Intuitive omnidirectional vibrotactile feedback from a sensorized insole for lower-limb prostheses users: a...

Area of Science:

• Biomedical Engineering
• Rehabilitation Technology
• Prosthetics

Background:

• Non-invasive sensory feedback for lower-limb prosthetics offers clinical convenience but often lacks information bandwidth and spatial resolution.
• Existing feedback systems are typically evaluated in specialized tasks, limiting insights into real-world applicability.

Purpose of the Study:

• To introduce and evaluate OmniFeel, a novel sensory feedback system designed to intuitively convey omnidirectional foot pressure information.
• To assess OmniFeel's effectiveness through psychophysical pattern recognition and holistic measures during ecological walking tasks.

Main Methods:

• OmniFeel utilizes a sensorized insole and eight vibration motors to provide tactile feedback.
• Evaluations included psychophysical pattern recognition (static and dynamic) and holistic assessments (biomechanics, gaze, task load, user experience).
• Participants (able-bodied and lower-limb amputees) performed overground walking and stair navigation tasks with and without cognitive load and feedback.

Main Results:

• The OmniFeel feedback scheme demonstrated high accuracy in recognizing spatial patterns (81.5% static, 95.75% dynamic) with minimal training.
• Feedback reduced task load and the need for visual floor monitoring during walking.
• In amputee participants, OmniFeel improved stance time symmetry and increased confidence, particularly during stair ambulation.

Conclusions:

• OmniFeel provides rich, interpretable foot sole pressure information through non-invasive tactile feedback.
• The system shows significant potential for enhancing the use of lower-limb prostheses in real-life environments.