Research ArticleCEREBRAL PALSY

A lower-extremity exoskeleton improves knee extension in children with crouch gait from cerebral palsy

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Science Translational Medicine  23 Aug 2017:
Vol. 9, Issue 404, eaam9145
DOI: 10.1126/scitranslmed.aam9145

A stand-up job for cerebral palsy

Neurological and movement disorders occurring during early childhood, collectively known as cerebral palsy, can limit mobility and independence throughout life. Lerner et al. investigated whether an exoskeleton worn on the legs could alleviate crouch gait in children with cerebral palsy. Crouch gait is characterized by excessive knee bending. The exoskeleton provided dynamic assistance during specific phases of the gait cycle. After six visits, six of seven participants showed improved knee extension during overground walking with the exoskeleton. Increased step length and gait speed suggest that the participants adapted to the assistive devices, warranting longer-term studies with robotic exoskeleton assistance in this patient population.


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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