The objective of this pilot study is to evaluate and compare the effect of three different perturbation based training devices on the reactive balance control among healthy young adults, healthy older adults, and neurologically impaired stroke individuals. Furthermore, the project aims to determine the feasibility and tolerability of 30-minutes of perturbation training using the SureFooted Trainer. Overall, the project directs to find out the long term effect of training on fall risk reduction and fall prevention. This study investigates the effects of perturbation training (slip and trip) based on the principles of motor learning. Perturbations in the form of slips and trips induced by the three different types of perturbation devices will displace the center of mass outside the base of support and challenge the stability, thereby inducing a fall and demand compensatory strategies in order to prevent it. Such perturbation training would train the motor system to improve stability control and vertical limb support. The project design aims to examine the ability of the central nervous system to mitigate the interference in stability control (if any) that is induced by opposing types of perturbations. The hypothesis of this study if supported by the results, will provide the difference in motor learning with training on three different perturbation devices. Furthermore, it would help to determine which of the three training devices is the most effective in developing defense mechanisms necessary to reduce fall-risk among community-living older adults and the neurological population.
About 34% of the community-dwelling older population experience a detrimental fall each year. Moreover, 40% of the individuals who suffer from pathological conditions such as stroke experience falls. Age-related changes and post-stroke impairments often lead to impaired balance and gait that are highly associated with falls. Most of these falls have been reported to occur during dynamic and complex activities such as walking, reaching out for objects that are a part of daily living. There are various clinical balance tests used to evaluate the balance in individuals suffering from a stroke. However, most of the tests measure only the static balance ability while performing voluntary/ self-generated activities. Hence, these measures fail to determine the reactive balance control or compensatory strategies used to recover from unexpected perturbations. Perturbation induced by various perturbation based devices such as Activestep treadmill, a motorized, custom-designed free-sliding over-ground walkway that aims to cause a loss of balance by presenting a threat to stability, thereby, challenging the reactive balance response of an individual. This interventional paradigm has now been widely used to quality and trains reactive balance control in older adults and neurologically affected populations. Previously studied along with emerging researches and numerous ongoing clinical trials focusing on perturbation training using a treadmill and overground walking, have already indicated its effectiveness in reducing fall risk. Literature states that more than half of the elderly population did not experience any fall after the first exposure of a novel slip during over-ground walking. However, the efficacy of a newly introduced equipment, Surefooted Trainer, which is a customized, moveable slippery platform where an individual walks safely along protected by a harness, has not yet been explored. Surefooted Trainer consists of the platform which causes slip-like perturbations and obstacles which cause trip-perturbation. Further, both the Activestep and Surefooted Trainer are more compact and can be easily installed in clinical settings. While the Activestep is a treadmill based system the Surefooted Trainer is an overground walkway perturbation system. The study aims to establish feasibility and tolerability for 30 minutes of the Surefooted Trainer first and then gather pilot data for assessing the efficacy of these three perturbation training systems. The perturbation training paradigm is based on the principle that the central nervous system adapts and learns from previous experience of perturbation and employs motor learning to prospective perturbation induced loss of balance. This helps to reduce the number of falls and improves dynamic stability in the laboratory setting which is later translated to real-life situations. The dose and intensity necessary to induce motor learning are not clearly known and therefore, the purpose of this study is to compare the results of perturbation training on three devices and identify the most effective training protocol with immediate and long term effects on the fall reduction. If the results from this study seem to be promising, it could help in translating the most beneficial protocol for clinical treatment for older adults and stroke population. To determine the long term effects in the community-dwelling, the study will monitor the physical activity of the elderly and stroke population during community ambulation. The aim of the study is to compare the effect of perturbation training between ActiveStep treadmill, a custom-designed over-ground walkway and the Sure-footed Trainer among healthy young adults, older adults, and neurologically impaired stroke survivors both immediately post-training and in long term on reduction in fall rate. Furthermore, to establish feasibility and tolerability of 30-minute training using Surefooted Trainer and then assess the efficacy of these three perturbation training systems.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
90
Participants will be given thirteen slips and thirteen trips in stance and walking, followed by two slips and two trips at a higher intensity (posttest). Subjects would be consented if they would like to undergo fMRI pre and post-training. Participants not willing to undergo imaging would not be excluded. Three day training consisting of blocks of five consecutive gait-slips at varying intensities will be provided. Individuals with stroke would undergo an additional session (total 4 training sessions over 4 weeks (1session/week) since these individuals get easily fatigued and also might need more training sessions with sufficient rest interval to induce reactive adaptation. Training at a specific level will persist until the subjects show a recovery step response in at least 3/5 trials in a single block. Once subjects successfully adapt to this level, the perturbation intensity will be increased until they show a recovery response in at least 3/5 trials.
Slips and trips could be induced under either of the limbs. The specialized walkway consists of two sliding platforms, each of which is mounted on two rows of low friction linear bearings (friction coefficient = 0.02). The base plate of each platform is bolted separately onto the top of a force platform embedded in the floor. An electronic-mechanical latch system is used to control the 2 states of the support platform; that is, the "locked" state for regular walking and the "release" state to initiate slipping are carefully controlled. The sliding top of the platform is released after the heel strike (vertical force to exceed 2% of the body weight). The slip distance would be adjusted between 30 to 60 centimeters depending upon the different population and their physical capacity.
During the first minute of each block, subjects would experience no perturbations followed by 3 minutes of single or multi-directional perturbations. A one minute break between each condition would be provided. Subject's fatigue would be assessed by Fatigue severity scale to determine the tolerability of 30 minute training protocol. The expected duration to complete the test would be a maximum of 1 hour including the preparation and training time.
University of Illinois at Chicago
Chicago, Illinois, United States
RECRUITINGChange in Stability gain or loss
Stability is defined by both the position of a person's center-of-mass (COM) with respect to his or her base-of-support (BOS) and it's velocity.
Time frame: Baseline (1st novel slip, week 1) and at Immediate post-training (after repeated perturbation training session, week 1)
Change in Limb support gain or loss
The inability to provide timely limb support due to insufficient amount of upward impulse generated from the ground reactive force can cause limb collapse, as characterized by the quotient of amount and rate of hip descent (Vhip/Zhip) measured from hip height and lead to an eventual fall.
Time frame: Baseline (1st novel slip, week 1) and Immediate post-training (after repeated perturbation training session, week 1)
Change in laboratory-induced falls
Perturbation is induced successfully and safely to reproduce inadvertent falls in a protective laboratory environment. Falls will be measured by the amount of body weight supported by the full-body harness system and measured by a load cell attached to this system. Instability of the body's COM and poor limb support prior to touchdown of the recovery step account for 90\~100% of subsequent falls (occurring \~500ms later) in both sit-to-stand-slip and in gait-slip, in the laboratory settings. Intervention consists of repeated perturbation training to induce a change in the laboratory induced falls immediately post-training and examine it's retention after the initial training session.
Time frame: Baseline (1st novel slip, week 1) and Immediate post-training (after repeated perturbation training session, week 1)
Number of Real life falls
Real life falls are measured to determine if training effect can be translated into everyday real life setting.
Time frame: prospective post-training over next 12 months (total falls tracked and reported at 12 months post-training will be compared between groups)
Center of mass excursion angle
the deviation of the Center of mass relative to the sagittal plane
Time frame: Baseline (natural walking) (Week 1), and Virtual reality walking trials at week 1
Medio-Lateral excursion of center of mass
The peak excursion of the COM perpendicular to the walking direction
Time frame: Baseline (natural walking) (Week 1), and Virtual reality walking trials at week 1
Change in Number of steps
The total number of steps and distance for each day will be calculated by patient's wearable sensor and their assistive device sensor. This parameter will be used to analyze improvement in physical activity of the patient and decrease reliance on the assistive device.
Time frame: One month before pretest till prospectively 12 months post training
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