The Sensorimotor Locus of Balance Control in Elderly Gait
Primary Purpose
Ambulation Difficulty, Gait, Unsteady, Fall
Status
Completed
Phase
Not Applicable
Locations
United States
Study Type
Interventional
Intervention
Optical flow perturbations
Normal walking
Sponsored by
About this trial
This is an interventional treatment trial for Ambulation Difficulty
Eligibility Criteria
Inclusion Criteria:
- Be able to walk without an assistive aid (i.e., walker, cane)
- Have the full capacity to provide informed consent
OLDER NON-FALLERS
- Age 65+ years
- No history of falls* in the prior 12 months
OLDER ADULTS WITH A HISTORY OF FALLS
- Age 65+ years
History of one or more falls* in the prior 12 months
- For the purposes of this study, falls counted towards the self-reported total will be defined as per the Kellogg International Work Group - a fall is "unintentionally coming to the ground or some lower level and other than as a consequence of sustaining a violent blow, loss of consciousness, sudden onset of paralysis as in stroke or an epileptic seizure"
Exclusion Criteria:
- Current lower extremity injury or fracture
- Taking medication that causes dizziness
- Have a leg prosthesis
- Prisoners
- Individuals clearly lacking the capacity to provide informed consent
Sites / Locations
- Applied Biomechanics Laboratory
Arms of the Study
Arm 1
Arm 2
Arm Type
Experimental
Experimental
Arm Label
Intervention, then Control
Control, then Intervention
Arm Description
Older adults will walk during exposure to optical flow perturbations
Older adults will walk normally (without optical flow perturbations)
Outcomes
Primary Outcome Measures
Change in Postural Sway After 10 Min of Walking
Magnitude of side-to-side postural sway
Change in Kinematic Variability After 10 Min of Walking
Magnitude of step-to-step corrections in step width measured in cm
Change in Foot Placement Targeting Accuracy After 10 Min of Walking
Accuracy of performing foot placement targeting task. i.e., distance between heel marker at initial contact and target line (measured using three-dimensional motion capture during walking).
Secondary Outcome Measures
Change in Cognitive-motor Interference Accuracy After 10 Min of Walking
Accuracy performing an auditory stroop test (cognitive dual-task)
Change in Cognitive-motor Interference Response Time After 10 Min of Walking
Response time in performing an auditory stroop test (cognitive dual-task)
Change in Margin of Stability Variability After 10 Min of Walking
Change in step-to-step fluctuations in margin of stability (the distance between the lateral boundary of the foot and the body's center of mass, measured in cm)
Full Information
NCT ID
NCT03341728
First Posted
October 31, 2017
Last Updated
June 27, 2019
Sponsor
University of North Carolina, Chapel Hill
Collaborators
National Institute on Aging (NIA)
1. Study Identification
Unique Protocol Identification Number
NCT03341728
Brief Title
The Sensorimotor Locus of Balance Control in Elderly Gait
Official Title
The Sensorimotor Locus of Balance Control in Elderly Gait
Study Type
Interventional
2. Study Status
Record Verification Date
February 2019
Overall Recruitment Status
Completed
Study Start Date
October 30, 2017 (Actual)
Primary Completion Date
July 25, 2018 (Actual)
Study Completion Date
July 25, 2018 (Actual)
3. Sponsor/Collaborators
Responsible Party, by Official Title
Sponsor
Name of the Sponsor
University of North Carolina, Chapel Hill
Collaborators
National Institute on Aging (NIA)
4. Oversight
Studies a U.S. FDA-regulated Drug Product
No
Studies a U.S. FDA-regulated Device Product
No
Data Monitoring Committee
No
5. Study Description
Brief Summary
The aging population is at an exceptionally high risk of debilitating falls, contributing significantly to reduced independence and quality of life. It remains extremely challenging to screen for falls risk, and programs designed to mitigate falls risk have only modestly influenced the sizeable portion of the aging population experiencing one or more falls annually. Balance control in standing and walking depends on integrating reliable sensory feedback and on planning and executing appropriate motor responses. Walking balance control is especially dynamic, requiring active and coordinated adjustments in posture (i.e., trunk stabilization) and foot placement from step to step. Accordingly, using a custom, immersive virtual environment, the investigators have shown that sensory (i.e., optical flow) perturbations, especially when applied during walking, elicit strong and persistent motor responses to preserve balance. Exciting pilot data suggest that these motor responses are remarkably more prevalent in old age, presumably governed by an increased reliance on vision for balance control. Additional pilot data suggest that prolonged exposure to these perturbations may effectively condition successful balance control strategies. Founded on these recent discoveries, and leveraging the increase reliance on vision for balance control in old age, the investigators stand at the forefront of a potentially transformative new approach for more effectively identifying and mitigating age-related falls risk. The investigator's overarching hypothesis is that optical flow perturbations, particularly when applied during walking, can effectively identify balance deficits due to aging and falls history and can subsequently condition the neuromechanics of successful balance control via training.
Detailed Description
Specific Aim 1. Investigate sensory, motor, and cognitive-motor mechanisms governing susceptibility to optical flow perturbations. Aging increases the reliance on vision for balance control. However, central and peripheral mechanisms underlying aging and falls history effects on the susceptibility to optical flow perturbations are unclear. Hypothesis 1: Entrainment to optical flow perturbations will correlate most strongly with visual dependence and decreased somatosensory function, alluding to an age-associated process of multi-sensory reweighting. Methods: Multivariate models will quantify the extent to which strategically-selected sensory (i.e., visual dependence via rod/frame test, somatosensory function), motor (i.e., rate of torque development, timed sit-to-stand) and cognitive-motor (i.e., interference) mechanisms underlie inter-individual differences in susceptibility to perturbations.
Specific Aim 2. Estimate the efficacy of prolonged optical flow perturbations to condition the neuromechanics of walking balance control in older adult fallers. Pilot data from young adults suggests that prolonged exposure to optical flow perturbations may condition reactive strategies used to successfully control walking balance. The investigator's premise is that dynamic perturbation training can improve resilience to unexpected balance disturbances. Here, the investigators conduct a preliminary test of the effects of training with optical flow perturbations on walking balance in older adult fallers. Hypothesis 2: (a) Older adults with a history of falls will adapt to prolonged exposure to perturbations, conditioning their step to step adjustments in walking balance control, and (b) improving their response to unexpected balance challenges following training. Methods: In two 20 min sessions, on different days in a randomized cross-over design, older adults with a history of falls will walk with ("treatment" session) and without ("control" session) prolonged exposure to optical flow perturbations. The investigators will assess time-dependent changes in the neuromechanics of walking balance during training and after-effects via gait variability, dynamic stability, and performance on a series of real-world like targeting and obstacle avoidance tasks.
6. Conditions and Keywords
Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Ambulation Difficulty, Gait, Unsteady, Fall, Position Sense Disorders
7. Study Design
Primary Purpose
Treatment
Study Phase
Not Applicable
Interventional Study Model
Crossover Assignment
Model Description
In two 20 min sessions, on different days in a randomized cross-over design, older adults will walk with ("treatment" session) and without ("control" session) prolonged exposure to optical flow perturbations.
Masking
None (Open Label)
Masking Description
No Masking
Allocation
Randomized
Enrollment
14 (Actual)
8. Arms, Groups, and Interventions
Arm Title
Intervention, then Control
Arm Type
Experimental
Arm Description
Older adults will walk during exposure to optical flow perturbations
Arm Title
Control, then Intervention
Arm Type
Experimental
Arm Description
Older adults will walk normally (without optical flow perturbations)
Intervention Type
Behavioral
Intervention Name(s)
Optical flow perturbations
Intervention Description
Continuous mediolateral (i.e., side-to-side) 20-minute perturbations of optical flow that elicit the visual perception of lateral imbalance via virtual reality during treadmill walking.
Intervention Type
Behavioral
Intervention Name(s)
Normal walking
Intervention Description
Usual treadmill walking without optical flow perturbations
Primary Outcome Measure Information:
Title
Change in Postural Sway After 10 Min of Walking
Description
Magnitude of side-to-side postural sway
Time Frame
Baseline, 10 minutes
Title
Change in Kinematic Variability After 10 Min of Walking
Description
Magnitude of step-to-step corrections in step width measured in cm
Time Frame
Baseline, 10 minutes
Title
Change in Foot Placement Targeting Accuracy After 10 Min of Walking
Description
Accuracy of performing foot placement targeting task. i.e., distance between heel marker at initial contact and target line (measured using three-dimensional motion capture during walking).
Time Frame
Baseline, 10 minutes
Secondary Outcome Measure Information:
Title
Change in Cognitive-motor Interference Accuracy After 10 Min of Walking
Description
Accuracy performing an auditory stroop test (cognitive dual-task)
Time Frame
Baseline, 10 minutes
Title
Change in Cognitive-motor Interference Response Time After 10 Min of Walking
Description
Response time in performing an auditory stroop test (cognitive dual-task)
Time Frame
Baseline, 10 minutes
Title
Change in Margin of Stability Variability After 10 Min of Walking
Description
Change in step-to-step fluctuations in margin of stability (the distance between the lateral boundary of the foot and the body's center of mass, measured in cm)
Time Frame
Baseline, 10 minutes
10. Eligibility
Sex
All
Minimum Age & Unit of Time
65 Years
Accepts Healthy Volunteers
Accepts Healthy Volunteers
Eligibility Criteria
Inclusion Criteria:
Be able to walk without an assistive aid (i.e., walker, cane)
Have the full capacity to provide informed consent
OLDER NON-FALLERS
Age 65+ years
No history of falls* in the prior 12 months
OLDER ADULTS WITH A HISTORY OF FALLS
Age 65+ years
History of one or more falls* in the prior 12 months
For the purposes of this study, falls counted towards the self-reported total will be defined as per the Kellogg International Work Group - a fall is "unintentionally coming to the ground or some lower level and other than as a consequence of sustaining a violent blow, loss of consciousness, sudden onset of paralysis as in stroke or an epileptic seizure"
Exclusion Criteria:
Current lower extremity injury or fracture
Taking medication that causes dizziness
Have a leg prosthesis
Prisoners
Individuals clearly lacking the capacity to provide informed consent
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Jason Franz, PhD
Organizational Affiliation
Unviersity of North Carolina at Chapel Hill
Official's Role
Principal Investigator
Facility Information:
Facility Name
Applied Biomechanics Laboratory
City
Chapel Hill
State/Province
North Carolina
ZIP/Postal Code
27514
Country
United States
12. IPD Sharing Statement
Plan to Share IPD
No
IPD Sharing Plan Description
There is no plan to share IPD with other researchers.
Citations:
PubMed Identifier
25687664
Citation
Franz JR, Francis CA, Allen MS, O'Connor SM, Thelen DG. Advanced age brings a greater reliance on visual feedback to maintain balance during walking. Hum Mov Sci. 2015 Apr;40:381-92. doi: 10.1016/j.humov.2015.01.012. Epub 2015 Feb 14.
Results Reference
result
PubMed Identifier
26233581
Citation
Francis CA, Franz JR, O'Connor SM, Thelen DG. Gait variability in healthy old adults is more affected by a visual perturbation than by a cognitive or narrow step placement demand. Gait Posture. 2015 Sep;42(3):380-5. doi: 10.1016/j.gaitpost.2015.07.006. Epub 2015 Jul 17.
Results Reference
result
PubMed Identifier
28371662
Citation
Thompson JD, Franz JR. Do kinematic metrics of walking balance adapt to perturbed optical flow? Hum Mov Sci. 2017 Aug;54:34-40. doi: 10.1016/j.humov.2017.03.004. Epub 2017 Apr 2.
Results Reference
result
PubMed Identifier
28400615
Citation
Stokes HE, Thompson JD, Franz JR. The Neuromuscular Origins of Kinematic Variability during Perturbed Walking. Sci Rep. 2017 Apr 11;7(1):808. doi: 10.1038/s41598-017-00942-x.
Results Reference
result
PubMed Identifier
31262319
Citation
Richards JT, Selgrade BP, Qiao M, Plummer P, Wikstrom EA, Franz JR. Time-dependent tuning of balance control and aftereffects following optical flow perturbation training in older adults. J Neuroeng Rehabil. 2019 Jul 1;16(1):81. doi: 10.1186/s12984-019-0555-3.
Results Reference
derived
Links:
URL
http://abl.bme.unc.edu
Description
Applied Biomechanics Laboratory
Learn more about this trial
The Sensorimotor Locus of Balance Control in Elderly Gait
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