Strength-Duration Properties of the Upper Limb under Surface Electrical Stimulation for Rehabilitation

We introduce a new experimental study on nerve excitability, when surface electrodes stimulate the upper arm in rehabilitative protocols. Nerve excitability is usually described by means of the strength-duration curve, i.e. the stimulation current amplitude versus the pulse duration for threshold activation. With the final aim of designing and validating a nerve model, in the present contribution an extensive experimental session is conducted to investigate how the nerve excitability is influenced by gender, subcutaneous fat layer thickness and FES parameters. Different experiments are conducted and the most appropriate curve-fitting equation for the data is identified. Beside the nerve model validation, the proposed approach can be used for automatic setting of stimulation parameters in FES-based rehabilitation treatments.