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Trial registered on ANZCTR


Registration number
ACTRN12623000444684p
Ethics application status
Not yet submitted
Date submitted
18/04/2023
Date registered
1/05/2023
Date last updated
1/05/2023
Date data sharing statement initially provided
1/05/2023
Type of registration
Prospectively registered

Titles & IDs
Public title
The effect of vestibular stimulation on postural control in people with bilateral vestibulopathy
Scientific title
The effect of noisy galvanic vestibular stimulation on postural control in people with bilateral vestibulopathy
Secondary ID [1] 308044 0
None
Universal Trial Number (UTN)
U1111-1283-0269 27/9/22
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Bilateral vestibulopathy 327732 0
Condition category
Condition code
Ear 324801 324801 0 0
Other ear disorders
Neurological 324802 324802 0 0
Other neurological disorders
Physical Medicine / Rehabilitation 324803 324803 0 0
Physiotherapy

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Vestibular rehabilitation plus noisy galvanic vestibular stimulation (nGVS)
Vestibular rehabilitation will be for 45 minutes twice a week for 4 weeks and carried out in face to face treatments by a registered Physiotherapist.
Vestibular rehabilitation will include exercises promoting:
• Vestibular adaptation (strengthening residual vestibular afferent information) eg. Visual fixation on an object while moving head (x1 exercise), Visual fixation on moving object with head moving in opposite direction (x2 exercise)
• Vestibular substitution (strengthening compensatory strategies) eg. Active eye and head movements between stationary targets, imaginary visual fixation with eyes closed, neck proprioception cueing
• Balance and gait exercises eg. Multisensory balance training, training limits of stability, task specific training with modification of sensory inputs (vestibular, visual, somatosensory)
• Reversing the effects of detraining/ sedentary lifestyle eg. Walking, stationary cycling, stationary rowing
During 30 minutes of the vestibular rehabilitation participants will receive nGVS applied at parameters that have been shown to optimise the participant's postural control during an assessment prior to the clinical study.
Machine: DC stimulator mobile
electrodes: 5cm x 5cm carbon rubber
electrode skin interface: saline soaked sponge
Waveform: Gaussian white noise
Frequency band: either 0.01- 10 or 0-30 depending on participant responsiveness
Amplitude: the subthreshold amplitude that improves lateral gait variability the most.
Adherence will be measured by participant attendance sheets
In this crossover trial there is a 12 week washout period between treatment periods
The order of treatment will be determined by random number generator. 50% of participants will receive the intervention treatment first, 50% of participants will receive the control treatment first.
Intervention code [1] 325872 0
Rehabilitation
Comparator / control treatment
Vestibular rehabilitation plus sham stimulation
Vestibular rehabilitation will be for 45 minutes twice a week for 4 weeks and carried out in face to face treatments by a registered Physiotherapist
Vestibular rehabilitation will include exercises promoting:
• Vestibular adaptation (strengthening residual vestibular afferent information)
• Vestibular substitution (strengthening compensatory strategies)
• Balance and gait exercises
• Reversing the effects of detraining/ sedentary lifestyle
During 30 minutes of the vestibular rehabilitation participants will receive sham nGVS applied at 0mA
Machine: DC stimulator mobile
electrodes: 5cm x 5cm carbon rubber
electrode skin interface: saline soaked sponge
Waveform: Gaussian white noise
Frequency band: either 0.01- 10 or 0-30 depending on participant responsiveness
Amplitude: nGVS will be ramped up to the optimum amplitude as determined in the optimisation assessment for 30 seconds and then return to 0mA for a further 29mins 30 seconds.
Adherence will be measured by participant attendance sheets
Control group
Placebo

Outcomes
Primary outcome [1] 334503 0
Assessment of Gait stability- coefficient of variance of step width (CV step width) as measured by 3D gait analysis (Optitrack flex-13)
Timepoint [1] 334503 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2
Primary outcome [2] 334504 0
Assessment of Standing postural control: mean centre of pressure velocity as measured by VALD portable forceplate
Timepoint [2] 334504 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2
Secondary outcome [1] 420912 0
Gait speed, as measured by 3D gait analysis (Optitrack flex-13)
Timepoint [1] 420912 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2
Secondary outcome [2] 420913 0
Centre of pressure sway, as measured by the VALD portable forceplate
Timepoint [2] 420913 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2
Secondary outcome [3] 420914 0
The functional impact of oscillopsia on day to day life: Oscillopsia functional impact scale (OFIS)
Timepoint [3] 420914 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2
Secondary outcome [4] 420915 0
The functional impact of Dizziness on quality of life: Dizziness handicap inventory (DHI)
Timepoint [4] 420915 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2
Secondary outcome [5] 420916 0
Quality of gait during functional tasks: Functional gait assessment (FGA)
Timepoint [5] 420916 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2
Secondary outcome [6] 421281 0
Step length, as measured by 3D gait analysis (Optitrack flex-13)
Timepoint [6] 421281 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2
Secondary outcome [7] 421283 0
Step time, as measured by 3D gait analysis (Optitrack flex-13)
Timepoint [7] 421283 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2
Secondary outcome [8] 421284 0
Step length variability as measured by 3D gait analysis (Optitrack flex-13)
Timepoint [8] 421284 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2
Secondary outcome [9] 421286 0
Centre of pressure sway path length, as measured by the VALD portable forceplate
Timepoint [9] 421286 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2
Secondary outcome [10] 421287 0
Centre of pressure sway area as measured by the VALD portable forceplate
Timepoint [10] 421287 0
Pre-commencement and post-completion of treatment block 1
Pre-commencement and post-completion of treatment block 2
3 month follow-up post-completion of treatment block 2

Eligibility
Key inclusion criteria
a. Probable diagnosis of Bilateral vestibulopathy (BVP) (determined by a neurologist, ENT consultant, GP, audiologist or specialist vestibular clinic).
b. Self-reported unsteadiness when walking
plus either
• oscillopsia during walking or quick head/body movements or
• worsening of balance in darkness or on uneven ground.
c. No symptoms when sitting or lying under static conditions (self-reported)
d. Aged between 18 and 80 years

After consent participants will undertake a vestibular assessment to ensure they meet the clinical criteria for BVP of

Bilaterally reduced vestibular function indicated by either
a. Horizontal angular VOR gain (<0.8) measured by video Head Impulse Testing or
b. Reduced caloric response (sum of bithermal maximal peak slow phase velocity on each side <6 degrees per second).
Participants who do not meet the clinical criteria for BVP will finish the study here.
Minimum age
18 Years
Maximum age
80 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Participants will be excluded from the study if they have:
a. They have any evidence of CNS involvement including hereditary ataxias or brain stem/ cerebellar abnormalities, or any central eye movement abnormalities or previously diagnosed neurological condition. (Participants will be screened by staff at the clinics they are recruited via).
b. Unable to stand independently for 5 minutes or ambulate for 10m without aid
c. Individuals who are medically required to restrict their head movement
d. Metal implants in the head or neck such as cochlea implants, clips, coilings, shunts or endoprosthesis
e. Pacemaker or implanted defibrillator
f. Previous open skull surgery or trepanation
g. Broken skin in the region of electrode placement

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation will be determined by a random number generator. The project manager will hold the allocation schedule and set up the stimulation machines appropriately. The nGVS machines are designed for research with a sham setting. Participants and treating physiotherpists will not know which treatment they are receiving.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Allocation is generated by random number generator, half the participants will receive vestibular rehabilitation + nGVS first, half the participants will receive vestibular rehabilitation plus sham nGVS first.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Linear mixed models will be used to evaluate the primary null hypotheses that the velocity of the centre of pressure trajectory and step width variability are equal across real and sham nGVS interventions. The models will estimate the mean difference in outcomes across interventions at the post-intervention timepoint while accounting for pre-intervention differences, and between/within participant variance. The presence of carry-over effects will be tested by including an interaction term between variables denoting period and intervention assignment. In the case of significant carry-over effects, results from each period will be reported separately. Estimated means and mean differences will be reported along with their 95% confidence interval. Statistical significance will be set at 5%. An intention to treat (ITT) dataset will be used for an assumption free primary analysis. Missing values will be examined and a sensitivity analysis consisting of best/worst case scenarios will be presented. In the case of significant protocol deviations, a secondary analysis based on instrumental variable modelling will be conducted to estimate the complier average causal effect. For the secondary outcome measures, similar analyses will be replicated. To account for multiple testing, the type I error rate will be controlled at 5% by applying a Benjamini-Hochberg procedure across all the secondary outcome measures.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
22/05/2023
Actual
Date of last participant enrolment
Anticipated
1/02/2025
Actual
Date of last data collection
Anticipated
31/10/2025
Actual
Sample size
Target
31
Accrual to date
Final
Recruitment outside Australia
Country [1] 25400 0
New Zealand
State/province [1] 25400 0
Auckland

Funding & Sponsors
Funding source category [1] 312301 0
Government body
Name [1] 312301 0
Health Research Council of New Zealand
Country [1] 312301 0
New Zealand
Primary sponsor type
University
Name
Auckland University of Technology
Address
Auckland University of Technology
90 Akoranga Drive
Northcote
Auckland 0627
Country
New Zealand
Secondary sponsor category [1] 315472 0
None
Name [1] 315472 0
Address [1] 315472 0
Country [1] 315472 0

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 311670 0
Northern A Health and Disability Ethics Committee of New Zealand
Ethics committee address [1] 311670 0
Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140
Ethics committee country [1] 311670 0
New Zealand
Date submitted for ethics approval [1] 311670 0
04/05/2023
Approval date [1] 311670 0
Ethics approval number [1] 311670 0

Summary
Brief summary
Bilateral vestibulopathy (BVP) is a diagnosis where the neural signals that travel from the vestibular apparatus to the central nervous system are either absent or significantly reduced on both sides. This leads to imbalance, oscillopsia (visual blurring with head movement) and difficulty walking in darkness or over uneven surfaces. Vestibular hair cells and neurons do not regenerate, and there is currently no established remedial medical treatment for BVP once damage has occurred. An emerging treatment option is noisy galvanic vestibular stimulation (nGVS). A weak vestibular signal is boosted by a small nGVS signal, enhancing vestibular system performance, and improving balance. Most trials that have investigated the use of nGVS in people with BVP to date demonstrate positive, but varied, effects to improve postural instability in standing or walking. These studies are during a single session or two session trials. nGVS was a feasible adjunct to vestibular rehabilitation in further study, however, the efficacy of nGVS delivered as a rehab treatment is not yet established. This two-period randomised crossover trial will investigate whether people with bilateral vestibulopathy undertaking vestibular rehabilitation augmented with nGVS improve their postural stability more than vestibular rehabilitation with sham nGVS. We hypothesise that vestibular rehabilitation plus nGVS will result in improved postural control after four weeks of treatment compared to vestibular rehabilitation and sham stimulation.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 121934 0
Prof Denise Taylor
Address 121934 0
Auckland University of Technology
90 Akoranga Drive
Northcote
Auckland 0627
Country 121934 0
New Zealand
Phone 121934 0
+64 09 921 9680
Fax 121934 0
Email 121934 0
denise.taylor@aut.ac.nz
Contact person for public queries
Name 121935 0
Mrs Ruth McLaren
Address 121935 0
Auckland University of Technology
90 Akoranga Drive
Northcote
Auckland 0627
Country 121935 0
New Zealand
Phone 121935 0
+64 09 921 9999
Fax 121935 0
Email 121935 0
ruth.mclaren@aut.ac.nz
Contact person for scientific queries
Name 121936 0
Mrs Ruth McLaren
Address 121936 0
Auckland University of Technology
90 Akoranga Drive
Northcote
Auckland 0627
Country 121936 0
New Zealand
Phone 121936 0
+64 09 921 9999
Fax 121936 0
Email 121936 0
ruth.mclaren@aut.ac.nz

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
De identified study data from assessment tools and outcome measures
When will data be available (start and end dates)?
Immediately following publication for a period of five years. Maori data will only be made available with the agreement of Maori
Available to whom?
Other researchers on reasonable request at the discretion of the primary investigator
Available for what types of analyses?
no limitations
How or where can data be obtained?
Data will be made available on request to the principal investigator denise.taylor@aut.ac.nz


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.