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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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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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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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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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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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Stultiens JJA, Postma AA, Guinand N, Pérez Fornos A, Kingma H, van de Berg R. Vestibular Implantation and the Feasibility of Fluoroscopy-Guided Electrode Insertion. Otolaryngol Clin North Am 2019; 53:115-126. [PMID: 31677739 DOI: 10.1016/j.otc.2019.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recent research has shown promising results for the development of a clinically feasible vestibular implant in the near future. However, correct electrode placement remains a challenge. It was shown that fluoroscopy was able to visualize the semicircular canal ampullae and electrodes, and guide electrode insertion in real time. Ninety-four percent of the 18 electrodes were implanted correctly (<1.5 mm distance to target). The median distances were 0.60 mm, 0.85 mm, and 0.65 mm for the superior, lateral, and posterior semicircular canal, respectively. These findings suggest that fluoroscopy can significantly improve electrode placement during vestibular implantation.
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Affiliation(s)
- Joost Johannes Antonius Stultiens
- Department of Otorhinolaryngology-Head and Neck Surgery, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, P.O. box 5800, 6202 AZ, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Alida Annechien Postma
- Department of Radiology and Nuclear Medicine, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, P.O. box 5800, 6202 AZ, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Nils Guinand
- Division of Otorhinolaryngology-Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Rue Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland
| | - Angélica Pérez Fornos
- Division of Otorhinolaryngology-Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Rue Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland
| | - Hermanus Kingma
- Department of Otorhinolaryngology-Head and Neck Surgery, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, P.O. box 5800, 6202 AZ, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Raymond van de Berg
- Department of Otorhinolaryngology-Head and Neck Surgery, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, P.O. box 5800, 6202 AZ, Maastricht University Medical Center, Maastricht, The Netherlands.
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Vestibular implant: does it really work? A systematic review. Braz J Otorhinolaryngol 2019; 85:788-798. [PMID: 31606334 PMCID: PMC9443005 DOI: 10.1016/j.bjorl.2019.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 07/11/2019] [Accepted: 07/29/2019] [Indexed: 11/25/2022] Open
Abstract
Introduction People with vestibular loss present a deficit in the vestibular system, which is primarily responsible for promoting postural control, gaze stabilization, and spatial orientation while the head moves. There is no effective treatment for a bilateral loss of vestibular function. Recently, a vestibular implant was developed for people with bilateral loss of vestibular function to improve this function and, consequently, the quality of life of these patients. Objective To identify in the scientific literature evidence that vestibular implants in people with vestibular deficit improves vestibular function. Methods One hundred and forty six articles were found from five databases and 323 articles from the gray literature mentioning the relationship between vestibular implant and vestibular function in humans. The PICOS strategy (Population, Intervention, Comparison and Outcome) was used to define the eligibility criteria. The studies that met the inclusion criteria for this second step were included in a qualitative synthesis, and each type of study was analyzed according to the bias risk assessment of the Joanna Briggs Institute through the critical assessment checklist Joanna Briggs institute for quasi-experimental studies and the Joanna Briggs institute critical assessment checklist for case reports. Results Of the 21 articles included in reading the full text, 10 studies were selected for the qualitative analysis in the present systematic review. All ten articles analyzed through the critical assessment checklist Joanna Briggs institute showed a low risk of bias. The total number of samples in the evaluated articles was 18 patients with vestibular implants. Conclusions Taken together, these findings support the feasibility of vestibular implant for restoration of the vestibulo-ocular reflex in a broad frequency range and illustrate new challenges for the development of this technology.
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Sluydts M, Curthoys I, Vanspauwen R, Papsin BC, Cushing SL, Ramos A, Ramos de Miguel A, Borkoski Barreiro S, Barbara M, Manrique M, Zarowski A. Electrical Vestibular Stimulation in Humans: A Narrative Review. Audiol Neurootol 2019; 25:6-24. [PMID: 31533097 DOI: 10.1159/000502407] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/29/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND In patients with bilateral vestibulopathy, the regular treatment options, such as medication, surgery, and/or vestibular rehabilitation, do not always suffice. Therefore, the focus in this field of vestibular research shifted to electrical vestibular stimulation (EVS) and the development of a system capable of artificially restoring the vestibular function. Key Message: Currently, three approaches are being investigated: vestibular co-stimulation with a cochlear implant (CI), EVS with a vestibular implant (VI), and galvanic vestibular stimulation (GVS). All three applications show promising results but due to conceptual differences and the experimental state, a consensus on which application is the most ideal for which type of patient is still missing. SUMMARY Vestibular co-stimulation with a CI is based on "spread of excitation," which is a phenomenon that occurs when the currents from the CI spread to the surrounding structures and stimulate them. It has been shown that CI activation can indeed result in stimulation of the vestibular structures. Therefore, the question was raised whether vestibular co-stimulation can be functionally used in patients with bilateral vestibulopathy. A more direct vestibular stimulation method can be accomplished by implantation and activation of a VI. The concept of the VI is based on the technology and principles of the CI. Different VI prototypes are currently being evaluated regarding feasibility and functionality. So far, all of them were capable of activating different types of vestibular reflexes. A third stimulation method is GVS, which requires the use of surface electrodes instead of an implanted electrode array. However, as the currents are sent through the skull from one mastoid to the other, GVS is rather unspecific. It should be mentioned though, that the reported spread of excitation in both CI and VI use also seems to induce a more unspecific stimulation. Although all three applications of EVS were shown to be effective, it has yet to be defined which option is more desirable based on applicability and efficiency. It is possible and even likely that there is a place for all three approaches, given the diversity of the patient population who serves to gain from such technologies.
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Affiliation(s)
- Morgana Sluydts
- European Institute for Otorhinolaryngology, GZA Hospitals Antwerp, Wilrijk, Belgium,
| | - Ian Curthoys
- Vestibular Research Laboratory, University of Sydney, Sydney, New South Wales, Australia
| | - Robby Vanspauwen
- European Institute for Otorhinolaryngology, GZA Hospitals Antwerp, Wilrijk, Belgium
| | - Blake Croll Papsin
- Department of Otolaryngology - Head and Neck Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sharon Lynn Cushing
- Department of Otolaryngology - Head and Neck Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Angel Ramos
- Hearing Loss Unit, Otorhinolaryngology, Head and Neck Department, Complejo Hospitalario Universitario Insular Materno Infantil, Las Palmas of Gran Canaria, Spain
| | - Angel Ramos de Miguel
- Hearing Loss Unit, Otorhinolaryngology, Head and Neck Department, Complejo Hospitalario Universitario Insular Materno Infantil, Las Palmas of Gran Canaria, Spain
| | - Silvia Borkoski Barreiro
- Hearing Loss Unit, Otorhinolaryngology, Head and Neck Department, Complejo Hospitalario Universitario Insular Materno Infantil, Las Palmas of Gran Canaria, Spain
| | | | - Manuel Manrique
- Otorhinolaryngology Department, Clinica Universidad de Navarra, Pamplona, Spain
| | - Andrzej Zarowski
- European Institute for Otorhinolaryngology, GZA Hospitals Antwerp, Wilrijk, Belgium
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Abstract
Purpose of review Bilateral vestibular deficits exist and their prevalence is more important than believed by the medical community. Their severe impact has inspired several teams to develop technical solutions in an attempt to rehabilitate patients. A particularly promising pathway is the vestibular implant. This article describes the main milestones in this field, mainly focusing on work conducted in human patients. Recent findings There have been substantial research efforts, first in animals and more recently in humans, toward the development of vestibular implants. Humans have demonstrated surprising adaptation capabilities to the artificial vestibular signal. Today, the possibility of restoring vestibular reflexes, particularly the vestibulo-ocular reflex, and even achieving useful function in close-to-reality tasks (i.e. improving visual abilities while walking) have been demonstrated in humans. Summary The vestibular implant opens new perspectives, not only as an effective therapeutic tool, but also pushes us to go beyond current knowledge and well-established clinical concepts.
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Schier P, Handler M, Johnson Chacko L, Schrott-Fischer A, Fritscher K, Saba R, Baumgartner C, Baumgarten D. Model-Based Vestibular Afferent Stimulation: Evaluating Selective Electrode Locations and Stimulation Waveform Shapes. Front Neurosci 2018; 12:588. [PMID: 30214391 PMCID: PMC6125370 DOI: 10.3389/fnins.2018.00588] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 08/06/2018] [Indexed: 12/02/2022] Open
Abstract
A dysfunctional vestibular system can be a severe detriment to the quality of life of a patient. Recent studies have shown the feasibility for a vestibular implant to restore rotational sensation via electrical stimulation of vestibular ampullary nerves. However, the optimal stimulation site for selective elicitation of the desired nerve is still unknown. We realized a finite element model on the basis of μCT scans of a human inner ear and incorporated naturally distributed, artificial neural trajectories. A well-validated neuron model of myelinated fibers was incorporated to predict nerve responses to electrical stimulation. Several virtual electrodes were placed in locations of interest inside the bony labyrinth (intra-labyrinthine) and inside the temporal bone, near the target nerves (extra-labyrinthine), to determine preferred stimulation sites and electrode insertion depths. We investigated various monopolar and bipolar electrode configurations as well as different pulse waveform shapes for their ability to selectively stimulate the target nerve and for their energy consumption. The selectivity was evaluated with an objective measure of the fiber recruitment. Considerable differences of required energy and achievable selectivity between the configurations were observed. Bipolar, intra-labyrinthine electrodes provided the best selectivities but also consumed the highest amount of energy. Bipolar, extra-labyrinthine configurations did not offer any advantages compared to the monopolar approach. No selective stimulation could be performed with the monopolar, intra-labyrinthine approach. The monopolar, extra-labyrinthine electrodes required the least energy for satisfactory selectivities, making it the most promising approach for functional vestibular implants. Different pulse waveform shapes did not affect the achieved selectivity considerably but shorter pulse durations showed consistently a more selective activation of the target nerves. A cathodic, centered triangular waveform shape was identified as the most energy-efficient of the tested shapes. Based on these simulations we are able to recommend the monopolar, extra-labyrinthine stimulation approach with cathodic, centered triangular pulses as good trade-off between selectivity and energy consumption. Future implant designs could benefit from the findings presented here.
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Affiliation(s)
- Peter Schier
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, UMIT-Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Michael Handler
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, UMIT-Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Lejo Johnson Chacko
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Karl Fritscher
- Department for Biomedical Computer Science and Mechatronics, Institute of Biomedical Image Analysis, UMIT-Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | | | - Christian Baumgartner
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, UMIT-Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria.,Faculty of Computer Science and Biomedical Engineering, Institute of Health Care Engineering, Graz University of Technology, Graz, Austria
| | - Daniel Baumgarten
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, UMIT-Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria.,Department of Computer Science and Automation, Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
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Hitier M, Sato G, Zhang YF, Zheng Y, Besnard S, Smith PF. Vestibular-related eye movements in the rat following selective electrical stimulation of the vestibular sensors. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:835-847. [DOI: 10.1007/s00359-018-1286-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/29/2018] [Accepted: 09/04/2018] [Indexed: 01/26/2023]
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Abstract
Sensorineural hearing loss (SNHL) in children occurs in 1 to 3% of live births and acquired hearing loss can additionally occur. This sensory deficit has far reaching consequences that have been shown to extend beyond speech and language development. Thankfully there are many therapeutic options that exist for these children with the aim of decreasing the morbidity of their hearing impairment. Of late, focus has shifted beyond speech and language outcomes to the overall performance of children with SNHL in real-world environments. To account for their residual deficits in such environments, clinicians must understand the extent of their sensory impairments. SNHL commonly coexists with other sensory deficits such as vestibular loss. Vestibular impairment is exceedingly common in children with SNHL with nearly half of children exhibiting vestibular end-organ dysfunction. These deficits naturally lead to impairments in balance and delay in motor milestones. However, this additional sensory deficit likely leads to further impairment in the performance of these children. This article focuses on the following: 1. Defining the coexistence of vestibular impairment in children with SNHL and cochlear implants. 2. Describing screening methods aimed at identifying vestibular dysfunction in children with SNHL. 3. Understanding the functional implications of this dual-sensory impairment. 4. Exploring possible rehabilitative strategies to minimize the impact of vestibular impairment in children with SNHL.
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Affiliation(s)
- Sharon L Cushing
- Department of Otolaryngology, Head and Neck Surgery, Hospital for Sick Children, Toronto, Ontario, Canada.,Cochlear Implant Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Blake C Papsin
- Department of Otolaryngology, Head and Neck Surgery, Hospital for Sick Children, Toronto, Ontario, Canada.,Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
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15
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Phillips JO, Ling L, Nowack AL, Phillips CM, Nie K, Rubinstein JT. The Dynamics of Prosthetically Elicited Vestibulo-Ocular Reflex Function Across Frequency and Context in the Rhesus Monkey. Front Neurosci 2018; 12:88. [PMID: 29867306 PMCID: PMC5962652 DOI: 10.3389/fnins.2018.00088] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 02/02/2018] [Indexed: 12/25/2022] Open
Abstract
Electrical vestibular neurostimulation may be a viable tool for modulating vestibular afferent input to restore vestibular function following injury or disease. To do this, such stimulators must provide afferent input that can be readily interpreted by the central nervous system to accurately represent head motion to drive reflexive behavior. Since vestibular afferents have different galvanic sensitivity, and different natural sensitivities to head rotational velocity and acceleration, and electrical stimulation produces aphysiological synchronous activation of multiple afferents, it is difficult to assign a priori an appropriate transformation between head velocity and acceleration and the properties of the electrical stimulus used to drive vestibular reflex function, i.e., biphasic pulse rate or pulse current amplitude. In order to empirically explore the nature of the transformation between vestibular prosthetic stimulation and vestibular reflex behavior, in Rhesus macaque monkeys we parametrically varied the pulse rate and current amplitude of constant rate and current amplitude pulse trains, and the modulation frequency of sinusoidally modulated pulse trains that were pulse frequency modulated (FM) or current amplitude modulated (AM). In addition, we examined the effects of differential eye position and head position on the observed eye movement responses. We conclude that there is a strong and idiosyncratic, from canal to canal, effect of modulation frequency on the observed eye velocities that are elicited by stimulation. In addition, there is a strong effect of initial eye position and initial head position on the observed responses. These are superimposed on the relationships between pulse frequency or current amplitude and eye velocity that have been shown previously.
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Affiliation(s)
- James O Phillips
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States.,Virginia Merril Bloedel Hearing Research Center, University of Washington, Seattle, WA, United States
| | - Leo Ling
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States
| | - Amy L Nowack
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States
| | - Christopher M Phillips
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States.,Epidemiology, University of Washington, Seattle, WA, United States
| | - Kaibao Nie
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Virginia Merril Bloedel Hearing Research Center, University of Washington, Seattle, WA, United States.,Bioengineering, University of Washington, Seattle, WA, United States
| | - Jay T Rubinstein
- Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States.,Virginia Merril Bloedel Hearing Research Center, University of Washington, Seattle, WA, United States.,Bioengineering, University of Washington, Seattle, WA, United States
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16
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Guinand N, Van de Berg R, Cavuscens S, Ranieri M, Schneider E, Lucieer F, Kingma H, Guyot JP, Pérez Fornos A. The Video Head Impulse Test to Assess the Efficacy of Vestibular Implants in Humans. Front Neurol 2017; 8:600. [PMID: 29184530 PMCID: PMC5694451 DOI: 10.3389/fneur.2017.00600] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 10/27/2017] [Indexed: 11/27/2022] Open
Abstract
The purpose of this study was to evaluate whether it is possible to restore the high-frequency angular vestibulo-ocular reflex (aVOR) in patients suffering from a severe bilateral vestibulopathy (BV) and implanted with a vestibular implant prototype. Three patients (S1–3) participated in the study. They received a prototype vestibular implant with one to three electrode branches implanted in the proximity of the ampullary branches of the vestibular nerve. Five electrodes were available for electrical stimulation: one implanted in proximity of the left posterior ampullary nerve in S1, one in the left lateral and another one in the superior ampullary nerves in S2, and one in the right lateral and another one in the superior ampullary nerves in S3. The high-frequency aVOR was assessed using the video head impulse test (EyeSeeCam; EyeSeeTec, Munich, Germany), while motion-modulated electrical stimulation was delivered via one of the implanted vestibular electrodes at a time. aVOR gains were compared to control measurements obtained in the same patients when the device was not activated. In three out of the five tested electrodes the aVOR gain increased monotonically with increased stimulation strength when head impulses were delivered in the plane of the implanted canal. In these cases, gains ranging from 0.4 to values above 1 were measured. A “reversed” aVOR could also be generated when inversed stimulation paradigms were used. In most cases, the gain for excitatory head impulses was superior to that recorded for inhibitory head impulses, consistent with unilateral vestibular stimulation. Improvements of aVOR gain were generally accompanied by a concomitant decrease of corrective saccades, providing additional evidence of an effective aVOR. High inter-electrode and inter-subject variability were observed. These results, together with previous research, demonstrate that it is possible to restore the aVOR in a broad frequency range using motion-modulated electrical stimulation of the vestibular afferents. This provides additional encouraging evidence of the possibility of achieving a useful rehabilitation alternative for patients with BV in the near future.
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Affiliation(s)
- Nils Guinand
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland.,Division of Balance Disorders, Department of ENT, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Raymond Van de Berg
- Division of Balance Disorders, Department of ENT, Maastricht University Medical Centre, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Samuel Cavuscens
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Maurizio Ranieri
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Erich Schneider
- Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
| | - Floor Lucieer
- Division of Balance Disorders, Department of ENT, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Herman Kingma
- Division of Balance Disorders, Department of ENT, Maastricht University Medical Centre, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Jean-Philippe Guyot
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Angélica Pérez Fornos
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
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17
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van de Berg R, Lucieer F, Guinand N, van Tongeren J, George E, Guyot JP, Kingma H, van Hoof M, Temel Y, van Overbeeke J, Perez-Fornos A, Stokroos R. The Vestibular Implant: Hearing Preservation during Intralabyrinthine Electrode Insertion-A Case Report. Front Neurol 2017; 8:137. [PMID: 28443060 PMCID: PMC5385458 DOI: 10.3389/fneur.2017.00137] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/24/2017] [Indexed: 11/30/2022] Open
Abstract
Objective The vestibular implant seems feasible as a clinically useful device in the near future. However, hearing preservation during intralabyrinthine implantation remains a challenge. It should be preserved to be able to treat patients with bilateral vestibulopathy and (partially) intact hearing. This case study investigated the feasibility of hearing preservation during the acute phase after electrode insertion in the semicircular canals. Methods A 40-year-old woman with normal hearing underwent a translabyrinthine approach for a vestibular schwannoma Koos Grade IV. Hearing was monitored using auditory brainstem response audiometry (ABR). ABR signals were recorded synchronously to video recordings of the surgery. Following the principles of soft surgery, a conventional dummy electrode was inserted in the lateral semicircular canal for several minutes and subsequently removed. The same procedure was then applied for the posterior canal. Finally, the labyrinthectomy was completed, and the schwannoma was removed. Results Surgery was performed without complications. No leakage of endolymph and no significant reduction of ABR response were observed during insertion and after removal of the electrodes from the semicircular canals, indicting no damage to the peripheral auditory function. The ABR response significantly changed when the semicircular canals were completely opened during the labyrinthectomy. This was indicated by a change in the morphology and latency of peak V of the ABR signal. Conclusion Electrode insertion in the semicircular canals is possible without acutely damaging the peripheral auditory function measured with ABR, as shown in this proof-of-principle clinical investigation.
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Affiliation(s)
- Raymond van de Berg
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Florence Lucieer
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Nils Guinand
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Joost van Tongeren
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Erwin George
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Jean-Philippe Guyot
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Herman Kingma
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Marc van Hoof
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Yasin Temel
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Jacobus van Overbeeke
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Angelica Perez-Fornos
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Robert Stokroos
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands
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18
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Perez Fornos A, Cavuscens S, Ranieri M, van de Berg R, Stokroos R, Kingma H, Guyot JP, Guinand N. The vestibular implant: A probe in orbit around the human balance system. J Vestib Res 2017; 27:51-61. [DOI: 10.3233/ves-170604] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Angelica Perez Fornos
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Samuel Cavuscens
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Maurizio Ranieri
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Raymond van de Berg
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, The Netherlands
- Faculty of Physics, Tomsk State University, Russian Federation
| | - Robert Stokroos
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Herman Kingma
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center, The Netherlands
- Faculty of Physics, Tomsk State University, Russian Federation
| | - Jean-Philippe Guyot
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Nils Guinand
- Department of Clinical Neurosciences, Service of Otorhinolaryngology, Head and Neck Surgery, University Hospitals, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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19
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Guinand N, van de Berg R, Ranieri M, Cavuscens S, DiGiovanna J, Nguyen TAK, Micera S, Stokroos R, Kingma H, Guyot JP, Perez Fornos A. Vestibular implants: Hope for improving the quality of life of patients with bilateral vestibular loss. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:7192-5. [PMID: 26737951 DOI: 10.1109/embc.2015.7320051] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The vestibular system plays an essential role in crucial tasks such as postural control, gaze stabilization, and spatial orientation. Currently, there is no effective treatment for a bilateral loss of the vestibular function (BVL). The quality of life of affected patients is significantly impaired. During the last decade, our group has explored the potential of using electrical stimulation to artificially restore the vestibular function. Our vestibular implant prototype consists of a custom modified cochlear implant featuring one to three vestibular electrodes implanted in the proximity of the ampullary branches of the vestibular nerve; in addition to the main cochlear array. Special surgical techniques for safe implantation of these devices have been developed. In addition, we have developed stimulation strategies to generate bidirectional eye movements as well as the necessary interfaces to capture the signal from a motion sensor (e.g., gyroscope) and use it to modulate the stimulation signals delivered to the vestibular nerves. To date, 24 vestibular electrodes have been implanted in 11 BVL patients. Using a virtual motion profile to modulate the "baseline" electrical stimulation, vestibular responses could be evoked with 21 electrodes. Eye movements with mean peak eye velocities of 32°/s and predominantly in the plane of the stimulated canal were successfully generated. These are within the range of normal compensatory eye movements during walking and were large enough to have a significant effect on the patients' visual acuity. These results indicate that electrical stimulation of the vestibular nerve has a significant functional impact; eye movements generated this way could be sufficient to restore gaze stabilization during essential everyday tasks such as walking. The innovative concept of the vestibular implant has the potential to restore the vestibular function and have a central role in improving the quality of life of BVL patients in the near future.
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20
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Nguyen TAK, DiGiovanna J, Cavuscens S, Ranieri M, Guinand N, van de Berg R, Carpaneto J, Kingma H, Guyot JP, Micera S, Fornos AP. Characterization of pulse amplitude and pulse rate modulation for a human vestibular implant during acute electrical stimulation. J Neural Eng 2016; 13:046023. [DOI: 10.1088/1741-2560/13/4/046023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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21
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DiGiovanna J, Nguyen TAK, Guinand N, Pérez-Fornos A, Micera S. Neural Network Model of Vestibular Nuclei Reaction to Onset of Vestibular Prosthetic Stimulation. Front Bioeng Biotechnol 2016; 4:34. [PMID: 27148528 PMCID: PMC4837148 DOI: 10.3389/fbioe.2016.00034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 03/30/2016] [Indexed: 11/24/2022] Open
Abstract
The vestibular system incorporates multiple sensory pathways to provide crucial information about head and body motion. Damage to the semicircular canals, the peripheral vestibular organs that sense rotational velocities of the head, can severely degrade the ability to perform activities of daily life. Vestibular prosthetics address this problem by using stimulating electrodes that can trigger primary vestibular afferents to modulate their firing rates, thus encoding head movement. These prostheses have been demonstrated chronically in multiple animal models and acutely tested in short-duration trials within the clinic in humans. However, mainly, due to limited opportunities to fully characterize stimulation parameters, there is a lack of understanding of “optimal” stimulation configurations for humans. Here, we model possible adaptive plasticity in the vestibular pathway. Specifically, this model highlights the influence of adaptation of synaptic strengths and offsets in the vestibular nuclei to compensate for the initial activation of the prosthetic. By changing the synaptic strengths, the model is able to replicate the clinical observation that erroneous eye movements are attenuated within 30 minutes without any change to the prosthetic stimulation rate. Although our model was only built to match this time point, we further examined how it affected subsequent pulse rate modulation (PRM) and pulse amplitude modulation (PAM). PAM was more effective than PRM for nearly all stimulation configurations during these acute tests. Two non-intuitive relationships highlighted by our model explain this performance discrepancy. Specifically, the attenuation of synaptic strengths for afferents stimulated during baseline adaptation and the discontinuity between baseline and residual firing rates both disproportionally boost PAM. Comodulation of pulse rate and amplitude has been experimentally shown to induce both excitatory and inhibitory eye movements even at high baseline stimulation rates. We also modeled comodulation and found synergistic combinations of stimulation parameters to achieve equivalent output to only amplitude modulation. This may be an important strategy to reduce current spread and misalignment. The model outputs reflected observed trends in clinical testing and aspects of existing vestibular prosthetic literature. Importantly, the model provided insight to efficiently explore the stimulation parameter space, which was helpful, given limited available patient time.
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Affiliation(s)
- Jack DiGiovanna
- Center for Neuroprosthetics, Bertarelli Foundation Chair in Translational Neuroengineering, École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland
| | - T A K Nguyen
- Center for Neuroprosthetics, Bertarelli Foundation Chair in Translational Neuroengineering, École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland
| | - Nils Guinand
- Cochlear Implant Center for French Speaking Switzerland, Service of Otorhinolaryngology - Head and Neck Surgery, Geneva University Hospitals , Geneva , Switzerland
| | - Angelica Pérez-Fornos
- Cochlear Implant Center for French Speaking Switzerland, Service of Otorhinolaryngology - Head and Neck Surgery, Geneva University Hospitals , Geneva , Switzerland
| | - Silvestro Micera
- Center for Neuroprosthetics, Bertarelli Foundation Chair in Translational Neuroengineering, École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland
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22
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Vestibular assistance systems: promises and challenges. J Neurol 2016; 263 Suppl 1:S30-5. [PMID: 27083882 PMCID: PMC4833784 DOI: 10.1007/s00415-015-7922-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 09/24/2015] [Accepted: 09/25/2015] [Indexed: 11/16/2022]
Abstract
The handicap resulting from a bilateral vestibular deficit is often underestimated. In most cases the deficit settles gradually. Patients do not understand what is happening to them and have many difficulties to describe their symptoms. They have to consult several doctors with different medical specialties before diagnosis. Once the diagnosis is made there is no biological way to “repair” the deficient vestibular apparatus and vestibular exercises are mildly effective. Attempts have been made to help patients using substitution devices replacing the defective vestibular information by tactile or acoustic cues. Currently, efforts are being made towards the development of a vestibular implant, conceptually similar to the cochlear implant for the rehabilitation of deaf patients. In recent years, several experiments on animal models have demonstrated the feasibility of this project. This paper reports the steps accomplished in human experiments and the main results obtained in our laboratory.
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23
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Hageman KN, Kalayjian ZK, Tejada F, Chiang B, Rahman MA, Fridman GY, Dai C, Pouliquen PO, Georgiou J, Della Santina CC, Andreou AG. A CMOS Neural Interface for a Multichannel Vestibular Prosthesis. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2016; 10:269-79. [PMID: 25974945 PMCID: PMC4641830 DOI: 10.1109/tbcas.2015.2409797] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We present a high-voltage CMOS neural-interface chip for a multichannel vestibular prosthesis (MVP) that measures head motion and modulates vestibular nerve activity to restore vision- and posture-stabilizing reflexes. This application specific integrated circuit neural interface (ASIC-NI) chip was designed to work with a commercially available microcontroller, which controls the ASIC-NI via a fast parallel interface to deliver biphasic stimulation pulses with 9-bit programmable current amplitude via 16 stimulation channels. The chip was fabricated in the ONSemi C5 0.5 micron, high-voltage CMOS process and can accommodate compliance voltages up to 12 V, stimulating vestibular nerve branches using biphasic current pulses up to 1.45±0.06 mA with durations as short as 10 μs/phase. The ASIC-NI includes a dedicated digital-to-analog converter for each channel, enabling it to perform complex multipolar stimulation. The ASIC-NI replaces discrete components that cover nearly half of the 2nd generation MVP (MVP2) printed circuit board, reducing the MVP system size by 48% and power consumption by 17%. Physiological tests of the ASIC-based MVP system (MVP2A) in a rhesus monkey produced reflexive eye movement responses to prosthetic stimulation similar to those observed when using the MVP2. Sinusoidal modulation of stimulus pulse rate from 68-130 pulses per second at frequencies from 0.1 to 5 Hz elicited appropriately-directed slow phase eye velocities ranging in amplitude from 1.9-16.7 °/s for the MVP2 and 2.0-14.2 °/s for the MVP2A. The eye velocities evoked by MVP2 and MVP2A showed no significant difference ( t-test, p=0.34), suggesting that the MVP2A achieves performance at least as good as the larger MVP2.
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Affiliation(s)
- Kristin N. Hageman
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Zaven K. Kalayjian
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Francisco Tejada
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Bryce Chiang
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Mehdi A. Rahman
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Gene Y. Fridman
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Chenkai Dai
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Philippe O. Pouliquen
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Julio Georgiou
- Department of Electrical and Computer Engineering, University of Cyprus, 1678 Nicosa, Cyprus
| | - Charles C. Della Santina
- Vestibular NeuroEngineering Lab (affiliated with the Departments of Biomedical Engineering and Otolaryngology Head and Neck Surgery), Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Andreas G. Andreou
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
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24
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Lucieer F, Vonk P, Guinand N, Stokroos R, Kingma H, van de Berg R. Bilateral Vestibular Hypofunction: Insights in Etiologies, Clinical Subtypes, and Diagnostics. Front Neurol 2016; 7:26. [PMID: 26973594 PMCID: PMC4777732 DOI: 10.3389/fneur.2016.00026] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/19/2016] [Indexed: 01/03/2023] Open
Abstract
Objective To evaluate the different etiologies and clinical subtypes of bilateral vestibular hypofunction (BVH) and the value of diagnostic tools in the diagnostic process of BVH. Materials and methods A retrospective case review was performed on 154 patients diagnosed with BVH in a tertiary referral center, between 2013 and 2015. Inclusion criteria comprised (1) imbalance and/or oscillopsia during locomotion and (2) summated slow phase velocity of nystagmus of less than 20°/s during bithermal caloric tests. Results The definite etiology of BVH was determined in 47% of the cases and the probable etiology in 22%. In 31%, the etiology of BVH remained idiopathic. BVH resulted from more than 20 different etiologies. In the idiopathic group, the percentage of migraine was significantly higher compared to the non-idiopathic group (50 versus 11%, p < 0.001). Among all patients, 23.4% were known with autoimmune disorders in their medical history. All four clinical subtypes (recurrent vertigo with BVH, rapidly progressive BVH, slowly progressive BVH, and slowly progressive BVH with ataxia) were found in this population. Slowly progressive BVH with ataxia comprised only 4.5% of the cases. The head impulse test was abnormal in 94% of the cases. The torsion swing test was abnormal in 66%. Bilateral normal hearing to moderate hearing loss was found in 49%. Blood tests did not often contribute to the determination of the etiology of the disease. Abnormal cerebral imaging was found in 21 patients. Conclusion BVH is a heterogeneous condition with various etiologies and clinical characteristics. Migraine seems to play a significant role in idiopathic BVH and autoimmunity could be a modulating factor in the development of BVH. The distribution of etiologies of BVH probably depends on the clinical setting. In the diagnostic process of BVH, the routine use of some blood tests can be reconsidered and a low-threshold use of audiometry and cerebral imaging is advised. The torsion swing test is not the “gold standard” for diagnosing BVH due to its lack of sensitivity. Future diagnostic criteria of BVH should consist of standardized vestibular tests combined with a history that is congruent with the vestibular findings.
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Affiliation(s)
- F Lucieer
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, Maastricht University Medical Center, School for Mental Health and Neuroscience , Maastricht , Netherlands
| | - P Vonk
- Faculty of Health, Medicine and life Sciences, University of Maastricht , Maastricht , Netherlands
| | - N Guinand
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals , Geneva , Switzerland
| | - R Stokroos
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, Maastricht University Medical Center, School for Mental Health and Neuroscience , Maastricht , Netherlands
| | - H Kingma
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, Maastricht University Medical Center, School for Mental Health and Neuroscience, Maastricht, Netherlands; Faculty of Physics, Tomsk State Research University, Tomsk, Russian Federation
| | - Raymond van de Berg
- Department of Otorhinolaryngology and Head and Neck Surgery, Division of Balance Disorders, Faculty of Health Medicine and Life Sciences, Maastricht University Medical Center, School for Mental Health and Neuroscience, Maastricht, Netherlands; Faculty of Physics, Tomsk State Research University, Tomsk, Russian Federation
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Loss of Afferent Vestibular Input Produces Central Adaptation and Increased Gain of Vestibular Prosthetic Stimulation. J Assoc Res Otolaryngol 2015; 17:19-35. [PMID: 26438271 DOI: 10.1007/s10162-015-0544-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 09/14/2015] [Indexed: 11/29/2022] Open
Abstract
Implanted vestibular neurostimulators are effective in driving slow phase eye movements in monkeys and humans. Furthermore, increases in slow phase velocity and electrically evoked compound action potential (vECAP) amplitudes occur with increasing current amplitude of electrical stimulation. In intact monkeys, protracted intermittent stimulation continues to produce robust behavioral responses and preserved vECAPs. In lesioned monkeys, shorter duration studies show preserved but with somewhat lower or higher velocity behavioral responses. It has been proposed that such changes are due to central adaptive changes in the electrically elicited vestibulo-ocular reflex (VOR). It is equally possible that these differences are due to changes in the vestibular periphery in response to activation of the vestibular efferent system. In order to investigate the site of adaptive change in response to electrical stimulation, we performed transtympanic gentamicin perfusions to induce rapid changes in vestibular input in monkeys with long-standing stably functioning vestibular neurostimulators, disambiguating the effects of implantation from the effects of ototoxic lesion. Gentamicin injection was effective in producing a large reduction in natural VOR only when it was performed in the non-implanted ear, suggesting that the implanted ear contributed little to the natural rotational response before injection. Injection of the implanted ear produced a reduction in the vECAP responses in that ear, suggesting that the intact hair cells in the non-functional ipsilateral ear were successfully lesioned by gentamicin, reducing the efficacy of stimulation in that ear. Despite this, injection of both ears produced central plastic changes that resulted in a dramatically increased slow phase velocity nystagmus elicited by electrical stimulation. These results suggest that loss of vestibular afferent activity, and a concurrent loss of electrically elicited vestibular input, produces an increase in the efficacy of a vestibular neurostimulator by eliciting centrally adapted behavioral responses without concurrent adaptive increase of galvanic afferent activation in the periphery.
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Gay A, Guinand N, Miffon M, Guyot JP. Perception of Discomfort Caused by a Unilateral Hearing Loss in People Suffering from a Total Bilateral Vestibular Loss. ORL J Otorhinolaryngol Relat Spec 2015; 77:248-253. [DOI: 10.1159/000433552] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Guinand N, van de Berg R, Cavuscens S, Stokroos RJ, Ranieri M, Pelizzone M, Kingma H, Guyot JP, Perez-Fornos A. Vestibular Implants: 8 Years of Experience with Electrical Stimulation of the Vestibular Nerve in 11 Patients with Bilateral Vestibular Loss. ORL J Otorhinolaryngol Relat Spec 2015; 77:227-240. [PMID: 26367113 DOI: 10.1159/000433554] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND The concept of the vestibular implant is primarily to artificially restore the vestibular function in patients with a bilateral vestibular loss (BVL) by providing the central nervous system with motion information using electrical stimulation of the vestibular nerve. Our group initiated human trials about 10 years ago. METHODS Between 2007 and 2013, 11 patients with a BVL received a vestibular implant prototype providing electrodes to stimulate the ampullary branches of the vestibular nerve. Eye movements were recorded and analyzed to assess the effects of the electrical stimulation. Perception induced by electrical stimulation was documented. RESULTS Smooth, controlled eye movements were obtained in all patients showing that electrical stimulation successfully activated the vestibulo-ocular pathway. However, both the electrical dynamic range and the amplitude of the eye movements were variable from patient to patient. The axis of the response was consistent with the stimulated nerve branch in 17 out of the 24 tested electrodes. Furthermore, in at least 1 case, the elicited eye movements showed characteristics similar to those of compensatory eye movements observed during natural activities such as walking. Finally, diverse percepts were reported upon electrical stimulation (i.e., rotatory sensations, sound, tickling or pressure) with intensity increasing as the stimulation current increased. CONCLUSIONS These results demonstrate that electrical stimulation is a safe and effective means to activate the vestibular system, even in a heterogeneous patient population with very different etiologies and disease durations. Successful tuning of this information could turn this vestibular implant prototype into a successful artificial balance organ.
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Marianelli P, Capogrosso M, Bassi Luciani L, Panarese A, Micera S. A Computational Framework for Electrical Stimulation of Vestibular Nerve. IEEE Trans Neural Syst Rehabil Eng 2015; 23:897-909. [DOI: 10.1109/tnsre.2015.2407861] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Phillips C, Ling L, Oxford T, Nowack A, Nie K, Rubinstein JT, Phillips JO. Longitudinal performance of an implantable vestibular prosthesis. Hear Res 2015; 322:200-11. [PMID: 25245586 PMCID: PMC4369472 DOI: 10.1016/j.heares.2014.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 08/20/2014] [Accepted: 09/08/2014] [Indexed: 11/30/2022]
Abstract
Loss of vestibular function may be treatable with an implantable vestibular prosthesis that stimulates semicircular canal afferents with biphasic pulse trains. Several studies have demonstrated short-term activation of the vestibulo-ocular reflex (VOR) with electrical stimulation. Fewer long-term studies have been restricted to small numbers of animals and stimulation designed to produce adaptive changes in the electrically elicited response. This study is the first large consecutive series of implanted rhesus macaque to be studied longitudinally using brief stimuli designed to limit adaptive changes in response, so that the efficacy of electrical activation can be studied over time, across surgeries, canals and animals. The implantation of a vestibular prosthesis in animals with intact vestibular end organs produces variable responses to electrical stimulation across canals and animals, which change in threshold for electrical activation of eye movements and in elicited slow phase velocities over time. These thresholds are consistently lower, and the slow phase velocities higher, than those obtained in human subjects. The changes do not appear to be correlated with changes in electrode impedance. The variability in response suggests that empirically derived transfer functions may be required to optimize the response of individual canals to a vestibular prosthesis, and that this function may need to be remapped over time. This article is part of a Special Issue entitled .
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Affiliation(s)
| | - Leo Ling
- Otolaryngology - HNS, University of Washington, Seattle, WA, USA; Washington National Primate Research Center, University of Washington, Seattle, WA, USA
| | - Trey Oxford
- Washington National Primate Research Center, University of Washington, Seattle, WA, USA
| | - Amy Nowack
- Washington National Primate Research Center, University of Washington, Seattle, WA, USA
| | - Kaibao Nie
- Otolaryngology - HNS, University of Washington, Seattle, WA, USA; Electrical Engineering, University of Washington, Seattle, WA, USA
| | - Jay T Rubinstein
- Otolaryngology - HNS, University of Washington, Seattle, WA, USA; Bioengineering, University of Washington, Seattle, WA, USA
| | - James O Phillips
- Otolaryngology - HNS, University of Washington, Seattle, WA, USA; Washington National Primate Research Center, University of Washington, Seattle, WA, USA.
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Phillips JO, Ling L, Nie K, Jameyson E, Phillips CM, Nowack AL, Golub JS, Rubinstein JT. Vestibular implantation and longitudinal electrical stimulation of the semicircular canal afferents in human subjects. J Neurophysiol 2015; 113:3866-92. [PMID: 25652917 DOI: 10.1152/jn.00171.2013] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 02/02/2015] [Indexed: 11/22/2022] Open
Abstract
Animal experiments and limited data in humans suggest that electrical stimulation of the vestibular end organs could be used to treat loss of vestibular function. In this paper we demonstrate that canal-specific two-dimensionally (2D) measured eye velocities are elicited from intermittent brief 2 s biphasic pulse electrical stimulation in four human subjects implanted with a vestibular prosthesis. The 2D measured direction of the slow phase eye movements changed with the canal stimulated. Increasing pulse current over a 0-400 μA range typically produced a monotonic increase in slow phase eye velocity. The responses decremented or in some cases fluctuated over time in most implanted canals but could be partially restored by changing the return path of the stimulation current. Implantation of the device in Meniere's patients produced hearing and vestibular loss in the implanted ear. Electrical stimulation was well tolerated, producing no sensation of pain, nausea, or auditory percept with stimulation that elicited robust eye movements. There were changes in slow phase eye velocity with current and over time, and changes in electrically evoked compound action potentials produced by stimulation and recorded with the implanted device. Perceived rotation in subjects was consistent with the slow phase eye movements in direction and scaled with stimulation current in magnitude. These results suggest that electrical stimulation of the vestibular end organ in human subjects provided controlled vestibular inputs over time, but in Meniere's patients this apparently came at the cost of hearing and vestibular function in the implanted ear.
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Affiliation(s)
- James O Phillips
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; National Primate Research Center, University of Washington, Seattle, Washington; and Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington
| | - Leo Ling
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; National Primate Research Center, University of Washington, Seattle, Washington; and
| | - Kaibao Nie
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington
| | - Elyse Jameyson
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington
| | - Christopher M Phillips
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; National Primate Research Center, University of Washington, Seattle, Washington; and
| | - Amy L Nowack
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; National Primate Research Center, University of Washington, Seattle, Washington; and
| | - Justin S Golub
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington
| | - Jay T Rubinstein
- Department of Otolaryngology-HNS, University of Washington, Seattle, Washington; Department of Bioengineering, University of Washington, Seattle, Washington; National Primate Research Center, University of Washington, Seattle, Washington; and Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, Washington
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Pelizzone M, Fornos AP, Guinand N, van de Berg R, Kos I, Stokroos R, Kingma H, Guyot JP. First functional rehabilitation via vestibular implants. Cochlear Implants Int 2015; 15 Suppl 1:S62-4. [PMID: 24869447 DOI: 10.1179/1467010014z.000000000165] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Jiang D, Cirmirakis D, Demosthenous A. A vestibular prosthesis with highly-isolated parallel multichannel stimulation. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2015; 9:124-137. [PMID: 25073175 DOI: 10.1109/tbcas.2014.2323310] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This paper presents an implantable vestibular stimulation system capable of providing high flexibility independent parallel stimulation to the semicircular canals in the inner ear for restoring three-dimensional sensation of head movements. To minimize channel interaction during parallel stimulation, the system is implemented with a power isolation method for crosstalk reduction. Experimental results demonstrate that, with this method, electrodes for different stimulation channels located in close proximity ( mm) can deliver current pulses simultaneously with minimum inter-channel crosstalk. The design features a memory-based scheme that manages stimulation to the three canals in parallel. A vestibular evoked potential (VEP) recording unit is included for closed-loop adaptive stimulation control. The main components of the prototype vestibular prosthesis are three ASICs, all implemented in a 0.6- μm high-voltage CMOS technology. The measured performance was verified using vestibular electrodes in vitro.
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Lacour M, Bernard-Demanze L. Interaction between Vestibular Compensation Mechanisms and Vestibular Rehabilitation Therapy: 10 Recommendations for Optimal Functional Recovery. Front Neurol 2015; 5:285. [PMID: 25610424 PMCID: PMC4285093 DOI: 10.3389/fneur.2014.00285] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 12/15/2014] [Indexed: 12/30/2022] Open
Abstract
This review questions the relationships between the plastic events responsible for the recovery of vestibular function after a unilateral vestibular loss (vestibular compensation), which has been well described in animal models in the last decades, and the vestibular rehabilitation (VR) therapy elaborated on a more empirical basis for vestibular loss patients. The main objective is not to propose a catalog of results but to provide clinicians with an understandable view on when and how to perform VR therapy, and why VR may benefit from basic knowledge and may influence the recovery process. With this perspective, 10 major recommendations are proposed as ways to identify an optimal functional recovery. Among them are the crucial role of active and early VR therapy, coincidental with a post-lesion sensitive period for neuronal network remodeling, the instructive role that VR therapy may play in this functional reorganization, the need for progression in the VR therapy protocol, which is based mainly on adaptation processes, the necessity to take into account the sensorimotor, cognitive, and emotional profile of the patient to propose individual or "à la carte" VR therapies, and the importance of motivational and ecologic contexts. More than 10 general principles are very likely, but these principles seem crucial for the fast recovery of vestibular loss patients to ensure good quality of life.
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Affiliation(s)
- Michel Lacour
- Laboratoire de Neurobiologie Intégrative et Adaptative, UMR 7260 CNRS/Université Aix-Marseille, Fédération de Recherche 3C, Centre de St Charles, Marseille, France
| | - Laurence Bernard-Demanze
- Laboratoire de Neurobiologie Intégrative et Adaptative, UMR 7260 CNRS/Université Aix-Marseille, Fédération de Recherche 3C, Centre de St Charles, Marseille, France
- Service d’otorhinolaryngologie et d’otoneurologie, CHU Nord, Assistance Publique-Hôpitaux de Marseille, Marseille, France
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Perez Fornos A, Guinand N, van de Berg R, Stokroos R, Micera S, Kingma H, Pelizzone M, Guyot JP. Artificial balance: restoration of the vestibulo-ocular reflex in humans with a prototype vestibular neuroprosthesis. Front Neurol 2014; 5:66. [PMID: 24808890 PMCID: PMC4010770 DOI: 10.3389/fneur.2014.00066] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Accepted: 04/16/2014] [Indexed: 12/05/2022] Open
Abstract
The vestibular system plays a crucial role in the multisensory control of balance. When vestibular function is lost, essential tasks such as postural control, gaze stabilization, and spatial orientation are limited and the quality of life of patients is significantly impaired. Currently, there is no effective treatment for bilateral vestibular deficits. Research efforts both in animals and humans during the last decade set a solid background to the concept of using electrical stimulation to restore vestibular function. Still, the potential clinical benefit of a vestibular neuroprosthesis has to be demonstrated to pave the way for a translation into clinical trials. An important parameter for the assessment of vestibular function is the vestibulo-ocular reflex (VOR), the primary mechanism responsible for maintaining the perception of a stable visual environment while moving. Here we show that the VOR can be artificially restored in humans using motion-controlled, amplitude modulated electrical stimulation of the ampullary branches of the vestibular nerve. Three patients received a vestibular neuroprosthesis prototype, consisting of a modified cochlear implant providing vestibular electrodes. Significantly higher VOR responses were observed when the prototype was turned ON. Furthermore, VOR responses increased significantly as the intensity of the stimulation increased, reaching on average 79% of those measured in healthy volunteers in the same experimental conditions. These results constitute a fundamental milestone and allow us to envision for the first time clinically useful rehabilitation of patients with bilateral vestibular loss.
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Affiliation(s)
- Angelica Perez Fornos
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals , Geneva , Switzerland
| | - Nils Guinand
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals , Geneva , Switzerland
| | - Raymond van de Berg
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center , Maastricht , Netherlands
| | - Robert Stokroos
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center , Maastricht , Netherlands
| | - Silvestro Micera
- Translational Neural Engineering Laboratory, Center for Neuroprosthetics, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland ; The BioRobotics Institute, Scuola Superiore Sant'Anna , Pisa , Italy
| | - Herman Kingma
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University Medical Center , Maastricht , Netherlands
| | - Marco Pelizzone
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals , Geneva , Switzerland
| | - Jean-Philippe Guyot
- Service of Otorhinolaryngology and Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals , Geneva , Switzerland
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Marianelli P, Bassi Luciani L, Micera S. Electrical potential distribution within the inner ear: a preliminary study for vestibular prosthesis design. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:3017-20. [PMID: 23366560 DOI: 10.1109/embc.2012.6346599] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rotational cues in patients that suffer from bilateral vestibular loss can be delivered by vestibular prosthesis. Even though great efforts towards the development of a vestibular implant have been made, many parameters have still to be optimized. Numerical simulations of the neural activation during electrical stimulation can give important indications about the optimal electrode insertion site, stimulation waveform and electrode configuration, in terms of the highest selectivity. The first step of this type of numerical simulation requires the digital reconstruction of the human inner ear and the calculation of the spatial electrical potential distribution by means of finite-element methods.
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Affiliation(s)
- Prisca Marianelli
- Biorobotics Institute - Scuola Superiore Sant’Anna - Via Rinaldo Piaggio 34, 56025 Pontedera (Italy)
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Phillips JO, Shepherd SJ, Nowack AL, Ling L, Bierer SM, Kaneko CRS, Phillips CMT, Nie K, Rubinstein JT. Longitudinal performance of a vestibular prosthesis as assessed by electrically evoked compound action potential recording. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:6128-31. [PMID: 23367327 DOI: 10.1109/embc.2012.6347392] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Electrical stimulation of the vestibular end organ with a vestibular prosthesis may provide an effective treatment for vestibular loss if the stimulation remains effective over a significant period of time after implantation of the device. To assess efficacy of electrical stimulation in an animal model, we implanted 3 rhesus monkeys with a vestibular prosthesis based on a cochlear implant. We then recorded vestibular electrically evoked compound action potentials (vECAPs) longitudinally in each of the implanted canals to see how the amplitude of the response changed over time. The results suggest that vECAPs, and therefore electrical activation of vestibular afferent fibers, can remain largely stable over time following implantation.
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Affiliation(s)
- James O Phillips
- Department of Otolaryngology and Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA 98195, USA.
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Postural responses to electrical stimulation of the vestibular end organs in human subjects. Exp Brain Res 2013; 229:181-95. [PMID: 23771587 DOI: 10.1007/s00221-013-3604-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 05/29/2013] [Indexed: 10/26/2022]
Abstract
A multichannel vestibular prosthesis that delivers electrical stimulation to the perilymph of individual semicircular canals is a potential new treatment modality for patients with vestibular deficiencies. Most research in this field has evaluated the efficacy of this approach by its ability to reproduce eye movements in response to head rotations. Our group has developed such a device and implanted it in four human subjects with intractable unilateral Meniere's disease. This allows us to evaluate individual semicircular canal contribution to the control of balance and posture in human subjects. In this report, we demonstrate that electrical stimulation trains delivered to the perilymph of individual semicircular canals elicit postural responses specific to the particular canal stimulated, with some current spread to adjacent end organs. Modulation of stimulation current modulates the amplitude of the postural response. However, eye movements elicited by the same electrical stimuli were not consistent with postural responses in magnitude or direction in all subjects. Taken together, these findings support the feasibility of a vestibular prosthesis for the control of balance and illustrate new challenges for the development of this technology.
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Valentin NS, Hageman KN, Dai C, Della Santina CC, Fridman GY. Development of a multichannel vestibular prosthesis prototype by modification of a commercially available cochlear implant. IEEE Trans Neural Syst Rehabil Eng 2013; 21:830-9. [PMID: 23649285 DOI: 10.1109/tnsre.2013.2259261] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
No adequate treatment exists for individuals who remain disabled by bilateral loss of vestibular (inner ear inertial) sensation despite rehabilitation. We have restored vestibular reflexes using lab-built multichannel vestibular prostheses (MVPs) in animals, but translation to clinical practice may be best accomplished by modification of a commercially available cochlear implant (CI). In this interim report, we describe preliminary efforts toward that goal. We developed software and circuitry to sense head rotation and drive a CI's implanted stimulator (IS) to deliver up to 1 K pulses/s via nine electrodes implanted near vestibular nerve branches. Studies in two rhesus monkeys using the modified CI revealed in vivo performance similar to our existing dedicated MVPs. A key focus of our study was the head-worn unit (HWU), which magnetically couples across the scalp to the IS. The HWU must remain securely fixed to the skull to faithfully sense head motion and maintain continuous stimulation. We measured normal and shear force thresholds at which HWU-IS decoupling occurred as a function of scalp thickness and calculated pressure exerted on the scalp. The HWU remained attached for human scalp thicknesses from 3-7.8 mm for forces experienced during routine daily activities, while pressure on the scalp remained below capillary perfusion pressure.
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Abstract
PURPOSE OF REVIEW To summarize the recent progress in the development of vestibular implants. The review is timely because of the recent advances in the field and because MED-EL has recently announced that they are developing a vestibular implant for clinical applications. RECENT FINDINGS The handicap experienced by patients suffering from bilateral vestibulopathy has a strong negative impact on physical and social functioning that appears to justify a surgical intervention. Two different surgical approaches to insert electrodes to stimulate ampullary neurons have been shown to be viable. The three-dimensional vestibulo-ocular reflex in rhesus monkeys produced with a three-dimensional vestibular implant showed gains that were relatively normal during acute stimulation. Rotation cues provided by an implant interact with otolith cues in a qualitatively normal manner. The brain appears to adapt plastically to the cues provided via artificial electrical stimulation. SUMMARY Research to date includes just a few human studies, but available data from both humans and animals support the technological and physiological feasibility of vestibular implants. Although vestibular implant users should not expect normal vestibular function - any more than cochlear implant users should expect normal hearing - data suggest that significant functional improvements are possible.
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Davidovics NS, Rahman MA, Dai C, Ahn J, Fridman GY, Della Santina CC. Multichannel vestibular prosthesis employing modulation of pulse rate and current with alignment precompensation elicits improved VOR performance in monkeys. J Assoc Res Otolaryngol 2013; 14:233-48. [PMID: 23355001 DOI: 10.1007/s10162-013-0370-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 01/02/2013] [Indexed: 11/30/2022] Open
Abstract
An implantable prosthesis that stimulates vestibular nerve branches to restore the sensation of head rotation and the three-dimensional (3D) vestibular ocular reflex (VOR) could benefit individuals disabled by bilateral loss of vestibular sensation. Our group has developed a vestibular prosthesis that partly restores normal function in animals by delivering biphasic current pulses via electrodes implanted in semicircular canals. Despite otherwise promising results, this approach has been limited by insufficient velocity of VOR response to head movements that should inhibit the implanted labyrinth and by misalignment between direction of head motion and prosthetically elicited VOR. We report that significantly larger VOR eye velocities in the inhibitory direction can be elicited by adapting a monkey to elevated baseline stimulation rate and current prior to stimulus modulation and then concurrently modulating ("co-modulating") both rate and current below baseline levels to encode inhibitory angular head velocity. Co-modulation of pulse rate and current amplitude above baseline can also elicit larger VOR eye responses in the excitatory direction than do either pulse rate modulation or current modulation alone. Combining these stimulation strategies with a precompensatory 3D coordinate transformation improves alignment and magnitude of evoked VOR eye responses. By demonstrating that a combination of co-modulation and precompensatory transformation strategies achieves a robust VOR response in all directions with significantly improved alignment in an animal model that closely resembles humans with vestibular loss, these findings provide a solid preclinical foundation for application of vestibular stimulation in humans.
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Affiliation(s)
- Natan S Davidovics
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
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Nie K, Ling L, Bierer SM, Kaneko CRS, Fuchs AF, Oxford T, Rubinstein JT, Phillips JO. An experimental vestibular neural prosthesis: design and preliminary results with rhesus monkeys stimulated with modulated pulses. IEEE Trans Biomed Eng 2013; 60:1685-92. [PMID: 23358943 DOI: 10.1109/tbme.2013.2241433] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A vestibular neural prosthesis was designed on the basis of a cochlear implant for treatment of Meniere's disease and other vestibular disorders. Computer control software was developed to generate patterned pulse stimuli for exploring optimal parameters to activate the vestibular nerve. Two rhesus monkeys were implanted with the prototype vestibular prosthesis and they were behaviorally evaluated post implantation surgery. Horizontal and vertical eye movement responses to patterned electrical pulse stimulations were collected on both monkeys. Pulse amplitude modulated (PAM) and pulse rate modulated (PRM) trains were applied to the lateral canal of each implanted animal. Robust slow-phase nystagmus responses following the PAM or PRM modulation pattern were observed in both implanted monkeys in the direction consistent with the activation of the implanted canal. Both PAM and PRM pulse trains can elicit a significant amount of in-phase modulated eye velocity changes and they could potentially be used for efficiently coding head rotational signals in future vestibular neural prostheses.
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Affiliation(s)
- Kaibao Nie
- Department of Otolaryngology, Department of Electrical Engineering, and Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA 98195, USA.
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Fridman GY, Della Santina CC. Progress toward development of a multichannel vestibular prosthesis for treatment of bilateral vestibular deficiency. Anat Rec (Hoboken) 2012; 295:2010-29. [PMID: 23044664 DOI: 10.1002/ar.22581] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 07/24/2012] [Indexed: 12/11/2022]
Abstract
This article reviews vestibular pathology and the requirements and progress made in the design and construction of a vestibular prosthesis. Bilateral loss of vestibular sensation is disabling. When vestibular hair cells are injured by ototoxic medications or other insults to the labyrinth, the resulting loss of sensory input disrupts vestibulo-ocular reflexes (VORs) and vestibulo-spinal reflexes that normally stabilize the eyes and body. Affected individuals suffer poor vision during head movement, postural instability, chronic disequilibrium, and cognitive distraction. Although most individuals with residual sensation compensate for their loss over time, others fail to do so and have no adequate treatment options. A vestibular prosthesis analogous to cochlear implants but designed to modulate vestibular nerve activity during head movement should improve quality of life for these chronically dizzy individuals. We describe the impact of bilateral loss of vestibular sensation, animal studies supporting feasibility of prosthetic vestibular stimulation, the current status of multichannel vestibular sensory replacement prosthesis development, and challenges to successfully realizing this approach in clinical practice. In bilaterally vestibular-deficient rodents and rhesus monkeys, the Johns Hopkins multichannel vestibular prosthesis (MVP) partially restores the three-dimensional (3D) VOR for head rotations about any axis. Attempts at prosthetic vestibular stimulation of humans have not yet included the 3D eye movement assays necessary to accurately evaluate VOR alignment, but these initial forays have revealed responses that are otherwise comparable to observations in animals. Current efforts now focus on refining electrode design and surgical technique to enhance stimulus selectivity and preserve cochlear function, optimizing stimulus protocols to improve dynamic range and reduce excitation-inhibition asymmetry, and adapting laboratory MVP prototypes into devices appropriate for use in clinical trials.
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Affiliation(s)
- Gene Y Fridman
- Department of Otolaryngology-Head & Neck surgery, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA.
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Guinand N, Boselie F, Guyot JP, Kingma H. Quality of Life of Patients with Bilateral Vestibulopathy. Ann Otol Rhinol Laryngol 2012; 121:471-7. [DOI: 10.1177/000348941212100708] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objectives: Currently, there is no evidence of an effective treatment for patients with bilateral vestibulopathy (BV). Their main complaints are oscillopsia and imbalance. Opinions about the impact of BV on their quality of life are controversial, and their handicap is not always recognized, even among otoneurologists. The aim of this study was to objectively assess the health status of BV patients in order to evaluate the need for pursuing efforts toward the development of new treatments. Methods: The Short-Form Health Survey (SF-36), the Dizziness Handicap Inventory (DHI), the Short Falls Efficacy Scale–International (Short FES-I), and an oscillopsia severity questionnaire were submitted to 39 BV patients. The SF-36 scores were compared to the scores of a general Dutch population. The DHI scores were correlated to the oscillopsia severity scores. The Short FES-I scores were compared to scores in an elderly population. Residual otolithic function was correlated to all scores, and hearing to SF-36 scores. Results: Compared to the general Dutch population, the BV patients scored significantly worse on the “physical functioning,” “role physical,” “general health,” “vitality,” and “social functioning” SF-36 variables (p < 0.05). The DHI scores were strongly correlated with the oscillopsia severity scores (r = 0.75; p < 0.000001). The Short FES-I scores indicated a slight to moderate increase in the patients' fear of falling. No significant score differences were found between BV patients with residual otolithic function and patients with complete BV. There was no correlation between hearing status and SF-36 scores. Conclusions: The results correlate with our clinical impression that BV has a strong negative impact on physical and social functioning, leading to a quality-of-life deterioration. There is a clear need for a therapeutic solution. Efforts toward the development of a vestibular implant are justified.
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Phillips JO, Bierer SM, Ling L, Nie K, Rubinstein JT. Real-time communication of head velocity and acceleration for an externally mounted vestibular prosthesis. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:3537-41. [PMID: 22255103 DOI: 10.1109/iembs.2011.6090588] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Loss of vestibular function results in imbalance, disorientation, and oscillopsia. Several groups have designed and constructed implantable devices to restore vestibular function through electrical stimulation of the vestibular nerve. We have designed a two-part device in which the head motion sensing and signal processing elements are externally mounted to the head, and are coupled through an inductive link to a receiver stimulator that is based on a cochlear implant. The implanted electrode arrays are designed to preserve rotational sensitivity in the implanted ear. We have tested the device in rhesus monkeys by rotating the animals in the plane of the implanted canals, and then using head velocity and acceleration signals to drive electrical stimulation of the vestibular system. Combined electrical and rotational stimulation results in a summation of responses, so that one can control the modulation of eye velocity induced by sinusoidal yaw rotation.
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Affiliation(s)
- James O Phillips
- Department of Otolaryngology and the Virginia Merrill Bloedel Hearing Research Center at the University of Washington, Seattle, WA 98195, USA.
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Allum JHJ, Carpenter MG, Horslen BC, Davis JR, Honegger F, Tang KS, Kessler P. Improving impaired balance function: real-time versus carry-over effects of prosthetic feedback. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:1314-8. [PMID: 22254558 DOI: 10.1109/iembs.2011.6090309] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This study investigated whether training with realtime prosthetic biofeedback (BF) of trunk sway induces a carry-over improvement in balance control once BF is removed. 12 healthy older adults and 7 uncompensated unilateral vestibular loss patients were tested. All participants performed a battery of 14 balance and gait tasks (pre-test) upon their initial lab visit during which trunk angular sway was measured at L1-3. They then received balance BF training on a subset of 7 tasks, three times per week, for two consecutive weeks. BF was provided using a multi-modal biofeedback system with graded vibrotactile, auditory, and visual cues in relation to subject-specific angular displacement thresholds. Performance on the battery of the 14 balance and gait tasks (without BF) was re-assessed immediately after the 2 week training period, as well as 1 week later to examine BF carry-over effects. Significant reductions in trunk angular displacement were observed with the real-time BF, compared to the pre-test trials. The effects of BF persisted when BF was removed immediately after the final training session. BF carry-over effects were less evident at one week post-training. This evidence supports the potential short-term effects of BF training in a limited number of tasks after the BF is removed in healthy elderly subjects and those with vestibular loss. However, the prospect for longer term (>1 week) effects of prosthetic training on balance control remains currently unknown.
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Guinand N, Guyot JP, Kingma H, Kos I, Pelizzone M. Vestibular implants: the first steps in humans. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:2262-4. [PMID: 22254791 DOI: 10.1109/iembs.2011.6090569] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Currently there is no efficient treatment for patients with severe bilateral vestibular function impairment. Presence of oscillopsia is their main complaint. It has a significant negative impact on their quality of life. Recently it has been shown that angular vestibulo-ocular reflex can be partially restored in animals. In humans it is possible to elicit a nystagmic response by electric stimulation of ampullary parts of the vestibular nerve. Controlled eye movements can be generated by frequency and intensity modulation of the restored baseline firing rate of the vestibular nerve. During adaptation phase to the electric stimulus, patients experience nystagmus with associated inconveniences. By repetition of "on/off periods" the duration of the adaptation phase can be significantly decreased. Results show that permanent electric stimulation is necessary to maintain this "optimal" adaptation state.
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Affiliation(s)
- N Guinand
- ENT Department, University Hospital, Faculty of Medicine, University of Geneva, Switzerland.
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Auditory outcomes following implantation and electrical stimulation of the semicircular canals. Hear Res 2012; 287:51-6. [PMID: 22504025 DOI: 10.1016/j.heares.2012.03.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 03/20/2012] [Accepted: 03/27/2012] [Indexed: 11/22/2022]
Abstract
We measured auditory brainstem responses (ABRs) in eight Rhesus monkeys after implantation of electrodes in the semicircular canals of one ear, using a multi-channel vestibular prosthesis based on cochlear implant technology. In five animals, click-evoked ABR thresholds in the implanted ear were within 10 dB of thresholds in the non-implanted control ear. Threshold differences in the remaining three animals varied from 18 to 69 dB, indicating mild to severe hearing losses. Click- and tone-evoked ABRs measured in a subset of animals before and after implantation revealed a comparable pattern of threshold changes. Thresholds obtained five months or more after implantation--a period in which the prosthesis regularly delivered electrical stimulation to achieve functional activation of the vestibular system--improved in three animals with no or mild initial hearing loss and increased in a fourth with a moderate hearing loss. These results suggest that, although there is a risk of hearing loss with unilateral vestibular implantation to treat balance disorders, the surgery can be performed in a manner that preserves hearing over an extended period of functional stimulation.
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van de Berg R, Guinand N, Guyot JP, Kingma H, Stokroos RJ. The modified ampullar approach for vestibular implant surgery: feasibility and its first application in a human with a long-term vestibular loss. Front Neurol 2012; 3:18. [PMID: 22363317 PMCID: PMC3282298 DOI: 10.3389/fneur.2012.00018] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 01/30/2012] [Indexed: 11/13/2022] Open
Abstract
Objective: To assess, for the first time in a human with a long-term vestibular loss, a modified approach to the ampullae and the feasibility of evoking a VOR by ampullar stimulation. Materials and methods: Peroperative stimulation of the ampullae, using the ampullar approach, was performed under full anesthesia during cochlear implantation in a 21-year-old female patient, who had experienced bilateral vestibular areflexia and sensorineural hearing loss for almost 20 years. Results: The modified ampullar approach was performed successfully with as minimally invasive surgery as possible. Ampullar stimulation evoked eye movements containing vectors congruent with the stimulated canal. As expected, the preliminary electrophysiological data were influenced by the general anesthesia, which resulted in current spread and reduced maximum amplitudes of eye movement. Nevertheless, they confirm the feasibility of ampullar stimulation. Conclusion: The modified ampullar approach provides safe access to the ampullae using as minimally invasive surgery as possible. For the first time in a human with long-term bilateral vestibular areflexia, it is shown that the VOR can be evoked by ampullar stimulation, even when there has been no vestibular function for almost 20 years. This approach should be considered in vestibular surgery, as it provides safe access to one of the most favorable stimulus locations for development of a vestibular implant.
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Affiliation(s)
- Raymond van de Berg
- Department of Otolaryngology and Head and Neck Surgery, Maastricht University Medical Centre Maastricht, Netherlands
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van de Berg R, Guinand N, Stokroos RJ, Guyot JP, Kingma H. The vestibular implant: quo vadis? Front Neurol 2011; 2:47. [PMID: 21991260 PMCID: PMC3181464 DOI: 10.3389/fneur.2011.00047] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 07/12/2011] [Indexed: 11/19/2022] Open
Abstract
Objective: To assess the progress of the development of the vestibular implant (VI) and its feasibility short-term. Data sources: A search was performed in Pubmed, Medline, and Embase. Key words used were “vestibular prosth*” and “VI.” The only search limit was language: English or Dutch. Additional sources were medical books, conference lectures and our personal experience with per-operative vestibular stimulation in patients selected for cochlear implantation. Study selection: All studies about the VI and related topics were included and evaluated by two reviewers. No study was excluded since every study investigated different aspects of the VI. Data extraction and synthesis: Data was extracted by the first author from selected reports, supplemented by additional information, medical books conference lectures. Since each study had its own point of interest with its own outcomes, it was not possible to compare data of different studies. Conclusion: To use a basic VI in humans seems feasible in the very near future. Investigations show that electric stimulation of the canal nerves induces a nystagmus which corresponds to the plane of the canal which is innervated by the stimulated nerve branch. The brain is able to adapt to a higher baseline stimulation, while still reacting on a dynamic component. The best response will be achieved by a combination of the optimal stimulus (stimulus profile, stimulus location, precompensation), complemented by central vestibular adaptation. The degree of response will probably vary between individuals, depending on pathology and their ability to adapt.
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Affiliation(s)
- Raymond van de Berg
- Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Centre Maastricht, Netherlands
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Guyot JP, Sigrist A, Pelizzone M, Kos MI. Adaptation to Steady-State Electrical Stimulation of the Vestibular System in Humans. Ann Otol Rhinol Laryngol 2011; 120:143-9. [DOI: 10.1177/000348941112000301] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objectives: Efforts are being made toward the development of a vestibular implant. If such a device is to mimic the physiology of the vestibular system, it must first be capable of restoring a baseline or “rest” activity in the vestibular pathways and then modulating it according to the direction and velocity of head movements. The aim of this study was to assess whether a human subject could adapt to continuous electrical stimulation of the vestibular system, and whether it was possible to elicit artificial smooth oscillatory eye movements via modulation of the stimulation. Methods: One bilaterally deaf patient with bilateral vestibular loss received a custom-modified Med-E1 cochlear implant in which one electrode was implanted in the vicinity of the left posterior ampullary nerve. This electrode was activated with biphasic pulse trains of 400-μs phase duration delivered at a repetition rate of 200 pulses per second. The resulting eye movements were recorded with 2-dimensional binocular video-oculography. Results: Successive “on-off” cycles of continuous electrical stimulation resulted in a progressively shorter duration of the nystagmic response. Once the adapted state was reached upon constant stimulation, amplitude or frequency modulations of electrical stimulation produced smooth oscillatory conjugated eye movements. Conclusions: Although this is a case study of one patient, the results suggest that humans can adapt to electrical stimulation of the vestibular system without too much discomfort. Once the subject is in the adapted state, the electrical stimulation can be modulated to artificially elicit smooth eye movements. Therefore, the major prerequisites for the feasibility of a vestibular implant for human use are fulfilled.
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