Assisting Sit-To-Stand Through Event-Based Electrical Stimulation of Trunk Control: A Preliminary Study

Area of Science:

• Biomedical Engineering
• Neurorehabilitation
• Assistive Technology

Background:

• Functional mobility is crucial for independence, yet spinal cord injury (SCI) severely impairs it.
• Existing assistive technologies like functional electrical stimulation (FES) and exoskeletons have limitations for sit-to-stand (STS) tasks.
• Hybrid FES exoskeletons offer potential but often neglect trunk muscle activation, critical for SCI individuals.

Purpose of the Study:

• To investigate the feasibility and effects of FES targeting the erector spinae muscles for STS assistance in conjunction with a wearable lower limb exoskeleton.
• To analyze joint kinematics during STS in healthy and SCI participants, with and without FES.
• To explore how FES of the erector spinae influences trunk motion during STS in SCI.

Main Methods:

• A wearable lower limb exoskeleton was utilized.
• Functional electrical stimulation (FES) was applied to the erector spinae muscles.
• Joint kinematics were measured for healthy and SCI participants performing STS with and without FES.

Main Results:

• SCI participants exhibited distinct hip motion patterns during STS, including excessive trunk flexion and delayed extension compared to healthy controls.
• Knee kinematics were comparable between healthy and SCI groups.
• FES application intensified trunk flexion in SCI participants and initiated movement post-extension, altering trunk dynamics.

Conclusions:

• FES of the erector spinae appears feasible for assisting STS in SCI individuals.
• This stimulation alters SCI trunk motion, potentially improving stability and promoting independence.
• Hybrid FES exoskeletons targeting trunk muscles could significantly advance mobility solutions for SCI.