Visual Influences on Vestibular Adaptation
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-60
SponsorEmory University
About this trial
The goal of this study is to learn whether a balance-training exercise called incremental vestibulo-ocular reflex adaptation (IVA) is safe and effective for adults with vision impairments, with or without additional vestibular (inner-ear balance) problems.
The main questions it aims to answer are:
* Does IVA cause only mild, temporary symptoms and no serious adverse events? * Does IVA improve eye-movement reflexes, balance, and walking, and do these improvements differ between people with vision problems alone and those with both vision and vestibular impairments?
Researchers will compare adults with vision impairment only to adults who have both vision and vestibular impairments to see whether the groups respond differently to IVA.
Participants will:
* Complete symptom ratings before and after IVA * Undergo tests of vestibular reflexes (e.g., VOR gain) * Complete balance and walking assessments
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Age 18 to 60 years
Able to provide informed consent
Group 1: Abnormal Uncorrected Static Visual Acuity (No Vestibular Hypofunction) Normal peripheral vestibular function
Group 2: Abnormal Uncorrected Static Visual Acuity + peripheral Vestibular Hypofunction
Disqualifiers
Diagnosis of fluctuating vestibular disorders (e.g., benign paroxysmal positional vertigo)
Neurologic conditions (e.g., multiple sclerosis), dementia,
Alcohol or drug abuse,
A major psychiatric disorder (e.g., schizophrenia),
Trial design
Design model
Crossover
Treatments tested in this trial
StableEyes: Incremental Vestibulo-Ocular Reflex Adaptation (IVA)
DeviceIVA is delivered using the StableEyes device, which includes a lightweight head-mounted unit with inertial sensors and a micromirror that controls the position of a low-power laser target projected onto a wall. The device adjusts the target's movement based on the participant's head velocity to create a controlled visual error signal that induces vestibulo-ocular reflex (VOR) adaptation. During each session, participants sit about one meter from a blank wall and perform rapid, self-generated head impulses while visually tracking the moving laser target. The target appears at neutral, moves at a fraction of head velocity during each impulse, and briefly disappears before reappearing at center. Each session lasts 15 minutes and includes roughly 150 head impulses in the horizontal or vertical plane. The procedure has been well-tolerated in prior studies with no reported adverse events.
Treatment groups
100 Participants
are divided into 4 treatment groupsGroup A: Group 1: Abnormal Uncorrected Static Visual Acuity (No Vestibular Hypofunction)Experimental treatment 1 intervention
Group B: Group 2: Abnormal Uncorrected Static Visual Acuity + Vestibular HypofunctionExperimental treatment 1 intervention
Group C: Group 3: Binocular Vision Abnormalities (No Vestibular Hypofunction)Experimental treatment 1 intervention
Group D: Group 4: Binocular Vision Abnormalities + Vestibular HypofunctionExperimental treatment 1 intervention
Trial outcomes
Primary outcomes
1
Change in Vestibulo-Ocular Reflex (VOR) Gain
VOR gain will be measured using the video head impulse test (vHIT). Gain is calculated as eye velocity divided by head velocity during high-acceleration, moderate velocity, small amplitude head rotations in the plane of the semicircular canals. This outcome quantifies the strength of the vestibulo-ocular reflex, with higher gain values indicating stronger VOR responses, with normal gain = 0.8 to 1.2. The change in VOR gain from before to after training will be used to assess VOR adaptation. IVA: Incremental Vestibulo-Ocular Reflex Adaptation
Time frame
Baseline (visit 1) (before and after after IVA intervention), Visit 2 (2-10 days from baseline) (before and after IVA intervention)Secondary outcomes
1
Change in Modified Clinical Test of Sensory Interaction in Balance (mCTSIB)
Participants stand under four sensory conditions (eyes open/closed on firm/foam surfaces). Outcomes include time maintained (0-120 seconds) and postural sway metrics from inertial measurement units. Higher times indicate better balance.
Time frame
Baseline (visit 1) (before and after after IVA intervention), Visit 2 (2-10 days from baseline) (before and after IVA intervention)2
Change in Gait Disorientation Test (GDT)
Participants walk 20 feet with eyes open and eyes closed. The GDT score is the difference in time between the two conditions. Larger differences indicate greater gait disorientation.
Time frame
Baseline (visit 1) (before and after after IVA intervention), Visit 2 (2-10 days from baseline) (before and after IVA intervention)3
Symptom Severity During IVA (Verbal Analog Scales)
Symptom tolerance during incremental VOR adaptation (IVA) will be assessed using verbal analog scales. Participants will rate the severity of blurry vision, eye strain, dizziness, and headache on 0-10 scales, where 0 indicates no symptoms and 10 indicates the worst imaginable symptoms. Ratings will be collected immediately before and after each IVA session to quantify changes in self-reported symptom severity.
Time frame
Baseline (visit 1) (before and after after IVA intervention), Visit 2 (2-10 days from baseline) (before and after IVA intervention)Sponsors and contacts
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Source ClinicalTrials.gov