Robotic Device Improves Crouch Gait in kids With Cerebral Palsy

Cerebral palsy refers to a group of neurological disorders which hamper the individuals’ moving, walking, balancing and posture maintaining ability, say the U.S. Centers for Disease Control and Prevention. This disorder which affects about one in every 323 kids is the most common motor disability in childhood.

Crouch gait is caused by spastic diplegia, a type of cerebral palsy. In spastic diplegia, a normal walking stride is hampered due to the presence of stiff muscles in both the legs which prevent the normal give-and-take of walking.

The walking ability in humans depend on two sets of muscles including the flexor muscles and the extensor muscles. The former group of muscles help in pulling while the latter in pushing. For instance, while bending your knee, you use your flexor muscles and while stretching your leg, you use the extensor muscles.

Kids with crouch gait are always flexed, with their ankles, knees and hips unable to move back and forth owing to the stiff flexor muscles and weak extensor muscles in these joints.

Typical physical therapy treatment for crouch gait uses weights, elastic bands, or even resistance offered by a professional therapist. These do improve the strength of extensor knee muscles, however the results are inconsistent due to the primary focus on knee strength.

Researchers say that providing training to kids with cerebral palsy using a robotic device may help them gain strength and improve their walking abilities and posture.

The results of a small study which was published in the Science Robotics journal on July 26 suggests that a robotic device named as Tethered Pelvic Assist Device(TPAD) could help kids with crouch gait.

Six kids with crouch gait participated in 15 training sessions with the TPAD systemover a course of six weeks. They showed improvement in muscle coordination and posture as well as walking features such as toe clearance, step length, heel-to-toe pattern and a range of motion.

Each of these training sessions that the kids participated were of 16 minutes duration; and the kids were analyzed at the start and end of the study period.

During these sessions, the kids wore the robotic device while walking on a treadmill. The device consisted of a pelvic belt attached to 8 cables running down from the belt to motors fixed to the treadmill. Physical therapists adjusted the tension on the wires real time by monitoring the kid’s gait captured by a camera system. The device pulls the kid downward as he or she walks on the treadmill, just like what a normal kid experiences while carrying a backpack. This help in retraining certain leg muscles. The physical therapists who monitor the kid over the camera adjusted the tension on the wires to strengthen the muscles that appear the weakest.

Sunil Agarwal, a professor of mechanical engineering and of rehabilitation and regenerative medicine at Columbia UniversitySchool of Engineering and Applied Sciences, who worked on this study said that there is no well-established strengthening exercise or physical therapy for the treating crouch gait at present. The TPAD system, which has received consistent feedback from the kids who participated in the study and their parents, could serve as a promising solution for such affected kids. They reported stronger legs, improved posture, improved walking symmetry and faster walking speed. The experts’ evaluation also confirm this. He stated “We think that our robotic TPAD training with downward pelvic pull could be a very promising intervention for these children.”

The researchers are now seeking to carryoutfurther clinical trials on the method by including more number of kids and evaluating the device for more variables. They also plan to take this robotic training beyond crouch gait, and reach out to kids with quadriplegic and hemiplegic cerebral palsy as well.

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