Somatosensory Evoked Responses Elicited by Haptic Sensations in Mid–Air

The design of human machine interfaces (HMIs) by virtual haptics is an emerging field of research. So far, the perception of virtual haptic feedback, e.g., generated by focused ultrasound in mid–air has not been objectively evaluated. This study demonstrates the feasibility of eliciting somatosensory evoked potentials (SEPs) with ultrasonic stimuli in mid–air for the first time. The palm was stimulated by short ultrasonic focal points generated by an ultrasound board. The results are compared with a no–stimulation condition as well as with the results of a vibro–tactile stimulation. The SEPs are analyzed with the wavelet phase synchronization stability (WPSS) and the M-consecutive averaged WPSS. The results indicate a clear SEP waveform elicited by ultrasound. It can be significantly differentiated from a no–stimulation condition by the M-consecutive averaged WPSS. These results could enable the possibility of developing an objective evaluation method for virtual haptic feedback in HMIs.