Intention-driven functional electrical stimulation therapy using a wearable high-density electrode sleeve in chronic stroke: a case report

BACKGROUND: Functional electrical stimulation (FES) has been recognized for decades as a method to retrain the motor system after stroke. Benefits of FES rehabilitation can be enhanced by (1) combining FES with task-oriented therapy (i.e. FES therapy (FEST)), (2) timing FES with the user's volitional motor intention and (3) incorporating multiple trained tasks, as opposed to high repetitions of single tasks. Using a novel wearable FES technology, we tested therapy incorporating these elements in two chronic stroke survivors. METHODS: Our group has developed the NeuroLife Sleeve, a wearable forearm sleeve that contains a high-density grid of embedded FES electrodes, that may be controlled by an operator or by the wearer's own electromyographic (EMG) signals. The system enables rapid software-based switching between stimulation configurations for different functional movements without repeated electrode repositioning. During eight weeks of FEST, intention-driven FES enabling multiple movements was delivered via operator control twice weekly and EMG control once weekly. RESULTS: At the end of the therapy period, subjects A and B had both improved their scores: Box and Blocks Test (A: +5, B: +7), the Action Research Arm Test (A: +7, B: +12), the Fugl Meyer Upper Extremity section (A: +11, B: +9), and the 9-Hole Peg Test (A: 158 s, B: 54 s, both previously unable). Clinical improvements persisted during the 10-week follow-up period, during which FES exposure was reduced by more than 80%. CONCLUSIONS: This case report provides a proof-of-concept demonstration of the NeuroLife Sleeve to support FEST and preliminary evidence that intention-driven FEST may support motor recovery in chronic stroke survivors. The NeuroLife Sleeve is a novel device designed to deliver this therapy through the easily donned wearable sleeve interface, support for both operator-triggered and EMG-controlled FES paradigms, and efficient transitions between tasks with programmable FES placement and parameters. Because both control modes were used throughout the intervention, the relative therapeutic contribution of each cannot be distinguished. TRIAL REGISTRATION: We retrospectively registered the trial with ClinicalTrials.gov (16/01/2024, NCT06207240).