Sensor-based hip control with hybrid neuroprosthesis for walking in paraplegia

Area of Science:

• Biomedical Engineering
• Rehabilitation Technology
• Neuroscience

Background:

• Gait impairment presents significant challenges for individuals requiring mobility assistance.
• Existing orthotic devices and functional neuromuscular stimulation (FNS) offer partial solutions but have limitations in improving posture and speed.
• Hybrid neuroprostheses (HNPs) integrating exoskeletal components with FNS show promise for enhanced gait rehabilitation.

Purpose of the Study:

• To evaluate a novel hybrid neuroprosthesis (HNP) featuring an exoskeletal variable-constraint hip mechanism (VCHM) and a functional neuromuscular stimulation (FNS) controller.
• To compare the HNP's effectiveness in maintaining upright posture and improving gait speed against an isocentric reciprocating gait orthosis (IRGO) and FNS alone.
• To assess the impact of the VCHM and the FNS controller on reducing upper-limb support requirements during walking.

Main Methods:

• Development and implementation of a hybrid neuroprosthesis (HNP) combining a VCHM with an FNS controller.
• Comparative gait analysis involving the HNP, IRGO, and FNS-only conditions.
• Measurement of upper-limb forces and assessment of postural stability (forward lean).
• Evaluation of walking speed under different HNP configurations (VCHM vs. fixed coupling, sensor-based FNS controller vs. fixed stimulation).

Main Results:

• The HNP significantly reduced forward lean compared to FNS-only walking.
• Maximum upper-limb forces were reduced by 42% compared to the IRGO and 19% compared to FNS-only gait.
• Walking speed increased significantly with the VCHM compared to 1:1 reciprocal coupling.
• A 15% increase in walking speed was observed using the sensor-based FNS controller compared to HNP with fixed baseline stimulation.

Conclusions:

• The hybrid neuroprosthesis (HNP) with VCHM and FNS controller effectively improves upright posture and reduces upper-limb support.
• The VCHM and sensor-based FNS controller contribute to enhanced gait speed and efficiency.
• This technology represents a significant advancement in neuroprosthetic gait assistance, offering improved mobility and reduced physical burden.