Robot-driven downward pelvic pull to improve crouch gait in children with cerebral palsy

Abstract

Children with cerebral palsy commonly exhibit an abnormality called crouch gait, which is characterized by excessive flexion of the hips/knees and weak plantar flexor muscles during the stance phase. One of the major reasons for this pathological gait is weakness in soleus muscles. During the mid-stance phase of gait when the toe and heel are both on the ground, the soleus keeps the shank upright and facilitates extension of the knee angle. It also provides propulsive forces on the body during the late stance phase of the gait cycle. We hypothesized that walking with downward pelvic pull will (i) strengthen extensor muscles, especially the soleus, against the applied downward force and (ii) improve muscle coordination during walking. We then tested a robotic training paradigm to improve both posture and gait of children with crouch gait. In this paradigm, participants with crouch gait were subjected to downward pelvic force when walking on a treadmill, provided by a cable-driven robot called Tethered Pelvic Assist Device. Electromyography of soleus and gastrocnemius muscles and walking kinematics of the participants showed the feasibility of this training, enhanced upright posture of the participants, and improved muscle coordination. In addition, walking features of these participants, such as increased step length, range of motion of the lower limb angles, toe clearance, and heel-to-toe pattern, improved. This robotic training method can be a promising intervention for children with cerebral palsy who have a crouch gait.

An Untethered Ankle Exoskeleton Improves Walking Economy in a Pilot Study of Individuals With Cerebral Palsy

“…Nevertheless, it was comparable to the number of participants in similar prominent multi-visit repeated-measures studies (e.g. n = 6 [36]), and was sufficient to demonstrate device efficacy through statistically and clinically significant improvements [37]. Due to the pioneering nature of this work and the significant time commitment and resources required to conduct a multi-visit study in individuals with neuromuscular deficits, the present sample size was selected to confirm the efficacy of the device and provide insight for the design of future larger-scale trials.…”

“…It is important that users of the device do not become dependent on powered assistance. Therefore, the present work may complement important research focused on encouraging improved motor control and strength for individuals with CP [34]–[36]. Due to the ability of our ankle exoskeleton to provide equal amounts of plantar-flexor and dorsi-flexor torque, there is the potential for the device to be used in a rehabilitation context, providing plantar-flexor resistance with the goal of strengthening the ankle plantar-flexor muscles during therapy.…”

Voluntary control of wearable robotic exoskeletons by patients with paresis via neuromechanical modeling

“…Noncommercial robotic exoskeletons use more complex schemes including HMIs inspired by mechanical principles, e.g., predefined moment patterns triggered at specific phases of the gait cycle [18–20]. These approaches were recently applied to poststroke and cerebral palsy individuals [19, 21, 22]. However, such approaches are limited to supporting a cyclic gait under specific patterns and speeds, thus limiting the patient’s self-pacing and voluntary control of the exoskeleton.…”

Adaptation of Stability during Perturbed Walking in Parkinson’s Disease

“…Desired forces and moments can be applied in any direction of the space and at precise time points in the gait cycle without adding inertia and rigid links to the human body. To date, it has been successfully used to improve gait in stroke survivors 30 and in children with cerebral palsy 31 by applying continuous forces at the waist-level. In this study, the A-TPAD was used to apply unpredictable force-controlled waist-pull perturbations for a short time duration.…”