Spatial Orientation, Navigation, and Neuropsychologic Function in Patients With Vestibular Implant

Summary

The vestibular system, located in the inner ear, provides information to the brain information about how head acceleration and orientation relative to gravity. Damage to the vestibular system is usually permanent and can contribute to a lower quality of life. The goal of this research is to to examine how vestibular implants (VI) may improve performance of cognitive tasks in patients with severe vestibular damage. These higher-level cognitive behaviors include (1) orientation relative to gravity, (2) navigation, and (3) neuropsychologic function. VI patients will be tested in these three cognitive domains across study sessions: pre-stimulation (VI implanted but stimulation OFF), following chronic stimulation (12 days, VI-ON), and then again 1 month later with the VI turned off. There will be both "true" stimulation experiments during which the VI will provide motion-modulated stimulation and also "placebo" stimulation (no motion cues, tonic stimulus). The order of these experiments will be randomized and separated by 3 months. Researchers will compare VI data in the three cognitive domains (spatial orientation, navigation, \& neuropsychologic function) with control data from non-implanted bilateral vestibular loss (BVL) and unilateral vestibular loss (UVL) patients and normal subjects.

Conditions

• Vestibular Dysfunction
• Bilateral Vestibular Loss
• Vestibular Implant

Interventions

DEVICE

vestibular implant stimulation

Two types of stimulation are used, tonic + motion-modulated ("true") \& tonic-only ("placebo") stimulation; order is randomized. The VI stimulation period prior to testing is 12 days. For the experiments, the VI is connected to the head-mounted prosthetic circuit and then stimulation is activated. The stimulation unit is the current-balanced biphasic pulse, and the pulse amplitude for each subject is determined through a tuning procedure. Experiments start with an adaptation to tonic baseline stimulation with the head stationary (\~30 min). Motion-modulated stimulation employs 3 angular velocity sensors (one aligned with the sensitive axis of each canal), the transduced head velocity signal is high-pass filtered to simulate normal canal dynamics, and filtered head velocity is used to modulate the strength (magnitude, rate) of the electrical stimulation provided by the corresponding implanted electrode. Stimulation strength adjusts for head rotations that change canal afference.

Sponsors & Collaborators

• National Institute on Deafness and Other Communication Disorders (NIDCD)

  collaborator NIH

• University of Geneva, Switzerland

  collaborator OTHER

• Maastricht University

  collaborator OTHER

• Massachusetts Eye and Ear Infirmary

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-01-22

Primary Completion

2029-07-31

Completion

2029-07-31

Countries

• Switzerland

Study Locations