What this trial measures

• Dizziness Handicap Inventory (DHI)Baseline, 3 weeks, 1-2-3-4-5-11-23-35 months

  The Dizziness Handicap Inventory (DHI) is a validated patient-reported outcome measure designed to assess the perceived impact of dizziness on daily function. It includes 25 items categorized into physical, emotional, and functional domains, with responses scored on a scale from 0 (no impact) to 100 (maximum impact). Higher scores indicate greater disability.

• Activities Balance Confidence Scale (ABC)Baseline, 3 weeks, 1-2-3-4-5-11-23-35 months

  The Activities Balance Confidence Scale (ABC) is a validated self-reported questionnaire designed to measure an individual's confidence in maintaining balance during various daily activities, such as walking on uneven surfaces, climbing stairs, or reaching overhead. The scale consists of 16 items, with each activity rated on a percentage scale from 0% (no confidence) to 100% (complete confidence). Higher scores indicate greater balance confidence.

• Bilateral Vestibular Questionnaire (BVQ)Baseline, 3 weeks, 1-2-3-4-5-11-23-35 months

  The Bilateral Vestibular Questionnaire (BVQ) is a 54-item patient-reported outcome measure designed to assess the range of symptoms experienced by individuals with bilateral vestibular dysfunction and the impact on daily life. The questionnaire evaluates seven domains: imbalance, oscillopsia, other physical symptoms, cognition, emotion, behavioral changes and limitations, and social life. Each item is scored on a six-point Likert scale ranging from "never" to "always." Score range 0-324. Higher scores reflect greater symptom severity and reduced quality of life.

• Single-Item and Visual Analog Scales (VAS)Baseline, 3 weeks, 1-2-3-4-5-11-23-35 months

  Single-item measures and Visual Analog Scales (VAS) will be used to assess specific aspects of participants' experiences and treatment responses. Each scale involves a numerical or visual rating system typically ranging from 0 to 10, or 0 to 100, depending on the domain being assessed. These scales measure variables such as limitations in daily life, perceived health, expectations for future recovery, and the overall effectiveness of previous rehabilitation therapies. A higher score indicates more positive outcomes or perceptions.

• Video Head Impulse Test (vHIT)Baseline, 3 weeks, 1-2-3-4 months

  The Video Head Impulse Test (vHIT) is a clinical test used to assess the vestibulo-ocular reflex (VOR) by measuring eye movement responses to head rotations. This test evaluates the function of the three semicircular canals, providing insight into vestibular physiology. During the test, participants wear video goggles that record eye movements while the head is gently rotated to either side at a velocity of \~150°/s, consistent with standardized vHIT protocols. The primary outcome measure is VOR gain (eye velocity/head velocity), with lower gain values potentially indicating vestibular dysfunction.

• Dynamic Visual Acuity (DVA)Baseline, 3 weeks, 1-2-3-4 months

  The Dynamic Visual Acuity (DVA) test is a validated clinical measure used to assess the ability to maintain clear vision during head movements. The test evaluates the vestibulo-ocular reflex (VOR) by comparing static visual acuity (head stationary) with visual acuity during dynamic head rotations in the horizontal and vertical planes (e.g., head movements right, left, up, and down). Participants are seated 2 meters from the testing screen, and head rotation speeds must reach a minimum of 80°/s to generate the randomized optotype. The primary measure is logMAR (logarithm of the minimum angle of resolution) scores, where higher logMAR values indicate worse visual acuity during movement.

• Functional Gait Assessment (FGA)Baseline, 3 weeks, 1-2-3-4 months

  The Functional Gait Assessment (FGA) is a clinical tool used to evaluate gait performance in individuals during different walking tasks. It consists of 10 tasks, including walking while changing speeds, walking with head turns, walking backward, stepping over obstacles, and walking in tandem. Each task is scored on a 0-3 scale, with a total score range of 0-30 indicating optimal performance, and lower scores reflecting greater balance impairments and reduced gait functionality. The FGA is validated for identifying fall risk. Scores below 22/30 indicate fall risk in older adults.

• Timed Up and Go (TUG)Baseline, 3 weeks, 1-2-3-4 months

  The Timed Up and Go (TUG) test is a validated tool for assessing functional mobility and fall risk. Participants are instructed to rise from a seated position, walk 3 meters, turn 180°, walk back, and return to a seated position. The time taken to complete the sequence is recorded as the primary outcome. Faster times indicate normal functional mobility, while slower times (\>13.5 seconds for older adults) are indicative of increased fall risk, particularly in individuals with vestibular disorders.

• Timed Up and Go Dual TaskBaseline, 3 weeks, 1-2-3-4 months

  The Timed Up and Go Dual Task test is a dual-task modified version of the traditional TUG protocol, which further assesses the impact of cognitive load on mobility and balance. Participants perform the same tasks as the TUG test (stand, walk 3 meters, turn, and return to sit) while simultaneously counting backwards from 100 by threes (or another similar cognitive challenge). Timings exceeding 15 seconds in elderly individuals are associated with increased fall risk.

• Gait Velocity (10-Meter Walk Test)Baseline, 3 weeks, 1-2-3-4 months

  Gait velocity will be measured using the 10-Meter Walk Test (10MWT), a validated assessment tool for evaluating walking speed during a self-selected comfortable pace over a short distance. Participants will be instructed to walk 10 meters while gait speed is recorded, with or without an assistive device as appropriate. The average speed (meters/second) is calculated and will be used as the primary outcome measure.

• Sway energy and sway over time (Adaptation Test)Baseline, 3 weeks, 1-2-3-4 months

  The Adaptation Test assesses participants' ability to maintain stability and adapt to unexpected changes in surface tilt. Testing is conducted using a rotating force plate, which provides controlled motion stimuli in two directions: toes-up and toes-down. Participants will stand on the force plate while wearing the Virtualis Motion (VR) headset, which provides immersive visual environments to simulate balance challenges and enhance sensorimotor engagement. Postural stability is evaluated by measuring sway energy, which quantifies force and the extent of anterior-posterior sway, as well as sway over time, which measures center of pressure (COP) movement across the duration of the trials. These measures provide insight into a participant's balance control and adaptive strategies during repeated tilt trials.