Dose of Vestibular Rehabilitation Required for Clinical Improvements in Individuals With Vestibular Hypofunction.
Phase: NA
Conditions: Vestibular Disorder
Sponsor: George Washington University

Title: Dose of Vestibular Rehabilitation Required for Clinical Improvements in 
Individuals With Vestibular Hypofunction 
NCT04851184  
Date Approved: 11/13/23 
Protocol and Statistical Analysis Plan. 
 
 

Description: 
When a potential subject is identiﬁed, the subject will be screened for appropriateness of 
inclusion for this study. The screen will include: questions regarding history of concussion, 
questions related to type of vestibular symptoms (dizziness, room spinning, imbalance, 
etc.), an oculomotor screen for gaze and spontaneous nystagmus, a Head Impulse Test, 
and a Dynamic Visual Acuity Test. Subjects will be excluded if they have a gaze nystagmus 
in room light, a convergence disorder detected with oculomotor screening, or are currently 
enrolled in vision therapy, as an adjunct treatment. These ﬁndings would indicate that the 
patient’s diagnosis falls in a category not included in this study, or that visual disturbances 
would be a confounding factor during this study. If, following screening, the potential 
subject is determined to be appropriate for this study, informed consent will be obtained 
after the potential subject has all their questions answered to their satisfaction.  
  
After informed consent has been obtained from a recruited subject, those with Unilateral 
Vestibular Hypofunction (UVH) will be asked to perform a 4-week intervention, while those 
with Bilateral Vestibular Hypofunction (BVH) or those post-concussion will each be asked 
to perform a 12-week intervention. Those with UVH will undergo a shorter intervention due 
to strong evidence that neural adaptation occurs much more quickly (usually 4 weeks) than 
those with BVH and history of concussion.9,10,17-19 The intervention will consist of physical 
therapy visits combined with a home program of speciﬁc vestibular exercises. Each subject 
will be asked to attend physical therapy visits at least one time per week throughout the 4- 
or 12-week period.  
  
Assessments will be performed on all groups and consist of a combination of vestibulo-
ocular assessment, balance and clinical functional outcome measures, a survey regarding 
the usability of the virutal reality device, and surveys of subject satisfaction (see table 
below).  Balance and functional outcome measures will include the Dizziness Handicap 
Inventory (DHI), Visual Analog Score (VAS) of symptoms, Visual Vertigo Analogue Scale, 
Functional Gait Assessment (FGA), Activities-Speciﬁc Balance Conﬁdence (ABC) Scale, 
and the modiﬁed Clinical Test of Sensory Organization and Balance (CTSIB). Vestibulo-
ocular assessment will be conducted using Frenzel goggles and will include tests of: 
Spontaneous Nystagmus, Gaze-evoked Nystagmus, Smooth Pursuit, Doll's Eyes, Head 
Impulse, Dynamic Visual Acuity, and Dix-Hallpike. Subjects will also perform the X1 
vestibulo-ocular reﬂex exercise using the virtual reality device for a maximum of 30 
seconds in incrementing levels. The X1 involves focusing on a stationary letter while 

moving the head back and forth or up and down at approximately 1 cycle per second. If at 
any point the patient experiences an increase of 3 points on a scale of 0 (no dizziness) to 10 
(worst imaginable) of symptoms, exercise in the device will stop. For instance, if a subject 
begins with a rating of 1/10 dizziness, they are instructed to stop if their symptoms reach a 
4/10 or greater. Additionally, at weeks 4, 8 and 12, surveys would ask about patient comfort 
and level of satisfaction with regards to the intervention protocol. At the conclusion of their 
participation, subjects will be asked to complete the System Usability Scale to determine 
the usability of the virtual reality device. On each day of testing, subjects are free to skip 
any tests or questions they do not want to perform. 
Subjects are randomly assigned to the usual rehabilitation or intervention group based on 
each of the following diagnostic categories: Unilateral Vestibular Hypofunction, Bilateral 
Vestibular Hypofunction, and post-Concussion. Therefore, there will be a total of three (3) 
usual rehabilitation and three (3) intervention groups (see table below). Additionally, there 
will be a seventh group consisting of healthy control subjects that have no history of 
vestibular symptoms. 
Each of the three usual rehabilitation groups will perform usual physical therapy including 
a home VOR retraining exercise program without the use of the virtual reality headset. The 
VOR exercise (commonly referred to as the "X1" exercise) will involve holding a piece of 
paper at arm’s length at eye level with an “X” written on the paper. The patient will then 
rotate their head right and left, reaching 30-45 degrees of excursion in each direction, while 
attempting to keep their eyes focused on the letter “X”. They will then repeat this procedure 
in the up and down direction. The complexity of the background and duration of exercise 
will be increased via instruction from the therapist. They will be asked to keep a log of their 
exercises to assess patient reported compliance. In general, Subjects will be instructed to 
begin performing the exercises for a duration of 30 seconds at the fastest rate possible so 
that the ‘X’ remains in focus and their symptoms are tolerable. As the days progress, 
Subjects should increase the duration and speed of the exercises as they are able, until 
they can perform each set for 2 minutes at approximately 1 Hz (1 head shake per second) 
without any aggravation of symptoms.  Once the patient has reached this point, the 
complexity of exercise background will be increased. Once the background complexity is 
increased, the patient will be instructed to again start at 30 second exercise bout durations 
and gradually increase until they are able to achieve 120 seconds without increase in 
symptoms. Once the patient achieves 120 seconds without symptoms, they will repeat the 
combination of exercise duration and background complexity increase in the standing 
position. To perform in a standing position, the patient will be instructed to stand in the 
corner of a room with a stable chair in front of them to provide a safe environment in which 
to perform the exercise and by preventing limit chance of falling. 

  
Subjects in the three intervention groups will be asked to perform the same type of 
exercises as the usual rehabilitation group, but using a virtual reality device that will be 
issued to the patient for home use. Subjects will use a custom designed program to 
perform the exercises using a commercially available virtual reality device (no specialized 
hardware or additions to the commercially available device will be performed). Subjects 
will be instructed on the ﬁrst day in how to operate the Virtual Reality Vestibular 
Rehabilitation (VRVR) program and how to properly perform the exercises. The VRVR device 
and software will simulate a virtual reality ‘room’ with an ‘X’ ﬁxed in front of a wall. Six 
different background complexities will be offered: 1) plain grey wall, 2) checker board wall, 
3) tight houndstooth wall, 4) visual ﬂow from top to bottom, 5) visual ﬂow to the direction of 
hypofunction, and 6) visual ﬂow moving away from the nose bilaterally. Exercise sessions 
will start seated upright in a chair and will progress to standing per the home exercise 
protocol. The system will prompt the patient to begin the exercise and will automatically 
log the frequency and duration of exercise performed. The system will ask the patient to 
rate the severity of their symptoms on a 0-10 scale before and after each bout of exercise. 
Subjects’ instruction regarding initial dose and progression will be identical to those given 
in the usual rehabilitation group. In addition to the general satisfaction survey given to the 
usual rehabilitation group, Subjects in the intervention group will also be asked to 
complete a survey regarding comfort, usability, and satisfaction with the VR instrument and 
with the VRVR software. Subjects will be asked to bring their device with them to their 4 
week, 8 week, and 12 weeks appointment to transfer their de-identiﬁed data and to insure 
integrity of the data and device. Subjects will be asked to return the device at the end of the 
intervention period. 
  
Per patient and therapist discretion, additional physical therapy visits may be scheduled to 
aid in patient understanding of exercise progression protocol, assess correct performance 
of exercise (with or without virtual reality device). Non-study related physical therapy visits 
may be scheduled between sessions in order to address impairments unrelated to 
vestibulo-ocular deﬁcits. These may include interventions to address musculoskeletal 
deﬁcits or other balance related impairments. Any additional sessions of physical therapy 
will be reported in order to determine possible confounding information. 
  
There will be an additional group of healthy control subjects that will be tested for only one 
day. Healthy subjects will be recruited through ﬂyers, approved email lists, and word of 

mouth in the general public. This healthy control group will perform the same tests as the 
other groups perform on Day 1. This group will be used to compare outcomes of usual 
rehabilitation and intervention groups, to the function of those without disorders of 
vestibular function. 
Statistical Analysis Plan:  
Similarities in subject group characteristics will be determined using a one-way ANOVA. 
Characteristics will include: Age, height, weight, questionnaire scores, and functional 
outcome scores. A two-way Repeated-Measures ANOVA will be used for analysis of 
functional outcomes measures for each assessment time (0,4,8, and 12 weeks) for each 
group of Unilateral Vestibular Hypofunction, Bilateral Hypofunction Dysfunction, and Post 
Concussion Syndrome compared to their respective controls. A one-way ANOVA will be 
used to compare functional outcome measures of all groups on the ﬁnal day of treatment 
only to healthy control performance. A multiple regression analysis will be used to 
determine the relationship between the exercise parameters and changes in outcome 
measures. 
  
Group 
Subgroup 
Home 
Program 
Intervention 
Visits 
Test performed by all 
groups 
  
Unilateral 
Vestibular 
Hypofunction 
Usual 
rehabilitation 
Usual 
Physical 
Therapy with 
patient self-
reported 
compliance 
log 
1)    Initial 
Evaluation 
2)    4-Weeks 
post 
Questionnaires 
    Dizziness 
Handicap Inventory 
    Activities-
Speciﬁc Balance 
Conﬁdence Scale 
    Visual Vertigo 
Analog Scale 
    Visual Analog 
Score of symptoms 
Functional 
Assessment 
Intervention 
Home 
exercises 
using Virtual 
Reality 
Vestibular 
Rehabilitation 
1)    Initial 
Evaluation 
2)    4-Weeks 
post 
Usual 
rehabilitation 
Usual 
Physical 
1)    Initial 
Evaluation 

Bilateral 
Vestibular 
Hypofunction 
Therapy with 
patient self-
reported 
compliance 
log 
2)    4-Weeks 
post 
3)    8-Weeks 
post 
4)    12-weeks 
post 
     Functional Gait 
Assessment 
    modiﬁed Clinical 
Test of Sensory 
Organization and 
Balance 
     Cervical Joint 
Position Error Test 
Vestibulo-ocular 
assessment using 
Frenzel goggles: 
    Spontaneous 
Nystagmus 
      Gaze-evoked 
Nystagmus 
      Smooth Pursuit 
      Doll's Eyes 
      Head Impulse 
Test 
      Dynamic Visual 
Acuity 
      Dix-Hallpike. 
VRVR Assessment 
      30 seconds of 
exercise, 
incrementing 
background 
complexity until an 
increase of 3/10 
symptoms 
occurs Device 
Intervention 
Home 
exercises 
using Virtual 
Reality 
Vestibular 
Rehabilitation 
1)    Initial 
Evaluation 
2)    4-Weeks 
post 
3)    8-Weeks 
post 
4)    12-weeks 
post 
Post-
Concussion 
Syndrome 
Usual 
rehabilitation 
Usual 
Physical 
Therapy with 
patient self-
reported 
compliance 
log 
1)    Initial 
Evaluation 
2)    4-Weeks 
post 
3)    8-Weeks 
post 
4)    12-weeks 
post 
Intervention 
Home 
exercises 
using Virtual 
Reality 
Vestibular 
Rehabilitation 
1)    Initial 
Evaluation 
2)    4-Weeks 
post 
3)    8-Weeks 
post 
4)    12-weeks 
post 

Healthy 
Control 
Control 
None 
1)    Single Visit 
Usability System 
Usability Scale