Engineering news
A team from Columbia University in New York published a study demonstrating their training method, which they said improves posture and walking in children with crouch gait.
Crouch gait is a symptom of cerebral palsy that involves excessive bending of hips, knees or ankles as well as the slow walking, reduced joint motion and body sway associated with the condition.
It is caused by a combination of some weak muscles and others which are too tight, limiting how much joints can move. The new technique uses a lightweight, cable-driven robot to apply forces to users as they walk, strengthening their muscles.
The team thought strengthening the soleus muscle in the lower leg could help patients stand and walk more easily, so they designed the Tethered Pelvic Assist Device (TPAD) in lead researcher Sunil Agrawal’s laboratory.
The TPAD controls the tension of several wires attached to users, applying downward forces equivalent to 10% of bodyweight through the centre of their pelvises, intensively retraining the soleus.
“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,” said engineer Agrawal.
Patients walked on the treadmill for 16-minute training sessions while cameras collected data. The team examined the children after 15 sessions and found the training improved posture and muscle co-ordination, as well as walking features such as step length, range of motion of the lower limb angles, toe clearance, and heel-to-toe pattern.
“The ability to walk confidently and efficiently is critical in all our activities of daily living,” said Agrawal to Professional Engineering. “This ability manifests in so many different ways to ensure physical, cognitive, and social health. It is a pleasure to see these changes in the children.”
Doctor Heakyung Kim treated patients who used the robotic method. “Feedback from the parents and children involved in this study was consistent,” she said. “They reported improved posture, stronger legs, and faster walking speed, and our measurements bear that out. We think that our robotic TPAD training with downward pelvic pull could be a very promising intervention for these children.”
Other teams around the world have tried different approaches to helping people walk. One common method is using exoskeletons, which sense very small movements and translate them into full strides. The "exosuits" can help people suffering from strokes or multiple sclerosis to regain mobility.
The Columbia researchers are now considering studying children with hemiplegic or quadriplegic cerebral palsy.
The research was published in Science Robotics.