Search Results (7)

Background: Vestibular function implements head position regulation and body spatial navigation. It matures during childhood and adolescence and integrates with the completion of an individual’s motor development. Nevertheless, vestibular impairment is associated with profound paediatric hearing loss and has a negative impact on the child’s motor proficiency. Cochlear implantation (CI) is the treatment of choice for severe hearing loss, where conservative treatment plans are not appropriate or fail. The Teenager and Young Adults Cochlear Implant (TAYACI) study investigates the long-term outcomes of early implantation with respect to the hearing, speech, psychological, and balance development among CI users. Methods: This study focuses on the vestibular function and the appropriate methods for vestibular assessment. The results of two established vestibular test methods are explored: the video head impulse test (vHIT) and cervical/ocular vestibular-evoked myogenic potentials (cVEMP, oVEMP) with air and bone conduction vibration stimulation. The results of vHIT, cVEMP, and oVEMP, per implanted ear and the relation to the aetiology of hearing loss are reported. An additional dynamic visual acuity (DVA) test was included to assess clinical oscillopsia. Results: Overall abnormal lateral canal testing was detected in 35/76 (46.1%) of the implanted ears. Bone-conducted cVEMP (BC cVEMP) was pathological in 33/76 (43.3%) and BC oVEMP in 42/76 (55.3%). Lateral canal impairment was associated with the background diagnosis of the hearing loss. Oscillopsia was related to bilateral canal impairment (sensitivity 73% specificity 100%). Conclusions: Lateral canal testing together with BC VEMPs were the most reproducible modules for vestibular testing The above tests were related to each other and complemented the overall vestibular assessment. DVA is a helpful tool to screen dynamic oscillopsia in patients with bilateral vestibular impairment. Full article

Bilateral vestibulopathy (BV) is a known cause of chronic vestibular syndrome. With the video head impulse test (VHIT), we can now evaluate all six semicircular canals independently and establish BV subgroups based on canal gain patterns. Background/objectives: To assess canal gain patterns for BV with VHIT, and evaluate subgroups with regard to sex, age, and hearing loss. Methods: A retrospective chart review was performed of all patients who underwent a VHIT between January 2021 and July 2024. Patients with decreased lateral canal gains, bilaterally, were included. Results of canal gains, VHIT patterns, audiometry, and videonystagmography (VNG) results were reviewed. Results: 101 cases were included. Patients were 75.5 ± 13.1 years old and 64.4% were women. Various VHIT patterns were observed; the most frequent being decreased canal gains across all six canals (44.6%), followed by a mix of canals with decreased gains with no clear pattern (34.7%). Decreased gains limited to the lateral canals were rare. We did not observe any significant difference between subgroups with regard to gender or age. Concomitant hearing loss was common (89.6%). A trend was noted, suggesting that severity of hearing loss increased with the number of affected canals. An abnormal VNG test was common (73.3%). Conclusions: Various patterns of canal gains were observed for patients with BV. Audiometry and VNG should be considered as part of BV studies since abnormalities are commonly found. Further research is needed to understand VHIT patterns in BV. Full article

(1) Background. Patients with bilateral vestibular disease (BVD) experience oscillopsia with a detriment to visual acuity (VA). This VA is driven mainly by the VOR that has two components: rotational and translational. VA can be tested by using dynamic visual acuity (DVA) on a treadmill because both systems are activated. The aim of this study is to compare VA before and after chronic electrical stimulation of the otolith organ. (2) Materials and Method. Five patients suffering from bilateral vestibular dysfunction (BVD), previously implanted with a new vestibular implant prototype, were included in this study with the aim to check VA with and without vestibular implant use (W and W/O) in static, 2 km/h and 4 km/h walking situations. DVAtreadmill was measured on a treadmill with a dynamic illegible E (DIE) test in static and dynamic conditions (while walking on the treadmill at 2 and 4 km/h). The DVA score was registered in a logarithm of the minimum angle of resolution (LogMAR) for each speed. In addition, every patient completed the oscillopsia severity questionnaire (OSQ) and video head impulse test (vHIT) before and after activation of the vestibular implant. (3) Results. The analysis shows a significant difference in OSQ scores and DVA with an improvement in dynamic conditions. Organized corrective saccades during the use of a vestibular implant with no changes in gain were also detected in the video head impulse tests (vHIT). (4) Conclusion. The vestibular implant with otolithic stimulation offers changes in the response of DVA, which makes this paper one of the first to address the possible restoration of it. It is not possible to rule out other contributing factors (presence of covert saccades, somatosensory system, …). More work seems necessary to understand the neurophysiological basis of these findings, but this implant is added as a therapeutic alternative for the improvement of oscillopsia. Full article

The importance of early evaluation by a neurotologist in patients with infective endocarditis treated with systemic gentamicin and its impact on the patients’ quality of life was evaluated. This is a longitudinal retrospective cohort study of 29 patients who received intravenous gentamicin for the treatment of infective endocarditis. Patients were classified into two groups: group A, before a neurotologist was included in the treatment protocol, and group B, after the inclusion of a neurotologist. The frequency of the different symptoms in each group was measured, and the gain of the vestibulo-ocular reflex (VOR) and its relationship with the presence of oscillopsia. In total, 13 and 16 patients were assigned to groups A and B, respectively. The mean gain of the VOR measured using the video head impulse test in group A was 0.44 in the best side and 0.39 in the worst side. In group B, the mean gain was 0.71 (best side) and 0.64 (worst side) (p < 0.0001). The patients who complained about oscillopsia had a main gain of 0.41 in the best side and 0.35 in the worst side. Evaluation of vestibular function should be included in the infective endocarditis treatment protocol, including the adverse effects of systemic gentamicin. Full article

Patients with bilateral vestibular hypofunction (BVH) often suffer from imbalance, gait problems, and oscillopsia. Noisy galvanic vestibular stimulation (GVS), a technique that non-invasively stimulates the vestibular afferents, has been shown to enhance postural and walking stability. However, no study has investigated how it affects stability and neural activities while standing and walking with a 2 Hz head yaw turning. Herein, we investigated this issue by comparing differences in neural activities during standing and walking with a 2 Hz head turning, before and after noisy GVS. We applied zero-mean gaussian white noise signal stimulations in the mastoid processes of 10 healthy individuals and seven patients with BVH, and simultaneously recorded electroencephalography (EEG) signals with 32 channels. We analyzed the root mean square (RMS) of the center of pressure (COP) sway during 30 s of standing, utilizing AMTI force plates (Advanced Mechanical Technology Inc., Watertown, MA, USA). Head rotation quality when walking with a 2 Hz head yaw, with and without GVS, was analyzed using a VICON system (Vicon Motion Systems Ltd., Oxford, UK) to evaluate GVS effects on static and dynamic postural control. The RMS of COP sway was significantly reduced during GVS while standing, for both patients and healthy subjects. During walking, 2 Hz head yaw movements was significantly improved by noisy GVS in both groups. Accordingly, the EEG power of theta, alpha, beta, and gamma bands significantly increased in the left parietal lobe after noisy GVS during walking and standing in both groups. GVS post-stimulation effect changed EEG activities in the left and right precentral gyrus, and the right parietal lobe. After stimulation, EEG activity changes were greater in healthy subjects than in patients. Our findings reveal noisy GVS as a non-invasive therapeutic alternative to improve postural stability in patients with BVH. This novel approach provides insight to clinicians and researchers on brain activities during noisy GVS in standing and walking conditions in both healthy and BVH patients. Full article

Low vision therapy, such as magnifiers or contrast enhancement, is widely used. Scientific evidence proving its efficacy is scarce however. The objective of this study was to investigate whether the benefits of magnification and contrast enhancement depended on the origin of low vision. For this purpose we measured reading speed with artificially induced low vision in 12 healthy subjects in conditions of a simulated central scotoma, blurred vision and oscillopsia. Texts were either blurred, set in motion or blanked at the gaze position by using eye tracking and gaze contingent display. The simulated visual impairment was calibrated such that all types of low vision caused equal reading impairment. We then tested the effect of magnification and contrast enhancement among the different types of low vision. We found that reading speed improved with increasing magnification and with higher contrast in all conditions. The effect of magnification was significantly different in the three low vision conditions: The gain from magnification was highest in simulated blur and least in central scotoma. Magnification eventually led to near normal reading speed in all conditions. High contrast was less effective than high magnification and the effect of contrast enhancement was similar in all low vision conditions. From these results we conclude that the type of low vision determines the benefit that can be expected from magnification. Contrast enhancement leads to similar improved reading speed in all low vision types. We provide evidence that supports the use of low vision aids. Full article

This paper presents an alternative approach for angular-rate sensing based on the way that the natural vestibular semicircular canals operate, whereby the inertial mass of a fluid is used to deform a sensing structure upon rotation. The presented gyro has been fabricated in a commercially available MEMS process, which allows for microfluidic channels to be implemented in etched glass layers, which sandwich a bulk-micromachined silicon substrate, containing the sensing structures. Measured results obtained from a proof-of-concept device indicate an angular rate sensitivity of less than 1 °/s, which is similar to that of the natural vestibular system. By avoiding the use of a continually-excited vibrating mass, as is practiced in today’s state-of-the-art gyroscopes, an ultra-low power consumption of 300 μW is obtained, thus making it suitable for implantation. Full article