Benefits of Applying Neuroprosthesis to Improve Grasping and Reaching in Spinal Cord Injury Patients

Functional electrical stimulation is a process that uses low intensity electrical pulses generated by an electric stimulator to create muscle contractions. By contracting muscles in a specific sequence, one can generate various body functions such as grasping, walking, and standing.The study is designed to evaluate the effectiveness and long term benefits of applying functional electrical simulation during early rehabilitation to improve grasping function in persons who have suffered a spinal cord injury. By using functional electrical stimulation,these patients could potentially improve their grasping function.

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.

Conventional Occupational Therapy pertaining to hand function represents the current best practice activities against which the FET was compared. The COT included the following: (a) muscle facilitation exercises emphasizing the neurodevelopmental treatment approach; (b) task-specific, repetitive functional training; (c) strengthening and motor control training using resistance to available arm motion to increase strength; (d) stretching exercises; (e) electrical stimulation applied primarily for muscle strengthening (this was neither FES nor FET, but electro muscular stimulation); (f) practice of activities of daily living (ADLs) including self-care where the upper extremities were used as appropriate; and (g) caregiver training.

The FES Therapy began by designing stimulation protocols to generate power (circular grip and lateral pinch) and precision (opposition with 2 and 3 fingers) grasps on demand. The stimulation sequence (protocol) for power and precision grasps was developed for each patient individually using the Compex Motion electric stimulator. Compex Motion is a fully programmable transcutaneous (surface) stimulator that uses self-adhesive surface electrodes.

The Compex Motion neuroprostesis, developed by Drs. R. Popovic and Thierry Keller,and company Compex SA, ia a flexible device designed to improve grasping function in both SCI and stroke patients.This multi-channel surface stimulation system for grasping provides both palmar and lateral grasp , and holds a number of advantages over the other existing neuroprostheses.

Conventional occupational therapy pertaining to hand function represents control activities against which the FES therapy was assessed. The conventional occupational therapy included: a) muscle facilitation exercises emphasizing the neurodevelopmental treatment approach; b) task-specific, repetitive functional training; c) strengthening and motor control training using resistance to available arm motion to increase strength; d) stretching exercises; e) electrical stimulation applied primarily for muscle strengthening (this is not FES but TENS application); f) activities of daily living including self-care where the upper limb was used as an assist if appropriate; and g) caregiver training.

Functional Independent Measure was employed to measure the degree of disability for daily self care. It capture data on self-care, sphincter management, transfers,locomotion,communication,and social cognition.The scale is divided according to no helper category (level 6 and 7) where no other person is required to help with the activity and a hel;per category(level 1 through 5)where the patient needs minimal to total assistance from another person to accomplish the activity Score range from 18-126. Higher values represent a better outcome.

The Toronto Rehabilitation Institute Hand Function Test (TRI-HFT) evaluates gross motor function of unilateral grasp (also referred to as the Rehabilitation Engineering Laboratory Hand Function Test). Hand functions that are assessed with TRI-HFT include the following: lateral or pulp pinch and palmar grasp.Score range from 0-70. Higher values represent a better outcome.

Inclusion Criteria: traumatic spinal cord lesion between C4 and C7(incomplete) participants will be recruited during the first six months post-SCI. Exclusion Criteria: uncontrolled hypertension susceptibility to autonomic dysreflexia pressure ulcer cardiac pacemakers skin rush

Popovic MR, Curt A, Keller T, Dietz V. Functional electrical stimulation for grasping and walking: indications and limitations. Spinal Cord. 2001 Aug;39(8):403-12. doi: 10.1038/sj.sc.3101191.

Kapadia NM, Bagher S, Popovic MR. Influence of different rehabilitation therapy models on patient outcomes: hand function therapy in individuals with incomplete SCI. J Spinal Cord Med. 2014 Nov;37(6):734-43. doi: 10.1179/2045772314Y.0000000203. Epub 2014 Jun 26.