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.
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.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
10
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.
Science and Engineering Complex
Boston, Massachusetts, United States
Neuromotor Recovery Laboratory
Boston, Massachusetts, United States
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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
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
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
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
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
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
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
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
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
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
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
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
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)
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)
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)
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.
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Time frame: Pre-Intervention; Non-Preferred Neurostimulation Timing Condition (propulsion-based tuning); Preferred Neurostimulation Timing Condition (propulsion-based tuning)
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)
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)
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
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
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
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
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
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
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
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