Reactive Balance Training for Fall Prevention

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.

Inclusion criteria

Healthy Young participants

• Age group: 18-55 years.
• Absence of any acute or chronic neurological, cardiopulmonary, musculoskeletal or systemic diagnosis.
• No recent major surgery (< 6 months) or hospitalization (< 3 months)
• Not on any sedative drugs.
• Can understand and communicate in English

Healthy older adults

• Age group: 56-90 years.
• Absence of any acute or chronic neurological, cardiopulmonary, musculoskeletal or systemic diagnosis.
• No recent major surgery (< 6 months) or hospitalization (< 3 months)
• Not on any sedative drugs.
• Ability to walk with or without an assistive device for 10 meters
• Can understand and communicate in English
• Berg balance scale score <45/56.

Persons with stroke

• Age group: 18-90 years.
• Absence of any acute or chronic neurological diagnosis except stroke (self reported)
• Onset of stroke (> 6 months)
• Absence of any cardiopulmonary, musculoskeletal or systemic diagnosis.
• No recent major surgery (< 6 months) or hospitalization (< 3 months)
• Not on any sedative drugs.
• Ability to walk with or without an assistive device for 10 meters
• Can understand and communicate in English

Exclusion criteria

Healthy subject:

• Subjects will not proceed with the test if any of the following occurs at baseline measurement: 1) HR > 85% of age-predicted maximal heart rate (HRmax) (HRmax = 220 - age), 2) systolic blood pressure (SBP) > 165 mmHg and/or diastolic blood pressure (DBP) > 110 mmHg during resting), and 3) oxygen saturation (measured by pulse oximeter) during resting < 95%.
• Body weight more than 250 lbs.

Healthy Older adults:

• Individuals with heel bone density with a T-score < -2, is classified as osteoporotic and will be excluded.
• Individuals with mild cognitive impairment (Mini-mental State Exam score < 25/30) will be excluded.
• Subjects will not proceed with the test if any of the following occurs at baseline measurement: 1) HR > 85% of age-predicted maximal heart rate (HRmax) (HRmax = 220 - age), 2) systolic blood pressure (SBP) > 165 mmHg and/or diastolic blood pressure (DBP) > 110 mmHg during resting), and 3) oxygen saturation (measured by pulse oximeter) during resting < 95%.
• 6 minute walk test. Subjects will also be screened out if on the 6 minute walk test they complain of shortness of breath or uncontrolled pain (> 3/10 on VAS) or pulse oxygen drops < 92% or are unable to achieve the age-specified minimal ambulation distance.
• Body weight more than 250 lbs.

Persons with stroke:

• Individuals with heel bone density with a T-score < -2, is classified as osteoporotic and will be excluded.
• Individuals with mild cognitive impairment (Mini-mental State Exam score < 25/30) will be excluded.
• Subjects will not proceed with the test if any of the following occurs at baseline measurement: 1) HR > 85% of age-predicted maximal heart rate (HRmax) (HRmax = 220 - age), 2) systolic blood pressure (SBP) > 165 mmHg and/or diastolic blood pressure (DBP) > 110 mmHg during resting), and 3) oxygen saturation (measured by pulse oximeter) during resting < 95%.
• 6 minute walk test. Subjects will also be screened out if on the 6 minute walk test they complain of shortness of breath or uncontrolled pain (> 3/10 on VAS) or pulse oxygen drops < 92% or are unable to achieve the age-specified minimal ambulation distance.
• Body weight more than 250 lbs.