Haptic Mirror Therapy Glove

UBICOMP/ISWC '15 ADJUNCT, SEPTEMBER 7–11, 2015, OSAKA, JAPAN

Haptic Mirror Therapy Glove: Aiding the treatment of a paretic limb after a stroke Abstract This paper describes the creation of a proof-of-concept design for an interactive glove that augments the mirror therapy protocol in the treatment of a paretic limb following a stroke. A review is completed of supporting literature that shows the potential of multisensory stimulation and augmentation to increase the efficacy of mirror therapy. Building on this background, a glove is designed to allow the user to stimulate the fingertips of their affected hand by tapping the fingers of their unaffected hand, using Force Sensing Resistors to trigger Linear Resonance Actuators on the corresponding fingers. This paper outlines the design considerations and methods used to create the glove, and discusses the potential for further work in the pursuit of a clinical trial.

James Hallam Georgia Institute of Technology 245 Fourth Street, NW Atlanta, GA., USA 30332 [email protected]

Author Keywords Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than the author(s) must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from [email protected]. Ubicomp/ISWC'15 Adjunct , September 07 - 11, 2015, Osaka, Japan Copyright is held by the owner/author(s). Publication rights licensed to ACM. ACM 978-1-4503-3575-1/15/09 $15.00 DOI: http://dx.doi.org/10.1145/2800835.2801648

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Stroke therapy, mirror therapy, rehabilitation, haptic interface, wearable technology, user-centered design

ACM Classification Keywords H.5.2. User Interfaces: User-centered design. H.5.2. User Interfaces: Haptic I/O

Introduction Recovery from a stroke poses a significant challenge for patients in treatment, both due to the difficulty of the rehabilitation process and the effects of the emotional


and social strain that can follow the injury. Patients who suffer from a stroke experience significant change in their lives, and struggle to accept the differences that may now dominate their lives as they begin their recovery. Rehabilitation promises at least a partial return to their prior way of life, but it requires dedication and a significant investment of time to a series of continuously repeated tasks, designed to prompt the brain to remap the lost function. Sticking with a therapeutic regime offers the stroke survivor the best chance for rehabilitation, yet doing so can be a monotonous task. Patients have a better recovery experience when these tasks are constantly changing, and when they are challenged in new and different ways, which stimulates the brain to learn more quickly and efficiently. One of the most common effects of stroke is hemiparesis, or the one-sided weakness of the body, particularly in the upper limbs. 80% or more of stroke survivors experience hemiparesis to some degree, with 55% to 75% having some ongoing limitations[7]. Mirror therapy has been proposed as a potential solution, as it is cost-effective and portable. The technique is comprised of a simple mirror positioned between the two outstretched arms of the user, reflecting the motions of the unaffected hand in a manner that superimposes the reflected image over the affected hand[6]. Clinic trials have indicated that it is a useful therapeutic intervention, demonstrating improvements in the range of motion, speed and accuracy of movement, squeeze strength, and improvements in motor function in chronic stroke patients[3]. Haptic feedback also shows new promise in therapeutic programs, aiding in motor learning functions through the directed application of vibration

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stimulus to the affected limbs[2]. We now see an opportunity to investigate the incorporation of both methods into a single unified therapy, suitable for use in the home.

Background The premise of mirror therapy is that by observing an unaffected limb in motion, the brain can map that stimulus to a damaged area controlling the affected limb, and use that stimulus to regrow function [1]. This is possibly due to the presence of mirror neurons, which can fire when the user observes someone else performing a movement. They may also be involved in multiple types of function – including vision, motor commands, and proprioception. It is this ability to interact with both vision and motor commands that suggests why mirror therapy might be effective [4].

Figure 1. Staged photo, illustrating the basic position of the arms during mirror therapy.

Design Considerations With the goal of improving on the delivery of the established mirror therapy protocol we set out to

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design a device that could enhance the exercises currently used by Occupational Therapists in a clinical setting. This requires a device that can deeply integrate with the motion and sensory systems of the hand. It also needs to build off of the key elements that make mirror therapy effective. Simulation and augmentation The mirror seems to be providing a simple but effective simulation of the affected hand in motion, and it is this simulation, in part, that is responsible for the therapeutic benefit of mirror therapy[5]. It therefore seems appropriate that any device built to augment mirror therapy is also increasing the veracity of the simulation. A device built for this use-case has the potential to interact with and augment the broader world, and allow the user to pursue a wide range of therapeutic activities. This device should also be able to interact with a range of objects prescribed by the occupational therapist. Tracking the hand in motion To better enhance therapeutic activities, the device needs to be able to accurately track the hand in motion – both to monitor the progress of the affected hand, and to use the unaffected hand as a baseline to measure against. The device should be able to monitor broad movements of the hand rotating over the wrist, monitor the position and flex of each phalange of the fingers relative to the knuckles, and monitor pressure measured against the fingertips. To do this, sensors will need to be designed or acquired, and used to build an effective model of the hand in motion.

Multi-sensory stimulation Adding multi-sensory stimulation to the foundational visual stimuli provided by the mirror may provide a way to increase the efficacy of the therapy – allowing for simultaneous multi-modal stimulation linked to symmetrical movements. The addition of haptics may also lead to increased efficacy, given the potential shown for direct stimulation or corrective feedback, and the combined utility of both.

Figure 2. Illustration of the proposed solution – showing symmetrical stimuli across the mirror.

Dosage and acceptance Establishing the most optimal dosage of therapeutic activity seems to be a key factor in the design of a therapeutic device for the home. With the understanding that usability and aesthetics will have an impact on acceptance, and therefore on potential dosage, we are working to design an attractive and comfortable device that will encourage frequent usage.

Proposal It is therefore our intent to build a haptic glove device that, used in conjunction with established mirror therapy protocol, could speed up the time to recovery

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and motor sensation in a limb weakened by the affects of stroke. We intend to develop this system with the goal of improving the rehabilitation experience, improving the efficacy of current methods by encouraging the user to perform their exercises more often, with an increased awareness of their progress, and increased agency and self-sufficiency in their development. Home use also means the glove must prove to be usable by patients with a paretic limb without assistance, and have its function and interface be easily understood. It is our intent that the glove attains a high level of aesthetic acceptance amongst the patients and therapists using it, and proves to be comfortable after extended use.

and tied them together using an Arduino microcontroller. We ran a number of prototypes as the system evolved, eventually adding LEDs on each finger to act as a cueing indicator for the exercises. Preliminary testing in the lab showed very promising performance from the device, as users were able to play piano notes with the pressure sensors, and feel simultaneous haptic feedback from the motors. We are working now to refine the sensor design to improve the accuracy, and to better integrate it into the fabric of the glove.

Prototype Design We began an iterative design process with the goal of creating a set of proof of concept models that proved the viability of the interaction concept, and allowed for exploration of fabrication techniques. To accommodate a wide range of users, rapid prototyping techniques that could allow sizing adaptation were explored – such as the use of laser cutters and computer embroidery machines. We have now created an ongoing series of prototypes, each tackling one the following areas of research: Pressure sensors, motors, and lights Early interactive prototypes were built as a proof of concept, showing that input could be taken from the fingertips of one hand, and transferred the sensory system of the other hand. To do this, we designed and fabricated a modified pressure sensor, well suited for mounting on the fingertips of a glove. We paired this input with the output of a Linear Resonance Actuator (LRA) motor, which has a very accurate response rate,

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Figure 3: Final working proof of concept model – with motor glove on the left, sensor glove on the right.

Fit, donning and doffing The fit of interactive gloves has a significant impact on the performance of the gloves with each user, due to the variability in the size and structure of each human hand. Fit helps to address both the comfort of the glove, as well as the accuracy of the sensors and effectors, which need precise positioning to be effective. We are tackling this challenge by developing a system built around a parametric model that can structure custom patterns for the fabric, circuit layer,

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and component positioning, based off the hand measurements and requirements of each user.

Figure 4. Glove prototype showing a proposed zipper system to aid in donning and doffing.

We are also pursuing the creation of gloves suited for donning and doffing by users with paretic limbs, potentially with hands in spasm. It is a key requirement that stroke survivor can easily manipulate the glove on their own, which requires the investigation of a number of novel closure mechanisms. We are currently looking at ways to have the entire back or face of the hand open up, and then reclose securely, allowing the user more direct access to the base of the fingers in the glove. Circuit density and printed circuits Given the large number of components required, and the un-insulated nature of many e-textile circuit technologies, circuit density becomes a problem in the arrangement of components and the circuit traces that connect them. We are pursuing many alternative circuit routing and printing technologies that maintain sufficient electrical performance, while allowing for unrestricted movement of the hand. To do this, we are

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working with emerging technology that allows for the depositing of circuits directly onto the surface of the glove. Using the parametric model described earlier, we hope to be able to produce individualized circuit traces that conform to the hand of each use, and preserve registration with the fabric cut pattern. Aesthetics and acceptance There are precedents on the market of interactive gloves, both as basic therapeutic devices, and in other applications. The most common form of interactive glove bristles with wires, and adds significant bulk to the hand – making the hand look unnatural and swollen. We see a link between aesthetics and acceptance in the therapeutic device market, and are working to design our future glove prototypes with a higher level of fit and finish, in more desirable materials. We are also intending to add color, material selection, and personalization to our list of options, to create a tailored experience for our users.

Future Work We will continue to work to integrate the models being produced by each of the preceding areas of study. Each model represents a production process that need to be brought into alignment to allow the creation of glove models suitable for trial. We have now started preliminary work with Occupational Therapists and stroke survivors in the Atlanta area, to get feedback about our current progress – our goal is to be able to run a small-scale trial that tests acceptance and usability for the glove, and continue to work towards a broader efficacy study. This project has many working parts, and it is hoped that feedback from the therapists engaged in the project will help refine the product to focus on the most suitable functional elements.


Objective for the ISWC Doctoral School This feels like the year I could gain the most from the ISWC Doctoral School, as my topic has narrowed onto a single intervention, yet that intervention still has many moving parts. I feel like I'm at the point where I can articulate what is meaningful about the research, but I am still grappling with how to best bring it to a conclusion. Being able to sit down with my peers from all over the world and to get not only their feedback, but also their strategies for tackling this subject would be invaluable. I would appreciate feedback on getting solid testable data out of a sprawling system design, and I think attending the Doctoral School this year gives me the best chance of making that happen.

control with vibrational haptic feedback for multiple sclerosis. In Proceedings of the IASTED International Conference on Telehealth/Assistive Technologies ACTA Press, 110-115. [3]

LEE, M.M., CHO, H.Y., and SONG, C.H., 2012. The Mirror Therapy Program Enhances Upper-Limb Motor Recovery and Motor Function in Acute Stroke Patients. American Journal of Physical Medicine & Rehabilitation 91, 8 (Aug), 689-696. DOI=

http://dx.doi.org/10.1097/PHM.0b013e31824fa 86d. [4]

RAMACHANDRAN, V.S. and ALTSCHULER, E.L., 2009. The use of visual feedback, in particular mirror visual feedback, in restoring brain function.

Biography

Brain 132(Jul), 1693-1710. DOI=

James Hallam is a PhD Student in Industrial Design at Georgia Tech, where he researches wearable technology and design strategy. James started his graduate studies at Georgia Tech in 2012, and is expected to complete in the summer of 2017.

http://dx.doi.org/10.1093/brain/awp135. [5]

STEVENS, J.A. and STOYKOV, M.E.P., 2004. Simulation of bilateral movement training through mirror reflection: a case report demonstrating an occupational therapy technique for hemiparesis. Topics in Stroke Rehabilitation 11, 1, 59-66.

Jim Budd is the Chair of Georgia Tech’s School of Industrial Design, and is James’ advisor. Jim brings 15 years of academic and research leadership in humancentered, interactive product design, as well as two decades of corporate design experience to the school.

[6]

SUTBEYAZ, S., YAVUZER, G., SEZER, N., and KOSEOGLU, B.F., 2007. Mirror therapy enhances lower-extremity motor recovery and motor functioning after stroke: A randomized controlled trial. Archives of Physical Medicine and Rehabilitation 88, 5 (May), 555-559. DOI=

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