Vestibular Implantation to Treat Adult-Onset Bilateral Vestibular Hypofunction

Study Overview
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Brief Summary
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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 focused on ototoxic cases 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 8 individuals with non-ototoxic bilateral vestibular hypofunction, yielding a total of fifteen adults (age 22-90 years at time of enrollment) divided as equally as possible between ototoxic and non-ototoxic cases.

Detailed Description
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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 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 examine long-term outcomes in that cohort and extend vestibular implant treatment to 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 and U01DC019364, the study will test the following hypotheses regarding unilateral vestibular implantation, activation and long-term (≥8 week) continuous/daily use: It is feasible, as quantified by implantation being achieved in all subjects undergoing attempted implantation surgery. It is safe, as determined by incidence of serious unanticipated adverse device-related events and as further quantified by proportions of: 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 guidelines13 ) 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%) participants with preservation of useful sound-field hearing by the above criteria, and implanted ears with preservation of otolith endorgan function, if present pre-operatively It is tolerable, as quantified by ≥6 mo duration of compliance with use. It is efficacious, as defined by nonzero improvement with respect to preoperative baseline in Vestibular Implant Composite Outcome score (VICO), 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).

Official Title
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Vestibular Implantation to Treat Adult-Onset Bilateral Vestibular Hypofunction

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

Intervention / Treatment
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* Device: Labyrinth Devices MVI™ Multichannel Vestibular Implant System


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults age 22-90 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 The participant must agree not to swim or to use or operate vehicles, heavy machinery, powered tools or other devices that could pose a threat to the participant, to others, or to property throughout the duration of participation in the study and until at least 1 month after final deactivation of the MVI Implant 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 Subjects with Child-Pugh class C cirrhosis Inadequately treated or unstable depression, suicidality as indicated by any affirmative answer to the 6-question screener version of the Columbia Suicide Severity Rating Scale (C-SSRS), or any other psychiatric disease or substance abuse history likely to interfere with protocol compliance Contraindications to scleral coil eye movement testing, including monocular blindness and a history of fainting vagal reactions to prior eye manipulations would exclude subjects from eye coil testing Inability to tolerate baseline testing protocols Recent corneal injury A history of cervical spine disease preventing head rotation A history of fainting or vagal reactions prior to eye manipulations that would preclude 3D eye movement coil testing Pregnancy, positive urine or serum pregnancy test at any time during study participation, Ability to become pregnant combined with failure or refusal to consistently use a highly effective method of contraception from at least 1 month prior to implantation to not before 1 month after both device deactivation and conclusion of study participation. Highly effective contraception methods include: Total abstinence. Periodic abstinence (e.g., calendar, ovulation, symptothermal, post ovulation methods) and withdrawal are not acceptable methods of contraception for purposes of defining exclusion criteria for this study Female sterilization (surgical bilateral oophorectomy with or without hysterectomy) or tubal ligation at least six weeks before entering the study. A woman who has undergone oophorectomy without hysterectomy may participate in the study only after her reproductive status has been confirmed by subsequent hormone level assessment For female subjects of child-bearing potential, study participation is not excluded if the study candidate's male partner is the sole partner of the study candidate and has been vasectomized. Combination of any two of the following: Use of oral, injected or implanted hormonal methods of contraception or other forms of hormonal contraception that have comparable efficacy (failure rate <1%), for example, hormone vaginal ring or transdermal hormone contraception Placement of an intrauterine device (IUD) or intrauterine system (IUS) Barrier methods of contraception: Condom or Occlusive cap (diaphragm or cervical/vault caps) with spermicidal foam/gel/film/cream/vaginal suppository In case of use of oral contraception, women should have been stabile on the same pill for a minimum of 3 months before taking study treatment. Women who are nursing/lactating Any medical condition, judged by the investigator team, that is likely to interfere with a study candidate's participation in the study or likely to cause serious adverse events during the study.

Ages Eligible for Study
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Minimum Age: 22 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: vestibular implant<br>Up to 8 participants will undergo implantation, activation and deactivation of a Labyrinth Devices MVI™ Multichannel Vestibular Implant System | Device: Labyrinth Devices MVI™ Multichannel Vestibular Implant System<br>* Unilateral implantation of a Labyrinth Devices MVI™ Multichannel Vestibular Implant System receiver/stimulator including insertion of electrode arrays in the semicircular canal ampullae of the inner ear, followed by motion-modulated prosthetic electrical stimulation.<br>* Other names: Vestibular implantation and continuously motion-modulated stimulation;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PM1: Vestibular Implant Composite Outcome (VICO) score at 6 months post-implantation, relative to pre-operative baseline, aggregated for all implanted participants. | Vestibular Implant Composite Outcome (VICO) score incorporates changes in vestibulo-ocular reflex gain during video head impulse testing, postural stability, gait, dizziness handicap, and health-related quality of life at 6 months post-implantation, relative to pre-operative baseline. VICO (t=6months post-op) score is the sum of changes, from preoperative baseline to 6 months post-implantation, in 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 SF6D health utility (SF6DU); with each component's contribution scaled to the corresponding test's minimally important difference (MID). Higher scores indicate better outcomes. | Pre-intervention to 6 months post-implantation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| EM1.1: vestibulo-ocular reflex (VOR) gain during video head impulse testing (vHIT) averaged for the three implanted semicircular canals (VHITG) at 6 months post-implantation, relative to pre-operative baseline, aggregated for all implanted participants. | 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. | Pre-intervention to 6 months post-implantation | 
| 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. | BOT comprises 9 postural tasks scored by an examiner: standing with both feet on a line, standing on one leg, tandem walking, walking on a line with eyes open and eyes closed, and standing on a balance beam. Each task is performed twice and scored (0-4 points, 4 is best). The BOT score is the sum of the best scores for each task. It ranges from 0 to 36 points, with higher scores meaning better outcome and minimally important difference 4.5 points. | Pre-intervention to 6 months post-implantation | 
| EM1.3: Dynamic Gait Index (DGI) score at 6 months post-implantation, relative to pre-operative baseline, aggregated for all implanted participants. | 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. | Pre-intervention to 6 months post-implantation | 
| EM1.4: Dizziness Handicap Inventory (DHI) score at 6 months post-implantation, relative to pre-operative baseline, aggregated for all implanted participants. | Dizziness Handicap Inventory (DHI) is a 25-question survey designed to quantify self-rated disability due to dizziness and unsteadiness, with scores ranging from 0 (least disabled, best outcome) to 100 (worst outcome). The minimally important difference is 18 points. | Pre-intervention to 6 months post-implantation | 
| EM1.5: SF6D utility (SF6DU) score at 6 months post-implantation, relative to pre-operative baseline, aggregated for all implanted participants. | SF6DU is a unitless health utility score computed from patient-reported replies to the SF6 health-related quality of life survey and ranging from 0 to 1, with higher scores meaning better outcome and minimally important difference 0.03 points. | Pre-intervention to 6 months post-implantation | 
| EM2.1: vestibulo-ocular reflex (VOR) gain during video head impulse testing (vHIT) averaged for the three implanted semicircular canals (VHITG), for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH | 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. | Pre-intervention to 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 | BOT includes 9 postural tasks scored by an examiner: standing with both feet on a line, standing on one leg, tandem walking, walking on a line with eyes open and eyes closed, and standing on a balance beam. Each task is performed twice and scored (0-4 points). The BOT score is the sum of the best scores for each task. It ranges from 0 to 36 points, with higher scores meaning better outcome and minimally important difference 4.5 points. | Pre-intervention to 6 months post-implantation | 
| EM2.3: 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 | 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. | Pre-intervention to 6 months post-implantation | 
| EM2.4: 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 | Dizziness Handicap Inventory (DHI) is a 25-question survey designed to quantify self-rated disability due to dizziness and unsteadiness, with scores ranging from 0 (least disabled, best outcome) to 100 (worst outcome). The minimally important difference is 18 points. | Pre-intervention to 6 months post-implantation | 
| EM2.5: 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 | SF6DU is a unitless health utility score computed from patient-reported replies to the SF6 health-related quality of life survey and ranging from 0 to 1, with higher scores meaning better outcome and minimally important difference 0.03 points. | Pre-intervention to 6 months post-implantation | 
| EM3.1: vestibulo-ocular reflex (VOR) gain during video head impulse testing (vHIT) averaged for the three implanted semicircular canals (VHITG), for the subgroup of participants who have ototoxic adult-onset BVH | 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. | 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 | BOT includes 9 postural tasks scored by an examiner: standing with both feet on a line, standing on one leg, tandem walking, walking on a line with eyes open and eyes closed, and standing on a balance beam. Each task is performed twice and scored (0-4 points). The BOT score is the sum of the best scores for each task. It ranges from 0 to 36 points, with higher scores meaning better outcome and minimally important difference 4.5 points. | Pre-intervention to 6 months post-implantation | 
| EM3.3: 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 | 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. | Pre-intervention to 6 months post-implantation | 
| EM3.4: 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 | Dizziness Handicap Inventory (DHI) is a 25-question survey designed to quantify self-rated disability due to dizziness and unsteadiness, with scores ranging from 0 (least disabled, best outcome) to 100 (worst outcome). The minimally important difference is 18 points. | Pre-intervention to 6 months post-implantation | 
| EM3.5: 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 | SF6DU is a unitless health utility score computed from patient-reported replies to the SF6 health-related quality of life survey and ranging from 0 to 1, with higher scores meaning better outcome and minimally important difference 0.03 points. | Pre-intervention to 6 months post-implantation | 
| SM0.1: Type of unanticipated adverse device effects as of 6 months post-implantation | Assess safety of the intervention, aggregating data across all implanted participants (diversified across ototoxic and non-ototoxic/non-central adult-onset BVH), as determined by (type of) changes from pre-intervention to 6 months post-implantation | Pre-intervention to 6 months post-implantation | 
| SM0.2: Incidence of unanticipated adverse device effects as of 6 months post-implantation | Assess safety of the intervention, aggregating data across all implanted participants (diversified across ototoxic and non-ototoxic/non-central adult-onset BVH), as determined by incidence of adverse device-related events from pre-intervention to 6 months post-implantation | Pre-intervention to 6 months post-implantation | 
| SM0.3: Severity of unanticipated adverse device effects as of 6 months post-implantation | Assess safety of the intervention, aggregating data across all implanted participants (diversified across ototoxic and non-ototoxic/non-central adult-onset BVH), as determined by severity of adverse device-related events from pre-intervention to 6 months post-implantation | Pre-intervention to 6 months post-implantation | 
| 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 | BonePTAi is the 4-frequency average of pure tone detection thresholds, in dBHL, for implant-side bone-conduction presentation of pure tones at 0.5, 1, 2 and 4 kHz. Range is -10 to 80 dBHL, with change toward smaller absolute values representing better (closer to normal) outcome. | Preoperative baseline to 6 month post-operative assessment | 
| SM1.2: Changes in implant-side air-conduction 4-frequency pure tone average detection threshold (AirPTAi), aggregated across all implant users | AirPTAi is the 4-frequency average of pure tone detection thresholds, in dBHL, for implant-side air-conduction presentation of pure tones at 0.5, 1, 2 and 4 kHz. Range is -10 to 120 dBHL, with change toward smaller absolute values representing better (closer to normal) outcome. | Preoperative baseline to 6 month post-operative assessment | 
| SM1.3: Changes in implant-side consonant-nucleus-consonant word discrimination score (CNCWi), aggregated across all implant users | CNCWi is the percentage of monosyllabic consonant-nucleus-consonant words correctly repeated when presented via an earphone speaker on the implanted side in a sound-isolation booth while a masking noise is played to the contralateral ear at 40 dB above its bone-conduction 4-frequency pure tone detection threshold if that threshold is at least 10 dB better than that of the ear being tested. CNCWi ranges from 0-100% correct, with higher score meaning better outcome. | 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 | AzBios is the percentage of words correctly repeated when a set of 20 Arizona Biology sentences (randomly chosen without repeats from 15 sets) is presented at a moderate level (60 dB SPL) along with masking noise (simultaneous presentation of ten sentences from another set at aggregate sound level 55 dBSPL) to both ears via a sound field speaker in a sound-isolation booth. Scores range from 0-100% correct, with higher score meaning better outcome. | Preoperative baseline to 6 month post-operative assessment | 
| 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) | For ClassABCNCW, AAO-HNS (American Academy of Otolaryngology - Head & Neck Surgery) 1995 Class A or B hearing is defined as AirPTAi not worse than 50 dBHL and CNCWi not worse than 50%. ClassABCNCW proportion ranges from 0-100%, with higher values meaning better outcomes. | Preoperative baseline to 6 month post-operative assessment | 
| 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) | For ClassABAzBio, AAO-HNS (American Academy of Otolaryngology - Head & Neck Surgery) 1995 Class A or B hearing is defined as AirPTAi not worse than 50 dBHL and sound-field-presentation Arizona Biology sentences-in-noise discrimination score (AzBios) not worse than 50%. ClassABAzBio proportion ranges from 0-100%, with higher values meaning better outcomes. | 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 | Distortion-product otoacoustic emissions (DPOAE) are sounds generated by a normal cochlea and detectable using a microphone in the ear canal when pairs of pure tones (centered on 0.75, 1, 1.5, 2, 3, 4, 6 and 8 kHz) are presented to the ear. DPOAE signals (and 8-valued vector for responses to stimuli centered on 0.75, 1, 1.5, 2, 3, 4, 6 and 8 kHz) are quantified in dB relative to the frequency-specific noise floor recorded by the same microphone before onset of stimulation. Response range is 0-15 dB, with higher values meaning better outcome. | 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 | Tympanometry involves using an ear canal microphone to measure ear canal acoustic admittance (conventionally reported in units of mL) and volume (in mL) by sensing reflection of a 226 Hz tone presented via a speaker in the ear canal while ear canal pressure is slowly varied from -400 to 200 decaPascals. Negative bias pressures pull the ear drum outward, positive bias pressures push the ear drum inward, and acoustic admittance is greatest when the ear drum is in a neutral anatomic position, neither retracted inward nor ballooned outward. Results are conventionally represented graphically then summarized by a three-valued vector comprising peak compliance (range 0-2mL, values closer to normal range of 0.3-1.4 mL meaning more normal outcome), pressure at which compliance peaks (range -400 to 200 decaPascal, values closer to 0 meaning more normal outcome), and ear canal volume (range 0-3 mL, values closer to normal adult range of 0.6-1.4 meaning more normal outcome). | Preoperative baseline to 6 month post-operative assessment | 
| SM1.9: Changes in Tinnitus Handicap Inventory (THI), aggregated across all implant users | The Tinnitus Handicap Inventory (THI) survey is set of questions designed to quantify self-perceived handicap due to tinnitus. THI score ranges from 0-100. Higher scores mean worse outcome. | Preoperative baseline to 6 month post-operative assessment | 
| SM1.10: Changes in Autophony Index (AI), aggregated across all implant users | The Autophony Index (AI) survey is set of questions designed to quantify self-perceived autophony (hearing one's voice or other internally-generated body sounds). AI score ranges from 0-104. Higher scores mean worse outcomes. | 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 | Cervical vestibular-evoked myogenic potentials (cVEMPs) are a measure of saccule-mediated inhibition of sternocleidomastoid muscle electromyographic (EMG) activity during presentation of loud tones to the ipsilateral ear. After normalizing to average rectified EMG activity (in microvolts) prior to sound stimulation, cVEMP amplitudes (in microvolts) are unitless. Values range from 0 to  10, with larger values suggesting increased saccule activity and generally indicating better outcomes, except that values above 3.0 suggest abnormally high saccule sensitivity to sound. | 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 | Ocular vestibular-evoked myogenic potentials (oVEMPs) are a measure of utricle-mediated electromyographic (EMG) activity of inferior oblique and inferior rectus extraocular muscles during presentation of loud tones to the contralateral ear. Amplitude ranges from 0 to  50 microvolts, with larger values generally suggesting increased utricle activity and better outcomes but values above 17 microvolts suggesting abnormally high utricle sensitivity to sound. | 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 | A participant's vision is occluded by a bucket oriented so that its axis aligns with the participant's nasooccipital axis. The examiner rotates the bucket about the axis to a new orientation, the participant reorients it until a line drawn on the floor of the bucket is judges by the participant to be Earth-vertical and deviation of that line from true vertical is recorded. Values range over -15 to 15 degrees, with smaller absolute values meaning more normal outcomes. | 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 | Scalp thickness at the location of implanted magnets (Tscalp) is measured in mm using a magnetic sensor. Range is 0 to 10 mm, with values closer to the range 3-7mm indicating better outcomes. | 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 | Assess safety of the intervention, aggregating data across all implanted participants (diversified across ototoxic and non-ototoxic/non-central adult-onset BVH), as determined by changes in hearing and otolith endorgan function indicated by changes in all adverse events, including but not limited to events related to the surgical procedure, device and device systems | 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 | BonePTAi is the 4-frequency average of pure tone detection thresholds, in dBHL, for implant-side bone-conduction presentation of pure tones at 0.5, 1, 2 and 4 kHz. Range is -10 to 80 dBHL, with change toward smaller absolute values representing better (closer to normal) outcome. | 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 | AirPTAi is the 4-frequency average of pure tone detection thresholds, in dBHL, for implant-side air-conduction presentation of pure tones at 0.5, 1, 2 and 4 kHz. Range is -10 to 120 dBHL, with change toward smaller absolute values representing better (closer to normal) outcome. | 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 | CNCWi is the percentage of monosyllabic consonant-nucleus-consonant words correctly repeated when presented via an earphone speaker on the implanted side in a sound-isolation booth while a masking noise is played to the contralateral ear at 40 dB above its bone-conduction 4-frequency pure tone detection threshold if that threshold is at least 10 dB better than that of the ear being tested. CNCWi ranges from 0-100% correct, with higher score meaning better outcome. | 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 | AzBios is the percentage of words correctly repeated when a set of 20 Arizona Biology sentences (randomly chosen without repeats from 15 sets) is presented at a moderate level (60 dB SPL) along with masking noise (simultaneous presentation of ten sentences from another set at aggregate sound level 55 dBSPL) to both ears via a sound field speaker in a sound-isolation booth. Scores range from 0-100% correct, with higher score meaning better outcome. | 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) | For ClassABCNCW, AAO-HNS (American Academy of Otolaryngology - Head & Neck Surgery) 1995 Class A or B hearing is defined as AirPTAi not worse than 50 dBHL and CNCWi not worse than 50%. ClassABCNCW proportion ranges from 0-100%, with higher values meaning better outcomes. | 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) | For ClassABAzBio, AAO-HNS (American Academy of Otolaryngology - Head & Neck Surgery) 1995 Class A or B hearing is defined as AirPTAi not worse than 50 dBHL and sound-field-presentation Arizona Biology sentences-in-noise discrimination score (AzBios) not worse than 50%. ClassABAzBio proportion ranges from 0-100%, with higher values meaning better outcomes. | Preoperative baseline to 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 | Distortion-product otoacoustic emissions (DPOAE) are sounds generated by a normal cochlea and detectable using a microphone in the ear canal when pairs of pure tones (centered on 0.75, 1, 1.5, 2, 3, 4, 6 and 8 kHz) are presented to the ear. DPOAE signals (and 8-valued vector for responses to stimuli centered on 0.75, 1, 1.5, 2, 3, 4, 6 and 8 kHz) are quantified in dB relative to the frequency-specific noise floor recorded by the same microphone before onset of stimulation. Response range is 0-15 dB, with higher values meaning better outcome. | 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 | Tympanometry involves using an ear canal microphone to measure ear canal acoustic admittance (conventionally reported in units of mL) and volume (in mL) by sensing reflection of a 226 Hz tone presented via a speaker in the ear canal while ear canal pressure is slowly varied from -400 to 200 decaPascals. Negative bias pressures pull the ear drum outward, positive bias pressures push the ear drum inward, and acoustic admittance is greatest when the ear drum is in a neutral anatomic position, neither retracted inward nor ballooned outward. Results are conventionally represented graphically then summarized by a three-valued vector comprising peak compliance (range 0-2mL, values closer to normal range of 0.3-1.4 mL meaning more normal outcome), pressure at which compliance peaks (range -400 to 200 decaPascal, values closer to 0 meaning more normal outcome), and ear canal volume (range 0-3 mL, values closer to normal adult range of 0.6-1.4 meaning more normal outcome). | 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 | The Tinnitus Handicap Inventory (THI) survey is set of questions designed to quantify self-perceived handicap due to tinnitus. THI score ranges from 0-100. Higher scores mean worse outcomes. | 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 | The Autophony Index (AI) survey is set of questions designed to quantify self-perceived autophony (hearing one's voice or other internally-generated body sounds). AI score ranges from 0-104. Higher scores mean worse outcomes. | 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 | Cervical vestibular-evoked myogenic potentials (cVEMPs) are a measure of saccule-mediated inhibition of sternocleidomastoid muscle electromyographic (EMG) activity during presentation of loud tones to the ipsilateral ear. After normalizing to average rectified EMG activity (in microvolts) prior to sound stimulation, cVEMP amplitudes (in microvolts) are unitless. Values range from 0 to  10, with larger values suggesting increased saccule activity and generally indicating better outcomes, except that values above 3.0 suggest abnormally high saccule sensitivity to sound. | 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 | Ocular vestibular-evoked myogenic potentials (oVEMPs) are a measure of utricle-mediated electromyographic (EMG) activity of inferior oblique and inferior rectus extraocular muscles during presentation of loud tones to the contralateral ear. Amplitude ranges from 0 to  50 microvolts, with larger values generally suggesting increased utricle activity and better outcomes but values above 17 microvolts suggesting abnormally high utricle sensitivity to sound. | 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 | A participant's vision is occluded by a bucket oriented so that its axis aligns with the participant's nasooccipital axis. The examiner rotates the bucket about the axis to a new orientation, the participant reorients it until a line drawn on the floor of the bucket is judges by the participant to be Earth-vertical and deviation of that line from true vertical is recorded. Values range over -15 to 15 degrees, with smaller absolute values meaning more normal outcomes. | 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 | Scalp thickness at the location of implanted magnets (Tscalp) is measured in mm using a magnetic sensor. Range is 0 to 10 mm, with values closer to the range 3-7mm indicating better outcomes. | 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 | Assess safety of the intervention, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH, as determined by changes in hearing and otolith endorgan function indicated by changes in all adverse events, including but not limited to events related to the surgical procedure, device and device systems | 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 | BonePTAi is the 4-frequency average of pure tone detection thresholds, in dBHL, for implant-side bone-conduction presentation of pure tones at 0.5, 1, 2 and 4 kHz. Range is -10 to 80 dBHL, with change toward smaller absolute values representing better (closer to normal) outcome. | 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 | AirPTAi is the 4-frequency average of pure tone detection thresholds, in dBHL, for implant-side air-conduction presentation of pure tones at 0.5, 1, 2 and 4 kHz. Range is -10 to 120 dBHL, with change toward smaller absolute values representing better (closer to normal) outcome. | 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 | CNCWi is the percentage of monosyllabic consonant-nucleus-consonant words correctly repeated when presented via an earphone speaker on the implanted side in a sound-isolation booth while a masking noise is played to the contralateral ear at 40 dB above its bone-conduction 4-frequency pure tone detection threshold if that threshold is at least 10 dB better than that of the ear being tested. CNCWi ranges from 0-100% correct, with higher score meaning better outcome. | 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 | AzBios is the percentage of words correctly repeated when a set of 20 Arizona Biology sentences (randomly chosen without repeats from 15 sets) is presented at a moderate level (60 dB SPL) along with masking noise (simultaneous presentation of ten sentences from another set at aggregate sound level 55 dBSPL) to both ears via a sound field speaker in a sound-isolation booth. Scores range from 0-100% correct, with higher score meaning better outcome. | 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) | For ClassABCNCW, AAO-HNS (American Academy of Otolaryngology - Head & Neck Surgery) 1995 Class A or B hearing is defined as AirPTAi not worse than 50 dBHL and CNCWi not worse than 50%. ClassABCNCW proportion ranges from 0-100%, with higher values meaning better outcomes. | 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) | For ClassABAzBio, AAO-HNS (American Academy of Otolaryngology - Head & Neck Surgery) 1995 Class A or B hearing is defined as AirPTAi not worse than 50 dBHL and sound-field-presentation Arizona Biology sentences-in-noise discrimination score (AzBios) not worse than 50%. ClassABAzBio proportion ranges from 0-100%, with higher values meaning better outcomes. | 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 | Distortion-product otoacoustic emissions (DPOAE) are sounds generated by a normal cochlea and detectable using a microphone in the ear canal when pairs of pure tones (centered on 0.75, 1, 1.5, 2, 3, 4, 6 and 8 kHz) are presented to the ear. DPOAE signals (and 8-valued vector for responses to stimuli centered on 0.75, 1, 1.5, 2, 3, 4, 6 and 8 kHz) are quantified in dB relative to the frequency-specific noise floor recorded by the same microphone before onset of stimulation. Response range is 0-15 dB, with higher values meaning better outcome. | Preoperative baseline to 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 | Tympanometry involves using an ear canal microphone to measure ear canal acoustic admittance (conventionally reported in units of mL) and volume (in mL) by sensing reflection of a 226 Hz tone presented via a speaker in the ear canal while ear canal pressure is slowly varied from -400 to 200 decaPascals. Negative bias pressures pull the ear drum outward, positive bias pressures push the ear drum inward, and acoustic admittance is greatest when the ear drum is in a neutral anatomic position, neither retracted inward nor ballooned outward. Results are conventionally represented graphically then summarized by a three-valued vector comprising peak compliance (range 0-2mL, values closer to normal range of 0.3-1.4 mL meaning more normal outcome), pressure at which compliance peaks (range -400 to 200 decaPascal, values closer to 0 meaning more normal outcome), and ear canal volume (range 0-3 mL, values closer to normal adult range of 0.6-1.4 meaning more normal outcome). | 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 | The Tinnitus Handicap Inventory (THI) survey is set of questions designed to quantify self-perceived handicap due to tinnitus. THI score ranges from 0-100. Higher scores mean worse outcomes. | 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 | The Autophony Index (AI) survey is set of questions designed to quantify self-perceived autophony (hearing one's voice or other internally-generated body sounds). AI score ranges from 0-104. Higher scores mean worse outcomes. | 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 | Cervical vestibular-evoked myogenic potentials (cVEMPs) are a measure of saccule-mediated inhibition of sternocleidomastoid muscle electromyographic (EMG) activity during presentation of loud tones to the ipsilateral ear. After normalizing to average rectified EMG activity (in microvolts) prior to sound stimulation, cVEMP amplitudes (in microvolts) are unitless. Values range from 0 to  10, with larger values suggesting increased saccule activity and generally indicating better outcomes, except that values above 3.0 suggest abnormally high saccule sensitivity to sound. | 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 | Ocular vestibular-evoked myogenic potentials (oVEMPs) are a measure of utricle-mediated electromyographic (EMG) activity of inferior oblique and inferior rectus extraocular muscles during presentation of loud tones to the contralateral ear. Amplitude ranges from 0 to  50 microvolts, with larger values generally suggesting increased utricle activity and better outcomes but values above 17 microvolts suggesting abnormally high utricle sensitivity to sound. | 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 | A participant's vision is occluded by a bucket oriented so that its axis aligns with the participant's nasooccipital axis. The examiner rotates the bucket about the axis to a new orientation, the participant reorients it until a line drawn on the floor of the bucket is judges by the participant to be Earth-vertical and deviation of that line from true vertical is recorded. Values range over -15 to 15 degrees, with smaller absolute values meaning more normal outcomes. | 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 | Scalp thickness at the location of implanted magnets (Tscalp) is measured in mm using a magnetic sensor. Range is 0 to 10 mm, with values closer to the range 3-7mm indicating better outcomes. | 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 | Assess safety of the intervention, for the subgroup of participants who have ototoxic adult-onset BVH, as determined by changes in hearing and otolith endorgan function indicated by changes in all adverse events, including but not limited to events related to the surgical procedure, device and device systems | 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 | Assess tolerance of the intervention, aggregating data across all implanted participants, as determined by the proportion of all implant recipients who continue to use the MVI system daily at 6 months post-implantation | 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 | Assess tolerance of the intervention, for the subgroup of participants who have non-ototoxic/non-central adult-onset BVH, as determined by the 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 | 
| TM3: Proportion of implanted participants with ototoxic adult-onset BVH who continue to use the MVI system daily at 6 months post-implantation | Assess tolerance of the intervention, for the subgroup of participants who have ototoxic adult-onset BVH, as determined by the 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 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Vestibular, implant, prosthesis, labyrinth, ototoxicity, gentamicin, oscillopsia, disequilibrium, dizziness, vestibulopathy, inner ear