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Final Program


Final Program

1267 - Stimulation of Forearm Extensors to Facilitate Tenodesis Grip: A Prototype Study

Thursday, February 27, 2025
5:00 PM - 6:30 PM MST
Objectives: This research aims to develop an assistive FES device to enable tenodesis grasp in C5 spinal cord injury (SCI) patients who maintain some proximal arm function but lack hand or wrist control. Artificially evoking a tenodesis grasp has the potential to increase a patient’s functional capabilities and independence by increasing their ability to directly manipulate objects in their environment. To achieve this objective, we developed a voice-controlled functional electrical stimulation to activate wrist extensors and provoke finger flexion via tenodesis.

Design: The system is comprised of a sleeve with two integrated electrodes positioned to target the extensor carpi ulnaris and flexor digitorum muscles. Voice commands are used to activate or deactivate the stimulation applied to the electrodes in real time. Motion capture imaging mounted below the hand was used to measure evoked wrist extension and finger flexion in four healthy participants and one SCI participant.

Results: Activating stimulation extended the wrist by 38.59+19.07° for the four healthy participants and by 57.98+5.86° for the SCI participant. Stimulation also decreased the distance from the distal end of the middle finger to the palm by 16.75+5.9 mm in healthy participants and by 10.14+0.08 mm for the SCI participant. Preliminary data tested on two of the healthy participants show that the system can be used to successfully grasp and move objects using the evoked tenodesis grip.

Conclusions: Voice-controlled FES appears effective in evoking the tenodesis grasp by inducing sufficient wrist extension paired with middle finger flexion. Future studies will assess the performance of evoked grasp in SCI patients completing functional tasks. This work constitutes an important step towards developing a patient-controlled assistive device that restores grasping function in C5 SCI patients.