Functional electrical stimulation reinforced tenodesis effect controlled by myoelectric activity from wrist extensors

Abstract

Abstract-We demonstrated a method for enhancing the tenodesis grip in individuals with sustained tetraplegia with spinal cord lesion at the C6-C7 neurological level. Subjects used the myoelectric activity from wrist extensor muscles to directly control the electrical stimulation of the extrinsic finger and thumb flexors (flexor pollicis longus and flexor digitorum superficialis/profondus) with the use of a specially designed system, Myoelectrically Controlled Functional Electrical Stimulation (MeCFES). We screened 20 medical records and selected 9 subjects. Of the nine subjects, five showed a positive response to the surface stimulation and could test the system; the other four failed to achieve functional finger flexion because of skin sensitivity or inadequate movement. We evaluated hand function, with and without the MeCFES system, using tests involving three everyday objects: manipulating a videocassette with the key grip, drinking from a bottle with the palmar grasp, and writing with a pen using the tripod grip. Without the system, none of the five subjects could complete all three tasks; but, when assisted with MeCFES, all subjects completed all the tasks. The system proved simple and intuitively easy to use, and no training was needed for subjects to obtain immediate functionality. We will need further research to evaluate the usefulness of the system in activities of daily living.

Effects of Functional Electrical Stimulation with and without a Wrist-Hand Orthosis on Hand Opening in Individuals with Chronic Hemiparetic Stroke: A Pilot Study

“…Our study demonstrated that FES increases finger-opening distance but decreases wrist extension angle, while WHO use slightly decreases finger opening distance, maybe due to the tenodesis effect [17], but increases wrist extension angle. A balance between finger opening distance and wrist extension angle is required for function.…”

Biomechanical evaluation of wrist-driven flexor hinge orthosis in persons with spinal cord injury

“…The FES system can also be a feasible solution for resolving the radial wrist extensors bias [18,[21][22]. Thorsen et al devised a myoelectrically controlled single-channel FES system to reinforce the tenodesis grasp in persons with C6 and C7 tetraplegia and found an imbalance of hand grasping muscles that resulted in reducing the grasp capability [18].…”

“…Until now, other rehabilitative approaches also have been attempted to improve hand function in persons with tetraplegic SCI [18][19][20][21][22][23][24][25]. Functional electrical stimulation (FES) enables persons with tetraplegia to restore grasp function [18][19][20][21][22].…”

“…Functional electrical stimulation (FES) enables persons with tetraplegia to restore grasp function [18][19][20][21][22]. This system uses electrical current pulses to excite nerves going to paralyzed muscles and provokes contraction of the muscles required for grasp and release.…”

“…Despite the emergence of new technologies and evolution of upper-limb rehabilitation for persons with tetraplegia, the WDFHO still continues to be used to improve hand function because of its noninvasiveness, simplicity of design, relatively low cost, and easy availability in the market [17][18]20]. However, little is known about the biomechanical properties of this orthosis.…”