The assistive potential of functional electrical stimulation to support object manipulation in functional upper extremity movements after stroke: A randomized cross-over study.

Background: After standard care, 55%-75% of patients after stroke show a persistent paresis of the upper limb (UL). Assistive devices are developed to increase the patients' level of independence in daily life.

Objectives: To investigate the potential of Functional Electrical Stimulation (FES) to assist object manipulation in activities of daily life.

Design: Seventeen patients after stroke were tested and analyzed in a randomized cross-over design.

Methods: Functional grasping was assessed by means of the Action Research Arm Test (ARAT) and the modified Box and Block Test (mBBT), in one session with and another without FES assistance. The order of sessions was randomized. Patients' motivation was assessed after each session. Task performance and motivation were compared between conditions using the Wilcoxon test and subgroup analyses were performed for impairment severity by distribution-based mixed-factor analyses.

Results: When analyzing the total ARAT, FES did not effectively assist the overall performance (P = .142), but did assist the performance of objects of the Grasp category (P = .020). Impairment severity showed an interaction with the orthotic effect (P = .012), as severely impaired patients profited from FES assistance and mild-moderately impaired did not. When focusing on the more functional items of the ARAT (i.e., excluding scores from thumb-middle and thumb-ring finger combinations), there was a significant orthotic effect of FES on task performance (P = .023). Further, there was an orthotic effect for the number of transported blocks in the mBBT (P = .033), exclusively prominent in the group of severely impaired patients. Functional Electrical Stimulation did not increase the patients' motivation (P = .959), which was high after both conditions.

Conclusion: Functional Electrical Stimulation has the potential to support object manipulation, but is dependent on impairment severity and object type. To observe a consistent orthotic effect, features of the stimulator should be further developed to generate appropriate grasps and forces across subjects and objects.

Trial registration: The trial was registered with the German Clinical Trials Register (DRKS00025889).