Design and Preliminary Feasibility Study of a Soft Robotic Glove for Hand Function Assistance in Stroke Survivors

Abstract

Various robotic exoskeletons have been proposed for hand function assistance during activities of daily living (ADL) of stroke survivors. However, traditional exoskeletons involve the use of complex rigid systems that impede the natural movement of joints, and thus reduce the wearability and cause discomfort to the user. The objective of this paper is to design and evaluate a soft robotic glove that is able to provide hand function assistance using fabric-reinforced soft pneumatic actuators. These actuators are made of silicone rubber which has an elastic modulus similar to human tissues. Thus, they are intrinsically soft and compliant. Upon air pressurization, they are able to support finger range of motion (ROM) and generate the desired actuation of the finger joints. In this work, the soft actuators were characterized in terms of their blocked tip force, normal and frictional grip force outputs. Combining the soft actuators and flexible textile materials, a soft robotic glove was developed for grasping assistance during ADL for stroke survivors. The glove was evaluated on five healthy participants for its assisted ROM and grip strength. Pilot test was performed in two stroke survivors to evaluate the efficacy of the glove in assisting functional grasping activities. Our results demonstrated that the actuators designed in this study could generate desired force output at a low air pressure. The glove had a high kinematic transparency and did not affect the active ROM of the finger joints when it was being worn by the participants. With the assistance of the glove, the participants were able to perform grasping actions with sufficient assisted ROM and grip strength, without any voluntary effort. Additionally, pilot test on stroke survivors demonstrated that the patient's grasping performance improved with the presence and assistance of the glove. Patient feedback questionnaires also showed high level of patient satisfaction and comfort. In conclusion, this paper has demonstrated the possibility of using soft wearable exoskeletons that are more wearable, lightweight, and suitable to be used on a daily basis for hand function assistance of stroke survivors during activities of daily living.

Hand Extension Robot Orthosis (HERO) Grip Glove: enabling independence amongst persons with severe hand impairments after stroke

“…A number of sensor types (i.e. button [12,14,16], electromyography [17,18], motion [10,14], force [19], voice [20], vision [21,22] and electroencephalography [13] have been selected to control robot assistance based on varied motivations such as robust operation or motivating neuromuscular activation. However, other than button control, these control strategies are still in an experimental stage that requires experts to manually tune each user's orthosis [17].…”

Flexible Actuators for Soft Robotics

“…Although the flexible actuating technology developed for the soft wearable fields is currently in its infancy, collaborative efforts toward functional materials, actuator devices, and integration approaches will lead to multiple applications for soft wearable robotics. In this section, several typical application scenarios will be introduced, such as medical and rehabilitation robots, designs for actively deformable apparel, and soft HMIs …”

Offering a helping hand

“…Except for pinch strength, no beneficial direct effect of the ironHand glove on JTHFT and a simulated functional reach-and-grasp task, analyzing specifically timed performance, was found. In contrast to studies that are performed with the ironHand [109,137], object manipulation improved with use of other soft-robotic gloves in two stroke patients [190], patients with a spinal cord injury [124] and a patient with muscular dystrophy [125]. The pilot study of Yap et al [190] with two stroke patients showed that the performance to grasp an empty bottle and tin can (subtasks of the JTHFT) improved with their soft-robotic glove when compared to without glove.…”

“…In contrast to studies that are performed with the ironHand [109,137], object manipulation improved with use of other soft-robotic gloves in two stroke patients [190], patients with a spinal cord injury [124] and a patient with muscular dystrophy [125]. The pilot study of Yap et al [190] with two stroke patients showed that the performance to grasp an empty bottle and tin can (subtasks of the JTHFT) improved with their soft-robotic glove when compared to without glove. In the study of Capello et al [124], a five-fingered glove manually controlled by the researcher with a switch was tested in one patient with a C4-C7 spinal cord injury.…”

“…By combining factors such as costs, expected usefulness, and safety aspects, a decision can be reached to purchase AT. If AT incorporates therapeutic principles (such as repetition, task [188,189], not all those of factors, and their interdependencies, are currently targeted, or at least not reported, in research on AT [26,84,124,190]. Additionally, although valuable information can be gathered prior to actual use, the chance of actual use of a device is believed to be predominantly related to the experienced ease of use and perceived usefulness of the system [19,24], which cannot always be predicted beforehand.…”