Vestibular prosthesis: from basic research to clinics

Abstract

Balance disorders are highly prevalent worldwide, causing substantial disability with high personal and socioeconomic impact. The prognosis in many of these patients is poor, and rehabilitation programs provide little help in many cases. This medical problem can be addressed using microelectronics by combining the highly successful cochlear implant experience to produce a vestibular prosthesis, using the technical advances in micro gyroscopes and micro accelerometers, which are the electronic equivalents of the semicircular canals (SCC) and the otolithic organs. Reaching this technological milestone fostered the possibility of using these electronic devices to substitute the vestibular function, mainly for visual stability and posture, in case of damage to the vestibular endorgans. The development of implantable and non-implantable devices showed diverse outcomes when considering the integrity of the vestibular pathways, the device parameters (current intensity, impedance, and waveform), and the targeted physiological function (balance and gaze). In this review, we will examine the development and testing of various prototypes of the vestibular implant (VI). The insight raised by examining the state-of-the-art vestibular prosthesis will facilitate the development of new device-development strategies and discuss the feasibility of complex combinations of implantable devices for disorders that directly affect balance and motor performance.

Exploring the Potentials of Wearable Technologies in Managing Vestibular Hypofunction

“…Vestibular implants/prostheses work by replacing the lost natural afferent spike activity in the vestibular nerve with electrical stimulation [4]. Vestibular implants take advantage of MEMS gyroscopes and accelerometers to provide head movement signals to trigger the stimulators [77]. The process of which is shown in Figure 3d.…”

“…Vestibular implants have been successfully demonstrated in clinical practice. Animal studies have been developed that stimulate the semicircular canals to control eye movements based on the perceived head movements [77]. This device uses multichannel sensing capable of sensing angular velocity about three orthogonal axes and asynchronously stimulating each of the three ampullary nerves, allowing partial restoration of VOR responses for head rotation about any axis.…”

“…This, however, necessitated the development of specific stimulation methods for encoding bidirectional movements using a unilateral device [74]. For the unilateral device, optimizing electrical stimulation parameters, considering electrode design and location, can improve dynamic range, selectivity, and end-organ responses [77] while limiting current spread to unintended targets [78]. For vestibular implants, the surgical procedure and electrode design need refinement for precise implantation, minimal labyrinth damage, and preservation of residual vestibular and cochlear function.…”