Lokomat: The New Treatment for Mobility Impairments

by Resource Center Staff Writer : 7/3/2011 5:37:10 PM : Category: research

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We spoke with Dr. Paulo Bonato, Director, and Pamela Reynolds, Project Coordinator, from the Motion Analysis Laboratory at Spaulding Rehabilitation Hospital in Boston, MA. They are at the forefront of exciting developments in the treatment of mobility impairments.

What is the Lokomat and what does it do for patients?
The Lokomat s a robotic machine built to provide intensive gait training for those who need it. People who might find it useful include children with Cerebral Palsy, adults who have suffered a stroke, as well as patients with spinal cord injury, traumatic brain injury, multiple sclerosis or other neurological disorders which can impair gait. The Motion Analysis Lab at Spaulding Rehabilitation Hospital is one of the very few labs in the country that offers gait training with the Lokomat and which studies how effective the machine actually is. There are only a few rehabilitation centers around the country that offer such an integrated research and clinical program focused on the use of robotics in rehabilitation.The Lokomat system is composed of a driven gait orthosis with a treadmill and bodyweight support. Patients are strapped into a body sling which might support most of their body weight, or provide no support at all, depending on the patients needs. Legs are strapped into an adjustable robotic exo-skeleton which extends from the hips down to the feet. When the treadmill is turned on, the exo-skeleton helps patients to walk correctly by applying pressure where needed. A computer monitors patients movements by providing a real-time analysis of the actual biomechanics of the movements. Studies, as well as the experiences of our own patients, show that this kind of robotic-assisted gait training facilitates motor recovery. Thats because the device retrains the brain by requiring patients to engage in numerous repetitive motions. Repetition is key in learning new movements or improving incorrect movements.Another big advantage of this kind of robot-assisted gait training is that it makes rehabilitation easier from the therapists perspective. Therapists are no longer burdened by the grueling, physically-exhausting labor required during manually-assisted treadmill training. Training sessions can be longer, the therapy is more efficient, and therapy achieves its training goals sooner.

How does the Lokomat individualize treatment?
The beauty of robot-assisted gait training is that it can be completely programmed to the specific needs of each patient. The adjustable exoskeleton can be manipulated to fit each patients body. The amount of pressure or help the exoskeleton provides can be set to a patients needs. And of course, the treadmill itself can be set to any walking speed.

Describe the use of Lokomat in individuals with Cerebral Palsy. How does having a "robot" move your legs to walk ultimately result in a patient being able to do it themselves?
Lets say a child with Cerebral Palsy uses the Lokomat machine. Maybe this child walks on his toes or the balls of his feet. This condition can be helped by using the Lokomat and its exoskeleton to encourage that child to bend his or her foot at the ankle. With training on the machine, many children improve such gait problems. They build muscle and muscle memory which allows for improved walking once theyre off the treadmill and in the school yard or at home. As patients improve their walking, the machine can be adjusted to account for these improvements, thus gradually allowing children to take on more and more of the business of walking correctly on their own.

How could the Lokomat help individuals with CMT?
Its too early to say whether gait training on the Lokomat can help children with CMT. However, there is strong reason to suspect that it might. Children with Cerebral Palsy and children with CMT suffer several common gait problems, such as toe-walking, a high-stepped gait or foot drop. In children with Cerebral Palsy, our studies, as well as the studies of others, have shown an average improvement in gait function of 20 to 30% when using clinical scales such as the Gross Motor Function Measure Scale or using clinical measures of gait speed and endurance such as the 10-meter walk test and the 6-minute walk test. So it may be that children with CMT may also experience such gains. There is one caveat, however. Whereas group average results demonstrate significant improvements in walking ability in children following robotic-assisted treadmill gait training, a closer inspection of results on an individual basis shows a large variability in the response to the intervention. This observation has led to a major effort by several research groups aimed at optimizing training procedures on an individual basis. We hope that our research into individualizing interventions will help us in tailoring robot-assisted interventions in children with CMT.

Does locomotion therapy depend on sensory feedback, which can be impaired by CMT?
Sensory impairments are expected to have an impact on the effectiveness of robot-assisted training. The most promising approach at the moment appears to be one that combines robot-assisted gait training with other techniques to overcome the negative consequences of sensory impairments. Among others, our group has focused on the use of sensory enhancement via the use of small currents that, when delivered to sensory organs embedded in muscles (i.e. spindles) or attached to our tendons (i.e. Golgi tendon organs) facilitate transferring sensory information to the central nervous system. It is our intention to experiment with the combination of robot-assisted therapy and sensory enhancement techniques to explore ways to maximize the benefits of gait training in individuals with sensory impairments.

How does the Lokomat provide feedback to the patient?
The robot provides guidance to subjects as they walk by generating forces with its motors that help people walk in a correct manner. The forces generated by the robot provide a first feedback mechanism (which is called haptic feedback) that relies on the fact that people can sense forces exerted on their lower limbs by the robot. These forces are large if the subject walks according to trajectories of movement that are very different to the desired ones. The forces become smaller as individuals walk better as they learn from the robot. There is also visual and auditory cues provided to patients. One way we work to engage patients is by using video games to provide feedback during a training session. We have experimented with this approach and found that kids who train with the robot while receiving feedback via video games do better than kids who train with the robot but without video games. Further research is necessary to make sure the video games effectively target the types of gait deviations that we observe in patients who can be helped with robot-assisted gait therapy.

Does locomotion training help with nerve functioning itself, the resulting muscle atrophy or both?
Numerous papers have been published showing the strong relationship between improvements in the mechanics of locomotion and function. Also, it has been shown that there is a high correlation between the efficiency of locomotion and quality of life. Therefore, achieving good walking patterns, gait speed and building endurance is a common goal in physical therapy and rehabilitation.

Is there a difference in possible application among the various types of CMT?
It is too early to say whether patients with type I CMT would respond better or worse than patients with type II CMT, but it is also possible that the two groups will respond equally well to robot-assisted gait training. In fact, recent literature has hypothesized that factors affecting the ability of different patients to learn new motor patterns might be the key factor in determining the effectiveness of robot-assisted gait training. The type of CMT each patient is affected by might be less relevant than the individual baseline ability of patients to learn new motor patterns.

Is there a difference in effectiveness of the Lokomat in children and adults?
Although additional research is needed to address this question, preliminary results suggests that children improve more than adults, given a certain amount of exposure to therapy. This is not an unusual observation. As they undergo developmental changes, it is not surprising that kids would be shaped more easily than adults. This observation has encouraged our team and others to put particular emphasis on pediatric rehabilitation, especially when dealing with a life-long condition that allows us to pursue pediatric interventions.

Where can people learn more about the Lokomat?They can start by visiting the companys website, Hocoma, of Switzerland, at: www.hocoma.com/produkte/lokomat

Where is the Lokomat available for treatment?
Only a few centers besides Spaulding Rehabilitation Hospital offer robot-assisted therapy (e.g. using the Lokomat system) for both children and adults. Among others, the Rehabilitation Institute of Chicago provides this service both clinically and as part of their research program. Pediatric systems are also available in Cincinnati and Detroit. Systems for adult training are available in a slightly larger number of rehabilitation centers such as Shepherd Center in Atlanta, the Miami Project to Cure Paralysis in Miami, and the Southwestern Medical Center in Dallas. This kind of treatment may be covered by insurance depending on an individuals coverage.



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