Implanted Myoelectric Control for Restoration of Hand Function in Spinal Cord Injury

Case Western Reserve University, VA Office of Research and Development, FDA Office of Orphan Products Development

The purpose of this study is to evaluate the effectiveness of an implanted stimulator and sensor for providing hand and arm function for individuals with cervical level spinal cord injury.

The design of this study is to determine the efficacy of improving upper extremity function in tetraplegic subjects after receiving an implantable device for neuromuscular control. Evaluations will be made so as to document changes in performance of manipulative tasks when using the stimulation system. Subjects who consent to participate in this project will have an implantable stimulator surgically placed in the upper extremity for control of the upper extremity. A series of tests will be performed before implantation, and repeated at intervals after implantation to assess changes in each subject's performance. This study is a non-randomized feasibility study with concurrent (neuroprosthesis on and off) and longitudinal (pre- and post-implantation/training) self-controls. Subjects participating in the study can expect to be actively involved in the study for two years after implantation and followed for life thereafter. The screening procedures take up to two days, depending on the specific evaluations necessary to determine candidacy. Pre-surgical exercise is conducted for at least two weeks. The implantation surgery itself lasts one day, with three to seven days of post-surgical hospitalization. Following an eight-week exercise program and a twelve-week training program, subjects are discharged from the active rehabilitation phase. They are followed quarterly for one year, and then annually thereafter. The device is referred to as the Implanted Stimulator-Telemeter (IST) -12. The device uses functional electrical stimulation (FES) to activate paralyzed muscles.

Implanted stimulator and sensor device, with twelve implanted stimulating electrodes and two myoelectric signal recording electrodes.

Grasp and Release Test (GRT) - The Grasp and Release Test (GRT) [Wuolle, 1994; Smith et al., 1996; Carroll et al., 2000; Taylor et al., 2002; Mulcahey et al., 2004], developed at the Cleveland FES Center, has been utilized by multiple centers to show improvements in hand function after implantation of a neuroprosthesis and tendon transfers [Peckham, 2001]. This pick-and-place test requires the participant to unilaterally acquire, move, and release six objects varying in weight and size. The objects are: 1) a small peg, 2) a wooden cube, 3) a small juice can, 4) a videotape, 5) a paperweight (~1000g) and a simulated fork task (spring-loaded plunger). The number of objects that the participant can successfully manipulate are scored. Success in manipulating each object in the GRT is defined as the ability to pick up and place the object at least once within 30 seconds.

The ADL Abilities Test was developed to measure differences in activity performance with and without a hand neuroprosthesis. Scoring is based on an activity analysis approach. The activities, which are chosen by the participant, are broken down into phases, and each phase is scored for the amount of assistance the participant uses: 1) "Physical Assistance" (PA): assistance from an attendant, 2) "Adaptive Equipment" (AE): any modifications of the activity or its components, 3) "Orthotic Assistance" (OA): an orthotic device that the participant normally wears all day (e.g., a dorsal wrist support), and that can be considered a modification of the hand, 4) "Self Assistance" (SA): use of any part of the body other than the dominant hand, or use of the test equipment in an adapted way to complete the activity (e.g., using two hands to hold a glass, or sliding an object to the end of the table for grasping), and 5) "Independent".

Inclusion Criteria: C5-C8 spinal cord injury Minimum of one-year post injury with no additional function prior to implantation surgery Male or female 18-60 years of age intact vision pharmacologically controlled spasticity, when applicable Functional in wheelchair with adequate trunk support to allow bimanual manipulation Positive attitude and motivation with supportive home environment Willingness to return to laboratory for periodic evaluation and testing Free of contractures known to diminish performance of the system (e.g., supination contracture of the wrist). Integrity of the lower motor neuron (peripheral nerve) to the muscles to be activated Adequate range of motion of joints of the shoulder, wrist, and hand (upper extremity). If an acute infection is present, the subject will not be considered for surgery until it clears. Exclusion Criteria: Prior history of a major chronic systemic infection or other illness that would increase the risk of surgery. Contraindications include immunologic diseases, cardiac arrhythmias, undiagnosed or high-risk breast masses, dermatologic conditions, and any major system failure. Acute infection currently present that has not cleared. Hypersensitivity that inhibits their ability to sustain pressure over their digits. Blind Uncontrolled disorders, i.e., seizures

Peckham PH, Kilgore KL, Keith MW, Bryden AM, Bhadra N, Montague FW. An advanced neuroprosthesis for restoration of hand and upper arm control using an implantable controller. J Hand Surg Am. 2002 Mar;27(2):265-76. doi: 10.1053/jhsu.2002.30919.

Kilgore KL, Bryden A, Keith MW, Hoyen HA, Hart RL, Nemunaitis GA, Peckham PH. Evolution of Neuroprosthetic Approaches to Restoration of Upper Extremity Function in Spinal Cord Injury. Top Spinal Cord Inj Rehabil. 2018 Summer;24(3):252-264. doi: 10.1310/sci2403-252.

Peckham PH, Keith MW, Kilgore KL, Grill JH, Wuolle KS, Thrope GB, Gorman P, Hobby J, Mulcahey MJ, Carroll S, Hentz VR, Wiegner A; Implantable Neuroprosthesis Research Group. Efficacy of an implanted neuroprosthesis for restoring hand grasp in tetraplegia: a multicenter study. Arch Phys Med Rehabil. 2001 Oct;82(10):1380-8. doi: 10.1053/apmr.2001.25910.

Kilgore KL, Hoyen HA, Bryden AM, Hart RL, Keith MW, Peckham PH. An implanted upper-extremity neuroprosthesis using myoelectric control. J Hand Surg Am. 2008 Apr;33(4):539-50. doi: 10.1016/j.jhsa.2008.01.007.