Expanding Dynamic Range of Electrical Stimulation Using Anesthetic Cream

Electrical stimulation is one of the methods to stimulate skin sensation, and can provide sensations such as vibration and pressure by changing the polarity of the stimulus. These stimuli can be combined to design a variety of tactile sensations. However, there is a major problem with electrical stimulation: As the amount of electric current is increased, itching or pain sensation is elicited. This study aims to suppress the itching and pain caused by electrical stimulation, and to present strong, clear, and stable, pressure and vibration sensations. We applied an anesthetic cream containing lidocaine, which is one of the most used local anesthetics, to reduce the induced pain and itching. Therefore, we specifically examine the applicability of lidocaine toward a desirable situation, in which pain thresholds are increased and tactile thresholds are not significantly affected. The results showed a significant relationship between the application of the cream and the dynamic range of stimulating current, and subsequently the quality of experience by human participants.