Biplanar Ankle Assistance for Dropfoot Gait Post-Stroke with Multi-Objective Human-In-the-Loop Optimization: A Case...

Area of Science:

• Rehabilitation Engineering
• Biomechanics
• Neurorehabilitation

Background:

• Exoskeletons show promise for motor disorder assistance, but lack personalized approaches and strong evidence.
• Stroke survivors often experience gait impairments like dropfoot and excessive inversion.

Purpose of the Study:

• To develop and evaluate a cable-driven ankle exoskeleton for individuals with post-stroke dropfoot and inversion.
• To implement a multi-objective human-in-the-loop optimization for personalized assistive profiles.

Main Methods:

• A cable-driven ankle exoskeleton was designed to assist ankle motion in two planes.
• A human-in-the-loop optimization strategy was used to minimize foot kinematics deviation and step length asymmetry.
• Experimental data from a single chronic stroke participant was collected to assess device feasibility and effectiveness.

Main Results:

• The exoskeleton successfully assisted ankle motion, improving foot inclination angle at initial contact (from -2° to 10°).
• Participant's ankle inversion angle decreased from 2° to 0°, and foot clearance during swing increased from 31 mm to 44 mm.
• Step length asymmetry was reduced from 12% to 6%, demonstrating improved gait quality.

Conclusions:

• The developed ankle exoskeleton and optimization approach are feasible for assisting individuals with post-stroke dropfoot and inversion.
• The human-in-the-loop optimization provides a set of individualized assistive profiles, allowing user-based prioritization.
• This technology holds significant potential for personalized rehabilitation and assistance in daily activities.