The effect of vestibular stimulation on postural control in people with bilateral vestibulopathy
The effect of noisy galvanic vestibular stimulation on postural control in people with bilateral vestibulopathy
Auckland University of Technology
31 participants
Jun 14, 2024
Interventional
Conditions
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.
Eligibility
Inclusion Criteria12
- 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.
Exclusion Criteria8
- 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
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Interventions
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.
Locations(1)
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ACTRN12623000444684