This Small Business Innovation Research (SBIR) Phase I project seeks to address the significant technical barriers associated with an untethered overground cooperative gait rehabilitation exoskeleton. Current gait rehabilitation techniques available to patients with gait abnormalities include conventional therapist based rehabilitation and more recently Body Weight Support Treadmill (BWST) robotic rehabilitation. The leading BWST devices employ a cooperative gait rehabilitation approach that varies the assistance to the user based on their ability. The conventional therapy approach is extremely labor intensive, but while the BWST therapy is the leading alternative it has shown mixed results. Researchers hypothesize that this is due to differences in the trained gait between BWST walking and overground walking. Mobile exoskeletons have emerged to better imitate overground walking, but to date no mobile device has implemented a cooperative control strategy, mainly due to the technical issues associated with its use. This SBIR intends to develop novel advances in cooperative rehabilitation control strategies along with innovative actuator designs to make possible the first mobile overground gait rehabilitation exoskeleton that implements a cooperative strategy. Specifically, it will address the major technical barriers to achieving this goal to increase the chances of successfully developing this technology in Phase II.

The broader impact/commercial potential of this project could directly impact the lives of patients with impaired gaits from a variety of symptoms including post-stroke, incomplete spinal cord injury, and multiple sclerosis. It is estimated that nearly 2 million patients in the U.S. could currently benefit from improved gait rehabilitation therapy. This technology can be sold directly to rehabilitation hospitals through existing distribution channels. This technology will have a significant impact on the lives of patients undergoing gait rehabilitation. It will enable a new level of effectiveness by providing a novel cooperative rehabilitation approach on an overground device. Existing conventional therapy often causes patients to transition to therapist-assisted overground walking prematurely, resulting in a gap in the progression of care. This device addresses that gap by supporting a patient from acute therapy until they are strong enough for therapist-assisted overground walking. Finally, this device will expand our technical understanding of the limits and effectiveness of robotic gait rehabilitation. The device will serve as a platform to develop the next generation of even more effective robotic rehabilitation control strategies, both for the investigators and the greater research community.

Project Report

Company Name: Ekso Bionics, Principle Investigator: Adam Zoss, This project has partially supported the development of Variable Assist at Ekso Bionics. The resulting outcome has been a successful software release of Variable Assist for Ekso™ which significantly increases the rehabilitation capabilities for patients with partial lower extremity strength (i.e. incomplete spinal cord injury patients and stroke survivors). Ekso is a bionic suit, or exoskeleton, which enables individuals with lower extremity paralysis to stand up and walk over ground with a weight bearing, four point reciprocal gait. Battery-powered motors drive the legs and replace neuromuscular function. The first generation of Ekso is intended for medically supervised use by individuals with complete or incomplete spinal cord injury (SCI) or disease, and other forms of lower extremity paralysis or weakness due to Multiple Sclerosis, amyotrophic lateral sclerosis, Parksinson’s, Guillain Barre, or other neurological disease. Ekso started selling to rehabilitation centers in the US and Europe in Spring of 2012. This project helped develop a major upgrade to Ekso which allows the device to better facilitate stroke populations which was launched in Summer of 2013. This new upgrade added variable assist and hemiplegic capabilities to the Ekso device. Variable Assist is a new feature which allows clinicians to augment their patients’ strength and provides the ability to strategically target deficient aspects of their gait. This means weak patients can now get up in a stable environment sooner, while helping them achieve optimal gait patterns and high step dosage. It engages patients by challenging their abilities; balancing the physical effort they exert with the amount of help they need to achieve a more normalized gait. Variable Assist works by allowing individuals with any amount of lower extremity strength to contribute their own power -- from either leg -- to achieve walking over ground. Based on the therapeutic goals, therapists now have the option to assign a specific amount of power contribution to augment their patients’ efforts, or to allow the Ekso suit to dynamically adjust to their needs in real-time. Along with Variable Assist, this upgrade has additional hemiplegic modes where the Ekso only assists with one leg, allowing the patient full control of the opposite leg. This is specifically targeted towards stroke patients who want to maintain the confidence and support from using their un-affected leg. As of September 2013, Ekso Bionics has sold over 40 Ekso devices to rehabilitation centers across the US and Europe. Hundreds of patients have walk millions of steps with assistance from Ekso. This amazing product, which has become the flagship device of Ekso Bionics, would not have been possible without the support of this grant. While funding has come from many different sources, this grant helped fund the very beginning efforts and has continuously supported the innovation and exploration necessary to make this product a reality.

National Science Foundation (NSF)
Division of Industrial Innovation and Partnerships (IIP)
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Muralidharan S. Nair
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Ekso Bionics, Inc.
United States
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