Exoskeleton improves walking in children with CP
Wearing leg braces powered by small motors improves gait in children with cerebral palsy...
An estimated 500,000 children in the U.S. have cerebral palsy (CP). According to the Centers for Disease Control and Prevention (CDC), cerebral palsy caused by neurological damage before, during or after birth is the most common movement disorder in children, limiting their mobility and independence throughout life.
Although nearly 60 percent of children with CP can walk independently, many have crouch gait, a walking pattern with excessive knee bending, which can cause an abnormally high level of stress on the knee. Crouch gait can lead to knee pain and progressive loss of joint function. It is often treated with orthopedic surgery.
Zach Lerner PhD, Assistant professor of mechanical engineering and leader of NAU’s Biomechatronics Lab, joined Northern Arizona University’s Center for Bioengineering Innovation in 2017. His study is published in the journal Science Translational Medicine investigating whether wearing a robotic exoskeleton, a leg brace powered by small motors, could alleviate crouch gait in children with cerebral palsy.
“We evaluated a novel exoskeleton for the treatment of crouch gait, one of the most debilitating pathologies in CP,” Lerner said. “In our exploratory, multi-week trial, we fitted seven participants between the ages of five and 19 with robotic exoskeletons designed to increase their ability to extend their knees at specific phases in the walking cycle.”
After being fitted with the device, children participated in several practice sessions. At the end of the trial, six of the seven participants showed improvement in walking posture equal to invasive orthopedic surgery outcomes. The research also demonstrated improvements in crouch gait increased over the course of the trial, conducted at the National Institutes of Health Clinical Center in Bethesda, Maryland.
Lerner: “Together, these results provide evidence supporting the use of wearable exoskeletons as a treatment strategy to improve walking in children with CP.”
Rather than guiding the lower limbs, the exoskeleton dynamically changed posture by introducing bursts of knee extension assistance during discrete portions of the walking cycle. This resulted in maintained or increased knee extensor muscle activity during exoskeleton use.
The exoskeleton was safe and well-tolerated, and all the children were able to walk independently with the device.
“Our results suggest powered knee exoskeletons should be investigated as an alternative to or in conjunction with existing treatments for crouch gait, including orthopedic surgery, muscle injections and physical therapy,” explains Lerner.
Lerner's goal is to improve mobility and function in individuals with neuromuscular and musculoskeletal disabilities through innovations in mechanical and biomedical engineering. Building on the encouraging results of this study, his team is working toward conducting longer-term exoskeleton interventions to take place at home and in the community.
The ability to walk contributes considerably to physical health and overall well-being, particularly in children with motor disability, and is therefore prioritized as a rehabilitation goal. However, half of ambulatory children with cerebral palsy (CP), the most prevalent childhood movement disorder, cease to walk in adulthood. Robotic gait trainers have shown positive outcomes in initial studies, but these clinic-based systems are limited to short-term programs of insufficient length to maintain improved function in a lifelong disability such as CP. Sophisticated wearable exoskeletons are now available, but their utility in treating childhood movement disorders remains unknown. We evaluated an exoskeleton for the treatment of crouch (or flexed-knee) gait, one of the most debilitating pathologies in CP. We show that the exoskeleton reduced crouch in a cohort of ambulatory children with CP during overground walking. The exoskeleton was safe and well tolerated, and all children were able to walk independently with the device. Rather than guiding the lower limbs, the exoskeleton dynamically changed the posture by introducing bursts of knee extension assistance during discrete portions of the walking cycle, a perturbation that resulted in maintained or increased knee extensor muscle activity during exoskeleton use. Six of seven participants exhibited postural improvements equivalent to outcomes reported from invasive orthopedic surgery. We also demonstrate that improvements in crouch increased over the course of our multiweek exploratory trial. Together, these results provide evidence supporting the use of wearable exoskeletons as a treatment strategy to improve walking in children with CP.
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Aug 25, 2017 Fetal Timeline Maternal Timeline News News Archive
Child wearing a robotic exoskeleton. Image credit: Northern Arizona University