REHABILITATION ROBOTICS

Director: Dr. Joe Hidler

The Center for Applied Biomechanics and Rehabilitation Research (CABRR) at the National Rehabilitation Hospital (NRH) provides a unique setting for junior clinical and PhD level investigators to develop and explore new hypotheses related to improving motor function through activity dependent neural plasticity. Within our laboratories we have developed new experimental methods to explore novel research questions such as investigating the influence of walking speed and body-weight support during step-training in SCI, quantifying and assessing EMG patterns during gait, examining the role of sensory afferents in individuals with neurological injuries, and developing mathematical models simulating sensory-motor impairment. We have also pioneered the use of robotic systems to quantify walking ability in individuals with gait disorders, an area of research which may enhance outcomes in rehabilitation clinics world wide. Our approach has been the bench-to-bedside model where the focus of our work has a direct impact on the individuals treated at NRH and at related centers across the world.

Utilizing the devices and techniques developed and utilized within CABRR at the National Rehabilitation Hospital, we are currently pursing a number of research studies that focus on activity dependent neural plasticity in neurologically impaired individuals as well as advancing the understanding of the underlying mechanisms responsible for motor impairment. The following is a sample set of the diverse work we are pursuing within the labs:

Gait Restoration of Hemiparetic Stroke Patients Using A Robotic Gait Orthosis: The focus of this work is to determine whether intensive step training in sub-acute stroke subjects (less than 6 months post-stroke) leads to stable over-ground walking ability beyond what can be expected from conventional gait training. As mentioned above, robotics is a medium that lends itself perfectly for repetitive therapeutic tasks such as gait training since these devices actively move the subject?s limbs through mechanical motors rather than through the hands of physical therapists. Thus accurately controlling the lower limbs in spastic subjects is readily achievable. In addition, we have developed a novel bio-feedback system at CABRR that is integrated into the Lokomat so that during the robot-assisted gait training, subjects can adapt their walking pattern in order to enhance the therapy. The results from this study are directly applicable clinically, and may reshape currently utilized gait training paradigms across neurorehabilitation centers.

Robotic-Assessment of Walking: A current limitation with body-weight supported locomotor training paradigms is that there are a number of variables within the training session that are not controlled for, yet may play an instrumental role in facilitating functional returns of movement in humans. For example, changing the loading conditions on the lower limbs, the speed at which the patient ambulates, and the kinematics of the legs throughout the gait cycle (in particular, the amount of hip extension) directly influence the firing patterns in the afferent receptors of the lower limbs which appear to be essential for inducing and facilitating central pattern generators. Utilizing a modified inverse-dynamics approach coupled with a one of a kind Lokomat, we are the only institute in the world able to accurately quantify walking ability in neurologically impaired subjects under well-controlled conditions, including those who cannot ambulate. The goal of this work is to develop techniques for optimizing training conditions in order to promote the highest returns in motor recovery.

Dynamic Synergy Patterns in Hemiparetic Subjects: This work explores the loss of coordination and abnormal synergy patterns that often accompanies stroke and spinal cord injury. We are utilizing the Lokomat with instrumented leg cuffs to measure the force components and surface EMG activity generated by the paretic leg musculature during robot assisted walking. This understanding is essential to understanding the potential mechanisms underlying motor impairment in neurological injuries which may lead to gait deficits and decreases in stability.

Improvements in Health and Well Being : The overall objective of this project is to determine whether long-term robotic-assisted locomotor training improves the overall health and quality of life of subjects with complete loss of motor function following spinal cord injury. After lesions to descending spinal pathways that result in a complete loss of motor function, patients often experience spasticity, loss in bone density, and a number of other secondary complications. We believe that intensive locomotor training with the Lokomat robotic gait orthosis (Hocoma, Inc., Zurich Switzerland) will lead to reductions in these negative health complications since this therapy promotes dynamic loading of the bones, increases in circulation, and continuous ranging of joint motion. As a result, we postulate that subjects who train on the device will experience improvements in health status and consequently improvements in quality of life. Conversely, we do not believe that the training of individuals with ASIA A and B SCI injuries on the Lokomat for up to six months will result in changes in ASIA motor levels and functional changes at an ambulatory level (as demonstrated by the Spinal Cord Index Measure, SCIM).

For a complete up to date list of CABRR projects, visit us at http://cabrr.cua.edu.

It is envisioned that both new clinicians in the areas of physical medicine and rehabilitation, physiatry, and neurology, along with PhD level junior faculty will be most suited to take advantage of the resources and techniques proposed in this research core. Since robotic rehabilitation is a new yet highly promising area, training new investigators in this area is critical for the future development of new devices and interventions. New physicians interested in clinical research can explore the use of combining various treatment options for subjects with neurological injuries, for example, accurately studying the effects of new spasticity drugs, botox, or other interventions on walking ability or upper limb function. Support staff in the CABRR laboratories will assist researchers in developing their study aims and hypotheses, can setup the necessary equipment to execute pilot data collection, and will assist in analyzing and interpreting all experimental data. For new PhD level junior faculty, this research core provides a rich set of resources and expertise for investigating some of the basic science questions involving sensory-motor impairment after SCI, stroke, and other pathologies. And for those investigators interested in developing new devices, the CABRR laboratories have extensive prototyping and test equipment which can be used to build and evaluate their performance. Since NRH has an extensive stroke and SCI patient population along with expert clinicians and therapists experienced in treating motor impairments resulting from neurological injuries, developing devices at NRH provides opportunities to test the device on actual patients and also receive feedback from patients and the medical staff. Specific resources available to NCARRN investigators includes the Lokomat robotic gait orthosis, an ADAL split-belt instrumented treadmill, a Codamotion motion capture system, DelSys EMG systems, and much more.

This NCARRN will also provide resources to allow robotic training and analysis in animal models of spinal cord injury using Robomedica, Inc.'s Rodent Robotic Motor Performance System. The Rodent Robotic System is the first and only device of its kind. The system allows programmable active control and quantification of rodent limb movements and weight-bearing levels during the performance of motor tasks. The device measures the weight bearing levels during motor task performance, allowing researchers the ability to record training and testing sessions over many weeks, as well as assures efficient and accurate data analysis. Investigators will be able to use the rodent robotic system to conduct animal experiments to parallel the human robotic studies. Thus, participants will have the resources available to examine activity-based neural plasticity and using the Cellular and Molecular Mechanisms core below, examine the reorganization of CNS pathways that accompanies robotic training.