Foot Drop, Stroke
Conditions
Keywords
Rehabilitation, Robotics, Gait
Brief summary
Deficits in ankle control after stroke can lead to foot drop, resulting in inefficient, aberrant gait and an elevated falls risk. Using a novel ankle robot and newly invented adaptive control system, this study tests whether robotic-assisted treadmill training will improve gait and balance functions in chronic stroke survivors with foot drop impairment. It is hypothesized that, compared to treadmill training alone, integrating adaptive ankle robotics with treadmill training will reduce drop foot during independent overground walking, resulting in greater mobility, improved postural control, and reduced fall risk.
Detailed description
This proposal investigates a novel ankle robot (anklebot) adaptive control approach integrated with treadmill training to reduce foot drop and improve mobility function in chronic hemiparetic stroke survivors. Currently, stroke survivors with foot drop are trained to live with a cane or other assistive device, and often ankle foot orthotics (AFOs) for safety. Neither mediates task-practice or neuromotor recovery. The investigators have developed an adaptive anklebot controller that detects gait cycle sub-events for precise timing of graded robotics assistance to enable deficit severity-adjusted ankle motor learning in the context of walking. The investigators' pilot findings show that 6 weeks treadmill training with anklebot (TMR) timed to assist swing phase dorsiflexion only is more effective than treadmill alone (TM) to improve free-walking swing dorsiflexion at foot strike, floor-walking speed, and the benefits are retained at 6 weeks post-training. Notably, swing-phase TMR training improved paretic leg push-off, and reduced center-of-pressure sway on standing balance, indicating potential benefits to other elements of gait and balance, beyond those robotically targeted toward foot drop. This randomized study investigates the hypothesis that 6 weeks TMR is more effective to improve durably gait biomechanics, static, and dynamic balance, and mobility function in chronic stroke survivors with dorsiflexion deficits, compared to TM alone. Aims are to determine the compare effectiveness of 6 weeks TMR vs. TM alone on: 1. Independent gait function indexed by gait velocity, swing-phase DF (dorsiflexion), terminal stance push-off. 2. Balance function indexed by measures of postural sway (CoP), asymmetric loading in quiet standing, peak paretic A-P forces in non-paretic gait initiation, and standardized scales for balance and fall risk. 3. Long-term mobility outcomes, assessed by repeated measures of all key gait and balance outcomes at 6 weeks and 3 months after formal training cessation.
Interventions
DEVICETreadmill plus anklebot
This intervention employs the use of the adaptive anklebot control system to complement treadmill exercise training over a 6-week intervention period.
BEHAVIORALTreadmill only
This intervention employs the use of a treadmill for gait exercise training over a 6-week intervention period
Sponsors
VA Office of Research and Development
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Ischemic or hemorrhagic stroke \> 2 months prior in men or women * Residual hemiparesis of the lower extremity that includes symptoms of foot drop * Capable of ambulating on a treadmill with handrail support * Already completed all conventional physical therapy * Adequate language and cognitive function to provide informed consent and participate in testing and training
Exclusion criteria
* Cardiac history of: * Unstable angina * Recent (\< 3 months) myocardial infarction * Congestive heart failure (NYHA category II or higher) * Hemodynamic valvular dysfunction * Hypertension that is a contraindication for a bout of treadmill training (\>160/100 mmHg on two assessments) * Medical history of: * Recent hospitalization (\< 3 months) for any serious condition leading to significant bed-rest or reduction in mobility function * Symptomatic peripheral arterial occlusive disease * Orthopedic or chronic pain conditions restricting exercise * Pulmonary failure requiring oxygen * Uncompensated renal failure * Active cancer * Neurological history and exam consistent with: * Dementia * Receptive or global aphasia that confounds testing and training, operationally defined as unable to follow 2-point commands * Non-stroke neurological disorder restricting exercise (e.g. Parkinson's Syndrome, myopathy) * Untreated major depression
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Gait Velocity During Self-selected Overground Walking | Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months after completion | Gait velocity during self-selected overground walking measured in cm/sec |
| Anterior-posterior Propulsion Forces of Paretic Side During Gait | Change from baseline to: Post 6-weeks training, 6 weeks after completion, and 3 (or 6) months | Newtons: anterior-posterior force generated during push-off phase of the gait cycle |
| Peak Dorsiflexion Angle During Swing Phase of Gait | Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months after completion | Degrees; extent of ankle dorsiflexion to enable foot clearance |
| Postural Sway Areas During Quiet Standing | Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months | cm\^2; extent of postural deviations to assess static postural control |
| Ratio of Asymmetric Loading in Quiet Standing | Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months | Ratio of Newtons of force per each leg (paretic/nonparetic) while standing quietly |
| Peak Paretic Push Off Forces During Gait Initiation | Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months | Newtons; magnitude of forward ground reaction forces |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Treadmill+Anklebot This group will receive gait training on a treadmill while wearing the anklebot with the adaptive control system.
Treadmill plus anklebot: This intervention employs the use of the adaptive anklebot control system to complement treadmill exercise training over a 6-week intervention period. | 23 |
| Treadmill Only This group will receive gait training on a treadmill, without use of the anklebot.
Treadmill only: This intervention employs the use of a treadmill for gait exercise training over a 6-week intervention period | 22 |
| Total | 45 |
Baseline characteristics
| Characteristic | Treadmill+Anklebot | Treadmill Only | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 15 Participants | 12 Participants | 27 Participants |
| Age, Categorical Between 18 and 65 years | 8 Participants | 10 Participants | 18 Participants |
| Age, Continuous | 64 years | 65 years | 65 years |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 2 Participants | 1 Participants | 3 Participants |
| Race (NIH/OMB) Black or African American | 15 Participants | 15 Participants | 30 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 6 Participants | 6 Participants | 12 Participants |
| Region of Enrollment United States | 23 Participants | 22 Participants | 45 Participants |
| Sex: Female, Male Female | 9 Participants | 8 Participants | 17 Participants |
| Sex: Female, Male Male | 14 Participants | 14 Participants | 28 Participants |
| Years since stroke <2 | 4 Participants | 2 Participants | 6 Participants |
| Years since stroke 2-4 | 7 Participants | 9 Participants | 16 Participants |
| Years since stroke 4-6 | 4 Participants | 7 Participants | 11 Participants |
| Years since stroke 6+ | 8 Participants | 4 Participants | 12 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 23 | 0 / 22 |
| other Total, other adverse events | 4 / 23 | 2 / 22 |
| serious Total, serious adverse events | 0 / 23 | 0 / 22 |
Outcome results
Primary
Anterior-posterior Propulsion Forces of Paretic Side During Gait
Newtons: anterior-posterior force generated during push-off phase of the gait cycle
Time frame: Change from baseline to: Post 6-weeks training, 6 weeks after completion, and 3 (or 6) months
Population: Only 38 are included in the intention-to-treat analysis, as we excluded patients with no baseline or follow-up data on the primary outcomes.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Treadmill+Anklebot | Anterior-posterior Propulsion Forces of Paretic Side During Gait | Baseline | 2.22 Force in Newtons | Standard Deviation 12.37 |
| Treadmill+Anklebot | Anterior-posterior Propulsion Forces of Paretic Side During Gait | Post 6-week training | 4.92 Force in Newtons | Standard Deviation 10.99 |
| Treadmill+Anklebot | Anterior-posterior Propulsion Forces of Paretic Side During Gait | 6 weeks after completion | 6.06 Force in Newtons | Standard Deviation 8.92 |
| Treadmill+Anklebot | Anterior-posterior Propulsion Forces of Paretic Side During Gait | 3 (or 6) months after completion | 4.88 Force in Newtons | Standard Deviation 10.74 |
| Treadmill Only | Anterior-posterior Propulsion Forces of Paretic Side During Gait | 3 (or 6) months after completion | 3.98 Force in Newtons | Standard Deviation 10.74 |
| Treadmill Only | Anterior-posterior Propulsion Forces of Paretic Side During Gait | Baseline | 2.22 Force in Newtons | Standard Deviation 12.37 |
| Treadmill Only | Anterior-posterior Propulsion Forces of Paretic Side During Gait | 6 weeks after completion | 4.14 Force in Newtons | Standard Deviation 8.92 |
| Treadmill Only | Anterior-posterior Propulsion Forces of Paretic Side During Gait | Post 6-week training | 3.03 Force in Newtons | Standard Deviation 10.99 |
Primary
Gait Velocity During Self-selected Overground Walking
Gait velocity during self-selected overground walking measured in cm/sec
Time frame: Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months after completion
Population: Only 38 of patients were included in the intention-to-treat analysis, as we excluded patients who had no baseline or follow-up data on the primary outcomes.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Treadmill+Anklebot | Gait Velocity During Self-selected Overground Walking | Baseline | 0.48 CM/SEC | Standard Deviation 0.21 |
| Treadmill+Anklebot | Gait Velocity During Self-selected Overground Walking | Post 6-week training | 0.54 CM/SEC | Standard Deviation 0.24 |
| Treadmill+Anklebot | Gait Velocity During Self-selected Overground Walking | 6 weeks after completion | 0.53 CM/SEC | Standard Deviation 0.24 |
| Treadmill+Anklebot | Gait Velocity During Self-selected Overground Walking | 3 (or 6) months after completion | 0.52 CM/SEC | Standard Deviation 0.23 |
| Treadmill Only | Gait Velocity During Self-selected Overground Walking | 3 (or 6) months after completion | 0.55 CM/SEC | Standard Deviation 0.33 |
| Treadmill Only | Gait Velocity During Self-selected Overground Walking | Baseline | 0.48 CM/SEC | Standard Deviation 0.34 |
| Treadmill Only | Gait Velocity During Self-selected Overground Walking | 6 weeks after completion | 0.55 CM/SEC | Standard Deviation 0.33 |
| Treadmill Only | Gait Velocity During Self-selected Overground Walking | Post 6-week training | 0.56 CM/SEC | Standard Deviation 0.32 |
Primary
Peak Dorsiflexion Angle During Swing Phase of Gait
Degrees; extent of ankle dorsiflexion to enable foot clearance
Time frame: Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months after completion
Population: Only 38 are included in the intention-to-treat analysis, as we excluded patients who had no baseline or follow-up data on the primary outcomes.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Treadmill+Anklebot | Peak Dorsiflexion Angle During Swing Phase of Gait | Baseline | 3.95 Degrees | Standard Deviation 6.83 |
| Treadmill+Anklebot | Peak Dorsiflexion Angle During Swing Phase of Gait | Post 6-week training | 4.84 Degrees | Standard Deviation 6.83 |
| Treadmill+Anklebot | Peak Dorsiflexion Angle During Swing Phase of Gait | 6 weeks after completion | 4.34 Degrees | Standard Deviation 6.26 |
| Treadmill+Anklebot | Peak Dorsiflexion Angle During Swing Phase of Gait | 3 (or 6) months after completion | 3.33 Degrees | Standard Deviation 6.72 |
| Treadmill Only | Peak Dorsiflexion Angle During Swing Phase of Gait | 3 (or 6) months after completion | 3.43 Degrees | Standard Deviation 6.72 |
| Treadmill Only | Peak Dorsiflexion Angle During Swing Phase of Gait | Baseline | 3.95 Degrees | Standard Deviation 6.83 |
| Treadmill Only | Peak Dorsiflexion Angle During Swing Phase of Gait | 6 weeks after completion | 3.27 Degrees | Standard Deviation 6.26 |
| Treadmill Only | Peak Dorsiflexion Angle During Swing Phase of Gait | Post 6-week training | 4.24 Degrees | Standard Deviation 6.83 |
Primary
Peak Paretic Push Off Forces During Gait Initiation
Newtons; magnitude of forward ground reaction forces
Time frame: Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months
Population: Only 38 are included in the intention-to-treat analysis, as we excluded patients who had no baseline or follow-up data on the primary outcomes.~The results should be interpreted with extreme caution as there was inconsistent use of AFO's (ankle-foot orthosis) during evaluations and/or the training focus was on dorsiflexion assistance.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Treadmill+Anklebot | Peak Paretic Push Off Forces During Gait Initiation | Baseline | 64.7 Newtons | Standard Deviation 28.5 |
| Treadmill+Anklebot | Peak Paretic Push Off Forces During Gait Initiation | Post 6-week training | 63.5 Newtons | Standard Deviation 27 |
| Treadmill+Anklebot | Peak Paretic Push Off Forces During Gait Initiation | 6 weeks after completion | 65.4 Newtons | Standard Deviation 30.6 |
| Treadmill+Anklebot | Peak Paretic Push Off Forces During Gait Initiation | 3 (or 6) months after completion | 66.1 Newtons | Standard Deviation 29.9 |
| Treadmill Only | Peak Paretic Push Off Forces During Gait Initiation | 3 (or 6) months after completion | 70.9 Newtons | Standard Deviation 29.9 |
| Treadmill Only | Peak Paretic Push Off Forces During Gait Initiation | Baseline | 64.7 Newtons | Standard Deviation 28.5 |
| Treadmill Only | Peak Paretic Push Off Forces During Gait Initiation | 6 weeks after completion | 69.8 Newtons | Standard Deviation 30.6 |
| Treadmill Only | Peak Paretic Push Off Forces During Gait Initiation | Post 6-week training | 62.8 Newtons | Standard Deviation 27 |
Primary
Postural Sway Areas During Quiet Standing
cm\^2; extent of postural deviations to assess static postural control
Time frame: Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months
Population: Only 38 are included in the intention-to-treat analysis, as we excluded patients who had no baseline or follow-up data on the primary outcomes.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Treadmill+Anklebot | Postural Sway Areas During Quiet Standing | Baseline | 1.16 CM^2 | Standard Deviation 0.64 |
| Treadmill+Anklebot | Postural Sway Areas During Quiet Standing | Post 6-week training | 1.51 CM^2 | Standard Deviation 0.82 |
| Treadmill+Anklebot | Postural Sway Areas During Quiet Standing | 6 weeks after completion | 1.44 CM^2 | Standard Deviation 0.57 |
| Treadmill+Anklebot | Postural Sway Areas During Quiet Standing | 3 (or 6) months after completion | 1.59 CM^2 | Standard Deviation 0.52 |
| Treadmill Only | Postural Sway Areas During Quiet Standing | 3 (or 6) months after completion | 1.14 CM^2 | Standard Deviation 0.52 |
| Treadmill Only | Postural Sway Areas During Quiet Standing | Baseline | 1.16 CM^2 | Standard Deviation 0.64 |
| Treadmill Only | Postural Sway Areas During Quiet Standing | 6 weeks after completion | 1.13 CM^2 | Standard Deviation 0.52 |
| Treadmill Only | Postural Sway Areas During Quiet Standing | Post 6-week training | 1.33 CM^2 | Standard Deviation 0.82 |
Primary
Ratio of Asymmetric Loading in Quiet Standing
Ratio of Newtons of force per each leg (paretic/nonparetic) while standing quietly
Time frame: Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months
Population: This data was not recorded during the study nor calculated as part of the analysis.
Post Hoc
Dorsiflexion Angle at Foot Strike
Degrees, extent of ankle dorsiflexion at initial foot contact with the floor
Time frame: Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months after completion
Population: Only 38 are included in the intention-to-treat analysis, as we excluded patients who had no baseline or follow-up data on the primary outcomes.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Treadmill+Anklebot | Dorsiflexion Angle at Foot Strike | Baseline | -1.83 Degrees | Standard Deviation 5.03 |
| Treadmill+Anklebot | Dorsiflexion Angle at Foot Strike | 3 (or 6) months after completion | -2.99 Degrees | Standard Deviation 5.96 |
| Treadmill+Anklebot | Dorsiflexion Angle at Foot Strike | Post 6-week training | -0.70 Degrees | Standard Deviation 6.55 |
| Treadmill+Anklebot | Dorsiflexion Angle at Foot Strike | 6 weeks after completion | -2.18 Degrees | Standard Deviation 6.27 |
| Treadmill Only | Dorsiflexion Angle at Foot Strike | 6 weeks after completion | -2.15 Degrees | Standard Deviation 6.16 |
| Treadmill Only | Dorsiflexion Angle at Foot Strike | Post 6-week training | -0.46 Degrees | Standard Deviation 5.7 |
| Treadmill Only | Dorsiflexion Angle at Foot Strike | 3 (or 6) months after completion | -1.58 Degrees | Standard Deviation 6.71 |
| Treadmill Only | Dorsiflexion Angle at Foot Strike | Baseline | -1.83 Degrees | Standard Deviation 7.31 |