This is an assessor-blinded neurophysiological study. Participants will be randomly assigned to a perturbation-based training (PBT) or a walking (control) group. Changes in postural stability and neurophysiology in the brain following PBT compared to walking exercise without perturbation will be investigated.
A total of 88 participants will be randomly assigned to two groups receiving perturbation-based training (PBT) or walking exercise without perturbation (control). Written informed consent will be obtained from participants prior to the baseline assessment. The study will be reported and conducted in line with the CONSORT statement. Participants will be recruited via convenience sampling in the local community. Both groups will receive two sessions of treadmill walking at their comfortable speed. Perturbations will be induced during treadmill walking only for the PBT group. As informed from previous literature, two sessions of PBT could have improved postural stability for up to 1.5 years. Between-group differences in behavioural and MRI findings will be examined before and after training to identify training-induced changes in postural stability, brain structures, and functional connectivities. Retention of the changes in the postural stability will be assessed four months after the training period. Incidents of falls will be followed up for 12 months after training.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
88
It will be a two-session training with each session lasting for approximately an hour. Perturbations will be induced during treadmill walking. Participants will be instructed to recover their balance and continue walking after the perturbations.
It will be a two-session training with each session lasting for approximately an hour. The same training duration and format will be used as the PBT group, except that no perturbations will be induced during the treadmill walking.
The Hong Kong Polytechnic University
Hong Kong, Hong Kong
RECRUITINGGray matter density in arbitrary units by structural Magnetic Resonance Imaging
Gray matter density at cortical and subcortical regions will be taken by structural MRI. The regions of interest include the cerebellum, basal ganglia, thalamus, hippocampus, inferior parietal cortex, occipital and frontal lobe.
Time frame: pre-intervention, and within 1-week after the intervention
Brain connectivity derived from the correlation between the Blood-oxygen-level-dependent (BOLD) signals from different brain regions in arbitrary units obtained during functional MRI
BOLD signal reflecting the brain connectivity during rest will be taken through resting-state functional MRI, during which subjects are instructed to relax with eyes open, to let their mind wander, and not think of anything specific. The regions of interest include the cerebellum, basal ganglia, thalamus, hippocampus, inferior parietal cortex, occipital and frontal lobe.
Time frame: pre-intervention, and within 1-week after the intervention
Postural stability
Postural stability at the recovery steps after the perturbation will be calculated as the distance between the absolute CoM position in an anteroposterior direction relative to the closest edge of Base of Support (BoS) and normalized by foot length. The absolute CoM position and BoS position will be traced by the motion capture system synchronized with the force plates embedded underneath the slip-treadmill belts.
Time frame: pre-intervention, within 1 week after intervention and 4 months after intervention
Number of laboratory-falls
The number of laboratory-falls following perturbation during assessment sessions will be recorded. A fall will be defined if there is a body-weight support of 30% or more from the full-body safety harness.
Time frame: pre-intervention, within 1 week after intervention and 4 months after intervention
Number of real-life-falls
The number of real-life falls in 12 months after randomization will be recorded. Fall circumstances and related injuries will be enquired via phone contact. A fall is defined as an event resulting in a person unintentionally coming to rest on the ground or other lower level, not as the result of a major intrinsic event e.g., syncope, stroke, seizure, or overwhelming hazard such as an earthquake.
Time frame: 1 month, 2 months, 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, 10 months, 11 months, and 12 months after the intervention.
Step time of the recovery steps in milliseconds (ms)
Step time of the recovery steps after the perturbation will be traced by the motion capture system synchronized with the force plates embedded underneath the slip-treadmill belts.
Time frame: pre-intervention, within 1 week after intervention and 4 months after intervention
Step length of the recovery steps in millimeters (mm)
Step length of the recovery steps after the perturbation will be traced by the motion capture system synchronized with the force plates embedded underneath the slip-treadmill belts.
Time frame: pre-intervention, within 1 week after intervention and 4 months after intervention
Trunk angle
The trunk angle at the recovery steps after the perturbation will be calculated as the angle between the trunk segment with the vertical line. The position of the trunk will be traced by the motion capture system synchronized with the force plates embedded underneath the slip-treadmill belts.
Time frame: pre-intervention, immediately after the intervention, 1 week after intervention and 4 months after intervention
Hip height in millimeters (mm)
Hip height at the recovery steps after the perturbation will be calculated as the vertical distance from the ground to the midpoint of bilateral hips and normalized by the subjects' height. The positions of bilateral hips will be traced by the motion capture system synchronized with the force plates embedded underneath the slip-treadmill belts.
Time frame: pre-intervention, immediately after the intervention, 1 week after intervention and 4 months after intervention
Responsive postural adjustment upon translation
Responsive postural adjustment upon translation will be assessed through Motor Control Test on a computerized dynamic posturography (Bertec® Balance Advantage® Dynamic System, Bertec® Corporation, Columbus, USA). During the Motor Control Test, participants will be requested to maintain their standing balance in response to 18 translations of the standing platform in either forward or backward direction with small, medium or large amplitudes. Weight symmetry, latency of reaction, and amplitude of sway will be recorded. Full-body safety harness will be worn throughout the tests to protect the participants from any potential loss of balance.
Time frame: pre-intervention, immediately after the intervention, 1 week after intervention and 4 months after intervention
Responsive postural adjustment upon tilting
Responsive postural adjustment upon tilting will be assessed through Adaptation Test on a computerized dynamic posturography (Bertec® Balance Advantage® Dynamic System, Bertec® Corporation, Columbus, USA). During the Adaptation Test, the force platform will either tilt up or down for a total of 10 repetitions. Sway energy will be recorded. Full-body safety harness will be worn throughout the tests to protect the participants from any potential loss of balance.
Time frame: pre-intervention, immediately after the intervention, 1 week after intervention and 4 months after intervention
Muscle activation onset latency in milliseconds
Muscle latency will be collected from trunk and leg muscles using electromyography.
Time frame: pre-intervention, immediately after the intervention, 1 week after intervention and 4 months after intervention
Balance confidence
Balance confidence will be measured with the Chinese version of the shortened version of Activities-Specific Balance Confidence Scale (ABC-6). The scale value is from 0 to 100, with higher values representing higher balance confidence.
Time frame: pre-intervention, immediately after the intervention, 1 week after intervention and 4 months after intervention, and at the last prospective fall follow-up
Cognitive flexibility and executive function
Cognitive flexibility and executive function assessed by Trial Making Tests A and B (in the unit of seconds)
Time frame: pre-intervention, immediately after the intervention, 1 week after intervention, and 4 months after intervention
Functional lower body strength
Functional lower body strength will be assessed by Five-time Sit to Stand Test (in the unit of seconds)
Time frame: pre-intervention, immediately after the intervention, 1 week after intervention, and 4 months after intervention
Dynamic balance
Dynamic balance will be assessed by Alternate Step Test (in the unit of seconds)
Time frame: pre-intervention, immediately after the intervention, 1 week after intervention, and 4 months after intervention
Mobility
Mobility will be assessed by Timed Up and Go test (in the unit of seconds).
Time frame: pre-intervention, immediately after the intervention, 1 week after intervention, and 4 months after intervention
White matter density in arbitrary units by structural Magnetic Resonance Imaging
White matter density at cortical and subcortical regions will be taken by structural MRI. The regions of interest include the cerebellum, basal ganglia, thalamus, hippocampus, inferior parietal cortex, occipital and frontal lobe.
Time frame: pre-intervention, and immediately after the intervention
Gray matter volume in cubic millimeters (mm³) by structural Magnetic Resonance Imaging (MRI)
Gray matter volume at cortical and subcortical regions will be measured by Structural MRI. The regions of interest include the cerebellum, basal ganglia, thalamus, hippocampus, inferior parietal cortex, occipital and frontal lobe.
Time frame: pre-intervention, and immediately after the intervention
White matter volume in cubic millimeters (mm³) by structural Magnetic Resonance Imaging (MRI)
White matter volume at cortical and subcortical regions will be measured by Structural MRI. The regions of interest include the cerebellum, basal ganglia, thalamus, hippocampus, inferior parietal cortex, occipital and frontal lobe.
Time frame: pre-intervention, and immediately after the intervention
Cortical thickness in mm measured by structural Magnetic Resonance Imaging
Cortical thickness in mm measured by structural MRI. The regions of interest include the cerebellar, inferior parietal, occipital, and frontal cortices.
Time frame: pre-intervention, and immediately after the intervention
Fractional anisotropy ranges from 0-1 derived from Diffusion Tensor Imaging
The degree of anisotropy of water diffusion in white matter tracts will be derived from the diffusion tensor. The regions of interest include the cerebellum, basal ganglia, thalamus, hippocampus, inferior parietal cortex, occipital and frontal lobe.
Time frame: pre-intervention, and immediately after the intervention
Mean diffusivity measures in mm²/s by Diffusion Tensor Imaging
Mean diffusivity will be derived from the diffusion tensor. The regions of interest include the cerebellum, basal ganglia, thalamus, hippocampus, inferior parietal cortex, occipital and frontal lobe.
Time frame: pre-intervention, and immediately after the intervention
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