Restoring Voluntary Grasping Function in Individuals with Incomplete Chronic Spinal Cord Injury: Pilot Study

Background:

Functional electrical stimulation (FES) therapy has been shown to be one of the most promising approaches for improving voluntary grasping function in individuals with subacute cervical spinal cord injury (SCI).

Objective:

To determine the effectiveness of FES therapy, as compared to conventional occupational therapy (COT), in improving voluntary hand function in individuals with chronic (≥24 months post injury), incomplete (American Spinal Injury Association Impairment Scale AIS] B-D), C4 to C7 SCI.

Methods:

Eight participants were randomized to the intervention group (FES therapy; n = 5) or the control group (COT; n = 3). Both groups received 39 hours of therapy over 13 to 16 weeks. The primary outcome measure was the Toronto Rehabilitation Institute-Hand Function Test (TRI-HFT), and the secondary outcome measures were Graded Redefined Assessment of Strength Sensibility and Prehension (GRASSP), Functional Independence Measure (FIM) self-care subscore, and Spinal Cord Independence Measure (SCIM) self-care subscore. Outcome assessments were performed at baseline, after 39 sessions of therapy, and at 6 months following the baseline assessment.

Results:

After 39 sessions of therapy, the intervention group improved by 5.8 points on the TRI-HFT’s Object Manipulation Task, whereas the control group changed by only 1.17 points. Similarly, after 39 sessions of therapy, the intervention group improved by 4.6 points on the FIM self-care subscore, whereas the control group did not change at all.

Conclusion:

The results of the pilot data justify a clinical trial to compare FES therapy and COT alone to improve voluntary hand function in individuals with chronic incomplete tetraplegia.Key words: chronic patients, functional electrical stimulation, grasping, therapy, upper limbIn the United States and Canada, there is a steady rate of incidence and an increasing rate of prevalence of individuals living with spinal cord injury (SCI). For individuals with tetraplegia, hand function is essential for achieving a high level of independence in activities of daily living.^1–5 For the majority of individuals with tetraplegia, the recovery of hand function has been rated as their highest priority.⁵Traditionally, functional electrical stimulation (FES) has been used as a permanent neuroprosthesis to achieve this goal.^6–14 More recently, researchers have worked toward development of surface FES technologies that are meant to be used as shortterm therapies rather than permanent prosthesis. This therapy is frequently called FES therapy or FET. Most of the studies published to date, where FES therapy was used to help improve upper limb function, have been done in both the subacute and chronic stroke populations^15–23 and 2 have been done in the subacute SCI population.^1–3 With respect to the chronic SCI population, there are no studies to date that have looked at use of FES therapy for retraining upper limb function. In a review by Kloosterman et al,²⁴ the authors have discussed studies that have used various combinations of therapies for improving upper extremity function in chronic SCI individuals; however, the authors found that the only study that showed significant improvements before and after was the study published by Needham-Shropshire et al.²⁵ This study examined the effectiveness of neuromuscular stimulation (NMS)–assisted arm ergometry for strengthening triceps brachii. In this study, electrical stimulation was used to facilitate arm ergometry, and it was not used in the context of retraining reaching, grasping, and/or object manipulation.Since 2002, our team has been investigating whether FES therapy has the capacity to improve voluntary hand function in complete and incomplete subacute cervical SCI patients who are less than 180 days post injury at the time of recruitment in the study.^1–3 In randomized controlled trials (RCTs) conducted by our team, we found that FES therapy is able to restore voluntary reaching and grasping functions in individuals with subacute C4 to C7 incomplete SCI.^1–3 The changes observed were transformational; individuals who were unable to grasp at all were able to do so after only 40 one-hour sessions of the FES therapy, whereas the control group showed significantly less improvement. Inspired by these results, we decided to conduct a pilot RCT with chronic (≥24 months following injury) C4 to C7 SCI patients (American Spinal Injury Association Impairment Scale AIS] B-D), which is presented in this article. The purpose of this pilot study was to determine whether the FES therapy is able to restore voluntary hand function in chronic tetraplegic individuals. Based on the results of our prior phase I¹ and phase II^2,3 RCTs in the subacute SCI population, we hypothesized that individuals with chronic tetraplegia who underwent the FES therapy (intervention group) may have greater improvements in voluntary hand function, especially in their ability to grasp and manipulate objects, and perform activities of daily living when compared to individuals who receive similar volume and duration of conventional occupational therapy (COT: control group).