Spatial Orientation, Navigation, and Neuropsychologic Function in Patients With Vestibular Implant
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-80
SponsorMassachusetts Eye and Ear Infirmary
About this trial
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.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Deaf, scheduled for CI surgery
Minimum of five year history of documented absence of bilateral auditory and vestibular function, based on review of their audiograms and vestibular tests.
Vestibular testing consistent with BVL
No neurologic disease. note: these patients are recruited and implanted by the group at the University of Geneva Hospital (UNIGE) as part of their ongoing research. The study team are not involved in any way with the decision to surgically implant patients with cochlear or vestibular implants, nor are the researchers involved in any way with pre- or post-operative clinical care. The researchers only involvement is to perform the cognitive tests before, during, and after relatively short periods of stimulation using the vestibular implant (VI)
Disqualifiers
No known neurologic or otologic disease other than the vestibular and auditory deficits noted above.
Pregnancy. Pregnant women and women up to 4 months postpartum will be excluded because of the known effects and unknown potential effects of pregnancy on sensory function.
Body weight >250 lbs (due to motion device safety limits)
The chronic use of vestibular suppressant medication (benzodiazepine, antihistamine, anticholinergic)
Trial design
Design model
Crossover
Treatments tested in this trial
vestibular implant stimulation
DeviceTwo 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.
Treatment groups
20 Participants
are divided into 2 treatment groupsGroup A: "true" stimulationActive comparator 1 intervention
Group B: "placebo" stimulationSham comparator 1 intervention
Trial outcomes
Primary outcomes
1
Spatial Orientation: Changes in Subjective Postural Vertical
Spatial orientation (subjective postural vertical) results are assessed for their accuracy and precision. Tests are repeated to look at changes for pre-stimulation (VI-OFF), following chronic stimulation (VI-ON), and post-stimulation (VI-OFF).
Time frame
pre-stim, chronic stim (1month + 12 days), and post-stim (1month)2
Spatial Orientation: Changes in Roll Tilt Perceptual Thresholds
Spatial orientation (roll tilt perceptual thresholds) results are assessed for their accuracy and precision. Tests are repeated to look at changes for pre-stimulation (VI-OFF), following chronic stimulation (VI-ON), and post-stimulation (VI-OFF).
Time frame
pre-stim, chronic stim (1month + 12 days), and post-stim (1month)3
Changes in Navigation
Navigation in a virtual reality visual environment is tested using a 'complete the triangle' task and results are assessed for their accuracy and precision. Tests are repeated to look at changes for pre-stimulation (VI-OFF), following chronic stimulation (VI-ON), and post-stimulation (VI-OFF).
Time frame
pre-stim, chronic stim (1month + 12 days), and post-stim (1month)4
Changes in Neuropsychologic Function
Visuospatial and non-visuospatial neuropsychologic function are assessed using a standard battery of neuropsychologic tests. Tests are repeated to look at changes for pre-stimulation (VI-OFF), following chronic stimulation (VI-ON), and post-stimulation (VI-OFF).
Time frame
pre-stim, chronic stim (1month + 12 days), and post-stim (1month)Sponsors and contacts
Click on the lead sponsor to view all of their trials.
Massachusetts Eye and Ear Infirmary
Lead sponsor
National Institute on Deafness and Other Communication Disorders (NIDCD)
Collaborator
University of Geneva, Switzerland
Collaborator
Maastricht University
Collaborator
Source ClinicalTrials.gov