Design, characterization and preliminary usability testing of a portable robot for unsupervised therapy of hand function

Abstract

Introduction: There is evidence that increasing therapy dose after stroke might promote recovery. Unfortunately, in clinical practice, therapy dose is limited by financial and organizational constraints. Simple robotic devices could be used without supervision in the clinic or at home to increase dose without requiring additional resources. For this purpose, we developed HandyBot, a portable three-degrees-of-freedom end-effector haptic device to perform sensorimotor task-oriented therapy of hand function (i.e., grasping, forearm pronosupination, wrist flexion-extension) in different environments.Methods: We present the mechatronic design of the device and its technical evaluation in terms of workspace, dynamics (i.e., max end-effector velocity, acceleration and force), sensing (i.e., position, velocity and force resolution) and haptic performance (i.e., transparency, maximum stable impedance range, rigid contact rendering accuracy). In addition, its feasibility and usability (in terms of System Usability Scale (SUS)) were assessed in a single-session experiment with four subjects with chronic stroke that tested the HandyBot therapy platform (i.e., haptic device with a graphical/physical user interface and a set of therapy exercises) while simulating unsupervised use (i.e., the subject used the device independently while a therapist was only observing the session).Results: HandyBot showed hardware and control performances comparable to other less portable therapy devices for hand function (e.g., 94% accuracy in stiffness rendering, low apparent mass of 0.2 kg in transparency mode), making it a suitable platform for the implementation of sensorimotor therapy exercises. HandyBot showed good platform usability in terms of SUS (i.e., above 75 out of 100 for device and graphical user interfaces, above 65 out of 100 for the exercises) when tested in simulated unsupervised settings. These tests underlined minor design improvements that should be considered to allow using such a device in uncontrolled settings.Discussion: HandyBot is a novel robot for hand rehabilitation after stroke that revealed high-quality hardware and haptic performance. HandyBot was usable for stroke patients at first exposure for (simulated) unsupervised robot-assisted sensorimotor therapy of hand function. This therapy approach combined with this novel portable robotic device has the potential to help increase therapy dose and decrease therapy-associated costs (e.g., therapist time to therapy time ratio) in different environments.

Designing for usability: development and evaluation of a portable minimally-actuated haptic hand and forearm trainer for unsupervised stroke rehabilitation

“…These values are in line with those from other studies of devices for similar applications. For example, the HandyBot was attributed a SUS score of 76.3 and 85.0 for the device itself and the GUI respectively (Ranzani et al, 2023 ). The user interface of the ReHapticKnob was rated 85.0 and two accompanying haptic games with 76.3 and 68.8 (Ranzani et al, 2021 ).…”

“…Although multiple robotic rehabilitation devices have specifically been developed to address this (e.g., Metzger et al 2011 ; Fong et al 2017 ; Rätz et al 2021a ), they are mostly intended for clinical rehabilitation. To our best knowledge, the recent ReHandyBot (Articares Pte Ltd, Singapore)—a commercial device based on the haptic tabletop device HandyBot (Ranzani et al, 2023 ) with two DoF, i.e., grasping and pronosupination—is currently the only commercial portable upper-limb device intended for home use which was explicitly designed to also address sensory deficits.…”

Enhancing Stroke Rehabilitation with Whole-Hand Haptic Rendering: Development and Clinical Usability Evaluation of a Novel Upper-Limb Rehabilitation Device

“…All three usability questionnaires (SUS) pointed to good to excellent usability from the perspectives of both patients and therapists with median scores between 75.0 and 80.0 out of 100. As a comparison, the three-DoF HandyBot scored 76.3 overall and 85.0 for its GUI [58]. The two-DoF ReHapticKnob's user interface scored 85.0, and its two games were rated at 76.3 and 68.8 [116].…”

“…HandyBot [58], FINGER [59], the portable hand trainer from Van Damme et al [60], or the OpenWrist [61]-and more wearable devices like gloves or hand and wrist exoskeletons-e.g., [62][63][64]. The latter usually only generate forces within the (distal) attachment points.…”