Abstract TP339: Feasibility of a Gamified Neurostimulation Platform for Retraining Neuromotor Control After Stroke

Introduction: Impaired control of the distal paretic limb muscles is a persistent neuromotor deficit after stroke that limits ground clearance and propulsion during walking. Neuromuscular stimulation (stim) offers a means to both evaluate and treat these deficits, particularly when paired with adaptive and engaging training paradigms. Here, we present a gamified, neurostimulation-augmented neuromotor intervention designed to retrain control of the paretic dorsiflexor and plantarflexor muscles. The platform combines bi-directional stimulation with an intuitive, adaptive, and motivational gaming interface to support dorsiflexion (DF) and plantarflexion (PF) within goal-directed tasks. We tested the feasibility of individuals post-stroke improving task performance with stimulation. Methods: Four healthy adults and two individuals with chronic stroke participated. An inertial sensor placed under the foot captured ankle joint angles, which a custom Python program translated into real-time control of a two-target, center-out cursor reaching task. Subjects completed three sequential blocks: (1) no stim, (2) stim (at the highest tolerable amplitude), and (3) no stim. Each block included four trials per target. During stimulation, continuous pulses (40 Hz, 400 μs) were delivered to dorsiflexors during center-up trials and plantarflexors during center-down trials. Stroke subjects completed an additional difficulty block (six trials per target) with progressively increasing angle requirements (1° to 6°). Task movement time (MT) and smoothness were calculated per trial, averaged across targets, and compared between blocks. Results: Healthy subjects showed minimal changes in MT or smoothness with stim, whereas stroke subjects demonstrated clear benefits. For S1, DF stim improved MT by 1.51 s (-37%) and smoothness by 0.65 (+7%); PF stim improved MT by 0.13 s (-7%) and smoothness by 0.14 (+2%). For S2, DF stim improved MT by 0.57 s (-28%) and smoothness by 0.39 (+5%); PF stim improved MT by 1.44 s (-37%) and smoothness by 0.90 (+10%). In the progressive difficulty block, stim supported S1 to complete 4/6 levels, and S2 completed 6/6 levels, whereas neither subject could complete any levels without stim. Conclusions: This study demonstrates the feasibility of a neurostimulation-augmented gaming platform for retraining paretic neuromuscular control after stroke. The immediate performance gains highlight the potential to advance both clinical and home-based rehabilitation.