Chronic Electrical Stimulation of the Otolith Organ: Preliminary Results in Humans with Bilateral Vestibulopathy and Sensorineural Hearing Loss

Abstract

Introduction: Bilateral vestibulopathy is an important cause of imbalance that is misdiagnosed. The clinical management of patients with bilateral vestibular loss remains difficult as there is no clear evidence for an effective treatment. In this paper, we try to analyze the effect of chronic electrical stimulation and adaptation to electrical stimulation of the vestibular system in humans when stimulating the otolith organ with a constant pulse train to mitigate imbalance due to bilateral vestibular dysfunction (BVD). Methods: We included 2 patients in our study with BVD according to Criteria Consensus of the Classification Committee of the Bárány Society. Both cases were implanted by using a full-band straight electrode to stimulate the otoliths organs and simultaneously for the cochlear stimulation we use a perimodiolar electrode. Results: In both cases Vestibular and clinical test (video head impulse test, videonistagmography cervical vestibular evoked myogenic potentials, cVEMP and oVEMP), subjective visual vertical test, computerized dynamic posturography, dynamic gait index, Time UP and Go test and dizziness handicap index) were performed. Posture and gait metrics reveal important improvement if compare with preoperartive situation. Oscillopsia, unsteadiness, independence and quality of life improved to almost normal situation. Discussion/Conclusion: Prosthetic implantation of the otolith organ in humans is technically feasible. Electrical stimulation might have potential effects on balance and this is stable after 1 year follow-up. This research provides new possibilities for the development of vestibular implants to improve gravito-inertial acceleration sensation, in this case by the otoliths stimulation.

Differences in Vestibular-Evoked Myogenic Potential Responses by Using Cochlear Implant and Otolith Organ Direct Stimulation

“…Electrical stimulation induces myogenic responses in the vestibulocollic pathway as has already been established before (15). We observe that otolith organ electrical stimulation can restore the vestibulocollic reflex in patients with BVD and vestibular implant, in all cases in this study, with an important effect on the clinical situation and BVD symptoms restoration (17). The shape of the EcVEMP was similar to the conventional acoustically elicited cVEMP.…”

“…In all cases, acoustic VEMP responses were present before cochlear implant implantation. In the vestibular implant group, three patients had bilateral vestibular dysfunction (BVD) and met the inclusion criteria for vestibular implantation research, which have been described in detail in a previous study ( 17 ). All three of these patients also had severe hearing loss.…”

“…Three patients with BVL received a new research vestibular implant (VI). The VI is a custom-modified cochlear implant with a full-band straight electrode, CI24RE (ST), from Cochlear Ltd (Lane Cove, NSW, Australia) with three active electrodes for VI stimulation ( 17 ). Full-band electrodes were selected to assure that the electrodes were facing the closest area of neural tissue related to the saccular area.…”

“…As previously described, vestibular costimulation may help to restore damaged vestibular function (17,32) but may not be considered for all situations in cochlear implant recipients TABLE 6 | An example of VOR gain in six canals (VHIT) before and after cochlear implant group (example of C1 patient).…”

Functional Loss After Meningitis—Evaluation of Vestibular Function in Patients With Postmeningitic Hearing Loss

“…In the future, vestibular implants ( 29 ) may also constitute a treatment option for patients with bilateral vestibulopathy after meningitis. Ramos Macias et al recently demonstrated that otolith organ implantation was feasible in two patients with bilateral vestibulopathy due to meningitis ( 30 ). Plausibly, this procedure may have a window of opportunity as for cochlear implantation, due to progressing ossification of the inner ear fluid compartments ( 21 ).…”