Current and frequency modulation for the characterization of electrically-elicited tactile sensations

Abstract

This study was aimed to characterize and investigate the feasibility of the electrically-elicited sensation as a sensory feedback technique. Two experiments were performed using a monophasic rectangular pulse train of which either the current or the frequency was modulated. The activation and pain thresholds, the discrimination ability and the description of the sensations were defined, measured and analyzed for ten healthy subjects. Diverse thresholds were acquired due to the individual differences in perceptual functioning, implying the technique should be intended for personalized systems. The discrimination ability was represented with a linear regression model providing the discrimination ability value that showed how much we have to change the parameter of interest in order to elicit a different sensation. 80% of the cases were well-represented by the linear regression models. The remaining 20% were better approximated by a curve, coinciding with the lowest discrimination ability values calculated for each experiment. The discrimination ability results provided an insight into the amount of information that can be transmitted to the body by our stimulation. The tactile sensations were reported as well-defined, describable and localizable. Our results supported the usability of electro-tactile stimulation as a non-invasive and easily-employable technique for the sensory feedback system.