Trial Outcomes & Findings for Effects of an Overground Propulsion Neuroprosthesis in Community-dwelling Individuals After Stroke (NCT NCT06459401)

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).

Effects of an Overground Propulsion Neuroprosthesis in Community-dwelling Individuals After Stroke

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).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Walking speed with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway.

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 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 with or without neurostimulation assistance measured at a self-selected fast pace across a straight 10-meter walkway.

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 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 without neurostimulation assistance measured at a self-selected fast pace using the 10-Meter Walk Test.

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.

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.

Walking speed without neurostimulation assistance measured at a self-selected comfortable pace using the 10-Meter Walk Test.

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.

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.

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.

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 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 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.

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.

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 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 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 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 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 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.

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.

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.

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.