Researchers at the Baltimore Veterans Affairs (VA) Medical Center and the University of Maryland School of Medicine are conducting research using a novel ankle robot ("Anklebot"), invented by researchers at the Massachusetts Institute of Technology and sponsored by the Department of Veterans Affairs, with stroke patients at the Baltimore VA Medical Center. The design, mechanical characterization and preliminary clinical application of this ankle robot are presented in the June issue of IEEE Transactions on Robotics: Special Issue on Rehabilitation Robotics, the premiere and most-cited journal in robotics research.
Baltimore, MD (PRWEB) June 25, 2009 -- Researchers at the Baltimore Veterans Affairs (VA) Medical Center and the University of Maryland School of Medicine are conducting research using a novel ankle robot ("Anklebot"), invented by researchers at the Massachusetts Institute of Technology and sponsored by the Department of Veterans Affairs, with stroke patients at the Baltimore VA Medical Center. The design, mechanical characterization and preliminary clinical application of this ankle robot are presented in the June issue of IEEE Transactions on Robotics: Special Issue on Rehabilitation Robotics, the premiere and most-cited journal in robotics research.
Over 790,000 Americans suffer strokes each year. In the United States, close to 5 million stroke victims are alive today. Reduced mobility and increased fall risk are significant long-term health problems facing those who have chronic gait deficits resulting from stroke. In response, researchers at the Baltimore VA Medical Center and the University of Maryland School of Medicine are using the Anklebot to augment current therapies for improving gait and balance function after stroke.
"Gait problems due to stroke and other neurological diseases are an important cause of disability," said Dr. Christopher Bever, co-author and director of Research & Development for the VA Maryland Health Care System. "Conventional treatments are not always effective. The availability of robotic assistive devices would represent an important new approach to therapy that would benefit many patients."
The Anklebot is an impedance-controlled exoskeleton that can be worn during over-ground or treadmill walking, or in seated-recumbent positions for ankle training. The Anklebot has versatile controls that allow for assisting users on an "assist-as-needed" basis when they cannot complete a movement. It can also resist movement providing a modality for ankle resistance training, or it can simply record ankle kinematics and kinetics for application as a clinical measurement or evaluation instrument.
In addition to reporting on the design and mechanical characteristics of the Anklebot, the study findings also present clinical data to demonstrate the potential of this device as an efficient clinical measurement tool to estimate intrinsic ankle properties; e.g. ankle stiffness in young healthy individuals.
"This study demonstrates that ankle stiffness is a strongly direction-dependent property, and we have for the first time, reported its behavior in the frontal plane, a degree of freedom that is critical in maintaining dynamic balance," said lead author Anindo Roy, PhD, assistant professor of neurology, University of Maryland School of Medicine and Robotics Engineer, Rehabilitation Research & Development at the Baltimore VA Medical Center.
In a separate but related study submitted to the Journal of Neurophysiology, Dr. Roy and colleagues have extended their results to measure ankle stiffness using the Anklebot in chronic stroke survivors and have identified frontal plane ankle stiffness to be a potential signature of ankle pathology following stroke.
An on-going clinical study is also being conducted at the Baltimore VA Medical Center that endeavors to help stroke survivors, including veterans, achieve improvement in their gait and balance function via ankle robot-assisted therapy. Using a paradigm that involves one of the video games, researchers found that subjects with stroke universally enjoyed and tolerated the robotic training. The video game requires patients to move their paretic toes "up or down" while wearing the Anklebot that moves a screen cursor "up or down" in order to maneuver through targets that approach across the screen at different vertical levels. With novel motivational elements of scoring and real-time performance feedback, the stroke patients were able to perform hundreds of targeted ankle movements in response to visual stimuli and robotic assistance in each training session.
Thus far, the study has demonstrated that stroke rehabilitation, when aided by the ankle robot that guides movement of ankles, providing customizable robotic assistance (as-needed), significantly improves walking function and ankle motor control recovery as well as decreases ankle impairments in chronic stroke survivors. "Our findings already indicate that this device has the potential to evoke positive changes in walking speed, reduce ankle stiffness and improve ankle motor control as indicated by increased smoothness and speed of targeted ankle movement," said Dr. Roy, one of the lead investigators of this study. "In fact, some of these benefits are gained and retained even after a single session of playing the video game with the robot engaged."
Based on current findings, VA, University of Maryland and MIT researchers ultimately envision the Anklebot to facilitate insights into human motor recovery, gait, balance and motor learning by providing a customizable, adaptive and quantifiable measurement and rehabilitative instrument.
Future studies will include testing the efficacy of VA intervention on acute stroke patients to evaluate whether robotic-assisted movement therapy has a significant and measurable impact on neurorecovery during the early phase following an injury. These studies will also look at developing impedance-controlled gait algorithms to provide Anklebot facilitated gait training in stroke populations.
Funding for this study was provided in part by the Department of Veterans Affairs Rehabilitation Research and Development Service and in part by Baltimore Veterans Affairs Medical Center's Center of Excellence on Task-Oriented Exercise and Robotics in Neurological Diseases.
For additional information or to request an expert interview contact Kenya Griffin at (410) 605-7098.
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