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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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An Implanted Vestibular Prosthesis Improves Spatial Orientation in Animals with Severe Vestibular Damage. J Neurosci 2021; 41:3879-3888. [PMID: 33731447 DOI: 10.1523/jneurosci.2204-20.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 02/10/2021] [Accepted: 03/08/2021] [Indexed: 11/21/2022] Open
Abstract
Gravity is a pervasive environmental stimulus, and accurate graviception is required for optimal spatial orientation and postural stability. The primary graviceptors are the vestibular organs, which include angular velocity (semicircular canals) and linear acceleration (otolith organs) sensors. Graviception is degraded in patients with vestibular damage, resulting in spatial misperception and imbalance. Since minimal therapy is available for these patients, substantial effort has focused on developing a vestibular prosthesis or vestibular implant (VI) that reproduces information normally provided by the canals (since reproducing otolith function is very challenging technically). Prior studies demonstrated that angular eye velocity responses could be driven by canal VI-mediated angular head velocity information, but it remains unknown whether a canal VI could improve spatial perception and posture since these behaviors require accurate estimates of angular head position in space relative to gravity. Here, we tested the hypothesis that a canal VI that transduces angular head velocity and provides this information to the brain via motion-modulated electrical stimulation of canal afferent nerves could improve the perception of angular head position relative to gravity in monkeys with severe vestibular damage. Using a subjective visual vertical task, we found that normal female monkeys accurately sensed the orientation of the head relative to gravity during dynamic tilts, that this ability was degraded following bilateral vestibular damage, and improved when the canal VI was used. These results demonstrate that a canal VI can improve graviception in vestibulopathic animals, suggesting that it could reduce the disabling perceptual and postural deficits experienced by patients with severe vestibular damage.SIGNIFICANCE STATEMENT Patients with vestibular damage experience impaired vision, spatial perception, and balance, symptoms that could potentially respond to a vestibular implant (VI). Anatomic features facilitate semicircular canal (angular velocity) prosthetics but inhibit approaches with the otolith (linear acceleration) organs, and canal VIs that sense angular head velocity can generate compensatory eye velocity responses in vestibulopathic subjects. Can the brain use canal VI head velocity information to improve estimates of head orientation (e.g., head position relative to gravity), which is a prerequisite for accurate spatial perception and posture? Here we show that a canal VI can improve the perception of head orientation in vestibulopathic monkeys, results that are highly significant because they suggest that VIs mimicking canal function can improve spatial orientation and balance in vestibulopathic patients.
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Hazen M, Cushing SL. Implications of Concurrent Vestibular Dysfunction in Pediatric Hearing Loss. CURRENT OTORHINOLARYNGOLOGY REPORTS 2020. [DOI: 10.1007/s40136-020-00298-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Fluctuations in Vestibular Afferent Excitability in Menière's Disease. Otol Neurotol 2020; 41:810-816. [PMID: 32229758 DOI: 10.1097/mao.0000000000002634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine if Menière's disease is associated with fluctuations in afferent excitability in four human subjects previously implanted with vestibular stimulators. STUDY DESIGN Longitudinal repeated measures. SETTING Tertiary referral center, human vestibular research laboratory. PATIENTS Four human subjects with previously uncontrolled Menière's disease unilaterally implanted in each semicircular canal with a vestibular stimulator. One subject had only two canals implanted. INTERVENTION(S) Repeated measures of electrically-evoked slow phase eye velocity and vestibular electrically-evoked compound action potentials (vECAP) over 2 to 4 years. MAIN OUTCOME MEASURE(S) Slow phase eye velocity and N1-P1 vECAP amplitudes as a function of time. RESULTS There were statistically significant fluctuations in electrically evoked slow phase eye velocity over time in at least one semicircular canal of each subject. vECAP N1-P1 amplitudes measured at similar time intervals and stimulus intensities seem to show somewhat correlated fluctuations. One of the subjects had a single Menière's attack during this time period. The others did not. CONCLUSIONS In these four subjects originally diagnosed with Menière's disease, there was fluctuating electrical excitability of the ampullar nerve of at least one canal in each subject. These fluctuations occurred without active symptoms of Menière's disease.
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Hageman KN, Chow MR, Roberts D, Boutros PJ, Tooker A, Lee K, Felix S, Pannu SS, Haque R, Della Santina CC. Binocular 3D otolith-ocular reflexes: responses of chinchillas to prosthetic electrical stimulation targeting the utricle and saccule. J Neurophysiol 2019; 123:259-276. [PMID: 31747349 DOI: 10.1152/jn.00883.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
From animal experiments by Cohen and Suzuki et al. in the 1960s to the first-in-human clinical trials now in progress, prosthetic electrical stimulation targeting semicircular canal branches of the vestibular nerve has proven effective at driving directionally appropriate vestibulo-ocular reflex eye movements, postural responses, and perception. That work was considerably facilitated by the fact that all hair cells and primary afferent neurons in each canal have the same directional sensitivity to head rotation, the three canals' ampullary nerves are geometrically distinct from one another, and electrically evoked three-dimensional (3D) canal-ocular reflex responses approximate a simple vector sum of linearly independent components representing relative excitation of each of the three canals. In contrast, selective prosthetic stimulation of the utricle and saccule has been difficult to achieve, because hair cells and afferents with many different directional sensitivities are densely packed in those endorgans and the relationship between 3D otolith-ocular reflex responses and the natural and/or prosthetic stimuli that elicit them is more complex. As a result, controversy exists regarding whether selective, controllable stimulation of electrically evoked otolith-ocular reflexes (eeOOR) is possible. Using micromachined, planar arrays of electrodes implanted in the labyrinth, we quantified 3D, binocular eeOOR responses to prosthetic electrical stimulation targeting the utricle, saccule, and semicircular canals of alert chinchillas. Stimuli delivered via near-bipolar electrode pairs near the maculae elicited sustained ocular countertilt responses that grew reliably with pulse rate and pulse amplitude, varied in direction according to which stimulating electrode was employed, and exhibited temporal dynamics consistent with responses expected for isolated macular stimulation.NEW & NOTEWORTHY As the second in a pair of papers on Binocular 3D Otolith-Ocular Reflexes, this paper describes new planar electrode arrays and vestibular prosthesis architecture designed to target the three semicircular canals and the utricle and saccule. With this technological advancement, electrically evoked otolith-ocular reflexes due to stimulation via utricle- and saccule-targeted electrodes were recorded in chinchillas. Results demonstrate advances toward achieving selective stimulation of the utricle and saccule.
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Affiliation(s)
- Kristin N Hageman
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Margaret R Chow
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Dale Roberts
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Peter J Boutros
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Angela Tooker
- Lawrence Livermore National Laboratory, Livermore, California
| | - Kye Lee
- Lawrence Livermore National Laboratory, Livermore, California
| | - Sarah Felix
- Lawrence Livermore National Laboratory, Livermore, California
| | | | - Razi Haque
- Lawrence Livermore National Laboratory, Livermore, California
| | - Charles C Della Santina
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
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Boutros PJ, Schoo DP, Rahman M, Valentin NS, Chow MR, Ayiotis AI, Morris BJ, Hofner A, Rascon AM, Marx A, Deas R, Fridman GY, Davidovics NS, Ward BK, Treviño C, Bowditch SP, Roberts DC, Lane KE, Gimmon Y, Schubert MC, Carey JP, Jaeger A, Della Santina CC. Continuous vestibular implant stimulation partially restores eye-stabilizing reflexes. JCI Insight 2019; 4:128397. [PMID: 31723056 DOI: 10.1172/jci.insight.128397] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 10/04/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUNDBilateral loss of vestibular (inner ear inertial) sensation causes chronically blurred vision during head movement, postural instability, and increased fall risk. Individuals who fail to compensate despite rehabilitation therapy have no adequate treatment options. Analogous to hearing restoration via cochlear implants, prosthetic electrical stimulation of vestibular nerve branches to encode head motion has garnered interest as a potential treatment, but prior studies in humans have not included continuous long-term stimulation or 3D binocular vestibulo-ocular reflex (VOR) oculography, without which one cannot determine whether an implant selectively stimulates the implanted ear's 3 semicircular canals.METHODSWe report binocular 3D VOR responses of 4 human subjects with ototoxic bilateral vestibular loss unilaterally implanted with a Labyrinth Devices Multichannel Vestibular Implant System vestibular implant, which provides continuous, long-term, motion-modulated prosthetic stimulation via electrodes in 3 semicircular canals.RESULTSInitiation of prosthetic stimulation evoked nystagmus that decayed within 30 minutes. Stimulation targeting 1 canal produced 3D VOR responses approximately aligned with that canal's anatomic axis. Targeting multiple canals yielded responses aligned with a vector sum of individual responses. Over 350-812 days of continuous 24 h/d use, modulated electrical stimulation produced stable VOR responses that grew with stimulus intensity and aligned approximately with any specified 3D head rotation axis.CONCLUSIONThese results demonstrate that a vestibular implant can selectively, continuously, and chronically provide artificial sensory input to all 3 implanted semicircular canals in individuals disabled by bilateral vestibular loss, driving reflexive VOR eye movements that approximately align in 3D with the head motion axis encoded by the implant.TRIAL REGISTRATIONClinicalTrials.gov: NCT02725463.FUNDINGNIH/National Institute on Deafness and Other Communication Disorders: R01DC013536 and 2T32DC000023; Labyrinth Devices, LLC; and Med-El GmbH.
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Affiliation(s)
| | - Desi P Schoo
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Mehdi Rahman
- Labyrinth Devices, LLC, Baltimore, Maryland, USA
| | | | | | | | | | | | | | | | | | - Gene Y Fridman
- Department of Biomedical Engineering and.,Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | | | - Bryan K Ward
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Carolina Treviño
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Stephen P Bowditch
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Dale C Roberts
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Kelly E Lane
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Yoav Gimmon
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Michael C Schubert
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - John P Carey
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | | | - Charles C Della Santina
- Department of Biomedical Engineering and.,Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.,Labyrinth Devices, LLC, Baltimore, Maryland, USA
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Wolter NE, Gordon KA, Campos JL, Vilchez Madrigal LD, Pothier DD, Hughes CO, Papsin BC, Cushing SL. BalanCI: Head-Referenced Cochlear Implant Stimulation Improves Balance in Children with Bilateral Cochleovestibular Loss. Audiol Neurootol 2019; 25:60-71. [PMID: 31678979 DOI: 10.1159/000503135] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 09/03/2019] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION To determine the impact of a head-referenced cochlear implant (CI) stimulation system, BalanCI, on balance and postural control in children with bilateral cochleovestibular loss (BCVL) who use bilateral CI. METHODS Prospective, blinded case-control study. Balance and postural control testing occurred in two settings: (1) quiet clinical setting and (2) immersive realistic virtual environment (Challenging Environment Assessment Laboratory [CEAL], Toronto Rehabilitation Institute). Postural control was assessed in 16 and balance in 10 children with BCVL who use bilateral CI, along with 10 typically developing children. Children with neuromotor, cognitive, or visual deficits that would prevent them from performing the tests were excluded. Children wore the BalanCI, which is a head-mounted device that couples with their CIs through the audio port and provides head-referenced spatial information delivered via the intracochlear electrode array. Postural control was measured by center of pressure (COP) and time to fall using the WiiTM (Nintendo, WA, USA) Balance Board for feet and the BalanCI for head, during the administration of the Modified Clinical Test of Sensory Interaction in Balance (CTSIB-M). The COP of the head and feet were assessed for change by deviation, measured as root mean square around the COP (COP-RMS), rate of deviation (COP-RMS/duration), and rate of path length change from center (COP-velocity). Balance was assessed by the Bruininks-Oseretsky Test of Motor Proficiency 2, balance subtest (BOT-2), specifically, BOT-2 score as well as time to fall/fault. RESULTS In the virtual environment, children demonstrated more stable balance when using BalanCI as measured by an improvement in BOT-2 scores. In a quiet clinical setting, the use of BalanCI led to improved postural control as demonstrated by significant reductions in COP-RMS and COP-velocity. With the use of BalanCI, the number of falls/faults was significantly reduced and time to fall increased. CONCLUSIONS BalanCI is a simple and effective means of improving postural control and balance in children with BCVL who use bilateral CI. BalanCI could potentially improve the safety of these children, reduce the effort they expend maintaining balance and allow them to take part in more complex balance tasks where sensory information may be limited and/or noisy.
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Affiliation(s)
- Nikolaus E Wolter
- Department of Otolaryngology, Head and Neck Surgery, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Otolaryngology, Head and Neck Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Karen A Gordon
- Department of Otolaryngology, Head and Neck Surgery, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Otolaryngology, Head and Neck Surgery, University of Toronto, Toronto, Ontario, Canada.,Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.,Department of Communication Disorders, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jennifer L Campos
- KITE, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada.,Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | | | - David D Pothier
- Department of Otolaryngology, Head and Neck Surgery, University of Toronto, Toronto, Ontario, Canada.,Centre for Advanced Hearing and Balance Testing, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Cían O Hughes
- UCL Ear Institute, Royal National Throat, Nose and Ear Hospital, London, United Kingdom
| | - Blake C Papsin
- Department of Otolaryngology, Head and Neck Surgery, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Otolaryngology, Head and Neck Surgery, University of Toronto, Toronto, Ontario, Canada.,Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Sharon L Cushing
- Department of Otolaryngology, Head and Neck Surgery, Hospital for Sick Children, Toronto, Ontario, Canada, .,Department of Otolaryngology, Head and Neck Surgery, University of Toronto, Toronto, Ontario, Canada, .,Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, Ontario, Canada, .,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada,
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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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Boutros PJ, Valentin NS, Hageman KN, Dai C, Roberts D, Della Santina CC. Nonhuman primate vestibuloocular reflex responses to prosthetic vestibular stimulation are robust to pulse timing errors caused by temporal discretization. J Neurophysiol 2019; 121:2256-2266. [PMID: 30995152 DOI: 10.1152/jn.00887.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Electrical stimulation of vestibular afferent neurons to partially restore semicircular canal sensation of head rotation and the stabilizing reflexes that sensation supports has potential to effectively treat individuals disabled by bilateral vestibular hypofunction. Ideally, a vestibular implant system using this approach would be integrated with a cochlear implant, which would provide clinicians with a means to simultaneously treat loss of both vestibular and auditory sensation. Despite obvious similarities, merging these technologies poses several challenges, including stimulus pulse timing errors that arise when a system must implement a pulse frequency modulation-encoding scheme (as is used in vestibular implants to mimic normal vestibular nerve encoding of head movement) within fixed-rate continuous interleaved sampling (CIS) strategies used in cochlear implants. Pulse timing errors caused by temporal discretization inherent to CIS create stair step discontinuities of the vestibular implant's smooth mapping of head velocity to stimulus pulse frequency. In this study, we assayed electrically evoked vestibuloocular reflex responses in two rhesus macaques using both a smooth pulse frequency modulation map and a discretized map corrupted by temporal errors typical of those arising in a combined cochlear-vestibular implant. Responses were measured using three-dimensional scleral coil oculography for prosthetic electrical stimuli representing sinusoidal head velocity waveforms that varied over 50-400°/s and 0.1-5 Hz. Pulse timing errors produced negligible effects on responses across all canals in both animals, indicating that temporal discretization inherent to implementing a pulse frequency modulation-coding scheme within a cochlear implant's CIS fixed pulse timing framework need not sacrifice performance of the combined system's vestibular implant portion. NEW & NOTEWORTHY Merging a vestibular implant system with existing cochlear implant technology can provide clinicians with a means to restore both vestibular and auditory sensation. Pulse timing errors inherent to integration of pulse frequency modulation vestibular stimulation with fixed-rate, continuous interleaved sampling cochlear implant stimulation would discretize the smooth head velocity encoding of a combined device. In this study, we show these pulse timing errors produce negligible effects on electrically evoked vestibulo-ocular reflex responses in two rhesus macaques.
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Affiliation(s)
- Peter J Boutros
- Department of Biomedical Engineering, Johns Hopkins School of Medicine , Baltimore, Maryland
| | - Nicolas S Valentin
- Department of Biomedical Engineering, Johns Hopkins School of Medicine , Baltimore, Maryland
| | - Kristin N Hageman
- Department of Biomedical Engineering, Johns Hopkins School of Medicine , Baltimore, Maryland
| | - Chenkai Dai
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine , Baltimore, Maryland
| | - Dale Roberts
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine , Baltimore, Maryland
| | - Charles C Della Santina
- Department of Biomedical Engineering, Johns Hopkins School of Medicine , Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine , Baltimore, Maryland
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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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11
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Handler M, Schier PP, Fritscher KD, Raudaschl P, Johnson Chacko L, Glueckert R, Saba R, Schubert R, Baumgarten D, Baumgartner C. Model-based Vestibular Afferent Stimulation: Modular Workflow for Analyzing Stimulation Scenarios in Patient Specific and Statistical Vestibular Anatomy. Front Neurosci 2017; 11:713. [PMID: 29311790 PMCID: PMC5742128 DOI: 10.3389/fnins.2017.00713] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 12/05/2017] [Indexed: 12/12/2022] Open
Abstract
Our sense of balance and spatial orientation strongly depends on the correct functionality of our vestibular system. Vestibular dysfunction can lead to blurred vision and impaired balance and spatial orientation, causing a significant decrease in quality of life. Recent studies have shown that vestibular implants offer a possible treatment for patients with vestibular dysfunction. The close proximity of the vestibular nerve bundles, the facial nerve and the cochlear nerve poses a major challenge to targeted stimulation of the vestibular system. Modeling the electrical stimulation of the vestibular system allows for an efficient analysis of stimulation scenarios previous to time and cost intensive in vivo experiments. Current models are based on animal data or CAD models of human anatomy. In this work, a (semi-)automatic modular workflow is presented for the stepwise transformation of segmented vestibular anatomy data of human vestibular specimens to an electrical model and subsequently analyzed. The steps of this workflow include (i) the transformation of labeled datasets to a tetrahedra mesh, (ii) nerve fiber anisotropy and fiber computation as a basis for neuron models, (iii) inclusion of arbitrary electrode designs, (iv) simulation of quasistationary potential distributions, and (v) analysis of stimulus waveforms on the stimulation outcome. Results obtained by the workflow based on human datasets and the average shape of a statistical model revealed a high qualitative agreement and a quantitatively comparable range compared to data from literature, respectively. Based on our workflow, a detailed analysis of intra- and extra-labyrinthine electrode configurations with various stimulation waveforms and electrode designs can be performed on patient specific anatomy, making this framework a valuable tool for current optimization questions concerning vestibular implants in humans.
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Affiliation(s)
- Michael Handler
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Peter P Schier
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Karl D Fritscher
- Department for Biomedical Computer Science and Mechatronics, Institute of Biomedical Image Analysis, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Patrik Raudaschl
- Department for Biomedical Computer Science and Mechatronics, Institute of Biomedical Image Analysis, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Lejo Johnson Chacko
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Rudolf Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria.,Department of Otolaryngology Tirol Kliniken, University Clinics Innsbruck, Innsbruck, Austria
| | | | - Rainer Schubert
- Department for Biomedical Computer Science and Mechatronics, Institute of Biomedical Image Analysis, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Daniel Baumgarten
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria.,Department of Computer Science and Automation, Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Christian Baumgartner
- Department for Biomedical Computer Science and Mechatronics, Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria.,Faculty of Computer Science and Biomedical Engineering, Institute of Health Care Engineering, Graz University of Technology, Graz, Austria
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12
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Toreyin H, Daruwalla A, Bhatti P, Ayazi F. A dual-axis single-proof-mass angular accelerometer for a vestibular prosthesis. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2016:4695-4698. [PMID: 28269320 DOI: 10.1109/embc.2016.7591775] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A dual-axis single-proof-mass angular accelerometer has been developed for a vestibular prosthesis. Designed to sense head rotations both in the yaw and the pitch planes, the output of the inertial sensor may be coded as amplitude or rate modulated biphasic current pulses to stimulate vestibular nerves. Fabricated with a high aspect ratio commercial process, a sensor with small form factor (1.4 mm × 0.8 mm) is achieved with a scale factor of 95.5 μV/rad/sec2 and 145.8 μV/rad/sec2 in the yaw and the pitch planes, respectively. Superior linear acceleration rejection was demonstrated for both rotating axis, and an overall power consumption of 296 μW was estimated including sensor and interface circuit.
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13
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Jiang D, Cirmirakis D, Schormans M, Perkins TA, Donaldson N, Demosthenous A. An Integrated Passive Phase-Shift Keying Modulator for Biomedical Implants With Power Telemetry Over a Single Inductive Link. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2017; 11:64-77. [PMID: 27654977 DOI: 10.1109/tbcas.2016.2580513] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This paper presents a passive phase-shift keying (PPSK) modulator for uplink data transmission for biomedical implants with simultaneous power and data transmission over a single 13.56 MHz inductive link. The PPSK modulator provides a data rate up to 1.35 Mbps with a modulation index between 3% and 38% for a variation of the coupling coefficient between 0.05 and 0.26. This modulation scheme is particularly suited for biomedical implants that have high power demand and low coupling coefficients. The PPSK modulator operates in conjunction with on-off-keying downlink communication. The same inductive link is used to provide up to 100 mW of power to a multi-channel stimulator. The majority of the system on the implant side was implemented as an application specific integrated circuit (ASIC), fabricated in 0.6- [Formula: see text] high voltage CMOS technology. The theory of PPSK modulation, simulated and measured performance evaluation, and comparison with other state-of-the-art impedance modulation techniques is presented. The measured bit error rate around critical coupling at 1.35 Mbps is below 6 ×10-8.
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14
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Vestibular ablation and a semicircular canal prosthesis affect postural stability during head turns. Exp Brain Res 2016; 234:3245-3257. [PMID: 27405997 DOI: 10.1007/s00221-016-4722-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 07/04/2016] [Indexed: 10/21/2022]
Abstract
In our study, we examined postural stability during head turns for two rhesus monkeys: one animal study contrasted normal and mild bilateral vestibular ablation and a second animal study contrasted severe bilateral vestibular ablation with and without prosthetic stimulation. The monkeys freely stood, unrestrained on a balance platform and made voluntary head turns between visual targets. To quantify each animals' posture, motions of the head and trunk, as well as torque about the body's center of mass, were measured. In the mildly ablated animal, we observed less foretrunk sway in comparison with the normal state. When the canal prosthesis provided electric stimulation to the severely ablated animal, it showed a decrease in trunk sway during head turns. Because the rhesus monkey with severe bilateral vestibular loss exhibited a decrease in trunk sway when receiving vestibular prosthetic stimulation, we propose that the prosthetic electrical stimulation partially restored head velocity information. Our results provide an indication that a semicircular canal prosthesis may be an effective way to improve postural stability in patients with severe peripheral vestibular dysfunction.
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15
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Hageman KN, Chow MR, Boutros PJ, Roberts D, Tooker A, Lee K, Felix S, Pannu SS, Della Santina CC. Design of a Vestibular Prosthesis for Sensation of Gravitoinertial Acceleration1. J Med Device 2016. [DOI: 10.1115/1.4033759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Kristin N. Hageman
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Margaret R. Chow
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Peter J. Boutros
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Dale Roberts
- Department of Otolaryngology—Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Angela Tooker
- Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Kye Lee
- Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Sarah Felix
- Lawrence Livermore National Laboratory, Livermore, CA 94550
| | | | - Charles C. Della Santina
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21205
- Department of Otolaryngology—Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, MD 21205
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16
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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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17
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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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18
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Poppendieck W, Sossalla A, Krob MO, Welsch C, Nguyen TAK, Gong W, DiGiovanna J, Micera S, Merfeld DM, Hoffmann KP. Development, manufacturing and application of double-sided flexible implantable microelectrodes. Biomed Microdevices 2015; 16:837-50. [PMID: 25078417 DOI: 10.1007/s10544-014-9887-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Many neuroprosthetic applications require the use of very small, flexible multi-channel microelectrodes (e.g. polyimide-based film-like electrodes) to fit anatomical constraints. By arranging the electrode contacts on both sides of the polyimide film, selectivity can be further increased without increasing size. In this work, two approaches to create such double-sided electrodes are described and compared: sandwich electrodes prepared by precisely gluing two single-sided structures together, and monolithic electrodes created using a new double-sided photolithography process. Both methods were successfully applied to manufacture double-sided electrodes for stimulation of the vestibular system. In a case study, the electrodes were implanted in the semicircular canals of three guinea pigs and proven to provide electrical stimulation of the vestibular nerve. For both the monolithic electrodes and the sandwich electrodes, long-term stability and functionality was observed over a period of more than 12 months. Comparing the two types of electrodes with respect to the manufacturing process, it can be concluded that monolithic electrodes are the preferred solution for very thin electrodes (<20 μm), while sandwich electrode technology is especially suitable for thicker electrodes (40-50 μm).
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Affiliation(s)
- Wigand Poppendieck
- Department Medical Engineering and Neuroprosthetics, Fraunhofer Institute for Biomedical Engineering, 66386, Ensheimer Strasse 48, St. Ingbert, Germany,
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19
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Advances in the diagnosis and treatment of vestibular disorders: psychophysics and prosthetics. J Neurosci 2015; 35:5089-96. [PMID: 25834036 DOI: 10.1523/jneurosci.3922-14.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although vestibular disorders are common and often disabling, they remain difficult to diagnose and treat. For these reasons, considerable interest has been focused on developing new ways to identify peripheral and central vestibular abnormalities and on new therapeutic options that could benefit the numerous patients who remain symptomatic despite optimal therapy. In this review, I focus on the potential utility of psychophysical vestibular testing and vestibular prosthetics. The former offers a new diagnostic approach that may prove to be superior to the current tests in some circumstances; the latter may be a way to provide the brain with information about head motion that restores some elements of the information normally provided by the vestibular labyrinth.
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20
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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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21
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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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22
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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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23
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Nguyen TAK, Ranieri M, DiGiovanna J, Peter O, Genovese V, Perez Fornos A, Micera S. A real-time research platform to study vestibular implants with gyroscopic inputs in vestibular deficient subjects. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2014; 8:474-484. [PMID: 25073124 DOI: 10.1109/tbcas.2013.2290089] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Researchers have succeeded in partly restoring damaged vestibular functionality in several animal models. Recently, acute interventions have also been demonstrated in human patients. Our previous work on a vestibular implant for humans used predefined stimulation patterns; here we present a research tool that facilitates motion-modulated stimulation. This requires a system that can process gyroscope measurements and send stimulation parameters to a hybrid vestibular-cochlear implant in real-time. To match natural vestibular latencies, the time from sensor input to stimulation output should not exceed 6.5 ms. We describe a system based on National Instrument's CompactRIO platform that can meet this requirement and also offers floating point precision for advanced transfer functions. It is designed for acute clinical interventions, and is sufficiently powerful and flexible to serve as a development platform for evaluating prosthetic control strategies. Amplitude and pulse frequency modulation to predetermined functions or sensor inputs have been validated. The system has been connected to human patients, who each have received a modified MED-EL cochlear implant for vestibular stimulation, and patient tests are ongoing.
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24
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Lumbreras V, Bas E, Gupta C, Rajguru SM. Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling. J Neurophysiol 2014; 112:1246-55. [PMID: 24920028 DOI: 10.1152/jn.00253.2014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cochlear implants are currently the most effective solution for profound sensorineural hearing loss, and vestibular prostheses are under development to treat bilateral vestibulopathies. Electrical current spread in these neuroprostheses limits channel independence and, in some cases, may impair their performance. In comparison, optical stimuli that are spatially confined may result in a significant functional improvement. Pulsed infrared radiation (IR) has previously been shown to elicit responses in neurons. This study analyzes the response of neonatal rat spiral and vestibular ganglion neurons in vitro to IR (wavelength = 1,863 nm) using Ca(2+) imaging. Both types of neurons responded consistently with robust intracellular Ca(2+) ([Ca(2+)]i) transients that matched the low-frequency IR pulses applied (4 ms, 0.25-1 pps). Radiant exposures of ∼637 mJ/cm(2) resulted in continual neuronal activation. Temperature or [Ca(2+)] variations in the media did not alter the IR-evoked transients, ruling out extracellular Ca(2+) involvement or primary mediation by thermal effects on the plasma membrane. While blockage of Na(+), K(+), and Ca(2+) plasma membrane channels did not alter the IR-evoked response, blocking of mitochondrial Ca(2+) cycling with CGP-37157 or ruthenium red reversibly inhibited the IR-evoked [Ca(2+)]i transients. Additionally, the magnitude of the IR-evoked transients was dependent on ryanodine and cyclopiazonic acid-dependent Ca(2+) release. These results suggest that IR modulation of intracellular calcium cycling contributes to stimulation of spiral and vestibular ganglion neurons. As a whole, the results suggest selective excitation of neurons in the IR beam path and the potential of IR stimulation in future auditory and vestibular prostheses.
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Affiliation(s)
- Vicente Lumbreras
- Department of Biomedical Engineering, University of Miami, Miami, Florida; and
| | - Esperanza Bas
- Department of Otolaryngology, University of Miami, Miami, Florida
| | - Chhavi Gupta
- Department of Otolaryngology, University of Miami, Miami, Florida
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami, Miami, Florida; and Department of Otolaryngology, University of Miami, Miami, Florida
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25
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Mitchell DE, Dai C, Rahman MA, Ahn JH, Della Santina CC, Cullen KE. Head movements evoked in alert rhesus monkey by vestibular prosthesis stimulation: implications for postural and gaze stabilization. PLoS One 2013; 8:e78767. [PMID: 24147142 PMCID: PMC3798420 DOI: 10.1371/journal.pone.0078767] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 09/14/2013] [Indexed: 11/18/2022] Open
Abstract
The vestibular system detects motion of the head in space and in turn generates reflexes that are vital for our daily activities. The eye movements produced by the vestibulo-ocular reflex (VOR) play an essential role in stabilizing the visual axis (gaze), while vestibulo-spinal reflexes ensure the maintenance of head and body posture. The neuronal pathways from the vestibular periphery to the cervical spinal cord potentially serve a dual role, since they function to stabilize the head relative to inertial space and could thus contribute to gaze (eye-in-head + head-in-space) and posture stabilization. To date, however, the functional significance of vestibular-neck pathways in alert primates remains a matter of debate. Here we used a vestibular prosthesis to 1) quantify vestibularly-driven head movements in primates, and 2) assess whether these evoked head movements make a significant contribution to gaze as well as postural stabilization. We stimulated electrodes implanted in the horizontal semicircular canal of alert rhesus monkeys, and measured the head and eye movements evoked during a 100 ms time period for which the contribution of longer latency voluntary inputs to the neck would be minimal. Our results show that prosthetic stimulation evoked significant head movements with latencies consistent with known vestibulo-spinal pathways. Furthermore, while the evoked head movements were substantially smaller than the coincidently evoked eye movements, they made a significant contribution to gaze stabilization, complementing the VOR to ensure that the appropriate gaze response is achieved. We speculate that analogous compensatory head movements will be evoked when implanted prosthetic devices are transitioned to human patients.
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Affiliation(s)
- Diana E. Mitchell
- Department of Physiology McGill University, Montreal, Quebec, Canada
| | - Chenkai Dai
- Department of Otolaryngology, Head & Neck Surgery Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Mehdi A. Rahman
- Department of Otolaryngology, Head & Neck Surgery Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Joong Ho Ahn
- Department of Otolaryngology, Head & Neck Surgery Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Charles C. Della Santina
- Department of Otolaryngology, Head & Neck Surgery Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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26
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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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