Robot-driven Device Improves Crouch Gait in Children with Cerebral Palsy
July 31, 2017 | Columbia EngineeringEstimated reading time: 4 minutes
In the U.S., 3.6 out of 1000 school-aged children are diagnosed with cerebral palsy (CP). Their symptoms include abnormal gait patterns which results in joint degeneration over time. Slow walking speed, reduced range of motion of the joints, small step length, large body sway, and absence of a heel strike are other difficulties that children with CP experience. A subset of these children exhibit crouch gait which is characterized by excessive flexion of the hips, knees, or ankles.
Today, a team led by Sunil Agrawal, professor of mechanical engineering and of rehabilitation and regenerative medicine at Columbia Engineering, has published a pilot study in Science Robotics that demonstrates a robotic training method that improves posture and walking in children with crouch gait by enhancing their muscle strength and coordination.
Crouch gait is caused by a combination of weak extensor muscles that do not produce adequate muscle forces to keep posture upright, coupled with tight flexor muscles that limit the joint range of motion. Among the extensor muscles, the soleus, a muscle that runs from just below the knee to the heel, plays an important role in preventing knee collapse during the middle of the stance phase when the foot is on the ground. Critical to standing and walking, the soleus muscle keeps the shank upright during the mid-stance phase of the gait to facilitate extension of the knee. It also provides propulsive forces on the body during the late-stance phase of the gait cycle.
“One of the major reasons for crouch gait is weakness in soleus muscles,” says 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.”
Video showing how the robot-driven TPAD training method works to improve crouch gait in children with cerebral palsy:
Video courtesy of Sunil Agrawal/Columbia Engineering
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.
“TPAD is a unique device because it applies external forces on the human body during walking,” says Jiyeon Kang, PhD candidate and lead author of the paper. “The training with this device is distinctive because it does not add mass/inertia to the human body during walking.”
Video showing how the robot-driven TPAD training method works to improve crouch gait in children with cerebral palsy:
Video courtesy of Sunil Agrawal/Columbia Engineering
The team examined the children’s muscle strength and coordination using electromyography data from the first and last sessions of training and also monitored kinematics and ground reaction forces continuously throughout the training. They found that their training was effective; it both enhanced the children’s upright posture and improved their muscle coordination. In addition, their walking features, including step length, range of motion of the lower limb angles, toe clearance, and heel-to-toe pattern, improved.
“Currently, there is no well-established physical therapy or strengthening exercise for the treatment of crouch gait,” Agrawal notes.
Heakyung Kim, A. David Gurewitsch Professor of Rehabilitation and Regenerative Medicine and Professor of Pediatrics at the Columbia University Medical Center, who treats these patients, added “Feedback from the parents and children involved in this study was consistent. 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.”
The researchers are planning more clinical trials, to test a larger group and changing more variables. They are also considering studying children with hemiplegic/quadriplegic CP.
Suggested Items
A Review of the 2024 Del Mar Electronics and Manufacturing Show
05/16/2024 | Barry Matties, I-Connect007The Del Mar Electronics and Manufacturing Show (DMEMS) in Del Mar, California, recently took place at an unlikely venue: the Del Mar Fairgrounds. Doug Bodenstab, founder and show organizer, says the show covers everything in electronics manufacturing: design tools, components, base materials, training, testing, board fabrication, AI, data analytics, and more. While you can find about anything online these days, Bodenstab adds that there is no substitute for meeting people in person.
IPC Focuses on Education and Onboarding
05/09/2024 | Andy Shaughnessy, Design007 MagazineI recently spoke with Carlos Plaza, senior director of education for IPC, about expanding educational efforts in the PCB design, fabrication, and assembly segments. As Carlos explains, PCB design is a hot topic, but onboarding may be the hottest one of all.
Real Time with…. IPC APEX EXPO 2024: Innovation and Collaboration at EPTAC
05/06/2024 | Real Time with...IPC APEX EXPOGuest Editor Kelly Dack and EPTAC Vice President Leo Lambert discuss the partnership between EPTAC and Blackfox, their program alignment, and future expansion plans. Leo introduces Burak Gokmen as the new "leader of the pack." The focus then shifts to Nano Dimensions' 3D printed circuit boards, emphasizing the need for proper documentation and training.
The Right Approach: I Hear the Train A Comin'
04/25/2024 | Steve Williams -- Column: The Right ApproachTraining is often an afterthought in many organizations, and the longer a company has been in business, the more this seems to apply. Over the past couple of decades, it has been amazing to observe that the biggest offenders of this are the companies that overuse the sound bite, “Our most important assets are our people.” When you dig into the process and peel back the onion, their commitment to training is not commensurate with that statement.
Real Time with… IPC APEX EXPO 2024: Tools, Training, and Trends in Manufacturing Engineering
04/25/2024 | Real Time with...IPC APEX EXPOGuest Editor Kelly Dack and Product Specialist Erik Bateham of Polar Instruments discuss Polar's latest technology, including their role in aiding manufacturing engineers. They highlight the advanced capabilities of Polar's tools and the critical role of signal integrity analysis, as well as the importance of accurate modeling in board manufacturing. Polar's unique training approach and demonstration contact details are also explored.