuit. APPROACH The electrical impedance was measured from 100 Hz to 50 kHz between a pair of platinum electrodes immersed in saline solution using sinusoidal voltage signals. The Randles circuit was fitted to the measured impedance in the saline solution in order to estimate the EDL parameters (C, W, and Rct) of the electrode interface in saline. Then, the electrical impedance was measured between all combinations of the electrodes located in semicircular canal ampullae and the vestibular nerve in the guinea pig in vitro. The extended Randles circuit considering the medium polarization (Ri, Re, Cm) together with EDL parameters (C, Rct) obtained from the saline solution was fitted to the measured impedance of the guinea pig inner ear. The Warburg element was assumed negligible and was not considered in the guinea pig model. MAIN RESULTS For the set-up used, the obtained EDL parameters were: C=27.09*10-8F, Rct=18.75 kΩ. The average values of intra-, extracellular resistances, and membrane capacitance were Ri=4.74 kΩ, Re=45.05 kΩ, Cm=9.69*10-8F, respectively. SIGNIFICANCE The obtained values of the model parameters can serve as a good estimation of the EDL for modelling work. The EDL, together with medium polarization, plays a significant role in the electrical impedance of the guinea pig inner ear, therefore, they should be considered in electrical conductivity models to increase the credibility of the simulations.
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Affiliation(s)
- Maksim Olegovich Pleshkov
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Maastricht University Medical Centre+, P. Debyelaan 25, Maastricht, Limburg, 6202 AZ, NETHERLANDS
| | | | - Mikhail Svetlik
- Biological Institute, National Research Tomsk State University, Lenin ave., 36, Tomsk, Tomskaâ, 634050, RUSSIAN FEDERATION
| | - Dmitrii Starkov
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Maastricht University Medical Centre+, P. Debyelaan 25, Maastricht, Limburg, 6229 HX, NETHERLANDS
| | - Vasilii Zaytsev
- Physics Faculty, Laboratory for modelling of physical processes in biology and medicine Tomsk, National Research Tomsk State University, Lenin ave., 36, Tomsk, Tomskaâ, 634050, RUSSIAN FEDERATION
| | - Michael Handler
- Institute of Electrical and Biomedical Engineering, UMIT, Eduard-Wallnöfer-Zentrum 1, Hall in Tirol, Tirol, 6060, AUSTRIA
| | - Daniel Baumgarten
- Institute of Electrical and Biomedical Engineering, UMIT, Eduard-Wallnöfer-Zentrum 1, Hall in Tirol, Tirol, 6060, AUSTRIA
| | - Rami Saba
- MED-EL Electromedical Equipment, Fürstenweg 77a, Innsbruck, Tyrol, 6020, AUSTRIA
| | - Raymond van de Berg
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Maastricht University Medical Centre+, P. Debyelaan 25, Maastricht, Limburg, 6229 HX, NETHERLANDS
| | - Vladimir Demkin
- Physics Faculty, National Research Tomsk State University, Lenin ave., 36, Tomsk, Tomskaâ, 634050, RUSSIAN FEDERATION
| | - Herman Kingma
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Maastricht University Medical Centre+, P. Debyelaan 25, Maastricht, Limburg, 6229 HX, NETHERLANDS
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18
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Peusner KD, Bell NM, Hirsch JC, Beraneck M, Popratiloff A. Understanding the Pathophysiology of Congenital Vestibular Disorders: Current Challenges and Future Directions. Front Neurol 2021; 12:708395. [PMID: 34589045 PMCID: PMC8475631 DOI: 10.3389/fneur.2021.708395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/13/2021] [Indexed: 12/13/2022] Open
Abstract
In congenital vestibular disorders (CVDs), children develop an abnormal inner ear before birth and face postnatal challenges to maintain posture, balance, walking, eye-hand coordination, eye tracking, or reading. Only limited information on inner ear pathology is acquired from clinical imaging of the temporal bone or studying histological slides of the temporal bone. A more comprehensive and precise assessment and determination of the underlying mechanisms necessitate analyses of the disorders at the cellular level, which can be achieved using animal models. Two main criteria for a suitable animal model are first, a pathology that mirrors the human disorder, and second, a reproducible experimental outcome leading to statistical power. With over 40 genes that affect inner ear development, the phenotypic abnormalities resulting from congenital vestibular disorders (CVDs) are highly variable. Nonetheless, there is a large subset of CVDs that form a common phenotype of a sac-like inner ear with the semicircular canals missing or dysplastic, and discrete abnormalities in the vestibular sensory organs. We have focused the review on this subset, but to advance research on CVDs we have added other CVDs not forming a sac-like inner ear. We have included examples of animal models used to study these CVDs. Presently, little is known about the central pathology resulting from CVDs at the cellular level in the central vestibular neural network, except for preliminary studies on a chick model that show significant loss of second-order, vestibular reflex projection neurons.
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Affiliation(s)
- Kenna D Peusner
- Department of Neurology, The George Washington University School of Medicine and Health Sciences, Washington, DC, United States
| | - Nina M Bell
- Department of Neurology, The George Washington University School of Medicine and Health Sciences, Washington, DC, United States
| | - June C Hirsch
- Department of Neurology, The George Washington University School of Medicine and Health Sciences, Washington, DC, United States
| | - Mathieu Beraneck
- Université de Paris, Integrative Neuroscience and Cognition Center, CNRS UMR 8002, Paris, France
| | - Anastas Popratiloff
- The George Washington University Nanofabrication and Imaging Center, Washington, DC, United States
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19
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Lanthaler D, Griessner A, Steixner V, Hubner PP, Ranieri M, Cavuscens S, Boutabla A, Zierhofer CM, Perez Fornos A. Speech Perception With Novel Stimulation Strategies for CombinedCochleo-Vestibular Systems. IEEE Trans Neural Syst Rehabil Eng 2021; 29:1644-1650. [PMID: 34398757 DOI: 10.1109/tnsre.2021.3105271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cochlear implants are very well established in the rehabilitation of hearing loss and are regarded as the most successful neuroprostheses to date. While a lot of progress has also been made in the neighboring field of specific vestibular implants, some diseases affect the entire inner ear, leading to both hearing and vestibular hypo- or dysfunction. The proximity of the cochlear and vestibular organs suggests a single combined implant as a means to alleviate the associated impairments. While both organs can be stimulated in a similar way with electric pulses applied through implanted electrodes, the typical phase durations needed in the vestibular system seem to be substantially larger than those typically needed in the cochlear system. Therefore, when using sequential stimulation in a combined implant, the pulse stream to the cochlea is interrupted by comparatively large gaps in which vestibular stimulation can occur. We investigate the impact of these gaps in the auditory stream on speech perception. Specifically, we compare a number of stimulation strategies with different gap lengths and distributions and evaluate whether it is feasible to use them without having a noticeable decline in perception and quality of speech. This is a prerequisite for any practicable stimulation strategy of a combined system and can be investigated even in recipients of a normal cochlear implant. Our results show that there is no significant deterioration in speech perception for the different strategies examined in this paper, leaving the strategies as viable candidates for prospective combined cochleo-vestibular implants.
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20
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Stultiens JJA, Guinand N, Van Rompaey V, Pérez Fornos A, Kunst HPM, Kingma H, van de Berg R. The resilience of the inner ear-vestibular and audiometric impact of transmastoid semicircular canal plugging. J Neurol 2021; 269:5229-5238. [PMID: 34374862 PMCID: PMC9467949 DOI: 10.1007/s00415-021-10693-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/18/2021] [Accepted: 06/28/2021] [Indexed: 11/30/2022]
Abstract
Background Certain cases of superior semicircular canal dehiscence or benign paroxysmal positional vertigo can be treated by plugging of the affected semicircular canal. However, the extent of the impact on vestibular function and hearing during postoperative follow-up is not known. Objective To evaluate the evolution of vestibular function and hearing after plugging of a semicircular canal. Methods Six patients underwent testing before and 1 week, 2 months, and 6 months after plugging of the superior or posterior semicircular canal. Testing included caloric irrigation test, video Head Impulse Test (vHIT), cervical and ocular Vestibular Evoked Myogenic Potentials (VEMPs) and audiometry. Results Initially, ipsilateral caloric response decreased in all patients and vHIT vestibulo-ocular reflex (VOR) gain of each ipsilateral semicircular canal decreased in 4/6 patients. In 4/6 patients, postoperative caloric response recovered to > 60% of the preoperative value. In 5/6 patients, vHIT VOR gain was restored to > 85% of the preoperative value for both ipsilateral non-plugged semicircular canals. In the plugged semicircular canal, this gain decreased in 4/5 patients and recovered to > 50% of the preoperative value. Four patients preserved cervical and ocular VEMP responses. Bone conduction hearing deteriorated in 3/6 patients, but recovered within 6 months postoperatively, although one patient had a persistent loss of 15 dB at 8 kHz. Conclusion Plugging of a semicircular canal can affect both vestibular function and hearing. After initial deterioration, most patients show recovery during follow-up. However, a vestibular function loss or high-frequency hearing loss can persist. This stresses the importance of adequate counseling of patients considering plugging of a semicircular canal. Supplementary Information The online version contains supplementary material available at 10.1007/s00415-021-10693-5.
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Affiliation(s)
- Joost J A Stultiens
- Department of Otorhinolaryngology & Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.
| | - Nils Guinand
- Division of Otorhinolaryngology and Head-and-Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Vincent Van Rompaey
- Department of Otorhinolaryngology and Head & Neck Surgery, Faculty of Medicine and Health Sciences, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
| | - Angélica Pérez Fornos
- Division of Otorhinolaryngology and Head-and-Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Henricus P M Kunst
- Department of Otorhinolaryngology & Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Hermanus Kingma
- Department of Otorhinolaryngology & Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Raymond van de Berg
- Department of Otorhinolaryngology & Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands
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21
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Jiang D, Liu F, Lancashire HT, Perkins TA, Schormans M, Vanhoestenberghe A, Donaldson NDN, Demosthenous A. A Versatile Hermetically Sealed Microelectronic Implant for Peripheral Nerve Stimulation Applications. Front Neurosci 2021; 15:681021. [PMID: 34366773 PMCID: PMC8339274 DOI: 10.3389/fnins.2021.681021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/15/2021] [Indexed: 11/25/2022] Open
Abstract
This article presents a versatile neurostimulation platform featuring a fully implantable multi-channel neural stimulator for chronic experimental studies with freely moving large animal models involving peripheral nerves. The implant is hermetically sealed in a ceramic enclosure and encapsulated in medical grade silicone rubber, and then underwent active tests at accelerated aging conditions at 100°C for 15 consecutive days. The stimulator microelectronics are implemented in a 0.6-μm CMOS technology, with a crosstalk reduction scheme to minimize cross-channel interference, and high-speed power and data telemetry for battery-less operation. A wearable transmitter equipped with a Bluetooth Low Energy radio link, and a custom graphical user interface provide real-time, remotely controlled stimulation. Three parallel stimulators provide independent stimulation on three channels, where each stimulator supports six stimulating sites and two return sites through multiplexing, hence the implant can facilitate stimulation at up to 36 different electrode pairs. The design of the electronics, method of hermetic packaging and electrical performance as well as in vitro testing with electrodes in saline are presented.
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Affiliation(s)
- Dai Jiang
- Department of Electronic and Electrical Engineering, University College London, London, United Kingdom
| | - Fangqi Liu
- Department of Electronic and Electrical Engineering, University College London, London, United Kingdom
| | - Henry T Lancashire
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Timothy A Perkins
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Matthew Schormans
- Department of Electronic and Electrical Engineering, University College London, London, United Kingdom
| | - Anne Vanhoestenberghe
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom.,Division of Surgery and Interventional Science, Aspire Centre for Rehabilitation Engineering and Assistive Technology, University College London, London, United Kingdom
| | - Nicholas De N Donaldson
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Andreas Demosthenous
- Department of Electronic and Electrical Engineering, University College London, London, United Kingdom
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22
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Carender WJ, Grzesiak M, Telian SA. Vestibular Physical Therapy and Fall Risk Assessment. Otolaryngol Clin North Am 2021; 54:1015-1036. [PMID: 34304897 DOI: 10.1016/j.otc.2021.05.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Vestibular physical therapy (VPT) is a specialized form of evidence-based therapy designed to alleviate primary (vertigo, dizziness, imbalance, gait instability, falls) and secondary (deconditioning, cervical muscle tension, anxiety, poor quality of life, fear of falling/fear avoidance behavior) symptoms related to vestibular disorders. This article provides an overview of VPT, highlighting various exercise modalities used to treat a variety of vestibular disorders. Patient safety and fall prevention are paramount; therefore, fall risk assessment and treatment are also addressed.
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Affiliation(s)
- Wendy J Carender
- Department of Otolaryngology-Head & Neck Surgery, Michigan Medicine, University of Michigan, Michigan Balance Vestibular Testing and Rehabilitation, Med Inn Building, Room C166A, 1500 East Medical Center Drive, Ann Arbor, MI 48109-5816, USA.
| | - Melissa Grzesiak
- Department of Otolaryngology-Head & Neck Surgery, Michigan Medicine, University of Michigan, Michigan Balance Vestibular Testing and Rehabilitation, Med Inn Building, Room C166A, 1500 East Medical Center Drive, Ann Arbor, MI 48109-5816, USA
| | - Steven A Telian
- Department of Otolaryngology-Head & Neck Surgery, University of Michigan, 1500 East Medical Center Drive, TC 1904L, Ann Arbor, MI 48109-5312, USA
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23
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Schoo DP, Ward BK. New Frontiers in Managing the Dizzy Patient. Otolaryngol Clin North Am 2021; 54:1069-1080. [PMID: 34294438 DOI: 10.1016/j.otc.2021.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Despite progress in vestibular research in the last 20 years, much remains poorly understood about vestibular pathophysiology and its management. A shared language is a critical first step in understanding vestibular disorders and is under development. Telehealth will continue for patients with dizziness, and ambulatory monitoring of nystagmus will become a diagnostic tool. In the next 2 decades, it is anticipated that vestibular perceptual threshold testing will become common in tertiary centers, imaging with improved spatial resolution will yield better understanding of vestibular pathophysiology, and that vestibular implants will become a part of clinical practice.
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Affiliation(s)
- Desi P Schoo
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, 601 North Caroline Street, Baltimore, MD 21287, USA
| | - Bryan K Ward
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, 601 North Caroline Street, Baltimore, MD 21287, USA.
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24
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Rodriguez Montesdeoca I, Ramos de Miguel A, González JCF, Barreiro SB, Pérez Fernández N, Vanspauwen R, Ramos-Macias A. Differences in Vestibular-Evoked Myogenic Potential Responses by Using Cochlear Implant and Otolith Organ Direct Stimulation. Front Neurol 2021; 12:663803. [PMID: 34113311 PMCID: PMC8185293 DOI: 10.3389/fneur.2021.663803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/08/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: Several studies have demonstrated the possibility to obtain vestibular potentials elicited with electrical stimulation from cochlear and vestibular implants. The objective of this study is to analyze the vestibular-evoked myogenic potentials (VEMPs) obtained from patients implanted with cochlear and vestibulo-cochlear implant. Material and Methods: We compared two groups: in the first group, four cochlear implant (CI) recipients with present acoustic cVEMPs before CI surgery were included. In the second group, three patients with bilaterally absent cVEMPs and bilateral vestibular dysfunction were selected. The latter group received a unilateral cochleo-vestibular implant. We analyze the electrically elicited cVEMPs in all patients after stimulation with cochlear and vestibular electrode array stimulation. Results: We present the results obtained post-operatively in both groups. All patients (100%) with direct electrical vestibular stimulation via the vestibular electrode array had present cVEMPs. The P1 and N1 latencies were 11.33-13.6 ms and 18.3-21 ms, respectively. In CI patients, electrical cVEMPs were present only in one of the four subjects (25%) with cochlear implant ("cross") stimulation, and P1 and N1 latencies were 9.67 and 16.33, respectively. In these patients, the responses present shorter latencies than those observed acoustically. Conclusions: Electrically evoked cVEMPs can be present after cochlear and vestibular stimulation and suggest stimulation of vestibular elements, although clinical effect must be further studied.
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Affiliation(s)
- Isaura Rodriguez Montesdeoca
- Department of Otolaryngology, Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, Las Palmas, Spain
| | - Angel Ramos de Miguel
- Hearing and Balance Laboratory, Las Palmas de Gran Canaria University (SIANI), Las Palmas, Spain
| | - Juan Carlos Falcon González
- Department of Otolaryngology, Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, Las Palmas, Spain
| | - Silvia Borkoski Barreiro
- Department of Otolaryngology, Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, Las Palmas, Spain
| | | | - Robby Vanspauwen
- European Institute for Otorhinolaryngology Head and Neck Surgery, Gasthuiszusters Antwerpen Hospitals Antwerp, Wilrijk, Belgium
| | - Angel Ramos-Macias
- Department of Otolaryngology, Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, Las Palmas, Spain.,Hearing and Balance Laboratory, Las Palmas de Gran Canaria University (SIANI), Las Palmas, Spain
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25
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Abstract
PURPOSE OF REVIEW Determining the etiology of disorders that manifest with chronic dizziness can seem a daunting task, but extracting some basic elements of the patient's history can reduce the differential diagnosis significantly. This includes determining initial triggers, timing of symptoms, associated features, and exacerbating factors. This article covers distinct causes of chronic dizziness including persistent postural perceptual dizziness, mal de débarquement syndrome, motion sickness and visually induced motion sickness, bilateral vestibulopathy, and persistent dizziness after mild concussion. RECENT FINDINGS To date, none of the disorders above has a cure but are considered chronic syndromes with fluctuations that are both innate and driven by environmental stressors. As such, the mainstay of therapy for chronic disorders of dizziness involves managing factors that exacerbate symptoms and adding vestibular rehabilitation or cognitive-behavioral therapy alone or in combination, as appropriate. These therapies are supplemented by serotonergic antidepressants that modulate sensory gating and reduce anxiety. Besides expectation management, ruling out concurrent disorders and recognizing behavioral and lifestyle factors that affect symptom severity are critical issues in reducing morbidity for each disorder. SUMMARY Many syndromes of chronic dizziness can be diagnosed by recognition of key features, although many symptoms overlap between these groups. Symptoms may be manageable and improve with time, but they are often incompletely relieved.
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26
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Abstract
PURPOSE OF REVIEW This article reviews the causes of tinnitus, hyperacusis, and otalgia, as well as hearing loss relevant for clinicians in the field of neurology. RECENT FINDINGS Important causes of unilateral and bilateral tinnitus are discussed, including those that are treatable or caused by serious structural or vascular causes. Concepts of hyperacusis and misophonia are covered, along with various types of neurologic disorders that can lead to pain in the ear. Hearing loss is common but not always purely otologic. SUMMARY Tinnitus and hearing loss are common symptoms that are sometimes related to a primary neurologic disorder. This review, tailored to neurologists who care for patients who may be referred to or encountered in neurology practice, provides information on hearing disorders, how to recognize when a neurologic process may be involved, and when to refer to otolaryngology or other specialists.
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27
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An Implanted Vestibular Prosthesis Improves Spatial Orientation in Animals with Severe Vestibular Damage. J Neurosci 2021; 41:3879-3888. [PMID: 33731447 DOI: 10.1523/jneurosci.2204-20.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 02/10/2021] [Accepted: 03/08/2021] [Indexed: 11/21/2022] Open
Abstract
Gravity is a pervasive environmental stimulus, and accurate graviception is required for optimal spatial orientation and postural stability. The primary graviceptors are the vestibular organs, which include angular velocity (semicircular canals) and linear acceleration (otolith organs) sensors. Graviception is degraded in patients with vestibular damage, resulting in spatial misperception and imbalance. Since minimal therapy is available for these patients, substantial effort has focused on developing a vestibular prosthesis or vestibular implant (VI) that reproduces information normally provided by the canals (since reproducing otolith function is very challenging technically). Prior studies demonstrated that angular eye velocity responses could be driven by canal VI-mediated angular head velocity information, but it remains unknown whether a canal VI could improve spatial perception and posture since these behaviors require accurate estimates of angular head position in space relative to gravity. Here, we tested the hypothesis that a canal VI that transduces angular head velocity and provides this information to the brain via motion-modulated electrical stimulation of canal afferent nerves could improve the perception of angular head position relative to gravity in monkeys with severe vestibular damage. Using a subjective visual vertical task, we found that normal female monkeys accurately sensed the orientation of the head relative to gravity during dynamic tilts, that this ability was degraded following bilateral vestibular damage, and improved when the canal VI was used. These results demonstrate that a canal VI can improve graviception in vestibulopathic animals, suggesting that it could reduce the disabling perceptual and postural deficits experienced by patients with severe vestibular damage.SIGNIFICANCE STATEMENT Patients with vestibular damage experience impaired vision, spatial perception, and balance, symptoms that could potentially respond to a vestibular implant (VI). Anatomic features facilitate semicircular canal (angular velocity) prosthetics but inhibit approaches with the otolith (linear acceleration) organs, and canal VIs that sense angular head velocity can generate compensatory eye velocity responses in vestibulopathic subjects. Can the brain use canal VI head velocity information to improve estimates of head orientation (e.g., head position relative to gravity), which is a prerequisite for accurate spatial perception and posture? Here we show that a canal VI can improve the perception of head orientation in vestibulopathic monkeys, results that are highly significant because they suggest that VIs mimicking canal function can improve spatial orientation and balance in vestibulopathic patients.
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28
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Chow MR, Ayiotis AI, Schoo DP, Gimmon Y, Lane KE, Morris BJ, Rahman MA, Valentin NS, Boutros PJ, Bowditch SP, Ward BK, Sun DQ, Treviño Guajardo C, Schubert MC, Carey JP, Della Santina CC. Posture, Gait, Quality of Life, and Hearing with a Vestibular Implant. N Engl J Med 2021; 384:521-532. [PMID: 33567192 PMCID: PMC8477665 DOI: 10.1056/nejmoa2020457] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Bilateral vestibular hypofunction is associated with chronic disequilibrium, postural instability, and unsteady gait owing to failure of vestibular reflexes that stabilize the eyes, head, and body. A vestibular implant may be effective in alleviating symptoms. METHODS Persons who had had ototoxic (7 participants) or idiopathic (1 participant) bilateral vestibular hypofunction for 2 to 23 years underwent unilateral implantation of a prosthesis that electrically stimulates the three semicircular canal branches of the vestibular nerve. Clinical outcomes included the score on the Bruininks-Oseretsky Test of Motor Proficiency balance subtest (range, 0 to 36, with higher scores indicating better balance), time to failure on the modified Romberg test (range, 0 to 30 seconds), score on the Dynamic Gait Index (range, 0 to 24, with higher scores indicating better gait performance), time needed to complete the Timed Up and Go test, gait speed, pure-tone auditory detection thresholds, speech discrimination scores, and quality of life. We compared participants' results at baseline (before implantation) with those at 6 months (8 participants) and at 1 year (6 participants) with the device set in its usual treatment mode (varying stimulus pulse rate and amplitude to represent rotational head motion) and in a placebo mode (holding pulse rate and amplitude constant). RESULTS The median scores at baseline and at 6 months on the Bruininks-Oseretsky test were 17.5 and 21.0, respectively (median within-participant difference, 5.5 points; 95% confidence interval [CI], 0 to 10.0); the median times on the modified Romberg test were 3.6 seconds and 8.3 seconds (difference, 5.1; 95% CI, 1.5 to 27.6); the median scores on the Dynamic Gait Index were 12.5 and 22.5 (difference, 10.5 points; 95% CI, 1.5 to 12.0); the median times on the Timed Up and Go test were 11.0 seconds and 8.7 seconds (difference, 2.3; 95% CI, -1.7 to 5.0); and the median speeds on the gait-speed test were 1.03 m per second and 1.10 m per second (difference, 0.13; 95% CI, -0.25 to 0.30). Placebo-mode testing confirmed that improvements were due to treatment-mode stimulation. Among the 6 participants who were also assessed at 1 year, the median within-participant changes from baseline to 1 year were generally consistent with results at 6 months. Implantation caused ipsilateral hearing loss, with the air-conducted pure-tone average detection threshold at 6 months increasing by 3 to 16 dB in 5 participants and by 74 to 104 dB in 3 participants. Changes in participant-reported disability and quality of life paralleled changes in posture and gait. CONCLUSIONS Six months and 1 year after unilateral implantation of a vestibular prosthesis for bilateral vestibular hypofunction, measures of posture, gait, and quality of life were generally in the direction of improvement from baseline, but hearing was reduced in the ear with the implant in all but 1 participant. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT02725463.).
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Affiliation(s)
- Margaret R Chow
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Andrianna I Ayiotis
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Desi P Schoo
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Yoav Gimmon
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Kelly E Lane
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Brian J Morris
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Mehdi A Rahman
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Nicolas S Valentin
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Peter J Boutros
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Stephen P Bowditch
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Bryan K Ward
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Daniel Q Sun
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Carolina Treviño Guajardo
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Michael C Schubert
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - John P Carey
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
| | - Charles C Della Santina
- From the Departments of Otolaryngology-Head and Neck Surgery (M.R.C., A.I.A., D.P.S., Y.G., K.E.L., B.J.M., P.J.B., S.P.B., B.K.W., D.Q.S., C.T.G., M.C.S., J.P.C., C.C.D.S.) and Biomedical Engineering (M.R.C., A.I.A., B.J.M., P.J.B., C.C.D.S.), Johns Hopkins University School of Medicine, and Labyrinth Devices (M.A.R., N.S.V., C.C.D.S.) - both in Baltimore
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29
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Hedjoudje A, Schoo DP, Ward BK, Carey JP, Della Santina CC, Pearl M. Vestibular Implant Imaging. AJNR Am J Neuroradiol 2021; 42:370-376. [PMID: 33361382 PMCID: PMC7872165 DOI: 10.3174/ajnr.a6991] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 09/10/2020] [Indexed: 11/07/2022]
Abstract
Analogous to hearing restoration via cochlear implants, vestibular function could be restored via vestibular implants that electrically stimulate vestibular nerve branches to encode head motion. This study presents the technical feasibility and first imaging results of CT for vestibular implants in 8 participants of the first-in-human Multichannel Vestibular Implant Early Feasibility Study. Imaging characteristics of 8 participants (3 men, 5 women; median age, 59.5 years; range, 51-66 years) implanted with a Multichannel Vestibular Implant System who underwent a postimplantation multislice CT (n = 2) or flat panel CT (n = 6) are reported. The device comprises 9 platinum electrodes inserted into the ampullae of the 3 semicircular canals and 1 reference electrode inserted in the common crus. Electrode insertion site, positions, length and angle of insertion, and number of artifacts were assessed. Individual electrode contacts were barely discernible in the 2 participants imaged using multislice CT. Electrode and osseous structures were detectable but blurred so that only 12 of the 18 stimulating electrode contacts could be individually identified. Flat panel CT could identify all 10 electrode contacts in all 6 participants. The median reference electrode insertion depth angle was 9° (range, -57.5° to 45°), and the median reference electrode insertion length was 42 mm (range, -21-66 mm). Flat panel CT of vestibular implants produces higher-resolution images with fewer artifacts than multidetector row CT, allowing visualization of individual electrode contacts and quantification of their locations relative to vestibular semicircular canals and ampullae. As multichannel vestibular implant imaging improves, so will our understanding of the relationship between electrode placement and vestibular performance.
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Affiliation(s)
- A Hedjoudje
- From the Department of Otolaryngology-Head and Neck Surgery (A.H., D.P.S., B.K.W., J.P.C., C.C.D.S.)
- Division of Interventional Neuroradiology (A.H., M.P.)
- Neuroradiology Unit (A.H.), Service of diagnostic and interventional imaging, Sion Hospital, Sion, Valais, Switzerland
| | - D P Schoo
- From the Department of Otolaryngology-Head and Neck Surgery (A.H., D.P.S., B.K.W., J.P.C., C.C.D.S.)
| | - B K Ward
- From the Department of Otolaryngology-Head and Neck Surgery (A.H., D.P.S., B.K.W., J.P.C., C.C.D.S.)
| | - J P Carey
- From the Department of Otolaryngology-Head and Neck Surgery (A.H., D.P.S., B.K.W., J.P.C., C.C.D.S.)
| | - C C Della Santina
- From the Department of Otolaryngology-Head and Neck Surgery (A.H., D.P.S., B.K.W., J.P.C., C.C.D.S.)
- Department of Biomedical Engineering (C.C.D.S.), Johns Hopkins University School of Medicine, Baltimore, Maryland
- Labyrinth Devices (C.C.D.S.), Baltimore, Maryland
| | - M Pearl
- Division of Interventional Neuroradiology (A.H., M.P.)
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Simultaneous activation of multiple vestibular pathways upon electrical stimulation of semicircular canal afferents. J Neurol 2020; 267:273-284. [PMID: 32778921 PMCID: PMC7718208 DOI: 10.1007/s00415-020-10120-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/02/2020] [Accepted: 07/27/2020] [Indexed: 11/23/2022]
Abstract
Background and purpose Vestibular implants seem to be a promising treatment for patients suffering from severe bilateral vestibulopathy. To optimize outcomes, we need to investigate how, and to which extent, the different vestibular pathways are activated. Here we characterized the simultaneous responses to electrical stimuli of three different vestibular pathways. Methods Three vestibular implant recipients were included. First, activation thresholds and amplitude growth functions of electrically evoked vestibulo-ocular reflexes (eVOR), cervical myogenic potentials (ecVEMPs) and vestibular percepts (vestibulo-thalamo-cortical, VTC) were recorded upon stimulation with single, biphasic current pulses (200 µs/phase) delivered through five different vestibular electrodes. Latencies of eVOR and ecVEMPs were also characterized. Then we compared the amplitude growth functions of the three pathways using different stimulation profiles (1-pulse, 200 µs/phase; 1-pulse, 50 µs/phase; 4-pulses, 50 µs/phase, 1600 pulses-per-second) in one patient (two electrodes). Results The median latencies of the eVOR and ecVEMPs were 8 ms (8–9 ms) and 10.2 ms (9.6–11.8 ms), respectively. While the amplitude of eVOR and ecVEMP responses increased with increasing stimulation current, the VTC pathway showed a different, step-like behavior. In this study, the 200 µs/phase paradigm appeared to give the best balance to enhance responses at lower stimulation currents. Conclusions This study is a first attempt to evaluate the simultaneous activation of different vestibular pathways. However, this issue deserves further and more detailed investigation to determine the actual possibility of selective stimulation of a given pathway, as well as the functional impact of the contribution of each pathway to the overall rehabilitation process.
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Guyot JP, Guinand N, Perez Fornos A. Tribute to Bernard Cohen - Whose Pioneering Work Made the Vestibular Implant Possible. Front Neurol 2020; 11:452. [PMID: 32536904 PMCID: PMC7267219 DOI: 10.3389/fneur.2020.00452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 04/28/2020] [Indexed: 11/13/2022] Open
Affiliation(s)
- Jean-Philippe Guyot
- Division of ENT and Head-and-Neck Surgery, Geneva University Hospitals, Geneva, Switzerland
| | - Nils Guinand
- Division of ENT and Head-and-Neck Surgery, Geneva University Hospitals, Geneva, Switzerland
| | - Angelica Perez Fornos
- Division of ENT and Head-and-Neck Surgery, Geneva University Hospitals, Geneva, Switzerland
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Crétallaz C, Boutabla A, Cavuscens S, Ranieri M, Nguyen TAK, Kingma H, Van De Berg R, Guinand N, Pérez Fornos A. Influence of systematic variations of the stimulation profile on responses evoked with a vestibular implant prototype in humans. J Neural Eng 2020; 17:036027. [PMID: 32213673 PMCID: PMC8630998 DOI: 10.1088/1741-2552/ab8342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE To explore the impact of different electrical stimulation profiles in human recipients of the Geneva-Maastricht vestibular implant prototypes. APPROACH Four implanted patients were recruited for this study. We investigated the relative efficacy of systematic variations of the electrical stimulus profile (phase duration, pulse rate, baseline level, modulation depth) in evoking vestibulo-ocular (eVOR) and perceptual responses. MAIN RESULTS Shorter phase durations and, to a lesser extent, slower pulse rates allowed maximizing the electrical dynamic range available for eliciting a wider range of intensities of vestibular percepts. When either the phase duration or the pulse rate was held constant, current modulation depth was the factor that had the most significant impact on peak velocity of the eVOR. SIGNIFICANCE Our results identified important parametric variations that influence the measured responses. Furthermore, we observed that not all vestibular pathways seem equally sensitive to the electrical stimulus when the electrodes are placed in the semicircular canals and monopolar stimulation is used. This opens the door to evaluating new stimulation strategies for a vestibular implant, and suggests the possibility of selectively activating one vestibular pathway or the other in order to optimize rehabilitation outcomes.
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Affiliation(s)
- Céline Crétallaz
- Division of Otorhinolaryngology Head and Neck Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
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Hazen M, Cushing SL. Implications of Concurrent Vestibular Dysfunction in Pediatric Hearing Loss. CURRENT OTORHINOLARYNGOLOGY REPORTS 2020. [DOI: 10.1007/s40136-020-00298-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Hageman KN, Chow MR, Roberts D, Boutros PJ, Tooker A, Lee K, Felix S, Pannu SS, Haque R, Della Santina CC. Binocular 3D otolith-ocular reflexes: responses of chinchillas to prosthetic electrical stimulation targeting the utricle and saccule. J Neurophysiol 2019; 123:259-276. [PMID: 31747349 DOI: 10.1152/jn.00883.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
From animal experiments by Cohen and Suzuki et al. in the 1960s to the first-in-human clinical trials now in progress, prosthetic electrical stimulation targeting semicircular canal branches of the vestibular nerve has proven effective at driving directionally appropriate vestibulo-ocular reflex eye movements, postural responses, and perception. That work was considerably facilitated by the fact that all hair cells and primary afferent neurons in each canal have the same directional sensitivity to head rotation, the three canals' ampullary nerves are geometrically distinct from one another, and electrically evoked three-dimensional (3D) canal-ocular reflex responses approximate a simple vector sum of linearly independent components representing relative excitation of each of the three canals. In contrast, selective prosthetic stimulation of the utricle and saccule has been difficult to achieve, because hair cells and afferents with many different directional sensitivities are densely packed in those endorgans and the relationship between 3D otolith-ocular reflex responses and the natural and/or prosthetic stimuli that elicit them is more complex. As a result, controversy exists regarding whether selective, controllable stimulation of electrically evoked otolith-ocular reflexes (eeOOR) is possible. Using micromachined, planar arrays of electrodes implanted in the labyrinth, we quantified 3D, binocular eeOOR responses to prosthetic electrical stimulation targeting the utricle, saccule, and semicircular canals of alert chinchillas. Stimuli delivered via near-bipolar electrode pairs near the maculae elicited sustained ocular countertilt responses that grew reliably with pulse rate and pulse amplitude, varied in direction according to which stimulating electrode was employed, and exhibited temporal dynamics consistent with responses expected for isolated macular stimulation.NEW & NOTEWORTHY As the second in a pair of papers on Binocular 3D Otolith-Ocular Reflexes, this paper describes new planar electrode arrays and vestibular prosthesis architecture designed to target the three semicircular canals and the utricle and saccule. With this technological advancement, electrically evoked otolith-ocular reflexes due to stimulation via utricle- and saccule-targeted electrodes were recorded in chinchillas. Results demonstrate advances toward achieving selective stimulation of the utricle and saccule.
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Affiliation(s)
- Kristin N Hageman
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Margaret R Chow
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Dale Roberts
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Peter J Boutros
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Angela Tooker
- Lawrence Livermore National Laboratory, Livermore, California
| | - Kye Lee
- Lawrence Livermore National Laboratory, Livermore, California
| | - Sarah Felix
- Lawrence Livermore National Laboratory, Livermore, California
| | | | - Razi Haque
- Lawrence Livermore National Laboratory, Livermore, California
| | - Charles C Della Santina
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
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Hageman KN, Chow MR, Roberts D, Della Santina CC. Binocular 3D otolith-ocular reflexes: responses of normal chinchillas to tilt and translation. J Neurophysiol 2019; 123:243-258. [PMID: 31747360 DOI: 10.1152/jn.00882.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Head rotation, translation, and tilt with respect to a gravitational field elicit reflexive eye movements that partially stabilize images of Earth-fixed objects on the retinas of humans and other vertebrates. Compared with the angular vestibulo-ocular reflex, responses to translation and tilt, collectively called the otolith-ocular reflex (OOR), are less completely characterized, typically smaller, generally disconjugate (different for the 2 eyes) and more complicated in their relationship to the natural stimuli that elicit them. We measured binocular 3-dimensional OOR responses of 6 alert normal chinchillas in darkness during whole body tilts around 16 Earth-horizontal axes and translations along 21 axes in horizontal, coronal, and sagittal planes. Ocular countertilt responses to 40-s whole body tilts about Earth-horizontal axes grew linearly with head tilt amplitude, but responses were disconjugate, with each eye's response greatest for whole body tilts about axes near the other eye's resting line of sight. OOR response magnitude during 1-Hz sinusoidal whole body translations along Earth-horizontal axes also grew with stimulus amplitude. Translational OOR responses were similarly disconjugate, with each eye's response greatest for whole body translations along its resting line of sight. Responses to Earth-horizontal translation were similar to those that would be expected for tilts that would cause a similar peak deviation of the gravitoinertial acceleration (GIA) vector with respect to the head, consistent with the "perceived tilt" model of the OOR. However, that model poorly fit responses to translations along non-Earth-horizontal axes and was insufficient to explain why responses are larger for the eye toward which the GIA vector deviates.NEW & NOTEWORTHY As the first in a pair of papers on Binocular 3D Otolith-Ocular Reflexes, this paper characterizes binocular 3D eye movements in normal chinchillas during tilts and translations. The eye movement responses were used to create a data set to fully define the normal otolith-ocular reflexes in chinchillas. This data set provides the foundation to use otolith-ocular reflexes to back-project direction and magnitude of eye movement to predict tilt axis as discussed in the companion paper.
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Affiliation(s)
- Kristin N Hageman
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Margaret R Chow
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Dale Roberts
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Charles C Della Santina
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
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