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

We demonstrated a method for enhancing the tenodesis grip in individuals with sustained tetraplegia at the 6th cervical vertebra 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.