teen male with cp standing straight with robotic device holding him up

Robot-driven Device Improves Crouch Gait in Children with Cerebral Palsy

June 1, 2017

Professor of Mechanical Engineering and of Rehabilitation and regenerative medicine at Columbia Engineering and a member of the Weinberg Family Cerebral Palsy Center Scientific Advisory Board Sunil Agrawal, PhD has published a pilot study in Science Robotics. The study demonstrates a robot-driven device that improves posture and walking in children with crouch gait by enhancing their muscle strength and coordination.

Testing the Robot-Driven Device

From Columbia Engineering‘s original article:

The research group knew that the soleus, the major weight-bearing muscle during single stance support, is activated more strongly among the lower leg muscles when more weight is added to the human body during gait. They reasoned that strengthening the soleus might help children with crouch gait to stand and walk more easily.

To test their hypothesis, the team used a robotic system—Tethered Pelvic Assist Device (TPAD)—invented in Agrawal’s Robotics and Rehabilitation (ROAR) Laboratory. The TPAD is a wearable, lightweight cable-driven robot that can be programmed to provide forces on the pelvis in a desired direction as a subject walks on a treadmill. The researchers worked with six children diagnosed with CP and exhibiting crouch gait for fifteen 16-minute training sessions over a duration of six weeks. While the children walked on treadmills, they wore the TPAD as a lightweight pelvic belt to which several wires were attached. The tension in each TPAD wire was controlled in real time by a motor placed on a stationary frame around the treadmill, based on real-time motion capture data from cameras. The researchers programmed the TPAD to apply an additional downward force through the center of the pelvis to intensively retrain the activity of the soleus muscles. They used a downward force equivalent to 10 percent of body weight, based on the results of healthy children carrying backpacks. This was the minimum weight needed to show notable changes in posture or gait during walking.

One of the major reasons for crouch gait is weakness in soleus muscles,” says Dr. Agrawal, who is also a member of the Data Science Institute. “We hypothesized that walking with a downward pelvic pull would strengthen extensor muscles, especially the soleus, against the applied downward pull and would improve muscle coordination during walking. We took an approach opposite to conventional therapy with these children: instead of partial body weight suspension during treadmill walking, we trained participants to walk with a force augmentation.

For more about the study and videos demonstrating the robot-driven device in action, visit here.