CONCURRENT VESTIBULAR-POSTURAL TRAINING PROMOTES POSTURAL REFLEXES AND STABILITY

K. Appiah-Kubi¹, A. Galgon², R. Tierney³, R. Lauer³, W.G. Wright³

¹Clarkson University, Physical Therapy, Potsdam, United States, ²Saint Joseph’s University, Physical Therapy, Philadelphia, United States, ³Temple University, Health & Rehabilitation Sciences Department, Philadelphia, United States

Background: Vestibular rehabilitation is effective in alleviating vestibular symptoms and improves postural control through sensory reweighting mechanisms. As part of the mechanisms, vestibular activation exercises through headshaking influence postural and vestibulo-motor responses. However, no study has employed a concurrent headshake and weight shift training (Concurrent HS-WST) to modify the pathways of vestibular reflexes for a more effective rehabilitation outcome.

Purpose: The purpose of the study was to assess sensory reweighting of postural control processing and changes in vestibular-motor responses after Concurrent HS-WST.

Methods: Forty-two young healthy individuals (23.0+3.9years; 1.6+0.1m) were randomly assigned into four groups: (i) No training (CTL), (ii) weight shift training (WST) with no headshake (NHS), (iii) WST with active horizontal headshake (HHS), or (iv) WST with vertical HS (VHS). Training was performed for 20 mins for five consecutive days using the training module of the NeuroCom^®. All groups performed baseline- and post-assessments on the sensory organization test (SOT) and ramp perturbation device with electromyography (EMG) sensors placed on postural muscles. Significance was set at p<0.05.

Results: Training resulted in significant decreases in lower limb muscle activation, which suggests recalibration of the vestibulo-spinal reflex(VSR). This was most evident by a decrease in mean medial gastrocnemius (MG) activation post-training as recorded by the SOT assessment (p= 0.03) in the VHS group. This decrease was predominantly found in SOT conditions 4, 5 and 6 indicating a visual, vestibular and visual-vestibular reweighting. A decreased onset amplitude in the neck and lower limb muscles in the headshake groups (i.e., HHS and VHS) suggest descending vestibular reflexes to postural muscles increased in efficiency. Specifically, for the ramp trials, the left cervical erector spinae (change = 64.15mv,p= 0.04) and right MG (change = 2.45mv,p= 0.03) showed a decrease in onset amplitude following the training in the VHS group. Similarly, there was a decreased onset amplitude in the left rectus femoris (change = 7.27mv,p= 0.02) for the HHS group.

Conclusions: Concurrent HS-WST modifies vestibular-dependent responses following the training intervention. The faster activation responses in the postural muscles suggest vestibular adaptation and or habituation of the vestibulo-colic reflex and VSR which would improve postural balance.

Implications: The findings may have implications for future development of vestibular rehabilitation protocols for neurological patients such as those with mild traumatic brain injuries, vestibular impairment, stroke and multiple sclerosis.

Funding acknowledgements: This study was funded, in part, by the Temple University doctoral dissertation completion grant.

Keywords:
Headshake activity
weight shift training
vestibular reflexes

Topics:
Neurology

Did this work require ethics approval? Yes

Institution: Temple University

Committee: Research Administration IRB

Ethics number: 23436