Efficacy of Vestibular Rehabilitation Using Computerized Dynamic Posturography With Virtual Reality for Stable Unilateral Vestibular Weakness
Phase: NA
Conditions: Dizziness, Equilibrium; Disorder, Labyrinth, Inner Ear Injury
Sponsor: Eytan A. David

 
Study Number H20-04045  
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Efficacy of vestibular rehabilitation using computerized dynamic 
posturography with virtual reality for stable unilateral vestibular 
weakness 
 
Version 1.2 
 
July 17, 2021 
 
PI:  
 
 
Dr. Eytan David 
Co-investigators: 
Navid Shahnaz 
 
Lay Summary 
People that have difficulty with balance, such as those with damage to their inner ear, have a 
higher risk of falling, which may lead to anxiety and reduced quality of life. Some individuals 
that have lost part of their sense of balance can learn to compensate using information from 
their vision, their sense of where their limbs are in space, and from other balance organs that 
are still intact. Our study aims to determine if virtual reality used together with information 
from footplate sensors can be used to train people with balance problems to compensate for 
their inner ear deficits. 
 
Background 
Vestibular dysfunction is common, with a reported prevalence of over 5% in children(1) and 
adults(2). In individuals with no equilibrium deficits, balance is maintained by integration of 
information from vision, somatosensory input, and from the vestibular sensors of the inner ear. 
Deficits in this system lead to imbalance symptoms, which adversely affect quality of life(3) and 
are associated with unemployment and poorer quality of life.(4) While most individuals with 
unilateral vestibular weakness are able to recover some of their balance function, either 
spontaneously or through rehabilitation, others suffer from persistent dizziness symptoms that 
are refractory to common rehabilitation approaches.(5) 
 
Two technological advancements may provide a new mode of treatment for such people. The 
first, virtual reality (VR) has shown promise for rehabilitation of vestibular and mobility 
deficits.(6) The second, computerized dynamic posturography (CDP), analyzes posture, balance, 
and sway of the subject using a force plates beneath their feet.(7) Together, these technologies 
allow for detailed assessment and tailored, interactive compensatory rehabilitation with 
quantitative measurement of the subject’s responses over time. 
 
VR and CDP allow for the controlled quantitative measurement of responses to rehabilitation 
treatment; however, they may not capture the qualitative changes that reflect improvements in 
the patient’s quality of life and functional capacity. Therefore, it is important to demonstrate 

 
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that any quantitative improvement measured by CDP translates to the patient-reported 
outcomes of increased activity, improved confidence, and reduced fear of falling.(8) 
 
Hypotheses 
VR-CDP-based rehabilitation will improve balance performance, as measured by Sensory 
Organization Test (SOT) scores, for individuals with unilateral vestibular loss. 
 
VR-CDP-based rehabilitation interventions will improve patient-reported vestibular function. 
 
Patients with unilateral vestibular weakness will consent to enrolment, will complete the initial, 
the post-intervention, and two follow-up assessments, and will successfully complete the 
prescribed course of 12 rehabilitation sessions. 
 
Justification 
Vestibular loss can be a major contributor to morbidity and loss of quality of life, increasing the 
risk of falls and leading to a reduction or avoidance of activity.(8) Many patients with unilateral 
vestibular loss report persistent symptoms of dizziness and imbalance despite rehabilitative 
attempts.  Currently, the most common treatment available to such patients are static 
physiotherapeutic exercises which have not been consistently clinically validated by objective 
outcomes. The current treatment modalities are limited with respect to targeted therapies for 
each of the five discreet vestibular end organs, as well and functional outcomes. VR with CDP 
may offer a more effective and targeted means of promoting global balance compensation to 
improve the symptoms of dizziness caused by a specific inner ear deficiency in these 
individuals. However, the efficacy of this type of technology has not been established in the 
literature and the details of the intervention and the number of sessions required to confer 
improvement are unknown. 
 
Objectives 
Primary objective: To evaluate the efficacy of vestibular rehabilitation therapy using 
computerized dynamic posturography (CDP) with interactive visual feedback for the 
amelioration of long-standing imbalance in patients with peripheral unilateral vestibular 
weakness.  
 
Secondary objectives:  
1) To determine the variances (or standard deviations), means, and correlations in order to 
design a larger study with sufficient statistical power to compare the IVR-CDP intervention with 
standard care. 
2) To estimate numbers of eligible patients and rates of consent for enrolment. 
3) To estimate rates of adherence to the study protocol; specifically, (a) the percentage of 
patients that complete the full course of treatment, (b) complete the initial and follow up 
measures and (c) the number of missed or rescheduled visits, and (d) the rate of withdrawal 
from the study. 

 
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4) To determine performance scores for the individual exercises within the rehabilitation 
program, to ensure the difficulty is well-matched to patients’ abilities.  
5) To evaluate the durability, at 6 weeks and 3 months post-intervention, of any changes in: 
 
a) Patient-reported vestibular symptoms (as measured by questionnaires); 
 
b) Objective measures of imbalance (SOT and LOS tests).  
 
Research Design 
Study type: Longitudinal cohort; single group assignment; interventional 
Intervention: 2x per week for 6 weeks of rehabilitation therapy  
 
Study population 
Adults (18-80 years of age) with stable unilateral vestibular weakness. 
 
Recruitment 
Subjects previously seen in the Principal Investigators clinic for unilateral vestibular weakness 
will be contacted and invited to enrol. We hope to enroll 25 subjects as a convenience sample 
for this single centre study.  
 
Inclusion criteria 
• Adult Age 18-80 
• Unilateral vestibular weakness confirmed one or more of:  
o Videonystagmography 
o VEMP  
• Or unilateral vestibular weakness idiopathic, not yet diagnosed (NYD) 
• Persistent imbalance following diagnosis of resolved benign paroxysmal positional 
vertigo (BPPV) 
• Symptomatic  
• Long-standing/persistent symptoms greater than one year 
 
Exclusion criteria 
• Orthopedic deficit (eg. lower body joint dysfunction or lower joint replacement) 
• Neurological deficit or proprioception deficit 
• Diabetes 
• Poor vision or blindness 
• Fluctuating vestibular symptoms, or condition known to fluctuate eg. Menière’s disease, 
perilymphatic fistula (PLF) or superior canal dehiscence (SDCS) 
• Active benign paroxysmal positional vertigo (BPPV) 
• Undergoing treatment which may affect balance or ability to stand 
• Cognitive impairment that prevents understanding and responding to instructions 
required to complete the study 
• Inability to provide informed consent 
 

 
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Study Procedures 
Study data will be collected during visit 1 and 14, with two additional follow up visits at 6 weeks 
(visit 15) and 3 months (visit 16) post-intervention: 
1) Validated questionnaires 
a) Dizziness Handicap Inventory (DHI)(9)  
b) Falls Efficacy Scale-International (FES-I)(10) 
c) Activities-specific Balance Confidence (ABC) scale(11) 
2) Quantitative posturography assessment 
a) Sensory organization test (SOT) 
b) Limits of Stability (LOS) test  
 
During all visits, a CDP instrument supplemented with interactive visuals will be employed to 
measure the subjects postural stability. Participants will stand on the instrument’s platform and 
will view the prescribed interactive visuals. They will be prompted to either maintain stable 
equilibrium or to modulate their COG in response to the interactive visuals, as required for the 
SOT and LOS tests, respectively. 
 
Details of the SOT Test (Visits 1, 14, 15 and 16) 
The SOT has been widely used for research of postural stability for over 30 years.(12) This 
purpose of this test is to assess the competency of the subject’s three modes of sensing 
equilibrium: vision, proprioception, and vestibular/inner ear sensors.  
 
The SOT consists of 6 conditions, during which the subject will try to maintain their equilibrium. 
Each trial takes 20 seconds to perform, and each is performed in triplicate for a total of 18 
trials. These 6 conditions test the three inputs to the subjects sense of equilibrium: vision, 
somatosensory, and vestibular. By having the subject close their eyes, by allowing the footplate 
to change in pitch, or by altering the visual stimulus, each of these inputs can be tested alone 
and in combination with the others. 
 
The 6 conditions are: (1) eyes open, stable support; (2) eyes closed, stable support; (3) sway-
referenced vision, stable support; (4) eyes open, sway-referenced support; (5) eyes closed, 
sway-referenced support; and (6) eyes open, sway-referenced vision, and sway-referenced 
support. 
 
Each condition is given a score out of 100 and a composite score is calculated by the software 
 
Details of the LOS test (Visits 1, 14, 15 and 16) 
The purpose of this test is to determine the distance that the patient is able to voluntarily 
displace their center of pressure in different directions without losing balance.  
 
Subjects will stand on the CDP platform with the arms at their sides. The test involves moving a 
pictogram, which represents their COG,  to targets indicated on the visual display. There are 
eight targets distributed around the subject and the subject’s performance in modulating their 
COG to meet the targets will be measured by software. 

 
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Study Intervention 
Details of the rehabilitation exercises (Visits 2 to 13) 
The rehabilitation exercises will employ the CDP instrument and visual feedback. Subjects will 
perform a series of exercises in which they will have to modulate their centre of gravity (COG), 
by shifting their weight side-to-side or front-to-back. By shifting their weight, subjects will direct 
a pictogram representing their COG to targets presented on the interactive display. All patients 
will receive the same series of exercises, except to account for the side, right or left, of the 
vestibular deficit (ie. the exercises for someone with a deficit on their right side will be a mirror 
image relative to someone with a deficit on their left side). 
 
Over the course of the 12 sessions, the exercises presented to the subjects will become 
progressively more difficult in order to promote global balance improvement by brain, 
proprioceptive, visual, and vestibular compensation. 
 
Study Schedule 
Visit 1 (75 minutes) – Initial assessment 
• Obtain written informed consent 
• Verbal health check, any illness/injury that might affect performance? 
• Questionnaires that measure disability caused by imbalance and risk of falling 
o Dizziness Handicap Inventory (DHI) 
o Falls Efficacy Scale-International (FES-I)  
o Activity-specific Balance Confidence Scale (ABC scale) 
• CDP assessment 
o Sensory organization test (SOT) 
o Limits of Stability (LOS) test 
 
Visit 2-13 (45 minutes) – Rehabilitation exercise 
• Verbal health check, any illness/injury that might affect performance? 
• Rehabilitation exercises 
 
Visit 14-16 (75 minutes) – Post-intervention assessment and follow up 
• Verbal health check, any illness/injury that might affect performance? 
• Questionnaires that measure disability caused by imbalance and risk of falling 
o Dizziness Handicap Inventory (DHI) 
o Falls Efficacy Scale-International (FES-I)  
o Activity-specific Balance Confidence Scale (ABC scale) 
• CDP assessment 
o Sensory organization test (SOT) 
o Limits of Stability (LOS) test 
 
Safety 

 
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When the participants are using the CDP instrument, both for assessment and rehabilitation, 
they will be secured by a harness at all times to prevent falls. Participants will be informed that 
they may stop the testing or training or withdraw from the study at any time. 
 
Time to participate 
This study will involve 16 biweekly visits to the clinic. Sessions 1, 14, 15 and 16 are expected to 
take 75 minutes. The 12 rehabilitation sessions are expected to take 45 minutes. In total, the 
time to participate for the entire study is estimated to be 13 hours. The rehabilitation sessions 
will take place over a period of approximately 7 weeks with addition follow up visits at 6 weeks 
and 3 months after the post-intervention assessment. 
 
Missed sessions 
Missed sessions will be rescheduled so that subjects may complete the full course of 12 
sessions. Subjects that have not completed the full 12 sessions by 10 weeks after their first visit 
will be scheduled for the post-intervention assessment. Subjects that have not completed the 
post-intervention assessments within 12 weeks will be excluded from further data collection 
and analysis. 
 
Follow up sessions will be schedule for 6 weeks (+/- 1 week) and 3 months (+/- 2 weeks) after 
the post-intervention assessment (visit 14).  
 
Study data and measurements 
Demographic and medical history 
Demographic and medical history data will be extracted from the patient charts. 
Data will be recorded in a Microsoft Excel database designed for this purpose. The PI will 
monitor the study and perform quality controls of the entered data and ensure the subject’s 
privacy and rights are protected. 
 
Demographic 
• Age 
• Gender 
Vestibular screening or medical history 
• Vestibular diagnosis 
• Result of tests 
o cVEMP 
o oVEMP 
o vHIT 
o Caloric response 
 
Outcome measurements 
Each of the following will be measured during visits 1, 14, 15 and 16 
1. Sensory organization test (SOT) composite score; 
2. Mean value of CDP SOT conditions 1 through 6: calculated by software; 

 
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3. CDP SOT vestibular contribution value: (mean value of condition 5/mean value of 
condition 1) × 100; 
4. Mean value of directional control of limits of stability in CDP: calculated by software; 
5. Mean endpoint excursion value and maximum excursion point of limits of stability in 
CDP: calculated by software; 
6. Dizziness handicap inventory (DHI) score  
7. FES-I score  
8. Activity-specific Balance Confidence Scale  
 
Statistical analysis 
We will enrol a convenience sample of patients previously seen in the Principal Investigator’s 
clinic in order to collect preliminary efficacy data and assess the feasibility of a larger trial. 
 
For continuous variables, we will report the mean, median, standard deviation, and 
interquartile range. For categorical variables, we will report the percentage of subjects in each 
category. 
 
Paired analysis by Wilcoxon signed-rank test will be used to compare initial scores to those 
post-intervention. 
 
 
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