Biofeedback Training for 3-Dimensional Finger Force Control to Improve Upper Limb Function Poststroke: An RCT

Abstract

Background: After stroke, impairment of hand sensorimotor control leads to improperly scaled and directed fingertip forces that disrupt object manipulation. The objective of this study was to determine the efficacy of finger force magnitude and direction training using 3-dimensional versus 1-dimensional biofeedback to enhance poststroke upper extremity motor recovery.

Methods: A double-blind randomized controlled trial took place in the Veterans Affairs laboratory from 2020 to 2023. Forty-five stroke survivors were randomly assigned to the experimental or control group. Both groups received 18 training sessions to generate digit force in the target magnitude and direction. The experimental group trained with visual feedback on the digit force magnitude in 3 dimensions. The control group trained with 1-dimensional visual feedback on the digit force magnitude along the target direction only. The primary outcome was the change in upper extremity function assessed using the Action Research Arm Test post-intervention.

Results: Baseline characteristics were comparable between the groups (mean age, 59 years, 60% male, 40% Black people). The change between pretraining and posttraining Action Research Arm Test scores was significantly greater for the experimental group than for the control group (experimental mean, 3.5 [CI, 2.2-4.8] versus control mean, 0.8 [CI, -0.5 to 2.1]; P=0.005). This difference was maintained at 1-month follow-up. Secondary analysis showed that individuals in the experimental group whose stroke occurred within a year prior improved more (mean, 6.1 [CI, 4.0-8.3]) than others (P<0.003).

Conclusions: Force direction feedback led to improved upper extremity motor recovery in stroke survivors. This biofeedback-based treatment may provide the needed explicit training in force direction control for more effective hand rehabilitation.

Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03995069.

Keywords: biomechanical phenomena; feedback, sensory; motor disorders; motor skills; psychomotor performance; stroke rehabilitation; upper extermity.