Purpose-The purpose of this study was evaluate the potential of a second-generation implantable neuroprosthesis that provides improved control of hand grasp and elbow extension for individuals with cervical level spinal cord injury. The key feature of this system is that users control their stimulated function through electromyographic (EMG) signals.Methods-The second-generation neuroprosthesis consists of 12 stimulating electrodes, 2 EMG signal recording electrodes, an implanted stimulator-telemeter device, an external control unit, and a transmit/receive coil. The system was implanted in a single surgical procedure. Functional outcomes for each subject were evaluated in the domains of body functions and structures, activity performance, and societal participation.Results-Three individuals with C5/C6 spinal cord injury received system implantation with subsequent prospective evaluation for a minimum of 2 years. All 3 subjects demonstrated that EMG signals can be recorded from voluntary muscles in the presence of electrical stimulation of nearby muscles. Significantly increased pinch force and grasp function was achieved for each subject. Functional evaluation demonstrated improvement in at least 5 activities of daily living using the Activities of Daily Living Abilities Test. Each subject was able to use the device at home. There were no system failures. Two of 6 EMG electrodes required surgical revision because of suboptimal location of the recording electrodes.Conclusions-These results indicate that a neuroprosthesis with implanted myoelectric control is an effective method for restoring hand function in midcervical level spinal cord injury. Type of study/level of evidence-Therapeutic IV.Keywords functional electrical stimulation; neuroprosthesis; spinal cord injury; electromyography; activities of daily livingThe Ability To Grasp And Manipulate objects is an important factor in determining if the tetraplegic individual can regain independence and return to a functional role in society. Implantable functional electrical stimulation systems, or neuroprostheses, provide hand and arm function that is both versatile and transparent. These systems have evolved from the feasibility stage through clinical evaluation in an outpatient population to a Food and DrugCorresponding author: Kevin L. Kilgore, PhD, MetroHealth Medical Center, Hamann 601, 2500 MetroHealth Dr., Cleveland, OH 44109; e-mail: klk4@case.edu. NIH Public Access NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptAdministration (FDA)-approved medical product. 1 Neuroprostheses provide the user with increased independence, thus improving the opportunity for a better quality of life.A first-generation upper-extremity neuroprosthesis (NP) for hand control 2 was first implanted in 1986 3 and became known as the Freehand System. [4][5][6][7][8][9][10][11][12] The Freehand NP (NeuroControl Corp., Valley View, OH) used an 8-channel implanted receiver-stimulator with 8 epimysial or intramuscular forearm and hand electrodes, leads...

Objective To develop and apply an implanted neuroprosthesis to restore arm and hand function to individuals with high level tetraplegia Design Case study. Setting Clinical research laboratory. Participants Two individuals with spinal cord injuries at or above the C4 motor level. Interventions The individuals were each implanted with two stimulators (24 stimulation channels and 4 myoelectric recording channels total). Stimulating electrodes were placed in the shoulder and arm, including the first chronic application of spiral nerve cuff electrodes to activate a human limb. Myoelectric recording electrodes were placed in the head and neck areas. Main Outcome Measures The successful installation and operation of the neuroprosthesis, along with the electrode performance, range of motion, grasp strength, joint moments, and performance in activities of daily living. Results The neuroprosthesis system was successfully implanted in both individuals. Spiral nerve cuff electrodes were placed around upper extremity nerves and activated the intended muscles. In both individuals, the neuroprosthesis has functioned properly for at least 2.5 years post-implant. Hand, wrist, forearm, elbow and shoulder movements were achieved. A mobile arm support was needed to support the mass of the arm during functional activities. One individual was able to perform several activities of daily living with some limitations due to spasticity. The second individual was able to partially complete two activities of daily living. Conclusions Functional electrical stimulation is a feasible intervention for restoring arm and hand functions to individuals with high tetraplegia. Forces and movements were generated at the hand, wrist, elbow and shoulder that allowed the performance of activities of daily living, with some limitations requiring the use of a mobile arm support to assist the stimulated shoulder forces.