Search

Purpose: Vestibular implant electrode positioning close to the afferent nerve fibers is considered to be key for effective and selective electrical stimulation. However, accurate positioning of vestibular implant electrodes inside the semicircular canal ampullae is challenging due to the inability to visualize the target during the surgical procedure. This study investigates the accuracy of a new surgical protocol with real-time fluoroscopy and intraoperative CT imaging, which facilitates electrode positioning during vestibular implant surgery. Methods: Single-center case-controlled cohort study with a historic control group at a tertiary referral center. Patients were implanted with a vestibulocochlear implant, using a combination of intraoperative fluoroscopy and cone beam CT imaging. The control group consisted of five patients who were previously implanted with the former implant prototype, without the use of intraoperative imaging. Electrode positioning was analyzed postoperatively with a high-resolution CT scan using 3D slicer software. The result was defined as accurate if the electrode position was within 1.5 mm of the center of the ampulla. Results: With the new imaging protocol, all electrodes could be positioned within a 1.5 mm range of the center of the ampulla. The accuracy was significantly higher in the study group with intraoperative imaging (21/21 electrodes) compared to the control group without intraoperative imaging (10/15 electrodes), (p = 0.008). Conclusion: The combined use of intraoperative fluoroscopy and CT imaging during vestibular implantation can improve the accuracy of electrode positioning. This might lead to better vestibular implant performance. [ABSTRACT FROM AUTHOR]

Objectives: Bilateral vestibulopathy (BVP) leads to unsteadiness when walking, which worsens in darkness or on uneven ground, as well as falls. Since simple balance tests struggle to distinguish between BVP and healthy participants, we aimed (1) to test if the Mini-BESTest is feasible in BVP, (2) how people with BVP perform on the Mini-BESTest and (3) to compare these scores with healthy reference data. Methods: Fifty participants with BVP completed the Mini-BESTest. 12-month falls incidence was obtained by questionnaire. To compare the overall and sub-scores between our participants with BVP and those of healthy participants from the literature (n = 327; obtained via PubMed searches), Mann–Whitney U tests were used. Sub scores within the BVP group were also compared. Spearman correlations were used to investigate the relationships between Mini-BESTest score and age. Results: No floor or ceiling effects were observed. Participants with BVP had significantly lower Mini-BESTest total scores than the healthy group. Anticipatory, reactive postural control and sensory orientation sub scores of the Mini-BESTest were significantly lower in BVP, while dynamic gait sub scores were not significantly different. A stronger negative correlation between age and Mini-BESTest total score was found in BVP than in the healthy group. Scores did not differ between patients with different falls history. Conclusion: The Mini-BESTest is feasible in BVP. Our results confirm the commonly reported balance deficits in BVP. The stronger negative association between age and balance in BVP might reflect the age-related decline in the remaining sensory systems with which people with BVP compensate. [ABSTRACT FROM AUTHOR]

Purpose: The goal of this study was to evaluate if bilaterally (partially) absent vestibular function during static sound localization testing, would have a negative impact on sound localization skills. Therefore, this study compared horizontal static sound localization skills of normal-hearing patients with bilateral vestibulopathy (BV) and healthy controls. Methods: Thirteen normal-hearing patients with BV and thirteen age-matched healthy controls were included. Sound localization skills were tested using seven loudspeakers in a frontal semicircle, ranging from − 90° to + 90°. Sound location accuracy was analyzed using the root-mean-square error (RMSE) and the mean absolute error (MAE). To evaluate the severity of the BV symptoms, the following questionnaires were used: Dizziness Handicap Inventory (DHI), Oscillopsia severity questionnaire (OSQ), 12-item Spatial, Speech, and Qualities Questionnaire (SSQ12), and Health Utilities Index Mark 3 (HUI3). Results: The RMSE and MAE were significantly larger (worse) in the BV group than in the healthy control group, with respective median RMSE of 4.6° and 0°, and a median MAE of 0.7° and 0°. The subjective reporting of speech perception, spatial hearing, and quality of life only demonstrated a moderate correlation between DHI (positive correlation) and HUI total score (negative correlation), and localization scores. Conclusion: Static sound localization skills of patients with BV were only mildly worse compared to healthy controls. However, this difference was very small and therefore most likely due to impaired cognitive function. The vestibular system does not seem to have a modulating role in sound localization during static conditions, and its impact is negligible in contrast to the impact of hearing impairment. Furthermore, the subjective reporting of speech perception, spatial hearing, and quality of life was not strongly correlated with localization scores. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to explore expectations of patients with bilateral vestibulopathy regarding vestibular implant treatment. This could advance the definition of recommendations for future core outcome sets of vestibular implantation and help to determine on which characteristics of bilateral vestibulopathy future vestibular implant research should focus. Methods: Semi-structured interviews were conducted with 50 patients diagnosed with bilateral vestibulopathy at Maastricht UMC +. Interviews followed a semi-structured interview guide and were recorded and transcribed. Transcripts were analyzed thematically by two independent researchers. A consensus meeting took place to produce a joint interpretation for greater dimensionality and to confirm key themes. Results: Overall, patient expectations centralized around three key themes: (physical) symptom reduction, functions and activities, and quality of life. These themes appeared to be interrelated. Patient expectations focused on the activity walking (in a straight line), reducing the symptom oscillopsia and being able to live the life they had before bilateral vestibulopathy developed. In general, patients indicated to be satisfied with small improvements. Conclusion: This study demonstrated that patient expectations regarding a vestibular implant focus on three key themes: symptom reduction, functions and activities, and quality of life. These themes closely match the functional improvements shown in recent vestibular implantation research. The results of this study provide a clear guideline from the patient perspective on which characteristics of bilateral vestibulopathy, future vestibular implant research should focus. Trial registration: NL52768.068.15/METC [ABSTRACT FROM AUTHOR]

Objective: Current diagnostic criteria for bilateral vestibulopathy (BV) primarily involve measurements of vestibular reflexes. Perceptual self-motion thresholds however, are not routinely measured and their clinical value in this specific population is not yet fully determined. Objectives of this study were (1) to compare perceptual self-motion thresholds between BV patients and control subjects, and (2) to explore patterns of self-motion perception performance and vestibular function in BV patients. Methods: Thirty-seven BV patients and 34 control subjects were included in this study. Perceptual self-motion thresholds were measured in both groups using a CAREN platform (Motek Medical BV, Amsterdam, The Netherlands). Vestibular function was evaluated (only in BV patients) by the caloric test, torsion swing test, video head impulse test of all semicircular canals, and cervical- and ocular vestibular-evoked myogenic potentials. Differences in thresholds between both groups were analyzed. Hierarchical cluster analysis was performed to visualize patterns between self-motion perception and vestibular function within the group of BV patients. Results: Perceptual self-motion thresholds were significantly higher in BV patients compared to control subjects, regarding nearly all rotations and translations (depending on the age group) (p ≤ 0.001). Cluster analysis showed that within the group of BV patients, higher perceptual self-motion thresholds were generally associated with lower vestibular test results (significant for yaw rotation, caloric test, torsion swing test, and video head impulse test (p ≤ 0.001)). Conclusion: Self-motion perception is significantly decreased in BV patients compared to control subjects regarding nearly all rotations and translations. Furthermore, decreased self-motion perception is generally associated with lower residual vestibular function in BV patients. Trial registration: Trial registration number NL52768.068.15/METC [ABSTRACT FROM AUTHOR]

Background: Certain cases of superior semicircular canal dehiscence or benign paroxysmal positional vertigo can be treated by plugging of the affected semicircular canal. However, the extent of the impact on vestibular function and hearing during postoperative follow-up is not known. Objective: To evaluate the evolution of vestibular function and hearing after plugging of a semicircular canal. Methods: Six patients underwent testing before and 1 week, 2 months, and 6 months after plugging of the superior or posterior semicircular canal. Testing included caloric irrigation test, video Head Impulse Test (vHIT), cervical and ocular Vestibular Evoked Myogenic Potentials (VEMPs) and audiometry. Results: Initially, ipsilateral caloric response decreased in all patients and vHIT vestibulo-ocular reflex (VOR) gain of each ipsilateral semicircular canal decreased in 4/6 patients. In 4/6 patients, postoperative caloric response recovered to > 60% of the preoperative value. In 5/6 patients, vHIT VOR gain was restored to > 85% of the preoperative value for both ipsilateral non-plugged semicircular canals. In the plugged semicircular canal, this gain decreased in 4/5 patients and recovered to > 50% of the preoperative value. Four patients preserved cervical and ocular VEMP responses. Bone conduction hearing deteriorated in 3/6 patients, but recovered within 6 months postoperatively, although one patient had a persistent loss of 15 dB at 8 kHz. Conclusion: Plugging of a semicircular canal can affect both vestibular function and hearing. After initial deterioration, most patients show recovery during follow-up. However, a vestibular function loss or high-frequency hearing loss can persist. This stresses the importance of adequate counseling of patients considering plugging of a semicircular canal. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Full-body kinematics and head stabilisation strategies during walking in patients with chronic unilateral and bilateral vestibulopathy." The original article contained an error in one of the references, which has been corrected. The corrected reference is about the influence of walking velocity on strategies of head stabilization. The authors of the original article are listed as Gautier Grouvel, Anissa Boutabla, Julie Corre, Rebecca Revol, Marys Franco Carvalho, Samuel Cavuscens, Maurizio Ranieri, Jean-François Cugnot, Christopher McCrum, Raymond van de Berg, Nils Guinand, Angélica Pérez Fornos, and Stéphane Armand. [Extracted from the article]

Background and purpose: Vestibular implants seem to be a promising treatment for patients suffering from severe bilateral vestibulopathy. To optimize outcomes, we need to investigate how, and to which extent, the different vestibular pathways are activated. Here we characterized the simultaneous responses to electrical stimuli of three different vestibular pathways. Methods: Three vestibular implant recipients were included. First, activation thresholds and amplitude growth functions of electrically evoked vestibulo-ocular reflexes (eVOR), cervical myogenic potentials (ecVEMPs) and vestibular percepts (vestibulo-thalamo-cortical, VTC) were recorded upon stimulation with single, biphasic current pulses (200 µs/phase) delivered through five different vestibular electrodes. Latencies of eVOR and ecVEMPs were also characterized. Then we compared the amplitude growth functions of the three pathways using different stimulation profiles (1-pulse, 200 µs/phase; 1-pulse, 50 µs/phase; 4-pulses, 50 µs/phase, 1600 pulses-per-second) in one patient (two electrodes). Results: The median latencies of the eVOR and ecVEMPs were 8 ms (8–9 ms) and 10.2 ms (9.6–11.8 ms), respectively. While the amplitude of eVOR and ecVEMP responses increased with increasing stimulation current, the VTC pathway showed a different, step-like behavior. In this study, the 200 µs/phase paradigm appeared to give the best balance to enhance responses at lower stimulation currents. Conclusions: This study is a first attempt to evaluate the simultaneous activation of different vestibular pathways. However, this issue deserves further and more detailed investigation to determine the actual possibility of selective stimulation of a given pathway, as well as the functional impact of the contribution of each pathway to the overall rehabilitation process. [ABSTRACT FROM AUTHOR]

Introduction: A horizontal vestibulo-ocular reflex gain (VOR gain) of < 0.6, measured by the video head impulse test (VHIT), is one of the diagnostic criteria for bilateral vestibulopathy (BV) according to the Báràny Society. Several VHIT systems are commercially available, each with different techniques of tracking head and eye movements and different methods of gain calculation. This study compared three different VHIT systems in patients diagnosed with BV. Methods: This study comprised 46 BV patients (diagnosed according to the Báràny criteria), tested with three commercial VHIT systems (Interacoustics, Otometrics and Synapsys) in random order. Main outcome parameter was VOR gain as calculated by the system, and the agreement on BV diagnosis (VOR gain < 0.6) between the VHIT systems. Peak head velocities, the order effect and covert saccades were analysed separately, to determine whether these parameters could have influenced differences in outcome between VHIT systems. Results: VOR gain in the Synapsys system differed significantly from VOR gain in the other two systems [F(1.256, 33.916) = 35.681, p < 0.000]. The VHIT systems agreed in 83% of the patients on the BV diagnosis. Peak head velocities, the order effect and covert saccades were not likely to have influenced the above mentioned results. Conclusion: To conclude, using different VHIT systems in the same BV patient can lead to clinically significant differences in VOR gain, when using a cut-off value of 0.6. This might hinder proper diagnosis of BV patients. It would, therefore, be preferred that VHIT systems are standardised regarding eye and head tracking methods, and VOR gain calculation algorithms. Until then, it is advised to not only take the VOR gain in consideration when assessing a VHIT trial, but also look at the raw traces and the compensatory saccades. [ABSTRACT FROM AUTHOR]

Understanding balance and gait deficits in vestibulopathy may help improve clinical care and our knowledge of the vestibular contributions to balance. Here, we examined walking speed effects on gait variability in healthy adults and in adults with bilateral vestibulopathy (BVP). Forty-four people with BVP, 12 healthy young adults and 12 healthy older adults walked at 0.4 m/s to 1.6 m/s in 0.2 m/s increments on a dual belt, instrumented treadmill. Using motion capture and kinematic data, the means and coefficients of variation for step length, time, width and double support time were calculated. The BVP group also completed a video head impulse test and examinations of ocular and cervical vestibular evoked myogenic potentials and dynamic visual acuity. Walking speed significantly affected all gait parameters. Step length variability at slower speeds and step width variability at faster speeds were the most distinguishing parameters between the healthy participants and people with BVP, and among people with BVP with different locomotor capacities. Step width variability, specifically, indicated an apparent persistent importance of vestibular function at increasing speeds. Gait variability was not associated with the clinical vestibular tests. Our results indicate that gait variability at multiple walking speeds has potential as an assessment tool for vestibular interventions. [ABSTRACT FROM AUTHOR]

Objectives: In vestibular implants (VI), the electrode position is thought to be important for optimal neural activation. The objective of this study was to evaluate the stability of the vestibular electrode position over time.Seven patients implanted with a VI were followed for one year. When possible, the fenestrations of the semicircular canals were kept very small (approximately 0.8 mm) to stabilize the electrode lead. Additionally, the electrodes were fixed at their fenestration sites using bone cement. A temporal bone CT scan was performed intraoperatively, and one week and one year postoperatively. In one patient reliable analysis of the intraoperative CT scan was not possible due to a technical error. A displacement of the vestibular electrodes of more than 0.5 mm was considered significant.Fourteen out of 18 electrodes did not show a significant displacement between the intraoperative scan and the first postoperative scan. In the remaining four electrodes, a displacement of ≥ 0.5 mm occurred (mean 0.54 mm, range 0.50–0.58 mm). These four electrodes were found in the two first implanted patients. In both cases, the intraoperative CT scan had a slice thickness of 0.5 mm and showed severe scattering. This might imply that the measured displacement was (partially) related to a higher measurement error. None of the vestibular electrodes migrated outside of the ampulla. No displacement was observed in any of the vestibular electrodes between the first postoperative scan and the one-year follow-up scan.The current surgical technique seems to securely stabilize the vestibular VI electrodes over time.Methods: In vestibular implants (VI), the electrode position is thought to be important for optimal neural activation. The objective of this study was to evaluate the stability of the vestibular electrode position over time.Seven patients implanted with a VI were followed for one year. When possible, the fenestrations of the semicircular canals were kept very small (approximately 0.8 mm) to stabilize the electrode lead. Additionally, the electrodes were fixed at their fenestration sites using bone cement. A temporal bone CT scan was performed intraoperatively, and one week and one year postoperatively. In one patient reliable analysis of the intraoperative CT scan was not possible due to a technical error. A displacement of the vestibular electrodes of more than 0.5 mm was considered significant.Fourteen out of 18 electrodes did not show a significant displacement between the intraoperative scan and the first postoperative scan. In the remaining four electrodes, a displacement of ≥ 0.5 mm occurred (mean 0.54 mm, range 0.50–0.58 mm). These four electrodes were found in the two first implanted patients. In both cases, the intraoperative CT scan had a slice thickness of 0.5 mm and showed severe scattering. This might imply that the measured displacement was (partially) related to a higher measurement error. None of the vestibular electrodes migrated outside of the ampulla. No displacement was observed in any of the vestibular electrodes between the first postoperative scan and the one-year follow-up scan.The current surgical technique seems to securely stabilize the vestibular VI electrodes over time.Results: In vestibular implants (VI), the electrode position is thought to be important for optimal neural activation. The objective of this study was to evaluate the stability of the vestibular electrode position over time.Seven patients implanted with a VI were followed for one year. When possible, the fenestrations of the semicircular canals were kept very small (approximately 0.8 mm) to stabilize the electrode lead. Additionally, the electrodes were fixed at their fenestration sites using bone cement. A temporal bone CT scan was performed intraoperatively, and one week and one year postoperatively. In one patient reliable analysis of the intraoperative CT scan was not possible due to a technical error. A displacement of the vestibular electrodes of more than 0.5 mm was considered significant.Fourteen out of 18 electrodes did not show a significant displacement between the intraoperative scan and the first postoperative scan. In the remaining four electrodes, a displacement of ≥ 0.5 mm occurred (mean 0.54 mm, range 0.50–0.58 mm). These four electrodes were found in the two first implanted patients. In both cases, the intraoperative CT scan had a slice thickness of 0.5 mm and showed severe scattering. This might imply that the measured displacement was (partially) related to a higher measurement error. None of the vestibular electrodes migrated outside of the ampulla. No displacement was observed in any of the vestibular electrodes between the first postoperative scan and the one-year follow-up scan.The current surgical technique seems to securely stabilize the vestibular VI electrodes over time.Conclusion: In vestibular implants (VI), the electrode position is thought to be important for optimal neural activation. The objective of this study was to evaluate the stability of the vestibular electrode position over time.Seven patients implanted with a VI were followed for one year. When possible, the fenestrations of the semicircular canals were kept very small (approximately 0.8 mm) to stabilize the electrode lead. Additionally, the electrodes were fixed at their fenestration sites using bone cement. A temporal bone CT scan was performed intraoperatively, and one week and one year postoperatively. In one patient reliable analysis of the intraoperative CT scan was not possible due to a technical error. A displacement of the vestibular electrodes of more than 0.5 mm was considered significant.Fourteen out of 18 electrodes did not show a significant displacement between the intraoperative scan and the first postoperative scan. In the remaining four electrodes, a displacement of ≥ 0.5 mm occurred (mean 0.54 mm, range 0.50–0.58 mm). These four electrodes were found in the two first implanted patients. In both cases, the intraoperative CT scan had a slice thickness of 0.5 mm and showed severe scattering. This might imply that the measured displacement was (partially) related to a higher measurement error. None of the vestibular electrodes migrated outside of the ampulla. No displacement was observed in any of the vestibular electrodes between the first postoperative scan and the one-year follow-up scan.The current surgical technique seems to securely stabilize the vestibular VI electrodes over time. [ABSTRACT FROM AUTHOR]