A kinematic-and-muscular modulation strategy for FES-assisted upper limb rehabilitation: a feasibility study

Functional Electrical Stimulation (FES) is widely adopted for patient rehabilitation since it provides electrical pulses and, consequently, muscle contractions. The aim of the study is to develop a novel closed-loop multichannel contralaterally controlled FES technique for upper limb rehabilitation. In the proposed approach (Kinematic-and-Muscular-based Modulation Strategy, KMMS), the stimulation is off-line modulated by the difference of the myoelectric activity of the same muscle between limbs with the addition of on-line feedback due to kinematic patterns. The reference signals for stimulation were extracted from a dataset of myoelectric and kinematic patterns acquired from the dominant upper limb of ten healthy participants. KMMS represents an improvement of a literature technique (Muscular-based Modulation Strategy, MMS) where the stimulation is off-line modulated exclusively by electromyographic patterns. KMMS and MMS performance were compared by applying them to eight muscles of the non-dominant upper limb of ten healthy participants during ADL execution. KMMS demonstrated an improved completion rate during drinking (from 70% to 89%, P = 0.0200), pouring (from 75% to 89%, P = 0.0435), eating (from 72% to 86%) and handling objects (from 80% to 93%, P = 0.0414).