Effects of Vestibular Training on Postural Control of Healthy Adults Using Virtual Reality

Study Overview
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Brief Summary
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Postural instability is a common symptom of vestibular dysfunction that impacts a person's day-to-day activities. Vestibular rehabilitation is effective in decreasing dizziness, visual symptoms and improving postural control through several mechanisms including sensory reweighting. As part of the sensory reweighting mechanisms, vestibular activation training with headshake activities influence vestibular reflexes. However, combining challenging vestibular and postural tasks to facilitate more effective rehabilitation outcomes is under-utilized. The novel concurrent headshake and weight shift training (Concurrent HS-WST) is purported to train the vestibular system to directly impact the postural control system simultaneously and engage sensory reweighting to improve balance. Young healthy participants will perform the training by donning a virtual reality headset with an overhead harness on and a spotter present to prevent any falls. The investigators propose that this training strategy would show improved outcomes over traditional training methods by improving vestibular-ocular reflex (VOR) gains, eye movement variability, sensory reweighting and promoting postural balance. The findings of this study may guide clinicians to develop rehabilitation methods for vestibular postural control in neurological populations with vestibular and/or sensorimotor control impairment.

Official Title
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Effects of Vestibular Training on Postural Control of Healthy Adults Using Virtual Reality

Conditions
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Virtual Reality, Vestibular Training, Balance Assessment

Intervention / Treatment
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* Device: Vestibular training using VR followed by Control
* Device: Control followed by Vestibular training using VR


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Able to stand independently (without an assistive device) This study requires participants to perform postural assessments including reactive balance following mechanical perturbations. Participants will also perform headshake activities and weight shift training in standing for 20 mins will mini breaks. Participants must be within the age of 18-35. A power analysis revealed that a sample of 24 participants will required for a two-group comparison to detect a significant difference at alpha=0.05 and 0.30 effect size at beta=0.8 (G*Power, Version 3.0.10)(Faul et al, 2007). Exclusion Criteria: Participants with an evidence of: Concussion, vestibular, balance or oculomotor issues for the prior 6 months. Neuropathic conditions, particularly affecting the lower extremities. Participants with this issue will have sensory impairments which can affect their sensory assessment. Current musculoskeletal deficits including significant postural abnormalities (signs of spinal, pelvic and leg length discrepancies). Pain or limitations in neck range of motion. Recent (within 6 months) orthopedic surgery that impacts postural training. Visual Impairment Participants must be able to see and follow targets on the computer monitor. Therefore, subjects must have 20/50 (corrected) vision. Subjects who are blind cannot participate.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Health Services Research
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Vestibular Activation Training<br> | Device: Vestibular training using VR followed by Control<br>* A cross-over design will be used with group one receiving the training intervention for 6 days, a 4-day washout period, and a 6-day no-training period.<br>Device: Control followed by Vestibular training using VR<br>* Group two will follow the reverse sequence.<br>|
| No Intervention: No Training<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vestibulo-ocular reflex (VOR) gain | Horizontal and vertical vestibulo-ocular reflex (VOR) gain will be assessed using the video head impulse test (vHIT; ICS, Otometrics, Taastrup, Denmark). Twenty head impulses each will be performed to assess each direction of the semicircular canals with participant in a seated position | Two week study period | 
| Eye movement variability | Horizontal and vertical eye movements will be assessed during force plate perturbation trials using BlueGain electro-oculography (EOG) device (Cambridge Research Systems). Participants will stand on a force plate perturbation device with EOG electrodes affixed on eye muscles to record eye movements during toes up (simulating being pushed backward) and toes down (simulating being pushed forward) perturbation rotation trials. | Two week study period | 
| Electromyography (EMG) amplitude | Electromyography (EMG) will be assessed during force plate perturbation trials using Delsys Trigno wireless sensors (Delsys Inc., Boston, MA). Participants will stand on a force plate perturbation device with EMG sensors placed on postural muscles to record electrical activity during toes up (simulating being pushed backward) and toes down (simulating being pushed forward) perturbation rotation trials. | Two week study period | 
| Electromyography (EMG) time onset | Electromyography (EMG) will be assessed during force plate perturbation trials using Delsys Trigno wireless sensors (Delsys Inc., Boston, MA). Participants will stand on a force plate perturbation device with EMG sensors placed on postural muscles to record electrical activity during toes up (simulating being pushed backward) and toes down (simulating being pushed forward) perturbation rotation trials. | Two week study period | 
| Balance equilibrium and composite scores | Equilibrium and composite scores will be assessed by the Modified Clinical Test for Sensory Interaction on Balance (MCTSIB; NeuroCom®, Natus Medical Inc., Pleasanton, CA) during quiet stance. The MCTSIB requires the participant to stand upright as stable as possible for 10 s under four different conditions: (1) eyes open (EO) on a stable surface (SS), (2) eyes closed (EC) on SS, (3) EO on foam surface (FS), (4) EC on FS. | Two week study period | 
| Sensory ratios | Sensory ratios will be assessed by the Modified Clinical Test for Sensory Interaction on Balance (MCTSIB; NeuroCom®, Natus Medical Inc., Pleasanton, CA) during quiet stance. The MCTSIB requires the participant to stand upright as stable as possible for 10 s under four different conditions: (1) eyes open (EO) on a stable surface (SS), (2) eyes closed (EC) on SS, (3) EO on foam surface (FS), (4) EC on FS. | Two week study period | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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VR, Balance, Vestibular Training, EMG, EOG