Stroke
Conditions
Keywords
Gait Rehabilitation, Functional Electrical Stimulation (FES), Stroke, Exosuit, Propulsion, Neuroprosthesis
Brief summary
This interventional study evaluates the effects of an overground propulsion neuroprosthesis that delivers adaptive neurostimulation assistance to the paretic plantarflexors and dorsiflexors of people post-stroke. Individuals with chronic post-stroke hemiparesis will walk with and without the neuroprosthesis overground and on a treadmill. The goal of the study is to understand how adaptive neurostimulation delivered by the neuroprosthesis affects clinical and biomechanical measures of walking function in order to guide future rehabilitation approaches for restoring walking ability after stroke.
Detailed description
This interventional study evaluates the effects of an overground propulsion neuroprosthesis that delivers adaptive neurostimulation assistance to the paretic plantarflexors and dorsiflexors of people post-stroke. Individuals with chronic post-stroke hemiparesis will walk with and without the neuroprosthesis overground and on a treadmill. The goal of the study is to understand how adaptive neurostimulation delivered by the neuroprosthesis affects clinical and biomechanical measures of walking function in order to guide future rehabilitation approaches for restoring walking ability after stroke. Ten individuals with chronic post-stroke hemiparesis will complete a single session of walking with and without the neuroprosthesis. Study evaluations will be conducted both before and after the session, without the neuroprosthesis active, and during the neuroprosthesis-supported walking.
Interventions
A neuroprosthesis is a textile-based surface neurostimulation system worn on the waist and paretic lower limb that delivers neurostimulation assistance via electroconductive pads placed on the skin over the target muscles. The neuroprosthesis provides dorsiflexor stimulation during swing phase for foot clearance and plantarflexor stimulation during stance phase for propulsion, delivered synchronously based on integrated sensors detecting the wearer's gait pattern.
Sponsors
Harvard University
National Institute for Biomedical Imaging and Bioengineering (NIBIB)
American Heart Association
Boston University Charles River Campus
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
All participants with stroke will complete study procedures that include walking with and without the intervention.
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Diagnosis of a stroke event occurring at least 6 months ago * Observable gait deficits * Independent ambulation for at least 30 meters (using an assistive device as needed but without a rigid brace or ankle foot orthosis) * Passive ankle dorsiflexion range of motion to neutral with the knee extended * Ability to follow a 3-step command * Resting heart rate between 40-100 bpm * Resting blood pressure between 90/60 and 170/90 mmHg * NIH Stroke Scale Question 1b score \> 1 and Question 1c score \> 0 * HIPAA Authorization to allow communication with healthcare provider * Medical clearance by a physician
Exclusion criteria
* Severe aphasia or inability to communicate with investigators * Neglect or hemianopia * Serious comorbidities that may interfere with ability to participate in the research (e.g. musculoskeletal, cardiovascular, pulmonary) * Pacemakers or similar electrical implants that could be affected by electrical stimulation * Metal implants directly under the stimulation sites * Pressure ulcers or skin wounds located near human-device interface sites * More than 2 unexplained falls in the previous month
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Unassisted Propulsion Symmetry at Comfortable Speed | Pre-Intervention; Post-Intervention | Propulsion symmetry during walking without neurostimulation assistance at a self-selected comfortable pace during the 10-Meter Walk Test. Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve. |
| Immediate Change in Walking Speed | Early Neurostimulation Timing Condition (40% stance); Late Neurostimulation Timing Condition (60% stance) | Change in walking speed from unassisted walking to walking with neurostimulation assistance at either an early or a late timing, measured at a self-selected fast pace across a straight 10-meter walkway. Early timing of plantarflexor neurostimulation was delivered at 40% of paretic limb support phase (before mid-stance). Late timing of plantarflexor neurostimulation was delivered at 60% of paretic limb support phase (after mid-stance). |
| Immediate Change in Paretic Propulsion | Early Neurostimulation Timing Condition (40% stance); Late Neurostimulation Timing Condition (60% stance) | Change in paretic propulsion from unassisted walking to walking with neurostimulation assistance at either an early or a late timing, measured at a self-selected fast pace across a straight 10-meter walkway. Early timing of plantarflexor neurostimulation was delivered at 40% of paretic limb support phase (before mid-stance). Late timing of plantarflexor neurostimulation was delivered at 60% of paretic limb support phase (after mid-stance). Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb. |
| Immediate Change in Propulsion Symmetry | Early Neurostimulation Timing Condition (40% stance); Late Neurostimulation Timing Condition (60% stance) | Change in propulsion symmetry from unassisted walking to walking with neurostimulation assistance at either an early or a late timing, measured at a self-selected fast pace across a straight 10-meter walkway. Early timing of plantarflexor neurostimulation was delivered at 40% of paretic limb support phase (before mid-stance). Late timing of plantarflexor neurostimulation was delivered at 60% of paretic limb support phase (after mid-stance). Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve. |
| Walking Speed at Non-Preferred Timing | Unassisted Walking Condition; Assisted Walking Condition | Walking speed with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. |
| Paretic Propulsion at Non-Preferred Timing | Unassisted Walking Condition; Assisted Walking Condition | Paretic propulsion with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb. |
| Propulsion Symmetry at Non-Preferred Timing | Unassisted Walking Condition; Assisted Walking Condition | Propulsion symmetry with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb. Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve. |
| Walking Speed at Preferred Timing | Unassisted Walking Condition; Assisted Walking Condition | Walking speed with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. |
| Paretic Propulsion at Preferred Timing | Unassisted Walking Condition; Assisted Walking Condition | Paretic propulsion with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb. |
| Propulsion Symmetry at Preferred Timing | Unassisted Walking Condition; Assisted Walking Condition | Propulsion symmetry with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb. Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve. |
| Unassisted Fast Walking Speed | Pre-Intervention; Post-Intervention | Walking speed without neurostimulation assistance measured at a self-selected fast pace using the 10-Meter Walk Test. |
| Unassisted Paretic Propulsion at Fast Speed | Pre-Intervention; Post-Intervention | Paretic propulsion during walking without neurostimulation assistance at a self-selected fast pace during the 10-Meter Walk Test. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb. |
| Unassisted Propulsion Symmetry at Fast Speed | Pre-Intervention; Post-Intervention | Propulsion symmetry during walking without neurostimulation assistance at a self-selected fast pace during the 10-Meter Walk Test. Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve. |
| Unassisted Comfortable Walking Speed | Pre-Intervention; Post-Intervention | Walking speed without neurostimulation assistance measured at a self-selected comfortable pace using the 10-Meter Walk Test. |
| Unassisted Paretic Propulsion at Comfortable Speed | Pre-Intervention; Post-Intervention | Paretic propulsion during walking without neurostimulation assistance at a self-selected comfortable pace during the 10-Meter Walk Test. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Onset Timing of Plantarflexor Neurostimulation | Early Neurostimulation Timing Condition (40% stance); Late Neurostimulation Timing Condition (60% stance) | The timepoint in the gait cycle when plantarflexor neurostimulation turns on. Early timing of plantarflexor neurostimulation was set at 40% of paretic limb support phase (before mid-stance). Late timing of plantarflexor neurostimulation was set at 60% of paretic limb support phase (after mid-stance). Actual delivery of neurostimulation may vary based on the inertial sensor based real-time control and sensing of gait features. |
| Preferred Neurostimulation Timing | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Early timing of plantarflexor neurostimulation was delivered at 40% of paretic limb support phase (before mid-stance). Late timing of plantarflexor neurostimulation was delivered at 60% of paretic limb support phase (after mid-stance). |
| Dorsiflexion Angle (No Dorsiflexor Impairment) | Pre-Intervention; Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning) | Dorsiflexion angle during walking at a self-selected fast pace across a straight 10-meter walkway for the subset of participants without paretic dorsiflexor impairment. Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture. |
| Dorsiflexion Angle (With Dorsiflexor Impairment) | Pre-Intervention; Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning) | Dorsiflexion angle during walking at a self-selected fast pace across a straight 10-meter walkway for the subset of participants with paretic dorsiflexor impairment. Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture. Negative dorsiflexion angle indicates plantarflexion of the foot, downwards from a neutral 90-degree position. |
| Immediate Change in Dorsiflexion Angle | Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning) | Change in dorsiflexion angle from unassisted walking to walking with neurostimulation assistance at either a non-preferred or a preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture. |
| Immediate Change in Plantarflexor Power | Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning) | Change in plantarflexor power from unassisted walking to walking with neurostimulation assistance at either a non-preferred or a preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Plantarflexor power is the peak rate of change in the rotation force of the foot towards the ground, measured using optical motion capture. |
| Dorsiflexion Angle at Non-Preferred Timing | Unassisted Walking Condition; Assisted Walking Condition | Dorsiflexion angle with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture. |
| Plantarflexor Power at Non-Preferred Timing | Unassisted Walking Condition; Assisted Walking Condition | Plantarflexor power with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Plantarflexor power is the peak rate of change in the rotation force of the foot towards the ground, measured using optical motion capture. |
| Dorsiflexion Angle at Preferred Timing | Unassisted Walking Condition; Assisted Walking Condition | Dorsiflexion angle with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture. |
| Plantarflexor Power at Preferred Timing | Unassisted Walking Condition; Assisted Walking Condition | Plantarflexor power with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Plantarflexor power is the peak rate of change in the rotation force of the foot towards the ground, measured using optical motion capture. |
| Unassisted Dorsiflexion Angle at Fast Speed | Pre-Intervention; Post-Intervention | Dorsiflexion angle during walking without neurostimulation assistance at a self-selected fast pace during the 10-Meter Walk Test. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture. |
| Unassisted Plantarflexor Power at Fast Speed | Pre-Intervention; Post-Intervention | Plantarflexor power during walking without neurostimulation assistance at a self-selected fast pace during the 10-Meter Walk Test. Plantarflexor power is the peak rate of change in the rotation force of the foot towards the ground, measured using optical motion capture. |
| Unassisted Plantarflexor Power at Comfortable Speed | Pre-Intervention; Post-Intervention | Plantarflexor power during walking without neurostimulation assistance at a self-selected comfortable pace during the 10-Meter Walk Test. Plantarflexor power is the peak rate of change in the rotation force of the foot towards the ground, measured using optical motion capture. |
| Unassisted Dorsiflexion Angle at Comfortable Speed | Pre-Intervention; Post-Intervention | Dorsiflexion angle during walking without neurostimulation assistance at a self-selected comfortable pace during the 10-Meter Walk Test. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture. |
Countries
United States
Participant flow
Recruitment details
Participants with chronic (\> 6 months) stroke were screened from a participant pool known to the Boston University Neuromotor Recovery Laboratory. Of the 18 participants screened, 13 participants were eligible for enrollment, and 10 participants completed the study. Exclusions: pacemaker (1), live far away / unwilling to travel (1), joint replacement (1), ankle dorsiflexion less than neutral (2), unable to be contacted (1), medical complications preventing participation (1), not interested (1).
Participants by arm
| Arm | Count |
|---|---|
| Neuroprosthesis-Assisted Walking Evaluation Participants with chronic stroke will perform a series of short overground walking evaluations at a self-selected fast walking speed with the neuroprosthesis powered and unpowered. When the neuroprosthesis is powered, it provides active neurostimulation assistance for foot clearance and propulsion. When the neuroprosthesis is unpowered, it is worn by the participant but does not provide active assistance.
Propulsion Neuroprosthesis: A neuroprosthesis is a textile-based surface neurostimulation system worn on the waist and paretic lower limb that delivers neurostimulation assistance via electroconductive pads placed on the skin over the target muscles. The neuroprosthesis provides dorsiflexor stimulation during swing phase for foot clearance and plantarflexor stimulation during stance phase for propulsion, delivered synchronously based on integrated sensors detecting the wearer's gait pattern. | 10 |
| Total | 10 |
Baseline characteristics
| Characteristic | Neuroprosthesis-Assisted Walking Evaluation |
|---|---|
| Age, Continuous | 52.5 years STANDARD_DEVIATION 10.6 |
| Comfortable Walking Speed | 0.93 meters per second (m/s) STANDARD_DEVIATION 0.23 |
| Dorsiflexion Angle | 2.07 degrees STANDARD_DEVIATION 5.04 |
| Dorsiflexor Impairment Dorsiflexor Impairment | 3 Participants |
| Dorsiflexor Impairment No Dorsiflexor Impairment | 7 Participants |
| Ethnicity (NIH/OMB) Hispanic or Latino | 1 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 6 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 3 Participants |
| Fast Walking Speed | 1.24 meters per second (m/s) STANDARD_DEVIATION 0.42 |
| Height | 176 centimeters (cm) STANDARD_DEVIATION 9 |
| Paretic Propulsion | 8.50 percent bodyweight (%bw) STANDARD_DEVIATION 4.6 |
| Paretic Side Left | 6 Participants |
| Paretic Side Right | 4 Participants |
| Propulsion Symmetry | 28.4 percent (%) STANDARD_DEVIATION 12.2 |
| Race/Ethnicity, Customized Race American Indian or Alaska Native | 0 Participants |
| Race/Ethnicity, Customized Race Asian | 0 Participants |
| Race/Ethnicity, Customized Race Black or African American | 0 Participants |
| Race/Ethnicity, Customized Race More than one race | 0 Participants |
| Race/Ethnicity, Customized Race Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race/Ethnicity, Customized Race Other: Iranian | 1 Participants |
| Race/Ethnicity, Customized Race Other: Puerto Rican | 1 Participants |
| Race/Ethnicity, Customized Race Unknown or Not Reported | 2 Participants |
| Race/Ethnicity, Customized Race White | 6 Participants |
| Sex/Gender, Customized Female | 2 Participants |
| Sex/Gender, Customized Male | 8 Participants |
| Sex/Gender, Customized Other | 0 Participants |
| Sex/Gender, Customized Unknown or Not Reported | 0 Participants |
| Stroke Chronicity | 7.5 years STANDARD_DEVIATION 4.5 |
| Weight | 87.77 kilograms (kg) STANDARD_DEVIATION 19.68 |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 10 |
| other Total, other adverse events | 0 / 10 |
| serious Total, serious adverse events | 0 / 10 |
Outcome results
Primary
Immediate Change in Paretic Propulsion
Change in paretic propulsion from unassisted walking to walking with neurostimulation assistance at either a late timing or an individual-specific preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Late timing of plantarflexor neurostimulation was delivered at 60% of paretic limb support phase (after mid-stance). Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb.
Time frame: Late Neurostimulation Timing Condition (60% stance); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Paretic Propulsion | Late Neurostimulation Timing Condition (60% stance) | 0.71 percent bodyweight (%bw) | Standard Error 0.6 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Paretic Propulsion | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 1.41 percent bodyweight (%bw) | Standard Error 0.48 |
Primary
Immediate Change in Paretic Propulsion
Change in paretic propulsion from unassisted walking to walking with neurostimulation assistance at either an early timing or an individual-specific preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Early timing of plantarflexor neurostimulation was delivered at 40% of paretic limb support phase (before mid-stance). Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb.
Time frame: Early Neurostimulation Timing Condition (40% stance); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Paretic Propulsion | Early Neurostimulation Timing Condition (40% stance) | 0.35 percent bodyweight (%bw) | Standard Error 0.41 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Paretic Propulsion | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 1.41 percent bodyweight (%bw) | Standard Error 0.48 |
Primary
Immediate Change in Paretic Propulsion
Change in paretic propulsion from unassisted walking to walking with neurostimulation assistance at either an early or a late timing, measured at a self-selected fast pace across a straight 10-meter walkway. Early timing of plantarflexor neurostimulation was delivered at 40% of paretic limb support phase (before mid-stance). Late timing of plantarflexor neurostimulation was delivered at 60% of paretic limb support phase (after mid-stance). Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb.
Time frame: Early Neurostimulation Timing Condition (40% stance); Late Neurostimulation Timing Condition (60% stance)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Paretic Propulsion | Early Neurostimulation Timing Condition (40% stance) | 0.35 percent bodyweight (%bw) | Standard Error 0.41 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Paretic Propulsion | Late Neurostimulation Timing Condition (60% stance) | 0.71 percent bodyweight (%bw) | Standard Error 0.6 |
Primary
Immediate Change in Paretic Propulsion
Change in paretic propulsion from unassisted walking to walking with neurostimulation assistance at either a non-preferred or a preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb.
Time frame: Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Paretic Propulsion | Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning) | -0.36 percent bodyweight (%bw) | Standard Error 0.36 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Paretic Propulsion | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 1.41 percent bodyweight (%bw) | Standard Error 0.48 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.00195% CI: [0.99, 2.56]t-test, 2 sided
Primary
Immediate Change in Propulsion Symmetry
Change in propulsion symmetry from unassisted walking to walking with neurostimulation assistance at either a non-preferred or a preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve.
Time frame: Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Propulsion Symmetry | Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning) | -2.13 percent (%) | Standard Error 0.78 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Propulsion Symmetry | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 1.19 percent (%) | Standard Error 1.26 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.01795% CI: [0.75, 5.89]t-test, 2 sided
Primary
Immediate Change in Propulsion Symmetry
Change in propulsion symmetry from unassisted walking to walking with neurostimulation assistance at either an early or a late timing, measured at a self-selected fast pace across a straight 10-meter walkway. Early timing of plantarflexor neurostimulation was delivered at 40% of paretic limb support phase (before mid-stance). Late timing of plantarflexor neurostimulation was delivered at 60% of paretic limb support phase (after mid-stance). Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve.
Time frame: Early Neurostimulation Timing Condition (40% stance); Late Neurostimulation Timing Condition (60% stance)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Propulsion Symmetry | Early Neurostimulation Timing Condition (40% stance) | -0.02 percent (%) | Standard Error 1.19 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Propulsion Symmetry | Late Neurostimulation Timing Condition (60% stance) | -0.92 percent (%) | Standard Error 1.16 |
Primary
Immediate Change in Propulsion Symmetry
Change in propulsion symmetry from unassisted walking to walking with neurostimulation assistance at either an early timing or an individual-specific preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Early timing of plantarflexor neurostimulation was delivered at 40% of paretic limb support phase (before mid-stance). Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve.
Time frame: Early Neurostimulation Timing Condition (40% stance); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Propulsion Symmetry | Early Neurostimulation Timing Condition (40% stance) | -0.02 percent (%) | Standard Error 1.19 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Propulsion Symmetry | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 1.19 percent (%) | Standard Error 1.26 |
Primary
Immediate Change in Propulsion Symmetry
Change in propulsion symmetry from unassisted walking to walking with neurostimulation assistance at either a late timing or an individual-specific preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Late timing of plantarflexor neurostimulation was delivered at 60% of paretic limb support phase (before mid-stance). Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve.
Time frame: Late Neurostimulation Timing Condition (60% stance); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Propulsion Symmetry | Late Neurostimulation Timing Condition (60% stance) | -0.92 percent (%) | Standard Error 1.16 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Propulsion Symmetry | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 1.19 percent (%) | Standard Error 1.26 |
Primary
Immediate Change in Walking Speed
Change in walking speed from unassisted walking to walking with neurostimulation assistance at either a non-preferred or a preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion.
Time frame: Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Walking Speed | Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 0.00 meters per second (m/s) | Standard Error 0.02 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Walking Speed | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 0.03 meters per second (m/s) | Standard Error 0.01 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.13195% CI: [-0.01, 0.07]t-test, 2 sided
Primary
Immediate Change in Walking Speed
Change in walking speed from unassisted walking to walking with neurostimulation assistance at either an early timing or an individual-specific preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Early timing of plantarflexor neurostimulation was delivered at 40% of paretic limb support phase (before mid-stance). Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion.
Time frame: Early Neurostimulation Timing Condition (40% stance); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Walking Speed | Early Neurostimulation Timing Condition (40% stance) | 0.01 meters per second (m/s) | Standard Error 0.01 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Walking Speed | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 0.03 meters per second (m/s) | Standard Error 0.01 |
Primary
Immediate Change in Walking Speed
Change in walking speed from unassisted walking to walking with neurostimulation assistance at either a late timing or an individual-specific preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Late timing of plantarflexor neurostimulation was delivered at 60% of paretic limb support phase (before mid-stance). Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion.
Time frame: Late Neurostimulation Timing Condition (60% stance); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Walking Speed | Late Neurostimulation Timing Condition (60% stance) | 0.03 meters per second (m/s) | Standard Error 0.02 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Walking Speed | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 0.03 meters per second (m/s) | Standard Error 0.01 |
Primary
Immediate Change in Walking Speed
Change in walking speed from unassisted walking to walking with neurostimulation assistance at either an early or a late timing, measured at a self-selected fast pace across a straight 10-meter walkway. Early timing of plantarflexor neurostimulation was delivered at 40% of paretic limb support phase (before mid-stance). Late timing of plantarflexor neurostimulation was delivered at 60% of paretic limb support phase (after mid-stance).
Time frame: Early Neurostimulation Timing Condition (40% stance); Late Neurostimulation Timing Condition (60% stance)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Walking Speed | Early Neurostimulation Timing (40% stance) | 0.01 meters per second (m/s) | Standard Error 0.01 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Walking Speed | Late Neurostimulation Timing (60% stance) | 0.03 meters per second (m/s) | Standard Error 0.02 |
Primary
Paretic Propulsion at Non-Preferred Timing
Paretic propulsion with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb.
Time frame: Unassisted Walking Condition; Assisted Walking Condition
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Paretic Propulsion at Non-Preferred Timing | Assisted Walking Condition | 11.83 percent bodyweight (%bw) | Standard Error 1.73 |
| Neuroprosthesis-Assisted Walking Evaluation | Paretic Propulsion at Non-Preferred Timing | Unassisted Walking Condition | 12.19 percent bodyweight (%bw) | Standard Error 1.51 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.34595% CI: [-1.18, 0.46]t-test, 2 sided
Primary
Paretic Propulsion at Preferred Timing
Paretic propulsion with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb.
Time frame: Unassisted Walking Condition; Assisted Walking Condition
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Paretic Propulsion at Preferred Timing | Unassisted Walking Condition | 11.87 percent bodyweight (%bw) | Standard Error 1.71 |
| Neuroprosthesis-Assisted Walking Evaluation | Paretic Propulsion at Preferred Timing | Assisted Walking Condition | 13.28 percent bodyweight (%bw) | Standard Error 1.89 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.01795% CI: [0.32, 2.5]t-test, 2 sided
Primary
Propulsion Symmetry at Non-Preferred Timing
Propulsion symmetry with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb. Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve.
Time frame: Unassisted Walking Condition; Assisted Walking Condition
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Propulsion Symmetry at Non-Preferred Timing | Unassisted Walking Condition | 32.2 percent (%) | Standard Error 2.7 |
| Neuroprosthesis-Assisted Walking Evaluation | Propulsion Symmetry at Non-Preferred Timing | Assisted Walking Condition | 30.0 percent (%) | Standard Error 3.1 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.02495% CI: [-3.9, -0.36]t-test, 2 sided
Primary
Propulsion Symmetry at Preferred Timing
Propulsion symmetry with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb. Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve.
Time frame: Unassisted Walking Condition; Assisted Walking Condition
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Propulsion Symmetry at Preferred Timing | Unassisted Walking Condition | 31.8 percent (%) | Standard Error 3.1 |
| Neuroprosthesis-Assisted Walking Evaluation | Propulsion Symmetry at Preferred Timing | Assisted Walking Condition | 33.0 percent (%) | Standard Error 3.4 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.37295% CI: [-1.67, 4.04]t-test, 2 sided
Primary
Unassisted Comfortable Walking Speed
Walking speed without neurostimulation assistance measured at a self-selected comfortable pace using the 10-Meter Walk Test.
Time frame: Pre-Intervention; Post-Intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Comfortable Walking Speed | Pre-Intervention | 0.93 meters per second (m/s) | Standard Error 0.07 |
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Comfortable Walking Speed | Post-Intervention | 1.06 meters per second (m/s) | Standard Error 0.08 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.01395% CI: [0.03, 0.21]t-test, 2 sided
Primary
Unassisted Fast Walking Speed
Walking speed without neurostimulation assistance measured at a self-selected fast pace using the 10-Meter Walk Test.
Time frame: Pre-Intervention; Post-Intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Fast Walking Speed | Pre-Intervention | 1.24 meters per second (m/s) | Standard Error 0.13 |
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Fast Walking Speed | Post-Intervention | 1.38 meters per second (m/s) | Standard Error 0.14 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.00195% CI: [0.07, 0.2]t-test, 2 sided
Primary
Unassisted Paretic Propulsion at Comfortable Speed
Paretic propulsion during walking without neurostimulation assistance at a self-selected comfortable pace during the 10-Meter Walk Test. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb.
Time frame: Pre-Intervention; Post-Intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Paretic Propulsion at Comfortable Speed | Pre-Intervention | 8.50 percent bodyweight (%bw) | Standard Error 1.46 |
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Paretic Propulsion at Comfortable Speed | Post-Intervention | 10.12 percent bodyweight (%bw) | Standard Error 1.24 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.01295% CI: [0.44, 2.78]t-test, 2 sided
Primary
Unassisted Paretic Propulsion at Fast Speed
Paretic propulsion during walking without neurostimulation assistance at a self-selected fast pace during the 10-Meter Walk Test. Paretic propulsion was calculated as the peak anterior-posterior ground reaction force of the paretic limb.
Time frame: Pre-Intervention; Post-Intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Paretic Propulsion at Fast Speed | Pre-Intervention | 11.20 percent bodyweight (%bw) | Standard Error 1.91 |
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Paretic Propulsion at Fast Speed | Post-Intervention | 13.44 percent bodyweight (%bw) | Standard Error 1.53 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.04395% CI: [0.09, 4.39]t-test, 2 sided
Primary
Unassisted Propulsion Symmetry at Comfortable Speed
Propulsion symmetry during walking without neurostimulation assistance at a self-selected comfortable pace during the 10-Meter Walk Test. Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve.
Time frame: Pre-Intervention; Post-Intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Propulsion Symmetry at Comfortable Speed | Pre-Intervention | 28.4 percent (%) | Standard Error 3.9 |
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Propulsion Symmetry at Comfortable Speed | Post-Intervention | 33.2 percent (%) | Standard Error 3.4 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.03695% CI: [0.39, 9.11]t-test, 2 sided
Primary
Unassisted Propulsion Symmetry at Fast Speed
Propulsion symmetry during walking without neurostimulation assistance at a self-selected fast pace during the 10-Meter Walk Test. Propulsion symmetry was calculated as the propulsion impulse of the paretic limb divided by the total propulsion impulse (paretic + nonparetic). Propulsion impulse is the area under the positive portion of the anterior-posterior ground reaction force curve.
Time frame: Pre-Intervention; Post-Intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Propulsion Symmetry at Fast Speed | Pre-Intervention | 28.7 percent (%) | Standard Error 4 |
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Propulsion Symmetry at Fast Speed | Post-Intervention | 33.2 percent (%) | Standard Error 3.2 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.04195% CI: [0.22, 8.83]t-test, 2 sided
Primary
Walking Speed at Non-Preferred Timing
Walking speed with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway.
Time frame: Unassisted Walking Condition; Assisted Walking Condition
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Walking Speed at Non-Preferred Timing | Unassisted Walking Condition | 1.30 meters per second (m/s) | Standard Error 0.14 |
| Neuroprosthesis-Assisted Walking Evaluation | Walking Speed at Non-Preferred Timing | Assisted Walking Condition | 1.30 meters per second (m/s) | Standard Error 0.15 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.87495% CI: [-0.034, 0.039]t-test, 2 sided
Primary
Walking Speed at Preferred Timing
Walking speed with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway.
Time frame: Unassisted Walking Condition; Assisted Walking Condition
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Walking Speed at Preferred Timing | Unassisted Walking Condition | 1.31 meters per second (m/s) | Standard Error 0.15 |
| Neuroprosthesis-Assisted Walking Evaluation | Walking Speed at Preferred Timing | Assisted Walking Condition | 1.34 meters per second (m/s) | Standard Error 0.15 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.04495% CI: [0, 0.06]t-test, 2 sided
Secondary
Dorsiflexion Angle at Non-Preferred Timing
Dorsiflexion angle with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture.
Time frame: Unassisted Walking Condition; Assisted Walking Condition
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Dorsiflexion Angle at Non-Preferred Timing | Unassisted Walking Condition | 2.16 degrees | Standard Error 1.93 |
| Neuroprosthesis-Assisted Walking Evaluation | Dorsiflexion Angle at Non-Preferred Timing | Assisted Walking Condition | 3.64 degrees | Standard Error 1.74 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.15295% CI: [-0.66, 3.63]t-test, 2 sided
Secondary
Dorsiflexion Angle at Preferred Timing
Dorsiflexion angle with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture.
Time frame: Unassisted Walking Condition; Assisted Walking Condition
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Dorsiflexion Angle at Preferred Timing | Unassisted Walking Condition | 1.83 degrees | Standard Error 1.98 |
| Neuroprosthesis-Assisted Walking Evaluation | Dorsiflexion Angle at Preferred Timing | Assisted Walking Condition | 3.29 degrees | Standard Error 1.73 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.15595% CI: [-0.67, 3.58]t-test, 2 sided
Secondary
Dorsiflexion Angle (No Dorsiflexor Impairment)
Dorsiflexion angle during walking at a self-selected fast pace across a straight 10-meter walkway for the subset of participants without paretic dorsiflexor impairment. Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture.
Time frame: Pre-Intervention; Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Dorsiflexion Angle (No Dorsiflexor Impairment) | Pre-Intervention | 4.50 degrees | Standard Deviation 3.56 |
| Neuroprosthesis-Assisted Walking Evaluation | Dorsiflexion Angle (No Dorsiflexor Impairment) | Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 5.15 degrees | Standard Deviation 5.52 |
| Neuroprosthesis-Assisted Walking Evaluation | Dorsiflexion Angle (No Dorsiflexor Impairment) | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 5.14 degrees | Standard Deviation 5.25 |
Secondary
Dorsiflexion Angle (With Dorsiflexor Impairment)
Dorsiflexion angle during walking at a self-selected fast pace across a straight 10-meter walkway for the subset of participants with paretic dorsiflexor impairment. Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture. Negative dorsiflexion angle indicates plantarflexion of the foot, downwards from a neutral 90-degree position.
Time frame: Pre-Intervention; Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Dorsiflexion Angle (With Dorsiflexor Impairment) | Pre-Intervention | -3.61 degrees | Standard Deviation 2.7 |
| Neuroprosthesis-Assisted Walking Evaluation | Dorsiflexion Angle (With Dorsiflexor Impairment) | Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 0.13 degrees | Standard Deviation 4.22 |
| Neuroprosthesis-Assisted Walking Evaluation | Dorsiflexion Angle (With Dorsiflexor Impairment) | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | -1.03 degrees | Standard Deviation 3.4 |
Secondary
Immediate Change in Dorsiflexion Angle
Change in dorsiflexion angle from unassisted walking to walking with neurostimulation assistance at either a non-preferred or a preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture.
Time frame: Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Dorsiflexion Angle | Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 1.48 degrees | Standard Error 0.95 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Dorsiflexion Angle | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 1.46 degrees | Standard Error 0.94 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.96295% CI: [-1.24, 1.19]t-test, 2 sided
Secondary
Immediate Change in Plantarflexor Power
Change in plantarflexor power from unassisted walking to walking with neurostimulation assistance at either a non-preferred or a preferred timing, measured at a self-selected fast pace across a straight 10-meter walkway. Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Plantarflexor power is the peak rate of change in the rotation force of the foot towards the ground, measured using optical motion capture.
Time frame: Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Plantarflexor Power | Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 0.13 watt per kilogram (W/kg) | Standard Error 0.08 |
| Neuroprosthesis-Assisted Walking Evaluation | Immediate Change in Plantarflexor Power | Preferred Neurostimulation Timing Condition (propulsion-based tuning) | 0.27 watt per kilogram (W/kg) | Standard Error 0.07 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.14695% CI: [-0.06, 0.35]t-test, 2 sided
Secondary
Onset Timing of Plantarflexor Neurostimulation
The timepoint in the gait cycle when plantarflexor neurostimulation turns on. Early timing of plantarflexor neurostimulation was set at 40% of paretic limb support phase (before mid-stance). Late timing of plantarflexor neurostimulation was set at 60% of paretic limb support phase (after mid-stance). Actual delivery of neurostimulation may vary based on the inertial sensor based real-time control and sensing of gait features.
Time frame: Early Neurostimulation Timing Condition (40% stance); Late Neurostimulation Timing Condition (60% stance)
Population: Neurostimulation timing information was not available for 2 participants due to issues with data streaming from the neuroprosthesis.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Onset Timing of Plantarflexor Neurostimulation | Early Neurostimulation Timing Condition (40% stance) | 46.9 percent stance (% stance) | Standard Deviation 2 |
| Neuroprosthesis-Assisted Walking Evaluation | Onset Timing of Plantarflexor Neurostimulation | Late Neurostimulation Timing Condition (60% stance) | 63.7 percent stance (% stance) | Standard Deviation 2 |
Secondary
Plantarflexor Power at Non-Preferred Timing
Plantarflexor power with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Plantarflexor power is the peak rate of change in the rotation force of the foot towards the ground, measured using optical motion capture.
Time frame: Unassisted Walking Condition; Assisted Walking Condition
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Plantarflexor Power at Non-Preferred Timing | Unassisted Walking Condition | 1.88 watts per kilogram (W/kg) | Standard Error 0.17 |
| Neuroprosthesis-Assisted Walking Evaluation | Plantarflexor Power at Non-Preferred Timing | Assisted Walking Condition | 2.00 watts per kilogram (W/kg) | Standard Error 0.2 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.15395% CI: [-0.06, 0.31]t-test, 2 sided
Secondary
Plantarflexor Power at Preferred Timing
Plantarflexor power with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway. Plantarflexor power is the peak rate of change in the rotation force of the foot towards the ground, measured using optical motion capture.
Time frame: Unassisted Walking Condition; Assisted Walking Condition
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Plantarflexor Power at Preferred Timing | Unassisted Walking Condition | 1.84 watts per kilogram (W/kg) | Standard Error 0.2 |
| Neuroprosthesis-Assisted Walking Evaluation | Plantarflexor Power at Preferred Timing | Assisted Walking Condition | 2.11 watts per kilogram (W/kg) | Standard Error 0.21 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.00495% CI: [0.11, 0.43]t-test, 2 sided
Secondary
Preferred Neurostimulation Timing
Timing preference was determined for each participant individually based on which of the early or late timings produced greater paretic propulsion. Early timing of plantarflexor neurostimulation was delivered at 40% of paretic limb support phase (before mid-stance). Late timing of plantarflexor neurostimulation was delivered at 60% of paretic limb support phase (after mid-stance).
Time frame: Preferred Neurostimulation Timing Condition (propulsion-based tuning)
| Arm | Measure | Category | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Preferred Neurostimulation Timing | Early Neurostimulation Timing Condition (40% stance) | 5 Participants |
| Neuroprosthesis-Assisted Walking Evaluation | Preferred Neurostimulation Timing | Late Neurostimulation Timing Condition (60% stance) | 5 Participants |
Secondary
Unassisted Dorsiflexion Angle at Comfortable Speed
Dorsiflexion angle during walking without neurostimulation assistance at a self-selected comfortable pace during the 10-Meter Walk Test. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture.
Time frame: Pre-Intervention; Post-Intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Dorsiflexion Angle at Comfortable Speed | Pre-Intervention | 2.07 degrees | Standard Error 1.59 |
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Dorsiflexion Angle at Comfortable Speed | Post-Intervention | 0.27 degrees | Standard Error 1.82 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.05295% CI: [-3.63, 0.02]t-test, 2 sided
Secondary
Unassisted Dorsiflexion Angle at Fast Speed
Dorsiflexion angle during walking without neurostimulation assistance at a self-selected fast pace during the 10-Meter Walk Test. Dorsiflexion angle is the positive angle between the foot and the shank from a neutral 90-degree position, measured using optical motion capture.
Time frame: Pre-Intervention; Post-Intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Dorsiflexion Angle at Fast Speed | Pre-Intervention | 2.85 degrees | Standard Error 1.98 |
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Dorsiflexion Angle at Fast Speed | Post-Intervention | 0.66 degrees | Standard Error 1.65 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.01495% CI: [-3.82, -0.56]t-test, 2 sided
Secondary
Unassisted Plantarflexor Power at Comfortable Speed
Plantarflexor power during walking without neurostimulation assistance at a self-selected comfortable pace during the 10-Meter Walk Test. Plantarflexor power is the peak rate of change in the rotation force of the foot towards the ground, measured using optical motion capture.
Time frame: Pre-Intervention; Post-Intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Plantarflexor Power at Comfortable Speed | Pre-Intervention | 1.25 watt per kilogram (W/kg) | Standard Error 0.12 |
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Plantarflexor Power at Comfortable Speed | Post-Intervention | 1.39 watt per kilogram (W/kg) | Standard Error 0.07 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.22195% CI: [-0.1, 0.39]t-test, 2 sided
Secondary
Unassisted Plantarflexor Power at Fast Speed
Plantarflexor power during walking without neurostimulation assistance at a self-selected fast pace during the 10-Meter Walk Test. Plantarflexor power is the peak rate of change in the rotation force of the foot towards the ground, measured using optical motion capture.
Time frame: Pre-Intervention; Post-Intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Plantarflexor Power at Fast Speed | Pre-Intervention | 1.78 watt per kilogram (W/kg) | Standard Error 0.2 |
| Neuroprosthesis-Assisted Walking Evaluation | Unassisted Plantarflexor Power at Fast Speed | Post-Intervention | 1.98 watt per kilogram (W/kg) | Standard Error 0.2 |
Comparison: An a priori power analysis (G\*Power 3.1.9.7) determined that a sample size of 10 participants could detect an effect size (Cohen's D) of 1.0 with 80% power and alpha = 0.05.p-value: 0.3595% CI: [-0.26, 0.66]t-test, 2 sided