Byl Journal of Medical Case Reports 2012, 6:216 http://www.jmedicalcasereports.com/content/6/1/216 R E S E A R C H A R T I C L E JOURNAL OF MEDICAL CASE REPORTS Open Access Mobility training using a bionic knee orthosis in patients in a post-stroke chronic state: a case series Nancy N Byl Abstract Introduction: An emerging area of neurorehabilitation is the use of robotic devices to enhance the efficiency and effectiveness of lower extremity physical therapy post-stroke. Many of the robotic devices currently available rely on computer-driven locomotive algorithms combined with partial bodyweight-supported treadmill training that drive reflex stepping with minimal patient intention during therapy. In this case series, we examined the effect of task-oriented mobility training in patients in a post-stroke chronic state using a novel, wearable, mobile, intention-based robotic leg orthosis. Case presentation: Three individuals, all of whom had reached a plateau with conventional bodyweight-supported treadmill training, participated in task-oriented mobility therapy (1.5 hours, two to four times per week for four weeks) with a robotic leg orthosis under supervision by a physical therapist. Participant 1 was a 59-year-old Caucasian man, who had an ischemic left stroke six years previously with resultant right hemiparesis. Participant 2 was a 42-year-old Caucasian woman with left hemiparesis after a right stroke 15 months previously. Participant 3 was a 62-year-old Caucasian woman with a history of a right middle cerebral artery aneurysm with third degree sub-arachnoid hemorrhage 10 years ago. Immediately after training, all participants demonstrated improved gait speed (10 meter walk), stride length and walking endurance (6 minute walk) compared with baseline measurements. Improvements were maintained one month after training. Timed up and go and five times sit-to-stand were maintained for all three participants, with only one individual remaining outside the safety performance norm. Conclusions: Lower extremity training integrating an intention-based robotic leg orthosis may improve gait speed, endurance and community levels of participation in select patients in a post-stroke chronic state after plateauing within a bodyweight-supported treadmill training program. The wearable, mobile assistive robotic device safely supplemented supervised physical therapy including mobility and balance skill training. Introduction Individuals who receive coordinated rehabilitation ser- vices after stroke demonstrate reduced mortality and achieve greater independence than those who do not [1]. Although early intervention and rehabilitation are pre- ferred in the recovery process, research indicates late re- covery may also occur for chronic stroke survivors. Late recovery mechanisms require patient effort and attention including progressive repetitive task-specific training to drive neural remodeling and reorganization [2]. Correspondence: byln@ptrehab.ucsf.edu Department of Physical Therapy and Rehabilitation Science, School of Medicine, University of California San Francisco (UCSF), PT Health and Wellness Center, Bakar Community Center, 1675 Owens Street, Box 0736, San Francisco 94158-2332, USA An emerging area in neurorehabilitation is the use of robotic devices to enhance the efficiency and effective- ness of post-stroke therapy. A number of designs have been commercialized. These wearable, assistive robotic devices typically demand attention and repetition from the patient, while providing feedback through various modes to improve performance. Early studies of upper- limb robotic devices remain inconclusive when evaluating their benefit over conventional physical therapy [3]. Robotic systems for lower extremity therapy on a bodyweight- supported treadmill are subject to many of the same limita- tions as conventional bodyweight-supported treadmill training (BWSTT) [4,5] as they do not compensate for the lack of visual flow, balance and intention requirements inherent to this kind of movement training. © 2012 Byl; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.