Vestibular Implantation in Older Adults

Johns Hopkins University1 site in 1 country15 target enrollmentApril 11, 2023

ConditionsOther Disorders of Vestibular Function, Bilateral Bilateral Vestibular Deficiency (BVD)Gentamicin Ototoxicity Labyrinth Diseases Vestibular Diseases Sensation Disorders Bilateral Vestibular Hypofunction Bilateral Vestibulopathy Presbyvestibulopathy Aminoglycoside Ototoxicity

Overview

Phase: N/A
Intervention: Not specified
Conditions: Other Disorders of Vestibular Function, Bilateral
Sponsor: Johns Hopkins University
Enrollment: 15
Locations: 1
Primary Endpoint: PM1.1: Dynamic Gait Index (DGI) during motion-modulated implant stimulation at 6 months post-implantation, relative to pre-operative baseline, aggregated across all implant users.
Status: Recruiting
Last Updated: 3 months ago

Overview Investigators Eligibility Criteria Outcomes Sites Similar Trials

Overview

Brief Summary

Although cochlear implants can restore hearing to individuals who have lost cochlear hair cell function, there is no widely available, adequately effective treatment for individuals suffering chronic imbalance, postural instability and unsteady vision due to bilateral vestibular hypofunction. Prior research has demonstrated that electrical stimulation of the vestibular nerve via a chronically implanted multichannel vestibular implant can partially restore vestibular reflexes that normally maintain steady posture and vision; improve performance on objective measures of postural stability and gait; and improve patient-reported disability and health-related quality of life. This single-arm open-label study extends that research to evaluate outcomes for up to fifteen older adults (age 65-90 years at time of enrollment) with ototoxic or non-ototoxic bilateral vestibular hypofunction.

Detailed Description

There is no adequately effective treatment for individuals suffering chronic imbalance, postural instability and unsteady vision due to loss of semicircular canal function despite vestibular rehabilitation exercises. The experience of seven adults aged 51-64 years with bilateral vestibular hypofunction due to ototoxicity who underwent unilateral surgical placement of a vestibular implant and have received continuously motion modulated electrical stimulation of the vestibular nerve for \>6 months revealed that this approach can partially restore vestibular sensation and reflexes that normally maintain steady posture and vision. This study will extend vestibular implant treatment to older adults with idiopathic or non-ototoxic/non-central bilateral vestibular hypofunction. Within constraints on power and/or minimum detectable effect size due to limits on the number of study participants permitted under IDE G150198, the study will test the following hypotheses regarding unilateral vestibular implantation, activation and long-term (≥8 week) continuous/daily use: 1. It is feasible, as quantified by implantation being achieved in all subjects undergoing attempted implantation surgery. 2. It is safe, as determined by incidence of serious unanticipated adverse device-related events and as further quantified by proportions of: 1. implanted ears with preservation of 4-frequency pure tone average for 0.5,1,2,4 kHz air-conducted audiometric detection thresholds ≤ 50 dB HL and ear-specific speech discrimination ≥50% (consistent with Class A or B per American Academy of Otolaryngology-Head and Neck Surgery 1995 guidelines) or ≤ 30 dB change from preoperative baseline (if preoperative baseline is ≥20 dBHL) and ear-specific speech discrimination ≤30% worse than preoperative baseline (if preoperative baseline is ≤80%) 2. participants with preservation of useful sound-field hearing by the above criteria, and 3. implanted ears with preservation of otolith endorgan function, if present pre-operatively 3. It is tolerable, as quantified by ≥6 mo duration of compliance with use. 4. It is efficacious, as defined by nonzero improvement with respect to preoperative baseline in Vestibular Implant Composite Outcome score, which incorporates vestibulo-ocular reflex gain during passive head impulse rotation (VHITG); postural stability as quantified by the Bruininks-Oseretsky Test of Motor Proficiency, 2nd Edition Balance Subtest 5 (BOT); gait stability as quantified by Dynamic Gait Index (DGI); Dizziness Handicap Inventory (DHI); and SF-6D health utility (SF6DU)

Registry

clinicaltrials.gov

Start Date

April 11, 2023

End Date

January 31, 2028

Last Updated

3 months ago

Study Type

Interventional

Study Design

Single Group

Sex

All

Investigators

Sponsor

Johns Hopkins University

Responsible Party

Sponsor

Eligibility Criteria

Inclusion Criteria

•Adults age 65-90 years diagnosed with ototoxic, idiopathic or non-ototoxic/non-central bilateral vestibular hypofunction inadequately responsive to vestibular rehabilitation for greater than 1 year as determined by pre-inclusion history, vestibular testing and clinical examination conducted by a board-certified neurotologist, neurologist or other physician skilled in diagnosis of vestibular disorders
•Hearing status: (1) Hearing in the candidate ear for implantation is equivalent to or worse than that in the contralateral ear; and (2) hearing in the contralateral ear is good enough to allow functional communication in case hearing in the implanted ear is lost after implantation. Specifically, the contralateral ear must satisfy all of the following criteria:
•0.5/1/2/4 kHz pure-tone-average threshold (PTA) hearing better than (i.e., less than) 70 dB HL; and
•ear-specific sentence recognition score using the recorded AzBio Sentence Test presented at 60 dB SPL-A in quiet must be \>60% when tested under either the unaided condition or, if 0.5/1/2/4 kHz PTA\>50 dB, the best-aided condition; and
•ear-specific word recognition score using the recorded Consonant-Nucleus-Consonant (CNC) Word Recognition Test presented at 60 dBHL in quiet must be \>60% when tested under either the unaided condition or, if 0.5/1/2/4 kHz PTA\>50 dB, the best-aided condition
•Caloric responses consistent with severe or profound bilateral loss of labyrinthine function, as indicated by one or more of the following: (a) summed speed of caloric responses to warm and cool supine caloric stimuli totaling \<10°/sec per ear for each of both ears; (b) summed speed of ice water caloric responses during supine and prone head orientation tests totaling \<10°/sec per ear for each of both ears; or (c) speed of ice water caloric responses during supine head orientation tests \<5°/sec per ear for each of both ears, with a lack of nystagmus reversal on quickly flipping from supine to prone
•Prior MRI imaging of the brain, internal auditory canals and cerebellopontine (CP) angle showing a patent labyrinth, present vestibular nerve, patent cochlea, present cochlear nerve, and absence of internal auditory canal/cerebellopontine angle tumors or other central causes of vestibulo-ocular reflex dysfunction or sensorineural hearing loss
•Prior CT imaging of the temporal bones showing a facial nerve canal with normal caliber and course, middle ear without evidence of chronic otitis media or tympani membrane perforation or cholesteatoma, a mastoid cavity with adequate aeration for surgical access to each semicircular canal, skull thickness ≥3 mm at the planned well site, and scalp soft tissue thickness ≤7 mm. This criterion may be satisfied without additional imaging if an existing head CT or MRI already demonstrates those findings
•Vaccinations as recommended per Johns Hopkins Cochlear Implant Center and United States Centers for Disease Control and Prevention protocols to reduce the risk of meningitis in subjects undergoing cochlear implantation, as described at this site: https://www.cdc.gov/vaccines/vpd/mening/public/dis-cochlear-faq-gen.html
•Motivated to travel to the study center, to undergo testing and examinations required for the investigational study, and to participate actively in a vestibular rehabilitation exercise regimen

Exclusion Criteria

•Inability to understand the procedures and the potential risks involved as determined by study staff
•Inability to participate in study procedures due to blindness, ≤ ±10° neck range of motion, cervical spine instability, ear canal stenosis or malformation sufficient to prevent caloric testing
•Diagnosis of acoustic neuroma/vestibular schwannoma, chronic middle ear disease, cholesteatoma, or central nervous system causes of vestibulo-ocular reflex dysfunction, including chronic and continuing use of medications, drugs or alcohol at doses sufficiently great to interfere with vestibular compensation
•Vestibular dysfunction known to be caused by reasons other than labyrinthine injury due to ototoxicity, ischemia, trauma, infection, Meniere's disease, or genetic defects known to act on hair cells
•Lack of labyrinth patency or vestibular nerve as determined by MRI of the brain with attention to the internal acoustic meatus
•Any contraindication to the planned surgery, anesthesia, device activation and deactivation, or participation in study assessments, as determined by the surgeon, anesthesiologist, or designee, including known intolerance of any materials used in any component of the investigational devices that will come in contact with the subject
•History of myocardial infarction, coronary bypass surgery, or any percutaneous coronary intervention (PCI) within 6 months prior to screening
•Orthopedic, neurologic or other nonvestibular pathologic conditions of sufficient severity to confound posture and gait testing or other tests used in the study to assay vestibular function.
•Subjects with estimated glomerular filtration rate (GFR) \< 30 ml/min (MDRD formula) at screening
•Subjects with heart failure NYHA class III or IV

Outcomes

Primary Outcomes

PM1.1: Dynamic Gait Index (DGI) during motion-modulated implant stimulation at 6 months post-implantation, relative to pre-operative baseline, aggregated across all implant users.

Time Frame: Pre-intervention baseline and 6 months post-implantation

DGI comprises 8 gait tasks scored by an examiner: walking on a level surface, changing gait speed, walking during horizontal head turns, walking during vertical head turns, pivoting, stepping over an obstacle, stepping around obstacles, and waling up and down stairs. Each task is scored (0-3 points, 3 is best). Raw DGI score is the sum of the eight subtest scores and ranges from 0 to 24, with higher scores meaning better outcome and minimally important difference 3.2 points.

PM1.2: Gain (VHITG) of the vestibulo-ocular reflex, as measured using the video head impulse test averaged for the three implanted semicircular canals, relative to pre-operative baseline, aggregated across all implant users.

Time Frame: Pre-intervention baseline and 6 months post-implantation

During video head impulse testing (vHIT), rotational eye and head movement are measured by a goggle-mounted camera and motion sensor during brief, fast \~10 degree head rotations about the axis of a semicircular canal being tested. Performance is quantified by vestibulo-ocular reflex (VOR) gain, which a ratio of eye movement to head movement (in this case the integral of eye velocity relative to the head and the additive inverse of the integral of head velocity, respectively). VHITG, the average vHIT VOR gain for each of the three semicircular canals of the implanted ear, typically ranges from 0 to 1, with higher numbers indicating better performance.

Secondary Outcomes

EM1.4: SF6D utility (SF6DU) score at 6 months post-implantation, relative to pre-operative baseline, aggregated for all implanted participants.(Pre-intervention to 6 months post-implantation)
EM2.5: Dynamic Gait Index (DGI) score at 6 months post-implantation, relative to pre-operative baseline, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Pre-intervention to 6 months post-implantation)
SM0.3: Severity of unanticipated adverse device effects as of 6 months post-implantation(Pre-intervention to 6 months post-implantation)
EM2.4: SF6D utility (SF6DU) score at 6 months post-implantation, relative to pre-operative baseline, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Pre-intervention to 6 months post-implantation)
EM2.6: Gain (VHITG) of the vestibulo-ocular reflex, measured using the vHIT averaged for the three implanted semicircular canals, relative to pre-operative baseline, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Pre-intervention to 6 months post-implantation)
SM1.6: Change in proportion of implanted ears with AAO-HNS 1995 Class A/B hearing or changes of ≤30dB and ≤30% from preoperative baseline AirPTAi ≥ 20dBHL and AzBios ≤ 80%, respectively, aggregating across all implanted participants (ClassABAzBioa)(Preoperative baseline to 6 month post-operative assessment)
SM1.11: Changes in cervical vestibular-evoked myogenic potential (cVEMP) response amplitude, aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM1.13: Changes in subjective visual vertical (SVV) as assessed using the Bucket Test, aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM2.1: Changes in implant-side bone-conduction 4-frequency (0.5, 1, 2, 4 kHz) pure tone average detection threshold (BonePTAi), for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM2.2: Changes in implant-side air-conduction 4-frequency pure tone average detection threshold (AirPTAi), for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
EM1.2: Bruininks-Oseretsky Test of Motor Proficiency 2nd Edition Balance Subtest 5 (BOT) score 6 months post-implantation, relative to pre-operative baseline, aggregated for all implanted participants.(Pre-intervention to 6 months post-implantation)
EM1.3: Dizziness Handicap Inventory (DHI) score at 6 months post-implantation, relative to pre-operative baseline, aggregated for all implanted participants.(Pre-intervention to 6 months post-implantation)
EM2.3: Dizziness Handicap Inventory (DHI) score at 6 months post-implantation, relative to pre-operative baseline, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Pre-intervention to 6 months post-implantation)
EM3.2: Bruininks-Oseretsky Test of Motor Proficiency 2nd Edition Balance Subtest 5 (BOT) score 6 months post-implantation, relative to pre-operative baseline, for the subgroup of participants who have ototoxic adult-onset BVH(Pre-intervention to 6 months post-implantation)
SM0.1: Type of unanticipated adverse device effects as of 6 months post-implantation(Pre-intervention to 6 months post-implantation)
EM1.1: Vestibular Implant Composite Outcome (VICO) score at 6 months post-implantation, relative to pre-operative baseline, aggregated for all implanted participants.(Pre-intervention baseline and 6 months post-implantation)
EM2.2: Bruininks-Oseretsky Test of Motor Proficiency 2nd Edition Balance Subtest 5 (BOT) score 6 months post-implantation, relative to pre-operative baseline, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Pre-intervention to 6 months post-implantation)
EM3.4: SF6D utility (SF6DU) score at 6 months post-implantation, relative to pre-operative baseline, for the subgroup of participants who have ototoxic adult-onset BVH(Pre-intervention to 6 months post-implantation)
SM0.2: Incidence of unanticipated adverse device effects as of 6 months post-implantation(Pre-intervention to 6 months post-implantation)
SM1.5: Change in proportion of implanted ears with AAO-HNS 1995 Class A/B hearing or changes of ≤30dB and ≤30% from preoperative baseline AirPTAi ≥ 20dBHL and CNCWi ≤ 80%, respectively, aggregating data across all implanted participants (ClassABCNCWa)(Preoperative baseline to 6 month post-operative assessment)
SM1.10: Changes in Autophony Index (AI), aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM2.3: Changes in implant-side consonant-nucleus-consonant word discrimination score (CNCWi), for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM2.4: Changes in sound-field Arizona Biology (AzBios) sentences-in-noise discrimination score, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM2.5: Change in proportion of implanted ears with AAO-HNS 1995 Class A/B hearing or changes of ≤30dB and ≤30% from preop baseline AirPTAi ≥ 20dBHL and CNCWi ≤ 80%, respectively, for non-ototoxic/non-central adult-onset BVH participants (ClassABCNCWn)(Preoperative baseline to 6 month post-operative assessment)
EM2.1: Vestibular Implant Composite Outcome (VICO) score at 6 months post-implantation, relative to pre-operative baseline, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Pre-intervention to 6 months post-implantation)
EM3.6: Gain (VHITG) of the vestibulo-ocular reflex, measured using the video head impulse test averaged for the three implanted semicircular canals, relative to pre-operative baseline, for the subgroup of participants who have ototoxic adult-onset BVH(Pre-intervention to 6 months post-implantation)
SM1.2: Changes in implant-side air-conduction 4-frequency pure tone average detection threshold (AirPTAi), aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM1.7: Change in implant-side ear distortion-product otoacoustic emission (DPOAE) signal-to-noise ratio for responses to tones centered on 0.75, 1, 1.5, 2, 3, 4, 6 and 8 kHz (an 8-valued vector), aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM1.9: Changes in Tinnitus Handicap Inventory (THI), aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM1.12: Changes in ocular vestibular-evoked myogenic potential (oVEMP) response amplitude, aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
EM3.1: Vestibular Implant Composite Outcome (VICO) score at 6 months post-implantation, relative to pre-operative baseline, for the subgroup of participants who have ototoxic adult-onset BVH(Pre-intervention to 6 months post-implantation)
EM3.3: Dizziness Handicap Inventory (DHI) score at 6 months post-implantation, relative to pre-operative baseline, for the subgroup of participants who have ototoxic adult-onset BVH(Pre-intervention to 6 months post-implantation)
EM3.5: Dynamic Gait Index (DGI) score at 6 months post-implantation, relative to pre-operative baseline, for the subgroup of participants who have ototoxic adult-onset BVH(Pre-intervention to 6 months post-implantation)
SM1.3: Changes in implant-side consonant-nucleus-consonant word discrimination score (CNCWi), aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM1.4: Changes in sound-field Arizona Biology (AzBios) sentences-in-noise discrimination score, aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM2.6: Change in proportion of implanted ears with AAO-HNS 1995 Class A/B hearing or changes of ≤30dB and ≤30% from preop baseline AirPTAi ≥ 20dBHL and AzBios ≤ 80%, respectively, for non-ototoxic/non-central BVH participants (ClassABAzBion)(Preoperative baseline to 6 month post-operative assessment)
SM2.13: Changes in subjective visual vertical (SVV) as assessed using the Bucket Test, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM1.1: Changes in implant-side bone-conduction 4-frequency (0.5, 1, 2, 4 kHz) pure tone average detection threshold (BonePTAi), aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM1.8: Changes in implant-side tympanometry responses (a 3-valued vector comprising peak compliance in mL, pressure in decaPascals at peak admittance, and ear canal volume in mL), aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM1.14: Changes in scalp thickness at the location of implanted magnets (Tscalp), aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM1.15: Changes in all adverse events, including but not limited to events related to the surgical procedure, device and device systems, aggregated across all implant users(Preoperative baseline to 6 month post-operative assessment)
SM3.2: Changes in implant-side air-conduction 4-frequency pure tone average detection threshold (AirPTAi), for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.7: Change in implant-side distortion-product otoacoustic emission (DPOAE) signal/noise ratio for response to tones centered on 0.75/1/1.5/2/3/4/6/8 kHz, for participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM2.12: Changes in ocular vestibular-evoked myogenic potential (oVEMP) response amplitude, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM2.15: Changes in all adverse events, including but not limited to events related to the surgical procedure, device and device systems, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.1: Changes in implant-side bone-conduction 4-frequency (0.5, 1, 2, 4 kHz) pure tone average detection threshold (BonePTAi), for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.4: Changes in sound-field Arizona Biology (AzBios) sentences-in-noise discrimination score, for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.5: Change in proportion of implanted ears with AAO-HNS 1995 Class A/B hearing or changes of ≤30dB and ≤30% from preoperative baseline AirPTAi ≥ 20dBHL and CNCWi ≤ 80%, respectively, aggregating across participants with ototoxic BVH (ClassABCNCWo)(Preoperative baseline to 6 month post-operative assessment)
SM3.6: Change in proportion of implanted ears with AAO-HNS 1995 Class A/B hearing or changes of ≤30dB and ≤30% from preoperative baseline AirPTAi ≥ 20dBHL and AzBios ≤ 80%, respectively, aggregating across participants with ototoxic BVH (ClassABAzBioo)(Preoperative baseline to 6 month post-operative assessment)
TM2: Proportion of implanted participants with non-ototoxic/non-central adult-onset BVH who continue to use the MVI system daily at 6 months post-implantation(6 month post-operative assessment)
SM2.7: Change in implant-side distortion-product otoacoustic emission (DPOAE) signal/noise ratio for response to tones centered on 0.75/1/1.5/2/3/4/6/8 kHz, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM2.9: Changes in Tinnitus Handicap Inventory (THI), for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM2.10: Changes in Autophony Index (AI), for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM2.11: Changes in cervical vestibular-evoked myogenic potential (cVEMP) response amplitude, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.9: Changes in Tinnitus Handicap Inventory (THI), for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.10: Changes in Autophony Index (AI), for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.11: Changes in cervical vestibular-evoked myogenic potential (cVEMP) response amplitude, for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.12: Changes in ocular vestibular-evoked myogenic potential (oVEMP) response amplitude, for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM2.8: Changes in implant-side tympanometry response (3-valued vector comprising peak admittance in mL, pressure in decaPascals at peak admittance, and ear canal volume in mL), for the participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.14: Changes in scalp thickness at the location of implanted magnets (Tscalp), for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM2.14: Changes in scalp thickness at the location of implanted magnets (Tscalp), for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.3: Changes in implant-side consonant-nucleus-consonant word discrimination score (CNCWi), for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.13: Changes in subjective visual vertical (SVV) as assessed using the Bucket Test, for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
TM1: Proportion of all implanted participants who continue to use the MVI system daily at 6 months post-implantation(6 month post-operative assessment)
SM3.8: Changes in implant-side tympanometry responses (a 3-valued vector comprising peak compliance in mL, pressure in decaPascals at peak admittance, and ear canal volume in mL), for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
SM3.15: Changes in all adverse events, including but not limited to events related to the surgical procedure, device and device systems, for the subgroup of participants who have ototoxic adult-onset BVH(Preoperative baseline to 6 month post-operative assessment)
TM3: Proportion of implanted participants with ototoxic adult-onset BVH who continue to use the MVI system daily at 6 months post-implantation(6 month post-operative assessment)