Ambulation DifficultyNCT03341728
The Sensorimotor Locus of Balance Control in Elderly Gait
A study testing Optical flow perturbations and Normal walking in people with Ambulation Difficulty and Gait, Unsteady, run by University of North Carolina, Chapel Hill at 1 site in United States.
Trial 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… Read more about this study
- Who is it for?
- Ages 65 years and olderHealthy volunteers can take part
- Conditions the study is for
- Ambulation Difficulty, Gait, Unsteady, Fall
- What is being tested?
- Optical flow perturbations and Normal walking
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 14 participants
- Where
- 1 siteUnited States
- Study dates
- 30 Oct 2017to 25 Jul 2018
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 65 years and older
- All sexes
- Healthy volunteers accepted
- Older adult
Who may be able to join
- 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
Show all 9Show fewer
- 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"
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
United States1 site
Applied Biomechanics Laboratory
Chapel Hill, North Carolina, 27514
About this study
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.
Read the 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.
- Conditions
- Ambulation Difficulty, Gait, Unsteady, Fall, Position Sense Disorders
- Being tested
- Optical flow perturbations, Normal walking
- Medical subject headings
- Mobility Limitation, Gait Disorders, Neurologic, Somatosensory Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Optical flow perturbationsBehavioural
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.
Normal walkingBehavioural
Usual treadmill walking without optical flow perturbations
| Study group | Role | What they receive |
|---|---|---|
| Intervention, then Control | Experimental | Older adults will walk during exposure to optical flow perturbations Receives: Behavioral: Optical flow perturbations; Behavioral: Normal walking |
| Control, then Intervention | Experimental | Older adults will walk normally (without optical flow perturbations) Receives: Behavioral: Optical flow perturbations; Behavioral: Normal walking |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Postural Sway After 10 Min of Walking
Magnitude of side-to-side postural sway
Measured: Baseline, 10 minutes
Change in Kinematic Variability After 10 Min of Walking
Magnitude of step-to-step corrections in step width measured in cm
Measured: 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).
Measured: Baseline, 10 minutes
Secondary outcomes (3)
Change in Cognitive-motor Interference Accuracy After 10 Min of Walking
Accuracy performing an auditory stroop test (cognitive dual-task)
Measured: 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)
Measured: 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)
Measured: Baseline, 10 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Nov 2017
- Study start30 Oct 2017
- Primary completion25 Jul 2018
- Study completion25 Jul 2018
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for Ambulation DifficultyStudies of the same condition, open and under way.
- More trials run by University of North Carolina, Chapel HillThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- 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)
- Enrolment
- 14 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of North Carolina, Chapel Hill
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute on Aging (NIA)
- Responsible party
- Sponsor
- Investigators
- Jason Franz, PhD, Principal investigator, Unviersity of North Carolina at Chapel Hill
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03341728
- Sponsor's protocol ID
- 15-2267
- Other IDs
- R56AG054797-01A1
- Status last verified
- Feb 2019
- First submitted
- 31 Oct 2017
- Last updated
- 5 Jul 2019
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: There is no plan to share IPD with other researchers.
Publications
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.
PubMed 25687664Francis 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.
PubMed 26233581Thompson 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.
PubMed 28371662Stokes 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.
PubMed 28400615Richards 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.
PubMed 31262319
Study at a glance
From the registry record, last updated by the sponsor on 5 Jul 2019. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Sensorimotor Locus of Balance Control in Elderly Gait
- ClinicalTrials.gov ID
- NCT03341728
- Acronym / sponsor ID
- 15-2267
- Conditions
- Ambulation Difficulty, Gait, Unsteady, Fall, Position Sense Disorders
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 14 participants (actual)
- Lead sponsor
- University of North Carolina, Chapel HillUniversity, hospital or other
- Collaborators
- National Institute on Aging (NIA)
- Study start
- 30 Oct 2017 (actual)
- Primary completion
- 25 Jul 2018 (actual)
- Study completion
- 25 Jul 2018 (actual)
- First posted
- 14 Nov 2017 (actual)
- Results
- Posted 5 Jul 2019
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- 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.
| Arm | Type | Receives |
|---|---|---|
| Intervention, then Control | Experimental | Behavioral: Optical flow perturbations, Behavioral: Normal walkingOlder adults will walk during exposure to optical flow perturbations |
| Control, then Intervention | Experimental | Behavioral: Optical flow perturbations, Behavioral: Normal walkingOlder adults will walk normally (without optical flow perturbations) |
Who may qualify
- Ages
- 65 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Older adult
Key inclusion criteria (9 listed)
- 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
Key exclusion criteria (5 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Optical flow perturbationsContinuous 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. | Behavioural | Control, then Intervention, Intervention, then Control |
| Normal walkingUsual treadmill walking without optical flow perturbations | Behavioural | Control, then Intervention, Intervention, then Control |
Primary outcome
Change in Postural Sway After 10 Min of Walking
Time frame: Baseline, 10 minutes
Magnitude of side-to-side postural sway
Change in Kinematic Variability After 10 Min of Walking
Time frame: Baseline, 10 minutes
Magnitude of step-to-step corrections in step width measured in cm
Change in Foot Placement Targeting Accuracy After 10 Min of Walking
Time frame: Baseline, 10 minutes
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).
3 secondary outcomes
Change in Cognitive-motor Interference Accuracy After 10 Min of Walking
Time frame: Baseline, 10 minutes
Change in Cognitive-motor Interference Response Time After 10 Min of Walking
Time frame: Baseline, 10 minutes
Change in Margin of Stability Variability After 10 Min of Walking
Time frame: Baseline, 10 minutes
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Jul 2019.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Results publication: PubMed 25687664Franz 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 publication: PubMed 26233581Francis 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 publication: PubMed 28371662Thompson 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 publication: PubMed 28400615Stokes 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.
- Derived from this study: PubMed 31262319Richards 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.
- Applied Biomechanics LaboratoryLink provided by the sponsor.
- Individual participant dataSharing planned: No. There is no plan to share IPD with other researchers.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Jason Franz, PhD principal investigator
Unviersity of North Carolina at Chapel Hill
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Optical flow perturbations and Normal walking in people with Ambulation Difficulty and Gait, Unsteady, run by University of North Carolina, Chapel Hill at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 5 Jul 2019. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 5 Jul 2019). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Postural Sway After 10 Min of Walking (time frame: Baseline, 10 minutes). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03341728, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Jul 2019.