Neuroprosthesis for Improving Grasping Function in Spinal Cord Injured Patients

The main objective of this study is to determine the effectiveness of a new treatment regime that uses a neuroprosthesis for the improvement and recovery of grasping functions in persons with spinal cord injuries (SCI). This treatment has been shown to be useful for stroke patients with hemiplegic arm in the recovery of reaching and grasping 1, and our preliminary work indicates that this may also be the case with SCI patients 3. Further, aside from the potential of promoting voluntary grasp in SCI patients, this novel therapeutic approach may also impact the way service is currently delivered in SCI rehabilitation settings.

A neuroprosthesis for grasping is a device that can improve or restore the grasping, holding, and releasing functions in persons with SCI 2, 3. The neuroprosthesis applies functional electrical stimulation (FES) to artificially generate a muscle contraction by applying short current pulses to motor nerves innervating muscles. FES can be applied to individuals with incomplete SCI to help them restore functions such as walking and grasping by contracting groups of paralyzed muscles in an orchestrated manner 4. FES was originally envisioned as an intervention that was 'permanent' in nature. In other words, an individual had to wear/use an FES orthotic device at all times if s/he wanted to generate the function that was impaired by SCI 4. Our application of the neuroprosthesis for grasping in this proposal presents a departure from this standard and established approach of FES application. Rather than having people be dependent on the neuroprosthesis to perform their activities of daily living (ADL), we plan to use the neuroprosthesis for grasping as a short-term intervention that will help SCI individuals recover voluntary grasping function. Hence, we believe that those participants who undergo our FES therapy with the neuroprosthesis should be able to perform grasping functions without its use once the treatment program is completed.

Recent innovative advances in FES applications, spearheaded by our team, clearly indicate that the short-term, therapeutic intervention of the neuroprosthesis for grasping can enhance voluntary function in individuals with SCI 3, 5, 6. These studies also suggest that this novel method of applying FES to augment functional improvement has the potential to improve overall physical and psychological well being of persons with incomplete SCI. Since 1999, the Co-PI of this application, Dr. Milos Popovic and Dejan Popovic's team from the University of Belgrade have reported anecdotal evidence that some C5 to C7 SCI individuals who were unable to voluntarily grasp, were later able to do so after intensive training with a neuroprosthesis for grasping 2, 7, 8, 9. They observed that approximately 20 to 25% of the individuals who trained with the FES systems were able to grasp without the assistance of the neuroprosthesis once the systems were removed. Although this evidence has been presented in several peer-reviewed publications, there have been no comprehensive studies to date that have investigated the long-term effects of FES treatment on recovery of the voluntary grasping function in persons with SCI. Consequently, this study seeks to 1) investigate whether a series of orchestrated FES therapies can be applied to re-train/improve voluntary grasping function in acute SCI individuals, and; 2) to determine whether this therapy will yield better results than conventional occupational therapy. Specifically, we will recruit participants who have C5 to C7 incomplete SCI. These individuals typically can generate weak wrist extension but can neither flex, extend, abduct or adduct the fingers, nor flex, extend, abduct or adduct the thumb. Our therapy will be used to help these individuals recover some or all of these functions.