The Design and Characterization of a Soft Haptic Interface for Rehabilitation of Impaired Hand Function

abstract: The human hand comprises complex sensorimotor functions that can be impaired by neurological diseases and traumatic injuries. Effective rehabilitation can bring the impaired hand back to a functional state because of the plasticity of the central nervous system to relearn and remodel the lost synapses in the brain. Current rehabilitation therapies focus on strengthening motor skills, such as grasping, employ multiple objects of varying stiffness and devices that are bulky, costly, and have limited range of stiffness due to the rigid mechanisms employed in their variable stiffness actuators. This research project presents a portable cost-effective soft robotic haptic device with a broad stiffness range that is adjustable and can be utilized in both clinical and home settings. The device eliminates the need for multiple objects by employing a pneumatic soft structure made with highly compliant materials that act as the actuator as well as the structure of the haptic interface. It is made with interchangeable soft elastomeric sleeves that can be customized to include materials of varying stiffness to increase or decrease the stiffness range. The device is fabricated using existing 3D printing technologies, and polymer molding and casting techniques, thus keeping the cost low and throughput high. The haptic interface is linked to either an open-loop system that allows for an increased pressure during usage or closed-loop system that provides pressure regulation in accordance with the stiffness the user specifies. A preliminary evaluation is performed to characterize the effective controllable region of variance in stiffness. Results indicate that the region of controllable stiffness was in the center of the device, where the stiffness appeared to plateau with each increase in pressure. The two control systems are tested to derive relationships between internal pressure, grasping force exertion on the surface, and displacement using multiple probing points on the haptic device. Additional quantitative evaluation is performed with study participants and juxtaposed to a qualitative analysis to ensure adequate perception in compliance variance. Finally, a qualitative evaluation showed that greater than 60% of the trials resulted in the correct perception of stiffness in the haptic device.Dissertation/ThesisMasters Thesis Biomedical Engineering 201

Usability of an Immersive Augmented Reality Based Telerehabilitation System with Haptics (ARTESH) for Synchronous Remote Musculoskeletal Examination

This study describes the features and utility of a novel augmented reality based telemedicine system with haptics that allows the sense of touch and direct physical examination during a synchronous immersive telemedicine consultation and physical examination. The system employs novel engineering features: (a) a new force enhancement algorithm to improve force rendering and overcoming the “just-noticeable-difference” limitation; (b) an improved force compensation method to reduce the delay in force rendering; (c) use of the “haptic interface point” to reduce disparity between the visual and haptic data; and (d) implementation of efficient algorithms to process, compress, decompress, transmit and render 3-D tele-immersion data. A qualitative pilot study (n=20) evaluated the usability of the system. Users rated the system on a 26-question survey using a seven-point Likert scale, with percent agreement calculated from the total users who agreed with a given statement. Survey questions fell into three main categories: (1) ease and simplicity of use, (2) quality of experience, and (3) comparison to in-person evaluation. Average percent agreements between the telemedicine and in-person evaluation were highest for ease and simplicity of use (86%) and quality of experience (85%), followed by comparison to in-person evaluation (58%). Eighty-nine percent (89%) of respondents expressed satisfaction with the overall quality of experience. Results suggest that the system was effective at conveying audio-visual and touch data in real-time across 20.3 miles, and warrants further development.

Robotics for rehabilitation of hand movement in stroke survivors

This article aims to give an overall review of research status in hand rehabilitation robotic technology, evaluating a number of devices. The main scope is to explore the current state of art to help and support designers and clinicians make better choices among varied devices and components. The review also focuses on both mechanical design, usability and training paradigms since these parts are interconnected for an effective hand recovery. In order to study the rehabilitation robotic technology status, the devices have been divided in two categories: end-effector robots and exoskeleton devices. The end-effector robots are more flexible than exoskeleton devices in fitting the different size of hands, reducing the setup time and increasing the usability for new patients. They suffer from the control of distal joints and haptic aspects of object manipulation. In this way, exoskeleton devices may represent a new opportunity. Nevertheless their design is complex and a deep investigation of hand biomechanics and physical human–robot interaction is required. The main hand exoskeletons have been developed in the last decade and the results are promising demonstrated by the growth of the commercialized devices. Finally, a discussion on the complexity to define which design is better and more effective than the other one is summarized for future investigations

Robot-Assisted Rehabilitation of Forearm and Hand Function After Stroke

Ph.DDOCTOR OF PHILOSOPH

ROBOT-ASSISTED PEDIATRIC REHABILITATION OF UPPER LIMB FUNCTIONS

Ph.DDOCTOR OF PHILOSOPH

Upper extremity rehabilitation using interactive virtual environments

Stroke affects more than 700,000 people annually in the U.S. It is the leading cause of major disability. Recovery of upper extremity function remains particularly resistant to intervention, with 80% to 95% of persons demonstrating residual upper extremity impairments lasting beyond six months after the stroke. The NJIT Robot Assistive Virtual Rehabilitation (NJIT-RAVR) system has been developed to study optimal strategies for rehabilitation of arm and hand function. Several commercial available devices, such as HapticMaster™, Cyberglove™, trakSTAR™ and Cybergrasp™, have been integrated and 11 simulations were developed to allow users to interact with virtual environments. Visual interfaces used in these simulations were programmed either in Virtools or in C++ using the Open GL library. Stereoscopic glasses were used to enhance depth perception and to present movement targets to the subjects in a 3-dimensional stereo working space. Adaptive online and offline algorithms were developed that provided appropriate task difficulty to optimize the outcomes. A pilot study was done on four stroke patients and two children with cerebral palsy to demonstrate the usability of this robot-assisted VR system. The RAVR system performed well without unexpected glitches during two weeks of training. No subjects experienced side effects such as dizziness, nausea or disorientation while interacting with the virtual environment. Each subject was able to finish the training, either with or without robotic adaptive assistance. To investigate optimal therapeutic approaches, forty stroke subjects were randomly assigned to two groups: Hand and Arm training Together (HAT) and Hand and Arm training Separately (HAS). Each group was trained in similar virtual reality training environments for three hours a day, four days a week for two weeks. In addition, twelve stroke subjects participated as a control group. They received conventional rehabilitation training of similar intensity and duration as the HAS and HAT groups. Clinical outcome measurements included the Jebsen Test of Hand Function, the Wolf Motor Function Test, and the ReachGrasp test. Secondary outcome measurements were calculated from kinematic and kinetic data collected during training in real time at 100 Hz. Both HAS and HAT groups showed significant improvement in clinical and kinematic outcome measurements. Clinical improvement compared favorably to the randomized clinical trials reported in the literature. However, there was no significant improvement difference between the two groups. Subjects from the control group improved in clinical measurements and in the ReachGrasp test. Compared to the control group, the ReachGrasp test showed a larger increase in movement speed during reaching and in the efficiency of lifting an object from the table in the combined HAS and HAT group. The NJIT-RAVR system was further modified to address the needs of children with hemiplegia due to Cerebral Palsy. Thirteen children with cerebral palsy participated in the total of nine sessions of one hour training that lasted for three weeks. Nine of the children were trained using the RAVR system alone, and another four had training with the combined Constraint-Induced Movement therapy and RAVR therapy. As a group, the children demonstrated improved performance across measurements of the Arm Range of Motion (AROM), motor function, kinematics and motor control. While subjects\u27 responses to the games varied, they performed each simulation while maintaining attention sufficient to improve in both robotic task performance and in measures of motor function

Review of control strategies for robotic movement training after neurologic injury

There is increasing interest in using robotic devices to assist in movement training following neurologic injuries such as stroke and spinal cord injury. This paper reviews control strategies for robotic therapy devices. Several categories of strategies have been proposed, including, assistive, challenge-based, haptic simulation, and coaching. The greatest amount of work has been done on developing assistive strategies, and thus the majority of this review summarizes techniques for implementing assistive strategies, including impedance-, counterbalance-, and EMG- based controllers, as well as adaptive controllers that modify control parameters based on ongoing participant performance. Clinical evidence regarding the relative effectiveness of different types of robotic therapy controllers is limited, but there is initial evidence that some control strategies are more effective than others. It is also now apparent there may be mechanisms by which some robotic control approaches might actually decrease the recovery possible with comparable, non-robotic forms of training. In future research, there is a need for head-to-head comparison of control algorithms in randomized, controlled clinical trials, and for improved models of human motor recovery to provide a more rational framework for designing robotic therapy control strategies

Robot Control for Remote Ophthalmology and Pediatric Physical Rehabilitation

The development of a robotic slit-lamp for remote ophthalmology is the primary purpose of this work. In addition to novel mechanical designs and implementation, it was also a goal to develop a control system that was flexible enough to be adapted with minimal user adjustment to various styles and configurations of slit-lamps. The system was developed with intentions of commercialization, so common hardware was used for all components to minimize the costs. In order to improve performance using this low-cost hardware, investigations were made to attempt to achieve better performance by applying control theory algorithms in the system software. Ultimately, the controller was to be flexible enough to be applied to other areas of human-robot interaction including pediatric rehabilitation via the use of humanoid robotic aids. This application especially requires a robust controller to facilitate safe interaction. Though all of the prototypes were successfully developed and made to work sufficiently with the control hardware, the application of advanced control did not yield notable gains as was hoped. Further investigations were made attempting to alter the performance of the control system, but the components selected did not have the physical capabilities for improved response above the original software implemented. Despite this disappointment, numerous novel advances were made in the area of teleoperated ophthalmic technology and pediatric physical rehabilitation tools. This includes a system that is used to remote control a slit-lamp and lens for examinations and some laser procedures. Secondly, a series of of humanoid systems suitable for both medical research and therapeutic modeling were developed. This included a robotic face used as an interactive system for ophthalmic testing and training. It can also be used as one component in an interactive humanoid robotic system that includes hands and arms to allow use of teaching sign language, social skills or modeling occupational therapy tasks. Finally, a humanoid system is presented that can serve as a customized surrogate between a therapist and client to model physical therapy tasks in a realistic manner. These systems are all functional, safe and low-cost to allow for feasible implementation with patients in the near future

An adaptive 4-week robotic training program of the upper limb for persons with multiple sclerosis

It is suggested that repetitive movements can initiate motor recovery and improve motor learning in populations with neurological impairments and this process can be optimized with robotic devices. The repetitive, reproducible and high dose motor movements that can be delivered by robotics have shown positive results in functional outcomes in stroke patients. However, there is little research on robotic neurorehabilitation for persons with multiple sclerosis (PwMS), more specifically there is lack of literature with focus on the upper extremity. Therefore, the purpose of this work was to use a robotic device to implement an adaptive training program of the forearm and wrist for PwMS. This approach is unique, as it incorporates real time learning from the robotic device to alter the level of assistance/resistance to the individual. This methodology is novel and could prove to be an effective way to properly individualize the therapy process with correct dosage and prescription. 7 individuals with varying levels of MS, placed their most affected limb (forearm) on a robotic device (Wristbot), grasped the handle, and using real-time visual feedback, traced a Lissajous curve allowing the wrist to move in flexion/extension, radial/ulnar directions. Robotic training occurred 3 times per week for 4 consecutive weeks and included 40 minutes of work. Robotic software was adaptive and updated every 3 laps to evaluate the average kinematic performance which modified the robotic assistance/resistance. Outcome measures were taken pre and post intervention. Improvements in performance were quantified by average tracking and figural error, which was significantly reduced from pre – post intervention. Isometric wrist strength and grip force endurance also significantly improved from pre to post intervention. However, maximum grip force, joint position matching, 9-hole peg test, and patient-rated wrist evaluation did not show any significant improvements. To our knowledge, this study was the first adaptive and individualized robotic rehabilitation program providing two opposing forces to the hand/wrist for PwMS. Results of this 4-week training intervention, provide a proof-of-concept that motor control and muscular strength can be improved by this rehabilitation modality. This work acts as a stepping-stone into future investigations of robotic rehabilitation for an MS population