Clinical effectiveness and participant perceptions of an implanted closed-loop neurostimulator-sensor system for arm rehabilitation post-stroke

Therapeutic functional electrical stimulation has been shown to be effective in improving upper limb function post-stroke and when stimulation is associated with a patient’s own voluntary activation the effect is enhanced. This paper presents results from the end phase of a feasibility study using implanted microstimulators with a closed-loop control system. The system used sensors (goniometer, touch mat and button switch) to allow voluntary activation and timing of stimulation to be responsive to participants’ speed of movement. Participants used the system in a daily home exercise programme for 12 weeks. Functional and impairment measures were taken before and after the treatment period and compared with participants’ perspectives assessed using a questionnaire. Clinical results showed this stimulation system effective to bring about a mean (SD) improvement of 5 (5.2) in the Action Research Arm Test and a statistically significant change in the Fugl Meyer test (5.3 (4.0), p=0.021). Participants also perceived the sensors to be effective but the goniometer and touch mat to be unreliable. Future systems with external control mechanisms need to be both effective and reliable.