A Comparison of Vibrotactile Feedback and Electrical Muscle Stimulation (EMS) for Motor Response During Active Hand Movement

Wearable haptic technologies have garnered recent widespread attention due to increased accessibility, functionality, and affordability. These systems typically provide haptic feedback to augment the human ability to interact with their environment. This study compares two haptic feedback modalities, vibrotactile and EMS, against visual feedback to elicit a motor response during active hand movement. Forty-five participants, divided into three groups, performed a task to touch their face and received one of three possible sensory feedback cues, namely visual, vibrotactile, and electrical muscle stimulation (EMS), to interrupt their movement and avoid touching their face. Two quantitative performance measures are used in the comparison, the response time (time elapsed from stimulation to motor response) and the error rate (percentage that the user fails to avoid touching their face). Results showed that vibrotactile and EMS feedback yielded significantly faster response time than visual feedback, while no significant differences between vibrotactile and EMS were observed. Furthermore, the error rate was significantly lower for EMS compared to visual feedback, whereas no significant differences were observed between vibrotactile and visual feedback. In conclusion, it seems that EMS feedback is preferable for applications where errors are not tolerable (critical medical applications), whereas vibrotactile is superior for non-critical applications due to its low cost and higher usability (more pleasant compared to EMS).