An interventional study of Optical flow perturbations and Normal walking in Ambulation Difficulty, Gait, Unsteady and Fall, sponsored by University of North Carolina, Chapel Hill. Completed at 1 site in United States. Open to participants aged 65 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2019-07-05.
Sponsored by University of North Carolina, Chapel Hill · Not applicable, Interventional, and Treatment
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.
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.
321 studies on the registry are indexed under Mobility Limitation; 97 are open to participants now.
This study's enrollment of 14 is below the median of 46 across 269 interventional studies indexed under Mobility Limitation.
Browse Mobility Limitation studies →University of North Carolina, Chapel Hill is the lead sponsor of 1,366 studies on the registry; 133 are open to participants now.
Of its 158 completed or terminated interventional studies of FDA-regulated products, 139 (88%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
OLDER NON-FALLERS
OLDER ADULTS WITH A HISTORY OF FALLS
History of one or more falls* in the prior 12 months
Exclusion Criteria:
Older adults will walk during exposure to optical flow perturbations
Behavioral: Optical flow perturbations · Behavioral: Normal walking
Older adults will walk normally (without optical flow perturbations)
Behavioral: Optical flow perturbations · Behavioral: Normal walking
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.
Usual treadmill walking without optical flow perturbations
Change in Postural Sway After 10 Min of Walking
Magnitude of side-to-side postural sway
Time frame: Baseline, 10 minutes
Change in Kinematic Variability After 10 Min of Walking
Magnitude of step-to-step corrections in step width measured in cm
Time frame: Baseline, 10 minutes
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).
Time frame: Baseline, 10 minutes
Change in Cognitive-motor Interference Accuracy After 10 Min of Walking
Accuracy performing an auditory stroop test (cognitive dual-task)
Time frame: Baseline, 10 minutes
Change in Cognitive-motor Interference Response Time After 10 Min of Walking
Response time in performing an auditory stroop test (cognitive dual-task)
Time frame: Baseline, 10 minutes
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)
Time frame: Baseline, 10 minutes
| Milestone | Intervention, Then Control | Control, Then Intervention |
|---|---|---|
| Started | 7 | 7 |
| Completed | 7 | 7 |
| Not completed | 0 | 0 |
| Milestone | Intervention, Then Control | Control, Then Intervention |
|---|---|---|
| Started | 7 | 7 |
| Completed | 7 | 7 |
| Not completed | 0 | 0 |
| Milestone | Intervention, Then Control | Control, Then Intervention |
|---|---|---|
| Started | 7 | 7 |
| Completed | 7 | 7 |
| Not completed | 0 | 0 |
Magnitude of side-to-side postural sway
| cm | Intervention | Normal Walking (Control) |
|---|---|---|
| Change in Postural Sway After 10 Min of Walking | -2.39 ± 1.10 | -0.01 ± 0.59 |
Magnitude of step-to-step corrections in step width measured in cm
| cm | Intervention | Normal Walking (Control) |
|---|---|---|
| Change in Kinematic Variability After 10 Min of Walking | 0.55 ± 0.35 | 0.00 ± 0.01 |
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).
No measurements were reported for this outcome.
Accuracy performing an auditory stroop test (cognitive dual-task)
No measurements were reported for this outcome.
Response time in performing an auditory stroop test (cognitive dual-task)
No measurements were reported for this outcome.
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)
| cm | Intervention | Normal Walking (Control) |
|---|---|---|
| Change in Margin of Stability Variability After 10 Min of Walking | -1.02 ± 0.99 | 0.16 ± 0.26 |
Collected over From the time of enrollment through the completion of the second 3-hour session approximately 1 week later. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Intervention | 0/14 (0%) | 0/14 (0%) | 0/14 (0%) |
| Normal Walking (Control) | 0/14 (0%) | 0/14 (0%) | 0/14 (0%) |
| Age, Categorical(Participants) | All Participants |
|---|---|
| <=18 years | 0 |
| Between 18 and 65 years | 0 |
| >=65 years | 14 |
| Sex: Female, Male(Participants) | All Participants |
|---|---|
| Female | 9 |
| Male | 5 |
| Ethnicity (NIH/OMB)(Participants) | All Participants |
|---|---|
| Hispanic or Latino | 0 |
| Not Hispanic or Latino | 14 |
| Unknown or Not Reported | 0 |
| Race (NIH/OMB)(Participants) | All Participants |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 0 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 1 |
| White | 13 |
| More than one race | 0 |
| Unknown or Not Reported | 0 |
| Region of Enrollment(Participants) | All Participants |
|---|---|
| United States | 14 |
| History of Falls(Participants) | All Participants |
|---|---|
| Count of participants | 4 |
Documents are hosted by the registry — open the source record to download them.
Plan to share: No — There is no plan to share IPD with other researchers.
Ran from Oct 2017 to primary completion in Jul 2018, 8 months.
Results were first posted in Jul 2019, 11 months after primary completion.
Of 179 non-industry interventional studies with no phase under Mobility Limitation, half reached primary completion within 18 months of starting (the median), counting those still running; a quarter within 8 and three quarters within 42. This study's 8 months is below that.
Counting every sponsor, half of 182 studies reached it within 18 months; a quarter within 8 and three quarters within 42.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Feb 2019. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of North Carolina, Chapel Hill →