An implanted myoelectrically-controlled neuroprosthesis for upper extremity function in spinal cord injury

Area of Science:

• Biomedical Engineering
• Neuroprosthetics
• Rehabilitation Engineering

Background:

• Cervical spinal cord injury (SCI) significantly impairs upper limb function, affecting grasp-release, forearm pronation, and elbow extension.
• Existing neuroprosthetic devices often require extensive external components, limiting user convenience and independence.

Purpose of the Study:

• To evaluate a second-generation implantable neuroprosthesis designed for improved control of upper limb functions in individuals with cervical SCI.
• To assess the feasibility and efficacy of using implanted myoelectric signal recording in conjunction with functional electrical stimulation.

Main Methods:

• Development of a neuroprosthesis with 12 stimulating and 2 myoelectric recording electrodes, integrated with an implanted stimulator-telemeter.
• Clinical implementation in seven individuals with C5/C6 SCI, involving nine arms.
• Simultaneous recording of myoelectric signals and electrical stimulation of muscles.

Main Results:

• Successful recording of myoelectric signals from voluntary muscles during concurrent electrical stimulation.
• Significant improvements in pinch force and grasp function observed in all participants.
• Enhanced independence and improved performance in activities of daily living reported by subjects.

Conclusions:

• The second-generation implantable neuroprosthesis demonstrates effective restoration of upper limb function for individuals with cervical SCI.
• Implanted myoelectric signal recording is a viable and beneficial control strategy for neuroprosthetic systems.
• The system offers a promising avenue for increasing independence and quality of life in SCI patients.