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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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Loos E, Stultiens JJA, Volpe B, Vermorken BL, Van Boxel SCJ, Devocht EMJ, van Hoof M, Postma AA, Guinand N, Pérez-Fornos A, Van Rompaey V, Denys S, Desloovere C, Verhaert N, van de Berg R. Optimizing vestibular implant electrode positioning using fluoroscopy and intraoperative CT imaging. Eur Arch Otorhinolaryngol 2024; 281:3433-3441. [PMID: 38180608 PMCID: PMC11211140 DOI: 10.1007/s00405-023-08428-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/18/2023] [Indexed: 01/06/2024]
Abstract
PURPOSE Vestibular implant electrode positioning close to the afferent nerve fibers is considered to be key for effective and selective electrical stimulation. However, accurate positioning of vestibular implant electrodes inside the semicircular canal ampullae is challenging due to the inability to visualize the target during the surgical procedure. This study investigates the accuracy of a new surgical protocol with real-time fluoroscopy and intraoperative CT imaging, which facilitates electrode positioning during vestibular implant surgery. METHODS Single-center case-controlled cohort study with a historic control group at a tertiary referral center. Patients were implanted with a vestibulocochlear implant, using a combination of intraoperative fluoroscopy and cone beam CT imaging. The control group consisted of five patients who were previously implanted with the former implant prototype, without the use of intraoperative imaging. Electrode positioning was analyzed postoperatively with a high-resolution CT scan using 3D slicer software. The result was defined as accurate if the electrode position was within 1.5 mm of the center of the ampulla. RESULTS With the new imaging protocol, all electrodes could be positioned within a 1.5 mm range of the center of the ampulla. The accuracy was significantly higher in the study group with intraoperative imaging (21/21 electrodes) compared to the control group without intraoperative imaging (10/15 electrodes), (p = 0.008). CONCLUSION The combined use of intraoperative fluoroscopy and CT imaging during vestibular implantation can improve the accuracy of electrode positioning. This might lead to better vestibular implant performance.
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Affiliation(s)
- Elke Loos
- Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience (MHeNS), Maastricht University Medical Center, Maastricht, The Netherlands.
- Department of Otorhinolaryngology-Head and Neck Surgery, University Hospitals Leuven, Leuven, Belgium.
- Department of Neurosciences, Research Group Experimental Oto-Rhino-Laryngology (ExpORL), KU Leuven, University of Leuven, Herestraat 49, 3000, Leuven, Belgium.
| | - Joost J A Stultiens
- Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience (MHeNS), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Benjamin Volpe
- Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience (MHeNS), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Bernd L Vermorken
- Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience (MHeNS), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Stan C J Van Boxel
- Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience (MHeNS), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Elke M J Devocht
- Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience (MHeNS), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Marc van Hoof
- Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience (MHeNS), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Alinda A Postma
- Department of Radiology and Nuclear Medicine, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience (MHeNS), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Nils Guinand
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Angelica Pérez-Fornos
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Vincent Van Rompaey
- Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
- Department of Otorhinolaryngology and Head and Neck Surgery, Antwerp University Hospital, Edegem, Belgium
| | - Sam Denys
- Department of Otorhinolaryngology-Head and Neck Surgery, University Hospitals Leuven, Leuven, Belgium
- Department of Neurosciences, Research Group Experimental Oto-Rhino-Laryngology (ExpORL), KU Leuven, University of Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Christian Desloovere
- Department of Otorhinolaryngology-Head and Neck Surgery, University Hospitals Leuven, Leuven, Belgium
- Department of Neurosciences, Research Group Experimental Oto-Rhino-Laryngology (ExpORL), KU Leuven, University of Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Nicolas Verhaert
- Department of Otorhinolaryngology-Head and Neck Surgery, University Hospitals Leuven, Leuven, Belgium
- Department of Neurosciences, Research Group Experimental Oto-Rhino-Laryngology (ExpORL), KU Leuven, University of Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Raymond van de Berg
- Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Health Medicine and Life Sciences, School for Mental Health and Neuroscience (MHeNS), Maastricht University Medical Center, Maastricht, The Netherlands
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Chen J, Sprigg J, Castle N, Matson C, Hedjoudje A, Dai C. A Virtual Inner Ear Model Selects Ramped Pulse Shapes for Vestibular Afferent Stimulation. Bioengineering (Basel) 2023; 10:1436. [PMID: 38136027 PMCID: PMC10740892 DOI: 10.3390/bioengineering10121436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/03/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Bilateral vestibular deficiency (BVD) results in chronic dizziness, blurry vision when moving the head, and postural instability. Vestibular prostheses (VPs) show promise as a treatment, but the VP-restored vestibulo-ocular reflex (VOR) gain in human trials falls short of expectations. We hypothesize that the slope of the rising ramp in stimulation pulses plays an important role in the recruitment of vestibular afferent units. To test this hypothesis, we utilized customized programming to generate ramped pulses with different slopes, testing their efficacy in inducing electrically evoked compound action potentials (eCAPs) and current spread via bench tests and simulations in a virtual inner model created in this study. The results confirmed that the slope of the ramping pulses influenced the recruitment of vestibular afferent units. Subsequently, an optimized stimulation pulse train was identified using model simulations, exhibiting improved modulation of vestibular afferent activity. This optimized slope not only reduced the excitation spread within the semicircular canals (SCCs) but also expanded the neural dynamic range. While the model simulations exhibited promising results, in vitro and in vivo experiments are warranted to validate the findings of this study in future investigations.
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Affiliation(s)
- Joseph Chen
- Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
- School of Medicine and Biomedical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Jayden Sprigg
- Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Nicholas Castle
- Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Cayman Matson
- School of Medicine and Biomedical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | | | - Chenkai Dai
- Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
- School of Medicine and Biomedical Engineering, University of Oklahoma, Norman, OK 73019, USA
- Biomedical Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA
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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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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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A prosthesis utilizing natural vestibular encoding strategies improves sensorimotor performance in monkeys. PLoS Biol 2022; 20:e3001798. [PMID: 36103550 PMCID: PMC9473632 DOI: 10.1371/journal.pbio.3001798] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 08/16/2022] [Indexed: 11/19/2022] Open
Abstract
Sensory pathways provide complex and multifaceted information to the brain. Recent advances have created new opportunities for applying our understanding of the brain to sensory prothesis development. Yet complex sensor physiology, limited numbers of electrodes, and nonspecific stimulation have proven to be a challenge for many sensory systems. In contrast, the vestibular system is uniquely suited for prosthesis development. Its peripheral anatomy allows site-specific stimulation of 3 separate sensory organs that encode distinct directions of head motion. Accordingly, here, we investigated whether implementing natural encoding strategies improves vestibular prosthesis performance. The eye movements produced by the vestibulo-ocular reflex (VOR), which plays an essential role in maintaining visual stability, were measured to quantify performance. Overall, implementing the natural tuning dynamics of vestibular afferents produced more temporally accurate VOR eye movements. Exploration of the parameter space further revealed that more dynamic tunings were not beneficial due to saturation and unnatural phase advances. Trends were comparable for stimulation encoding virtual versus physical head rotations, with gains enhanced in the latter case. Finally, using computational methods, we found that the same simple model explained the eye movements evoked by sinusoidal and transient stimulation and that a stimulation efficacy substantially less than 100% could account for our results. Taken together, our results establish that prosthesis encodings that incorporate naturalistic afferent dynamics and account for activation efficacy are well suited for restoration of gaze stability. More generally, these results emphasize the benefits of leveraging the brain’s endogenous coding strategies in prosthesis development to improve functional outcomes.
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Liang J, Ke Z, Welch PV, Gan RZ, Dai C. A comprehensive finite element model for studying Cochlear-Vestibular interaction. Comput Methods Biomech Biomed Engin 2021; 25:204-214. [PMID: 34641759 DOI: 10.1080/10255842.2021.1946522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
We present a 3-D finite element (FE) model of the chinchilla's inner ear consisting of the entire cochlea structure and the vestibular system. The reaction of the basilar membrane to the head rotation and the reaction of ampulla to the stapes movement were investigated. These results demonstrate the existence of hearing-vestibular system interaction. They provide an explanation to the clinical finding on the coexistence between hearing loss and equilibration dysfunction. It is a preliminary, yet critical step toward the development of a comprehensive FE model of an entire ear for mechano-acoustic analysis.
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Affiliation(s)
- Junfeng Liang
- Aerospace & Mechanical Engineering, University of Oklahoma, Norman, OK, USA
| | - Zhang Ke
- Aerospace & Mechanical Engineering, University of Oklahoma, Norman, OK, USA
| | - Paige V Welch
- Aerospace & Mechanical Engineering, University of Oklahoma, Norman, OK, USA
| | - Rong Z Gan
- Aerospace & Mechanical Engineering, University of Oklahoma, Norman, OK, USA
| | - Chenkai Dai
- Aerospace & Mechanical Engineering, University of Oklahoma, Norman, OK, USA
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Hedjoudje A, Schoo DP, Ward BK, Carey JP, Della Santina CC, Pearl M. Vestibular Implant Imaging. AJNR Am J Neuroradiol 2021; 42:370-376. [PMID: 33361382 PMCID: PMC7872165 DOI: 10.3174/ajnr.a6991] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 09/10/2020] [Indexed: 11/07/2022]
Abstract
Analogous to hearing restoration via cochlear implants, vestibular function could be restored via vestibular implants that electrically stimulate vestibular nerve branches to encode head motion. This study presents the technical feasibility and first imaging results of CT for vestibular implants in 8 participants of the first-in-human Multichannel Vestibular Implant Early Feasibility Study. Imaging characteristics of 8 participants (3 men, 5 women; median age, 59.5 years; range, 51-66 years) implanted with a Multichannel Vestibular Implant System who underwent a postimplantation multislice CT (n = 2) or flat panel CT (n = 6) are reported. The device comprises 9 platinum electrodes inserted into the ampullae of the 3 semicircular canals and 1 reference electrode inserted in the common crus. Electrode insertion site, positions, length and angle of insertion, and number of artifacts were assessed. Individual electrode contacts were barely discernible in the 2 participants imaged using multislice CT. Electrode and osseous structures were detectable but blurred so that only 12 of the 18 stimulating electrode contacts could be individually identified. Flat panel CT could identify all 10 electrode contacts in all 6 participants. The median reference electrode insertion depth angle was 9° (range, -57.5° to 45°), and the median reference electrode insertion length was 42 mm (range, -21-66 mm). Flat panel CT of vestibular implants produces higher-resolution images with fewer artifacts than multidetector row CT, allowing visualization of individual electrode contacts and quantification of their locations relative to vestibular semicircular canals and ampullae. As multichannel vestibular implant imaging improves, so will our understanding of the relationship between electrode placement and vestibular performance.
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Affiliation(s)
- A Hedjoudje
- From the Department of Otolaryngology-Head and Neck Surgery (A.H., D.P.S., B.K.W., J.P.C., C.C.D.S.)
- Division of Interventional Neuroradiology (A.H., M.P.)
- Neuroradiology Unit (A.H.), Service of diagnostic and interventional imaging, Sion Hospital, Sion, Valais, Switzerland
| | - D P Schoo
- From the Department of Otolaryngology-Head and Neck Surgery (A.H., D.P.S., B.K.W., J.P.C., C.C.D.S.)
| | - B K Ward
- From the Department of Otolaryngology-Head and Neck Surgery (A.H., D.P.S., B.K.W., J.P.C., C.C.D.S.)
| | - J P Carey
- From the Department of Otolaryngology-Head and Neck Surgery (A.H., D.P.S., B.K.W., J.P.C., C.C.D.S.)
| | - C C Della Santina
- From the Department of Otolaryngology-Head and Neck Surgery (A.H., D.P.S., B.K.W., J.P.C., C.C.D.S.)
- Department of Biomedical Engineering (C.C.D.S.), Johns Hopkins University School of Medicine, Baltimore, Maryland
- Labyrinth Devices (C.C.D.S.), Baltimore, Maryland
| | - M Pearl
- Division of Interventional Neuroradiology (A.H., M.P.)
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Ren P, Li B, Dong S, Lyu B, Qu J, Gong S, Zhang Q, Han P. The real identity and sensory overlap mechanism of special vestibular afferent neurons that sense both rotation and linear force. Life Sci 2020; 259:118144. [PMID: 32755624 DOI: 10.1016/j.lfs.2020.118144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/12/2020] [Accepted: 07/21/2020] [Indexed: 10/23/2022]
Abstract
AIMS Although the vestibular system has been widely investigated over the past 50 years, there is still an unsolved mystery. Some special vestibular afferent (SVA) neurons responding to both rotation and linear force were found through neurophysiological techniques, however, the sensory overlap mechanism of SVA neurons is still unclear, which may be closely related to vestibular-related diseases. MATERIALS AND METHODS To address the above-mentioned problem, a cupula buoyancy theory was established in the present study, where SVA neurons were considered semicircular canal afferent (SCCA) neurons. Then labyrinth anatomy and neural response dynamics of vestibular afferent neurons in chinchilla were investigated through vestibular labyrinth reconstruction and single unit recording technique, respectively. KEY FINDINGS We analyzed the deflections of cupulae under multiple conditions with the help of Amira Software and predicted the neural response law of SCCA neurons to linear force based on the cupula buoyancy theory. Data analysis confirmed that the basic response characteristic of SVA neurons had no significant difference to those of SCCA neurons, but were significantly different from those of otolith afferent neurons. Further, the actual responses of SVA neurons to linear force are completely consistent with our predictions. These results strongly suggest that SVA neurons actually are SCCA neurons, and the cupula buoyancy theory is the key to the sensory overlap mechanism of SCCA neurons. SIGNIFICANCE Our study revealed the real identity of SVA neurons and provided a reasonable mechanism for sensory overlap of rotation and linear force, which improved our understanding about the vestibular system.
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Affiliation(s)
- Pengyu Ren
- Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China; Departments of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205, USA
| | - Bowen Li
- Division of Health Sciences Informatics, Johns Hopkins University School of Medicine, 2024 E Monument St, Baltimore, MD 21205, USA
| | - Shiyao Dong
- Departments of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205, USA
| | - Boqiang Lyu
- Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China
| | - Jianqiang Qu
- Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China
| | - Shouping Gong
- Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China
| | - Qing Zhang
- Department of Otolaryngology-Head & Neck Surgery, Xinhua Hospital of Shanghai Jiaotong University, 1665 Kongjiang Rd, Shanghai 200093, China
| | - Peng Han
- Department of Otolaryngology-Head & Neck Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, 227 Yanta West Roud, Xi'an, Shaanxi 710061, China.
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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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Phillips JO, Ling L, Nowack A, Rebollar B, Rubinstein JT. Interactions between Auditory and Vestibular Modalities during Stimulation with a Combined Vestibular and Cochlear Prosthesis. Audiol Neurootol 2020; 25:96-108. [PMID: 31968338 DOI: 10.1159/000503846] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 10/01/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND A combined vestibular and cochlear prosthesis may restore hearing and balance to patients who have lost both. To do so, the device should activate each sensory system independently. OBJECTIVES In this study, we quantify auditory and vestibular interactions during interleaved stimulation with a combined 16-channel cochlear and 6-channel vestibular prosthesis in human subjects with both hearing and vestibular loss. METHODS Three human subjects were implanted with a combined vestibular and cochlear implant. All subjects had severe-to-profound deafness in the implanted ear. We provided combined stimulation of the cochlear and vestibular arrays and looked for interactions between these separate inputs. Our main outcome measures were electrically evoked slow-phase eye velocities during nystagmus elicited by brief trains of biphasic pulse stimulation of the vestibular end organs with and without concurrent stimulation of the cochlea, and Likert scale assessments of perceived loudness and pitch during stimulation of the cochlea, with and without concurrent stimulation of the vestibular ampullae. RESULTS All subjects had no auditory sensation resulting from semicircular canal stimulation alone, and no sensation of motion or slow-phase eye movement resulting from cochlear stimulation alone. However, interleaved cochlear stimulation did produce changes in the slow-phase eye velocities elicited by electrical stimulation. Similarly, interleaved semicircular canal stimulation did elicit changes in the perceived pitch and loudness resulting from stimulation at multiple sites in the cochlea. CONCLUSIONS There are significant interactions between different sensory modalities during stimulation with a combined vestibular and cochlear prosthesis. Such interactions present potential challenges for stimulation strategies to simultaneously restore auditory and vestibular function with such an implant.
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Affiliation(s)
- James O Phillips
- Department of Otolaryngology, University of Washington, Seattle, Washington, USA, .,Center for Integrative Brain Research, Seattle Children's Hospital, Seattle, Washington, USA,
| | - Leo Ling
- Department of Otolaryngology, University of Washington, Seattle, Washington, USA
| | - Amy Nowack
- Department of Otolaryngology, University of Washington, Seattle, Washington, USA
| | - Brenda Rebollar
- Center for Integrative Brain Research, Seattle Children's Hospital, Seattle, Washington, USA
| | - Jay T Rubinstein
- Department of Otolaryngology, University of Washington, Seattle, Washington, USA.,Department of Bioengineering, University of Washington, Seattle, Washington, USA
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Ramos Macias A, Ramos de Miguel A, Rodriguez Montesdeoca I, Borkoski Barreiro S, Falcón González JC. Chronic Electrical Stimulation of the Otolith Organ: Preliminary Results in Humans with Bilateral Vestibulopathy and Sensorineural Hearing Loss. Audiol Neurootol 2019; 25:79-90. [PMID: 31801137 DOI: 10.1159/000503600] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 09/16/2019] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Bilateral vestibulopathy is an important cause of imbalance that is misdiagnosed. The clinical management of patients with bilateral vestibular loss remains difficult as there is no clear evidence for an effective treatment. In this paper, we try to analyze the effect of chronic electrical stimulation and adaptation to electrical stimulation of the vestibular system in humans when stimulating the otolith organ with a constant pulse train to mitigate imbalance due to bilateral vestibular dysfunction (BVD). METHODS We included 2 patients in our study with BVD according to Criteria Consensus of the Classification Committee of the Bárány Society. Both cases were implanted by using a full-band straight electrode to stimulate the otoliths organs and simultaneously for the cochlear stimulation we use a perimodiolar electrode. RESULTS In both cases Vestibular and clinical test (video head impulse test, videonistagmography cervical vestibular evoked myogenic potentials, cVEMP and oVEMP), subjective visual vertical test, computerized dynamic posturography, dynamic gait index, Time UP and Go test and dizziness handicap index) were performed. Posture and gait metrics reveal important improvement if compare with preoperartive situation. Oscillopsia, unsteadiness, independence and quality of life improved to almost normal situation. DISCUSSION/CONCLUSION Prosthetic implantation of the otolith organ in humans is technically feasible. Electrical stimulation might have potential effects on balance and this is stable after 1 year follow-up. This research provides new possibilities for the development of vestibular implants to improve gravito-inertial acceleration sensation, in this case by the otoliths stimulation.
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Affiliation(s)
- Angel Ramos Macias
- Department of Otolaryngology, Faculty of Medicine, University of Las Palmas de Gran Canaria, Las Palmas, Spain,
| | - Angel Ramos de Miguel
- Hearing and Balance Laboratory, University of Las Palmas de Gran Canaria, Las Palmas, Spain
| | - Isaura Rodriguez Montesdeoca
- Department of Otolaryngology, and Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, Las Palmas, Spain
| | - Silvia Borkoski Barreiro
- Department of Otolaryngology, and Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, Las Palmas, Spain
| | - Juan Carlos Falcón González
- Department of Otolaryngology, and Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, Las Palmas, Spain
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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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