Characterization and wearability evaluation of a fully portable wrist exoskeleton for unsupervised training after stroke

Abstract

Background Chronic hand and wrist impairment are frequently present following stroke and severely limit independence in everyday life. The wrist orientates and stabilizes the hand before and during grasping, and is therefore of critical importance in activities of daily living (ADL). To improve rehabilitation outcomes, classical therapy could be supplemented by novel therapies that can be applied in unsupervised settings. This would enable more distributed practice and could potentially increase overall training dose. Robotic technology offers new possibilities to address this challenge, but it is critical that devices for independent training are easy and appealing to use. Here, we present the development, characterization and wearability evaluation of a fully portable exoskeleton for active wrist extension/flexion support in stroke rehabilitation. Methods First we defined the requirements, and based on these, constructed the exoskeleton. We then characterized the device with standardized haptic and human-robot interaction metrics. The exoskeleton is composed of two modules placed on the forearm/hand and the upper arm. These modules weigh 238 g and 224 g, respectively. The forearm module actively supports wrist extension and flexion with a torque up to 3.7 Nm and an angular velocity up to 530 deg/s over a range of 154∘. The upper arm module includes the control electronics and battery, which can power the device for about 125 min in normal use. Special emphasis was put on independent donning and doffing of the device, which was tested via a wearability evaluation in 15 healthy participants and 2 stroke survivors using both qualitative and quantitative methods. Results All participants were able to independently don and doff the device after only 4 practice trials. For healthy participants the donning and doffing process took 61 ±15 s and 24 ±6 s, respectively. The two stroke survivors donned and doffed the exoskeleton in 54 s/22 s and 113 s/32 s, respectively. Usability questionnaires revealed that despite minor difficulties, all participants were positive regarding the device. Conclusions This study describes an actuated wrist exoskeleton which weighs less than 500 g, and which is easy and fast to don and doff with one hand. Our design has put special emphasis on the donning aspect of robotic devices which constitutes the first barrier a user will face in unsupervised settings. The proposed device is a first and intermediate step towards wearable rehabilitation technologies that can be used independently by the patient and in unsupervised settings.

Robotic Home-Based Rehabilitation Systems Design: From a Literature Review to a Conceptual Framework for Community-Based Remote Therapy During COVID-19 Pandemic

“…Lambelet et al developed a fully portable sEMG-based force-controlled wrist exoskeleton offering extension/flexion assistance, eWrist. Given the prominence of the donning aspects of rehabilitation robots in unsupervised settings, the device was iteratively designed emphasizing attachment mechanism and distal weight reduction to enable one-hand and independent donning of the device ( Lambelet et al, 2020 ).…”

“… Robotic exoskeleton and end-effector devices for home-based upper-limb rehabilitation: (A) SpringWear ( Chen and Lum, 2018 ), (B) RUPERT ( Tu et al, 2017 ), (C) eWrist ( Lambelet et al, 2020 ), (D) Soft robotic elbow sleeve ( Koh et al, 2017 ), (E) Portable device for wrist rehabilitation ( Ambar et al, 2017 ), and (F) HomeRehab ( Díaz et al, 2018 ). …”

Neurorehabilitation From a Distance: Can Intelligent Technology Support Decentralized Access to Quality Therapy?

“…A common digital therapy platform offers the unique advantage of sharing user-interaction features between devices, to improve usability and help seamlessly transition from one device to the other (e.g., within a therapy session, or over the course of rehabilitation). Figure 2 presents a possible set of selected user-friendly, mobile, complementary robotic systems targeting different components of the upper limb, that could be used as a basis to implement such a connected RehabGym concept ( Chua et al, 2018 ; Butzer et al, 2020 ; Lambelet et al, 2020 ; Ranzani et al, 2020 ; Ranzani et al, 2021 ).…”

Discussion on the Rehabilitation of Stroke Hemiplegia Based on Interdisciplinary Combination of Medicine and Engineering

“…However, these plans rely on the patient's consciousness, and are unsupervised, which can limit efficacy. To address this, mobile health (mHealth) can provide remote monitoring and remote consultation [ 31 ]. mHealth can also provide people living in remote and impoverished areas with access to equitable rehabilitation services [ 32 ].…”