Variation of Finger Activation Patterns Post-stroke Through Non-invasive Nerve Stimulation

Area of Science:

• Neuroscience
• Rehabilitation Engineering
• Biomedical Engineering

Background:

• Stroke survivors often experience severe hand impairment, limiting daily activities.
• Previous research demonstrated flexible multi-finger activation using transcutaneous proximal nerve stimulation (TPNS) with electrode grids.
• This case study investigates TPNS for inducing diverse finger grasp patterns in a stroke survivor.

Observation:

• An individual with chronic hemiplegia and severe hand impairment received TPNS via an electrode grid targeting ulnar and median nerves.
• Selective activation of finger flexor muscles was achieved using an automated electrode switching method.
• Isometric flexion forces and high-density electromyography (HDEMG) were recorded to analyze finger activation patterns.

Findings:

• Both contralateral and paretic hands exhibited single and multi-finger activation patterns.
• The paretic hand, despite fewer patterns, showed combinations activating all four fingers.
• Contralateral hand activation primarily involved median nerve stimulation of the index, middle, and ring fingers.

Implications:

• TPNS can elicit varied finger activation patterns in stroke survivors with limited hand function.
• This technology holds potential for enhancing rehabilitative training for functional grasp patterns.
• The system may aid in regaining muscle mass and improving hand function post-stroke.