Eye Movements in Response to Electric Stimulation of the Human Posterior Ampullary Nerve

Abstract

We have been able to replicate in humans a finding somewhat similar to that of Suzuki and Cohen in monkeys for electric stimulation of the posterior semicircular canal. The similarity is an eye movement with a large, predominant vertical component. The difference is that we saw no horizontal response component, and were not able to measure a torsional response, because we used 2-dimensional video methods. In addition, we found a robust nystagmus with slow component velocities that are large enough to compensate for vertical head movements. This is an essential step in demonstrating the feasibility of a vestibular prosthesis using electric stimulation.

Vestibulo-Ocular Reflex Responses to a Multichannel Vestibular Prosthesis Incorporating a 3D Coordinate Transformation for Correction of Misalignment

“…Distances between neighboring ampullary nerves in the human labyrinth are larger than those in chinchillas, while precision of surgical positioning should be about the same, so the amount of current spread to non-target nerve branches might be less in humans and might be low enough that precompensation becomes unnecessary. The few data available are inconclusive: recent attempts to selectively stimulate the posterior ampullary nerve intraoperatively in alert humans apparently did not result in eye rotations purely about the desired axis (Wall et al 2007), whereas the posterior ampullary nerve is usually the easiest branch of the chinchilla vestibular nerve to stimulate intensely with high selectivity and low misalignment. Tests of vestibular prosthetic stimulation in rhesus monkeys, which are intermediate in size between chinchillas and humans, suggest that misalignment may be slightly better than in chinchillas implanted using similar techniques (Lewis et al 2009;Dai et al 2010).…”

Adaptation to Steady-State Electrical Stimulation of the Vestibular System in Humans

“…Several experiments on animal models have shown that electrical stimulation of the vestibular nerve can elicit responses resembling the normal functioning vestibular apparatus [1,2]. Recently, similar observations were made in humans [3,4]. Subjects of these experiments were patients suffering from unilateral disabling Menière"s disease with recurrent spells of vertigo, with no useful hearing in the affected ear, making them eligible for a surgical labyrinthectomy or patients with a profound bilateral hearing loss programmed for a cochlear implantation.…”

Multichannel Vestibular Prosthesis Employing Modulation of Pulse Rate and Current with Alignment Precompensation Elicits Improved VOR Performance in Monkeys

“…By delivering biphasic, symmetric, charge-balanced, rate-modulated pulses, the device generated partly compensatory eye movements for head rotations about the gyro's axis of rotational sensitivity. Wall, Guyot, and colleagues have applied a similar approach to single-channel vestibular nerve stimulation in humans (Wall et al 2007;Guyot et al 2011aGuyot et al , b, 2012, and Nie, Phillips, Rubinstein, and colleagues have recently applied analogous technology to monkeys and a human subject as part of an effort to develop a vestibular pacing device for treatment of Ménière's disease (Nie et al 2011;Rubinstein et al 2012).…”