Preliminary Study of Portable Vibrotactile and Electrical Stimulation System for Knee Proprioception Enhancement

Wearable robots assist elderly people with daily living activities like walking. The majority of walking or falling problems in the elderly stem from the reduction of skeletal muscle mass and proprioceptive performance. The existing wearable robots can help with muscle strength but not proprioception. In this paper, we perform a preliminary study of a lightweight, compact, and portable stimulation device for enhancing knee proprioception that combines stochastic resonance-based vibrotactile stimulation with transcutaneous electrical nerve stimulation. To assess proprioceptive acuity, we develop an experimental setup and protocol for a joint position matching test. Pilot tests of the proposed system with five young and healthy subjects are performed, and their results show a smaller matching error where vibrotactile and electrical stimulation is applied compared to where stimulation is not applied. We foresee that the developed system can be easily integrated into wearable robots to enhance muscle strength and proprioceptive function simultaneously.