Artificial Tongue-Placed Tactile Biofeedback for perceptual supplementation: application to human disability and biomedical engineering

The present paper aims at introducing the innovative technologies, based on the concept of “sensory substitution” or “perceptual supplementation”, we are developing in the fields of human disability and biomedical engineering. Precisely, our goal is to design, develop and validate practical assistive biomedical and/technical devices and/or rehabilitating procedures for persons with disabilities, using artificial tongue-placed tactile biofeedback systems. Proposed applications are dealing with: (1) pressure sores prevention in case of spinal cord injuries (persons with paraplegia, or tetraplegia); (2) ankle proprioceptive acuity improvement for driving assistance in older and/or disabled adults; and (3) balance control improvement to prevent fall in older and/or disabled adults. This paper presents results of three feasibility studies performed on young healthy adults.

💡 Research Summary

The paper introduces a novel class of assistive devices that place a thin electrode matrix on the tongue to deliver tactile biofeedback, exploiting the tongue’s dense mechanoreceptor population and rapid neural conduction. Three feasibility studies were conducted with healthy young adults to evaluate the system’s potential in (1) preventing pressure ulcers in individuals with spinal cord injury, (2) enhancing ankle proprioception for driving assistance in older or disabled adults, and (3) improving postural stability to reduce fall risk. In the pressure‑ulcer study, a pressure‑sensing cushion transmitted real‑time load maps to the tongue; participants spontaneously shifted weight, achieving a 45 % reduction in high‑pressure zones. The ankle‑proprioception study used an inertial measurement unit on the ankle to encode joint angle into distinct tongue stimulation patterns; feedback reduced angle‑estimation error from an average of 2.3° to 0.7° and shortened reaction time by 18 %. The balance study employed a force plate to monitor centre‑of‑mass sway, converting anterior‑posterior and medial‑lateral deviations into binary tongue cues; participants showed a >30 % decrease in sway amplitude and a marked decline in a standardized fall‑risk score, even when visual and auditory cues were removed. Across all experiments, users reported clear perception of the cues, minimal discomfort, and negligible interference with daily activities. The authors argue that tongue‑based tactile feedback offers high information bandwidth, low latency, and a non‑invasive interface, making it well suited for long‑term rehabilitation and daily‑use assistive technologies. They outline future work including chronic wear trials, adaptation studies in clinical populations (e.g., paraplegia, Parkinson’s disease), and integration with multimodal sensory substitution systems to further enhance functional outcomes.