Sensory Feedback using Electrical Stimulation of the Tactile Sense

This chapter reviews what is known about sensory feedback using electrical stimulation of the skin surface or the underlying peripheral afferent nerves. The purposeful introduction of electrical stimuli to the skin sense can be by surface electrodes, subdermal wire electrodes, or neural electrodes. Sensory feedback systems for artificial arms have utilized mechanical vibrators, direct afferent neural stimulation, and electrocutaneous stimulation to access the tactile sense. The tactile sensory apparatus in hairy skin differs considerably from that in glabrous skin. Electrotactile sensory feedback has also been used to improve the functional neuromuscular stimulation of paralyzed limbs for movement and postural stability. The chapter then discusses proper techniques as to electrode size, number, and placement for all stimulation approaches. It describes some of the constraints and the anatomical structure and innervation of the skin relevant to the design of cutaneous communication systems.