Pain Sensations Associated with Electrocutaneous Stimulation

This paper discusses the results of experiments carried out to determine the feasibility of using electrocutaneous stimulation in sensory substitution systems. The sharp, pricking pain often associated with electrocutaneous stimulation has been found to be a result of thermal damage to the corneal layer of the skin. The high-energy densities required to create this damage often occur, even at moderate stimulation currents, because of the highly nonhomogeneous nature of the skin-electrode interface. However, this pain can be controlled without resorting to electrode pastes by adopting a simple procedure for applying the electrode. The dynamic range and the stability of the sensation magnitude have been measured under paste-free conditions and the conclusion is reached that electrocutaneous stimulation would be a viable alternative to mechanical stimulation in certain sensory substitution applications.