U.S. Government work not protected by U.S. copyright.
This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TNSRE.2016.2595501, IEEE
Transactions on Neural Systems and Rehabilitation Engineering
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Abstract— Crouch gait, a pathological pattern of walking
characterized by excessive knee flexion, is one of the most common
gait disorders observed in children with cerebral palsy (CP).
Effective treatment of crouch during childhood is critical to
maintain mobility into adulthood, yet current interventions do not
adequately alleviate crouch in most individuals. Powered
exoskeletons provide an untapped opportunity for intervention.
The multiple contributors to crouch, including spasticity,
contracture, muscle weakness, and poor motor control make
design and control of such devices challenging in this population.
To our knowledge, no evidence exists regarding the feasibility or
efficacy of utilizing motorized assistance to alleviate knee flexion
in crouch gait. Here, we present the design of and first results from
a powered exoskeleton for extension assistance as a treatment for
crouch gait in children with CP. Our exoskeleton, based on the
architecture of a knee-ankle-foot orthosis, is lightweight (3.2 kg)
and modular. On board sensors enable knee extension assistance
to be provided during distinct phases of the gait cycle. We tested
our device on one 6 year old male participant with spastic diplegia
from CP. Our results show that the powered exoskeleton
improved knee extension during stance by 18.1° while total knee
range of motion improved 21.0°. Importantly, we observed no
significant decrease in knee extensor muscle activity, indicating
the user did not rely solely on the exoskeleton to extend the limb.
These results establish the initial feasibility of robotic exoskeletons
for treatment of crouch and provide impetus for continued
investigation of these devices with the aim