Haptic Biofeedback for Wakeful Rest: Does Stimulation Location Make a Difference?

TL;DR

This study compares different body locations for wearable haptic biofeedback during wakeful rest, finding that forearm and shoulder placements enhance relaxation and comfort more effectively than the wrist.

Contribution

It systematically evaluates how biofeedback location affects relaxation, comfort, and physiological responses during wakeful rest, guiding better design of wearable relaxation devices.

Findings

Forearm and shoulder placements increase subjective relaxation and comfort.

Wrist placement reduces recognition but less effective for relaxation.

Heart rate decreases at wrist, shoulder, and forearm, but alpha activity remains unchanged.

Abstract

Wearable haptic interventions offer promising support for relaxation through slow, vibrotactile biofeedback. Despite their potential, current applications focus on stress-inducing procedures and fixed vibration patterns, with limited consideration of body location and dynamic biofeedback during restful states. This study investigates the effects of haptic biofeedback adjusted from real-time heart rate during eyes-closed wakeful rest, comparing four wearable body placements: the wrist, hand, forearm, and shoulder. Heart rate, alpha wave activity on the ear, subjective restfulness, and vibration experience were measured across these conditions. Results show that biofeedback reduced heart rate at the wrist, shoulder, and forearm, while alpha power measured at the ear remained unchanged. Subjective restfulness was rated highest at the shoulder and forearm, which were also the most preferred locations. In addition, participants reported greater comfort, relaxation, and further increased sleepiness at the forearm compared to the wrist, which was more easily recognizable. These findings suggest that the forearm and shoulder are ideal for unobtrusive relaxation feedback for wakeful rest, while the wrist may require design improvements for subjective experience.