Patient-Reported Outcomes After Vestibular Implantation for Bilateral Vestibular Hypofunction

Key Points

Question

How do patient-reported dizziness, disability, and quality of life change after vestibular implantation?

Findings

In this cohort study of individuals with bilateral vestibular hypofunction, 10 participants who underwent unilateral vestibular implantation and received continuously motion-modulated prosthetic vestibular nerve stimulation reported statistically and clinically significant improvements 6 months postimplantation on instruments assessing symptom severity and health-related quality of life. A separate cohort of 10 respondents awaiting implantation did not report a mean change in symptom severity.

Meaning

The study results suggest that patient-reported benefit supports the use of vestibular implantation for treating bilateral vestibular hypofunction.

Abstract

Importance

Standard-of-care treatment proves inadequate for many patients with bilateral vestibular hypofunction (BVH). Vestibular implantation is an emerging alternative.

Objective

To examine patient-reported outcomes from prosthetic vestibular stimulation.

Design, Setting, and Participants

The Multichannel Vestibular Implant (MVI) Early Feasibility Study is an ongoing prospective, nonrandomized, single-group, single-center cohort study conducted at Johns Hopkins Hospital that has been active since 2016 in which participants serve as their own controls. The study includes adults with severe or profound adult-onset BVH for at least 1 year and inadequate compensation despite standard-of-care treatment. As of March 2023, 12 candidates completed the eligibility screening process.

Intervention

The MVI system electrically stimulates semicircular canal branches of the vestibular nerve to convey head rotation.

Main Outcomes and Measures

Patient-reported outcome instruments assessing dizziness (Dizziness Handicap Inventory [DHI]) and vestibular-related disability (Vestibular Disorders–Activities of Daily Living [VADL]). Health-related quality of life (HRQOL) assessed using the Short Form-36 Utility (SF36U) and Health Utilities Index Mark 3 (HUI3), from which quality-adjusted life-years were computed.

Results

Ten individuals (5 female [50%]; mean [SD] age, 58.5 [5.0] years; range, 51-66 years) underwent unilateral implantation. A control group of 10 trial applicants (5 female [50%]; mean [SD] age, 55.1 [8.5] years; range, 42-73 years) completed 6-month follow-up surveys after the initial application. After 0.5 years of continuous MVI use, a pooled mean (95% CI) of within-participant changes showed improvements in dizziness (DHI, −36; 95% CI, −55 to −18), vestibular disability (VADL, −1.7; 95% CI, −2.6 to −0.7), and HRQOL by SF36U (0.12; 95% CI, 0.07-0.17) but not HUI3 (0.02; 95% CI, −0.22 to 0.27). Improvements exceeded minimally important differences in the direction of benefit (exceeding 18, 0.65, and 0.03, respectively, for DHI, VADL, and SF36U). The control group reported no mean change in dizziness (DHI, −4; 95% CI, −10 to 2), vestibular disability (VADL, 0.1; 95% CI, −0.9 to 1.1) or HRQOL per SF36U (0; 95% CI, −0.06 to 0.05) but an increase in HRQOL per HUI3 (0.10; 95% CI, 0.04-0.16). Lifetime HRQOL gain for MVI users was estimated to be 1.7 quality-adjusted life-years (95% CI, 0.6-2.8) using SF36U and 1.4 (95% CI, −1.2 to 4.0) using HUI3.

Conclusions and Relevance

This cohort study found that vestibular implant recipients report vestibular symptom improvements not reported by a control group. These patient-reported benefits support the use of vestibular implantation as a treatment for bilateral vestibular hypofunction.

This ongoing prospective single-center cohort study assesses patient-reported outcomes from prosthetic vestibular stimulation.

Introduction

Bilateral vestibular hypofunction (BVH) due to ototoxic injury or other causes of inner ear dysfunction impairs reflexes that normally maintain stable vision, posture, gait, and spatial perception. Affected individuals endure blurred vision during head movement, postural instability, increased frequency of falls, chronic dizziness, fatigue, and increased mental exertion to perform normally automatic tasks like walking down a grocery store aisle.^1,2 Estimates based on US National Health Interview Survey data indicate that BVH severely affects approximately 64 000 US adults and 1.8 million adults worldwide.³ Adults with severe BVH have a 31-fold increase in risk of falling, incur a mean annual economic burden per capita of $13 000 (range, $0-$49 000), and report lower mean health-related quality of life (HRQOL) than reported by individuals with severe adult-onset hearing loss or kidney insufficiency.⁴ Standard-of-care treatment options for severe BVH are limited, often inadequate, and have changed little over the past century.⁵ Patients are advised to avoid medications that could further suppress vestibular reflexes (eg, sedatives and ototoxic medications), decrease risk of injury by using a cane or walking stick, exercise care when walking in dim light or on uneven surfaces, remove tripping hazards in the home, and not drive if they cannot see clearly during head motion. They are also advised to participate actively in a course of vestibular rehabilitation therapy, which focuses on supervised and/or home exercises intended to recruit central nervous system plasticity, early corrective saccades, the cervico-ocular reflex, and other nonvestibular systems to help stabilize the head, eyes, and body.⁶ Most patients with sudden-onset BVH report symptom improvement within approximately 6 months of onset, and those who participate actively in standard-of-care vestibular rehabilitation therapy typically improve more quickly.⁷ However, all nonvestibular eye-stabilizing and head-stabilizing systems have longer latencies than the vestibulo-ocular reflex (VOR) and vestibular-spinal reflexes, so even with standard-of-care treatment, compensation for loss of vestibular function is often incomplete.⁸

Analogous to cochlear implants, which provide artificial auditory sensation to nearly a million people worldwide with hearing loss, vestibular implants have garnered attention as a restorative treatment for BVH. Prior studies have demonstrated the ability to drive vestibular reflexes and perception during brief periods of stimulation in a laboratory setting.^9,10,11,12 Active since 2016, the Multichannel Vestibular Implant (MVI) Early Feasibility Study (ClinicalTrials.gov: NCT02725463 and NCT05674786) is the first treatment trial in which patients use a vestibular implant able to continuously provide long-term artificial sensory input 24 hours per day outside of a clinical setting via head motion–modulated electrical stimulation of the 3 semicircular canals of the implanted ear. In prior reports on this trial, we described 3-dimensional VOR responses to prosthetic stimulation, objective measures of posture and gait, hearing outcomes, and patient-reported outcomes quantifying dizziness, disability, and HRQOL at 0.5 and 1 year postimplantation for 8 patients.^13,14 In this article, we present the vestibular-focused patient-reported outcomes (vPRO) and HRQOL outcomes for the first 10 individuals to undergo long-term (1.5-6 years) motion-modulated vestibular stimulation and compare their outcomes to those for people with BVH who have not yet undergone intervention.

Methods

This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines. The Labyrinth Devices MVI Vestibular Implant System is intended to treat chronic, adult-onset, severe BVH in individuals who remain symptomatic for more than 1 year after symptom onset despite receiving vestibular rehabilitation and cessation of vestibular-suppressant medications. Individuals applied to the trial by submitting relevant records and completing online or paper vPRO and HRQOL screening surveys that were intended to identify people with BVH who were otherwise healthy. Clinician study team members identified candidates and obtained written informed consent to complete further in-person vestibular testing. Follow-up survey completion for enrolled individuals and candidates to the trial was done via email. Age, sex, race, and ethnicity were collected from submitted medical records or self-reported by each participant. Participants were classified using categories defined in the US National Health Interview Survey analysis manual to estimate life span when calculating quality-adjusted life-years. The study was reviewed and approved by the Johns Hopkins Medicine institutional review board.

The Labyrinth Devices MVI System’s implanted component is a modified MED-EL GmbH cochlear implant receiver-stimulator with an array of electrodes designed for insertion into each semicircular canal in the implanted ear. Device design, surgical implantation technique, stimulation parameters, and device programming protocols have been described previously.^13,14 Device implantations took place from August 2016 to July 2021. After onset of stimulation, participants wore the external components of their MVI systems 24 hours per day for at least 0.5 years, after which some converted to removing the system’s external components when in bed. Each completed vPRO and HRQOL questionnaires before implantation, postoperatively before device activation, and at subsequent visits.

Vestibular-Focused Patient-Reported Outcomes

Dizziness Handicap Inventory

The Dizziness Handicap Inventory (DHI) measures the patient-reported effects of dizziness on daily activities, with a minimum score of 0 meaning no handicap and a maximum of 100 meaning severe handicap. The minimal clinically important difference (MID) is 18 points.¹⁵ The version of the DHI this study administered from 2016 to October 2022 replaced “your problem” with “your dizziness” for all questions.³ A study of healthy older adults aged 70 to 95 years reported a mean (95% CI) DHI score of 5.6 (2.5-8.7).¹⁶

Vestibular Disorders–Activities of Daily Living

The Vestibular Disorders–Activities of Daily Living (VADL) assesses self-perceived disability in performing daily tasks due to vestibular disorders on a scale of 1 (independent) to 10 (no longer can perform most activities).^17,18,19 A study of healthy older adults 65 years or older reported a mean (95% CI) VADL score of 1.71 (1.15-2.67) and standard deviation of 1.30, from which an MID of 0.65 can be defined.^20,21

Health-Related Quality of Life

Utility values calculated from health-related quality of life (HRQOL) instruments use common anchors of 0 (worst health, dead) to 1 (best health). Scores typically decrease over age and are not directly comparable across instruments. We used a minimal important difference of 0.03 for all HRQOL instruments.^22,23,24,25

Health Utilities Index Mark 3

Published values for Health Utilities Index Mark 3 (HUI3) assessments for a general adult (18 years or older) population show a mean (95% CI) HUI3 of 0.812 (0.799-0.825).^26,27 For the HUI3, a score less than 0 is possible and corresponds to a health state imagined to be worse than death.

Short Form-36

Short Form 36 (SF36) does not define a utility, so we used a transformation described from the SF36 domain to the Short Form-6D (SF6D), a value we refer to as SF36 utility (SF36U).^28,29,30 Normative published values for SF6D in a general adult (18 years or older) population reported a mean (95% CI) of 0.711 (0.708-0.714).³¹

Analysis

When applied to DHI, VADL, HUI3, and SF36U scores for the preoperative MVI cohort, the Shapiro-Wilk test of normality did not reject the null hypothesis of normality for any instrument (P > .05). Therefore, we reported means or estimated marginal means with the SD or 95% CI. Statistical testing and analyses were conducted using custom code written in MATLAB, version 2023a.

Candidates who were recruited to the trial but did not undergo implantation were excluded from the data set. As of March 2023, no individuals who underwent implantation had been lost to follow-up, and 3 of 10 individuals who underwent implantation had missing data from missing an in-person visit. For the 9 of 13 416 questions left incomplete in otherwise complete surveys, that person’s most recent answer or “NA” was used.

To compute cumulative postimplantation health utility gain or loss in quality-adjusted life-years (QALY), we summed each implant recipient’s change in utility during the first 10 years of device use and during that participant’s projected life span using the SF36U and HUI3. We integrated the area under the curve of postimplantation utility compared with preoperative baseline by linearly interpolating between temporally adjacent data points and propagating the last measured utility as the best future estimate. Life spans were estimated using actuarial tables for US adults using each participant’s race, ethnicity, sex, and age at time of implantation.³² Utility values were discounted at an annual rate of r = 3%, meaning that for the j^th year after implantation (with j = 1 denoting the first year), the change in utility was multiplied by (1-r)^(j-1) to discount the utility for that year.

We characterized the time course of changes in scores reported by MVI recipients after device implantation by modeling scores as Y(t) = Y₀ + (Y_ss- Y₀) × (1 - exp(-t/τ)), with measured initial score Y₀, and fitting the time constant τ and steady state value Y_ss. Fits minimized root mean squared error and constrained Y_ss to be between the maximum and minimum score for each survey. We report time constants extracted from the fits resulting in τ > 0 and R² > 0.5; lower R² values correspond to nonexponential trends or high survey-to-survey noise.

Results

The present study analyzed data for 20 individuals who applied to participate in the MVI study and completed vPRO and HRQOL questionnaires from 2016 to 2023. From a total 62 applicants, 22 (35.5%) passed screening for BVH using the case definition as described by Ward et al³ using questions from the 2008 US National Health Interview Survey. All reported having already had standard-of-care treatment and having participated in vestibular rehabilitation therapy exercises while abstaining from vestibular suppressant medications. As of March 2023, 2 participants received a failed screening during in-person assessment, 10 underwent MVI implantation (5 female and 5 male individuals; mean age at time of implantation, 59 years [range, 51-66 years]), and as of last follow-up the remaining 10 respondents await in-person screening and implantation (5 female and 5 male individuals; mean age at time of initial survey completion, 55 years [range, 42-73 years]). The applicants who had not yet undergone vestibular implantation completed initial vPRO and HRQOL questionnaires as well as follow-up questionnaires at a mean (SD) of 0.55 (0.06) years, thereby constituting a control group without vestibular implantation.

At the time of initial survey completion, vPRO and HRQOL scores were similar between the participants who later underwent MVI implantation and the control group (Figure 1; Table). Mean initial scores on DHI, VADL, and SF36U for MVI recipients were close to those of the BVH control group, while HUI3 scores of the MVI candidates exceeded their BVH control counterparts by a mean (95% CI) of 0.23 (0.03-0.44). Both groups had mean scores reflecting greater dizziness, more vestibular-related disability, and poorer HRQOL than the expected values for heathy adults in the general population.^16,21,27,31

Figure 1. Patient-Reported Outcomes at 0.5 Years.

Pooled mean scores with 95% CIs and individual participant scores are shown for the control group (n = 10) and multichannel vestibular implant (MVI) users (n = 10) before implantation and 0.5 years later for the Dizziness Handicap Inventory (DHI) (A). B, Within-participant changes for these cohorts and the minimum important difference for the DHI. These metrics are also shown for the Vestibular Disorders–Activities of Daily Living (VADL; C and D), Short Form-36 Utility (SF36U; E and F), and Health Utilities Index Mark 3 (HUI3; G and H). Axes in panels A to D are inverted so that the direction of improvement is upward for all panels. These values can be found in Table 1.

Table. Patient-Reported Outcomes^a.

Group	DHI	VADL	SF36U	HUI3
Cohort scores at first survey, mean (SD)
Control	75 (17)	4.0 (1.1)	0.67 (0.10)	0.39 (0.21)
Implant	70 (19)	3.6 (1.5)	0.69 (0.08)	0.62 (0.22)
Cohort scores at 0.5-y follow-up, mean (SD)
Control	71 (19)	4.1 (1.6)	0.66 (0.10)	0.49 (0.23)
Implant	34 (28)	1.9 (1.6)	0.80 (0.08)	0.65 (0.30)
Within-participant change in score after 0.5 y, mean (95% CI), % who achieved a clinically meaningful benefit
Control	−4 (−10 to 2)	0.1 (−0.9 to 1.1)	0 (−0.06 to 0.05)	0.10 (0.04 to 0.16)
%	0%	20%	50%	70%
Implant	−36 (−55 to −18)	−1.7 (−2.6 to −0.7)	0.12 (0.07 to 0.17)	0.02 (−0.22 to 0.27)
%	80%	80%	90%	60%

Abbreviations: DHI, Dizziness Handicap Inventory; HUI3, Health Utilities Index Mark 3; SF36U, Short-Form 36 Utility; VADL, Vestibular Disorders–Activities of Daily Living.

^a The values in this table correspond to the control group (n = 10) and implant user group (n = 10). For implant users, scores are shown before implantation and after 0.5 years of device use. These values are graphically shown in Figure 1.

The control group had neither statistically nor clinically significant group mean within-participant changes in dizziness as measured by DHI (−4; 95% CI, −10 to 2), vestibular-related disability as measured by VADL (0.1; 95% CI, −0.9 to 1.1), or health-related quality of life as measured by the SF36U (0; 95% CI, −0.06 to 0.05) at the 0.5-year follow-up assessment but did have a significant improvement of more than 3 MID for HUI3 (0.10; 95% CI, 0.04-0.16). At 0.5 years postimplantation, the difference in the pooled within-participant changes between the MVI users and control group for DHI (−32; 95% CI, −50 to −14), VADL (−1.8; 95% CI, −3.0 to −0.5]), and SF36U (0.12; 95% CI, 0.05-0.19) were statistically and clinically significant, but not for HUI3 (−0.08; 95% CI, −0.31 to 0.16). There was a difference in the percentage of participants in the 2 groups who achieved a clinically meaningful improvement on the DHI (MVI: 80%, control 0%; difference, 80%; 95% CI, 55%-105%), VADL (MVI: 80%, control 20%; difference, 60%; 95% CI, 25%-95%), and SF36U (MVI: 90%, control 50%; difference, 40%; 95% CI, 4%-76%), but not the HUI3 (MVI: 60%, control 70%; difference, −10%; 95% CI, −52% to 32%).

The full set of all responses from MVI users shows that mean improvements in dizziness, vestibular-related disability, and HRQOL as measured by the SF36U were sustained during follow-up assessments 1 to 6 years after implantation (Figure 2). Most MVI users reached a plateau by 0.5 years postimplantation, but participants varied in the time from implantation to plateau. Single-exponential fits to each participant’s DHI scores (Figure 3) revealed a median (range) time constant of 0.16 (0.15-1.13) years for the 7 MVI users for whom R² was greater than 0.5. Individual participants’ VADL, SF36U, and HUI3 data were not well fit by this exponential model, with only 2 to 3 MVI users each having a fit with R²> 0.5.

Figure 2. Patient-Reported Outcomes for Multichannel Vestibular Implant (MVI) Users Over Time.

The pooled mean and 95%CI for the MVI users at each time as well as each participant’s score (A) and within-participant change in score from preoperative measurements (B) for the Dizziness Handicap Inventory. Scores and change in scores are also shown for the Vestibular Disorders Activities of Daily Living (C and D), Short Form-36 Utility (E and F) and Health Utilities Index Mark 3 (G and H). Dark gray shading denotes the minimal clinically important difference (MID) for a change in score. Axes in panels A to D are inverted so that the direction of improvement is upward for all panels.

Figure 3. Time Course of Benefit for Vestibular Implantation.

Time course of benefit was estimated for each participant’s responses to the Dizziness Handicap Inventory (DHI) (A), Vestibular Disorders Activities of Daily Living (VADL) (B), Short Form-36 Utility (SF36U) (C), and Health Utilities Index Mark 3 (HUI3) (D). Axes in panels A and B are inverted so that the direction of improvement is upward for all panels. The time constant tau was derived from the shown exponential fit that starts at each participant’s preoperative value and grows or decays to a final value bounded by the survey’s maximum and minimum. The vertical dashed lines show the time constants estimated for the fits in which R² > 0.5. Best fit time constants show that most participants perceived benefit after less than 0.5 years of device use, with 2 participants having time constants of longer than 1 year of device use to see benefit.

Estimates of lifetime QALYs gained after MVI implantation were 1.7 (95% CI, 0.6-2.8) years using the SF36U and 1.4 (95% CI, −1.2 to 4.0) years using the HUI3 (Figure 4³²). The MVI group gained 1.7 (95% CI, 0.3-3.1) and −0.5 (95% CI, −3.2 to 2.2) more QALYs than the control group during their lifetimes using the SF36U and HUI3, respectively. QALYs gained by each MVI recipient during the first 10 years of device use were estimated to be 0.8 (95% CI, 0.4-1.3) using SF36U and 0.5 (95% CI, −0.7 to 1.6) using HUI3. The MVI group gained 0.9 (95% CI, 0.2-1.5) and −0.4 (95% CI, −1.6 to 0.8) more QALYs than the control group during the first 10 years of device use using the SF36U and HUI3, respectively.

Figure 4. Quality-Adjusted Life-Years (QALYs).

A, QALYs gained or lost estimated by integrating discounted within-participant change in utility over time for the Short Form-36 Utility (SF36U) and Health Utilities Index Mark 3 (HUI3) using the most recent value as the projected future value. Utility values were discounted by multiplying utility by (1-r)^(j-1) at the annual rate of r = 3% for year j. Expected future lifespans used for calculation were based on actuarial tables for US adults based on race, ethnicity, sex, and age.³² B, QALY for the first 10 years are shown to not overweigh results from younger participants or underweigh results from older participants because of differences in projected life span.

Discussion

In this cohort study, individuals using a vestibular implant system that continuously provided artificial sensation of head rotational motion reported mean improvement in vestibular symptoms, self-perceived disability, and quality of life scores at 0.5 years postimplantation that persisted in measurements up to 6 years postimplantation. In contrast, we did not detect clinically meaningful score changes in vestibular symptom severity or self-perceived disability over a 0.5-year interval for individuals with BVH who reported having already received standard-of-care treatment and did not undergo implantation. However, we did detect a clinically meaningful change in HRQOL as measured by the HUI3 for that group. Whereas 8 of 10 MVI users underwent implantation and completed 0.5-year follow-up visits before the start of the COVID-19 pandemic, the control group’s screening assessments occurred between mid 2020 and 2022. That cohort’s initial and follow-up HRQOL measures are more likely to have been affected by the pandemic’s negative effects on daily life, social interaction, and emotional well-being, which peaked in mid 2020 and generally improved during the subsequent 3 years.

In addition to differential effects of the COVID-19 pandemic on MVI user and control survey responses, another reason for the disparity between changes in HRQOL quantified by SF36U and HUI3 is that the HUI3’s utility score depends heavily on the respondent’s self-perceived hearing ability with and without use of hearing aids. Four of the 10 MVI recipients experienced a new severe or profound unilateral hearing loss in the implanted ear, and 1 developed a correctable moderate-to-severe loss.¹⁴ One MVI recipient had no measurable change in hearing postoperatively compared with their preoperative baseline of symmetric bilateral high-frequency sensorineural hearing loss¹⁴ but had large perceived within-survey fluctuations in hearing measured by transient decreases in an HUI3 score of 0.52 (>14 MID). Given those changes in patient-reported hearing status, the fact that mean HUI3 did not significantly fall for the MVI user group as a whole is consistent with changes in hearing being at least balanced (and outweighed, according to the DHI, VADL, and SF36U) by the benefits MVI recipients report experiencing along dimensions to which HUI3 is evidently less sensitive, such as the ability to walk without devoting conscious effort to avoiding a fall.

QALY estimates are typically reported in terms of the actuarial remaining lifespan of the participant, but that makes those estimates depend on each individual participant’s age. To provide more generalizable results, we also report QALY values computed for the first 10 years of device use. The values estimated for MVI recipients are similar to the 1.6-QALY gains projected by a prospective 2015 cost-utility analysis that assumed unilateral vestibular implantation would yield benefit equal to 75% of the difference from mean HRQOL utility reported by patients with BVH to utility reported by individuals with unilateral vestibular hypofunction and 1 normally working labyrinth.⁴ The control cohort’s lifetime QALY gain estimates reveal a large difference between the groups when measured by the SF36U but little difference between the groups as measured by the HUI3.

As is true for cochlear implantation for hearing loss, preoperative counselling before vestibular implantation for BVH should include discussion of expectations regarding the pace, variation, and extent of improvement postimplantation. The time course analysis of DHI data showed that individual participants’ time constants were bimodally distributed, with a larger peak (5 participants) around 2 months and smaller peak (2 participants) around 1 year, similar to the time course of hearing improvement after cochlear implantation.³³ Active participation in vestibular rehabilitation therapy and similar activities that encourage central nervous system compensation may be associated with increased pace and extent of benefit after vestibular implantation.

Limitations

The clinical trial for which this report describes vPRO and HRQOL data is a nonrandomized, open-label study of vestibular implantation in a small (n = 10) convenience sample of applicants willing to undergo implantation of a novel neuroelectronic prosthesis. MVI users were not masked to the occurrence of vestibular implant surgery or presence of prosthetic stimulation, and patient-reported outcomes are susceptible to positive and negative placebo influence.

Data sets poorly fit by an exponential rise or decay typically included nonmonotonic variations or outliers coinciding with extraneous factors, such as contracting COVID-19 or other medical conditions apparently unassociated with vestibular implantation or inner ear function. Such factors can lead to large shifts in some vPRO and/or QOL scores. Even respondents who did not contract SARS-CoV-2 commonly reported negative outcomes associated with social functioning, lethargy, and mental health during the pandemic, which typically evolved in parallel with the pandemic’s effect at a societal level. Most MVI users completed initial and 0.5-year postimplantation surveys before the pandemic, so the main effect that the pandemic had with their vPRO and QOL data was a negative association with their most recent scores and, therefore, lower estimates of QALY benefit. In contrast, all control respondents completed their first and second surveys after mid 2020, so the main self-reported outcome of the pandemic was likely a gradual improvement corresponding to society-wide recovery from greatest depth of pandemic effects on daily life. Comparing vPRO and QOL outcomes for current MVI users with those of new participants recruited in coming years may help clarify how the pandemic influenced data presented in this report.

Moreover, the vPRO or HRQOL surveys we used did not capture the association of BVH symptoms completely or specifically. Study participants expressed frustration with redundant surveys and the time required to complete them. The DHI and VADL were designed to assess vestibular disorders manifest by episodic dizziness and vertigo, which are rare among individuals with disabilities from BVH. The HUI3 assigns such a high weight to self-perceived hearing handicap that it is more sensitive to hearing status than to the functions lost in BVH and improved by vestibular implant stimulation. The field of vestibular implantation needs a well-designed and efficiently completed BVH-specific instrument. The Bilateral Vestibulopathy Questionnaire is one promising instrument for that role.³⁴

Conclusions

Vestibular implantation has emerged as a promising treatment for bilateral vestibular hypofunction. In comparison to individuals who received standard-of-care treatment, individuals with vestibular implants reported less dizziness, less disability, and higher quality of life.

Supplement.

Data Sharing Statement