Date Presented Accepted for AOTA INSPIRE 2021 but unable to be presented due to online event limitations.
Regaining adequate hand function for participation is a challenge for many stroke survivors. Eleven participants completed 12 grasp–transport–release training sessions with a user-driven hand robot that provides active assist for finger extension. A mean gain of 2.64 points (p = .03) on the Fugl–Meyer was observed, with most gains on the distal subscale (2.27 points, p < .001). This intervention is a promising adjunct to conventional therapy to promote typical grasp patterns and functional use.
Primary Author and Speaker: Michaela Fraser
Additional Authors and Speakers: Daniel Geller
Contributing Authors: Sangwoo Park, Lynne Weber, Cassie Meeker, Lauri Bishop, Joel Stein, and Matei Ciocarlie
PURPOSE: Upper extremity (UE) hemiparesis is a challenging complication of stroke. Regaining sufficient hand function for independent participation in occupations remains a challenge. Robotics as an intervention tool for chronic stroke survivors can facilitate remediation or serve as a compensatory device for participation. The robot in this study is a wearable, user-driven, active-assist device that provides powered assistance for finger extension while allowing active flexion.
DESIGN: This interventional pilot case series had a pre-test, post-test design. For inclusion, adults had to consent; be at least 6 months post stroke; have passive range at the wrist to neutral and digits within functional limits; have active range to 30° shoulder flexion, 20° shoulder abduction, and 20° elbow flexion; have gross grasp; and have at least trace digit extension. Participants were excluded if they had a comorbidity or recent botulinum toxin injection (< 13 weeks) in the affected UE, had another neurological disorder, or had significant spasticity (> 2 on Modified Ashworth Scale).
METHOD: 11 participants completed 12 training sessions over 4 weeks. Each 30-minute session involved repetition of grasp, transport, and release tasks with a variety of common objects, bimanual tasks, and simulated ADLs. Outcome measures were the Fugl-Meyer UE (FM), Action Research Arm Test (ARAT), and Box and Block Test (BBT). All assessments were performed at pre-test and post-test without device assistance. ARAT and BBT were performed a second time at post-test with device assistance. The robot has a motor mounted on a dorsal forearm splint that powers 4 cables to act as ‘tendons' for digits 2-5. Fingertip mounts increase the tendons' moment arms over joints to allow the motor to overcome spasticity without exerting high forces. The thumb is splinted in opposition. The device can use two control mechanisms to infer the participant's intention to open, relax, or close the hand: forearm EMG or contralateral shoulder harness.
RESULTS: Paired sample t-tests were utilized to analyze FM and ARAT data, as they passed normality and homogeneity tests. Data from BBT failed, so a nonparametric paired sample Wilcoxon test was used. Statistically significant mean gains of 2.64 (P = .03) were achieved on FM. Notably, most gains occurred in the distal (hand/wrist) subscale (2.27 points, P < .001). The device shows promise as a restorative tool. Statistically significant gains were not achieved globally on ARAT and BBT, but positive trends were noted. On the grasp subtest of ARAT, there was a mean gain of 1.64 (P = .01) with robotic assisted post-test compared to unassisted post-test. This effect was amplified for subjects with lower baseline capacity: 3.00 (P = .003). Similarly, though not statistically significant, subjects who could not perform BBT at baseline, had a mean gain of 1.71 (P = .14) with robotic assistance compared to without assistance at post-test. These outcomes suggest possibility utility as an assistive device for clients with limited capacity. Critically, participants reported enjoyment, functional improvement, and a desire to continue training. They stated: ‘It encourages me to use my hand more'; ‘I can mop with 2 hands and do my own toothpaste.'
CONCLUSION: Training with this device is a promising intervention for stroke survivors as an adjunct to conventional therapy in order to promote typical grasp patterns and increased functional use of the hand. Further study is warranted.
IMPACT STATEMENT: Grasp, transport, and release training with this robot device yielded functional gains and was acceptable to clients. For chronic stroke survivors, wearable robotics may facilitate functional recovery and encourage use of their hemiparetic UE in daily occupations.
References
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Park, S., Weber, L., Bishop, L., Stein, J., & Ciocarlie, M. (2018). Design and development of effective transmission mechanisms on a tendon driven hand orthosis for stroke patients. Robotics and Automation (ICRA), 2018. https://doi.org/10.1109/ICRA.2018.8461069
