Robot-Assisted Gait Training Helps Motor Function in Kids With Cerebral Palsy

Among 6- to 15-year-olds with cerebral palsy, gait training with a wearable, untethered exoskeleton robot improved gross motor function, a randomized clinical trial showed.

Six weeks of overground robot-assisted gait training (RAGT) significantly improved Gross Motor Function Measure (GMFM)-88 scores by a mean of 2.64 (95% CI 0.50-4.78) points more on the 100-point scale than with standard physical therapy, researchers led by Min-Keun Song, MD, PhD, of Chonnam National University Medical School and Hospital in Gwangju, South Korea, reported in JAMA Network Open.

Improvements among the RAGT group were also seen in balance control, gait pattern, and involvement in daily living tasks.

“This new torque-assisted, wearable RAGT benefits children with [cerebral palsy], supporting power-as-needed control, motivating children to explore walking, and providing intensive gait training. These benefits could also apply to children with prewalking motor abilities,” the group suggested.

While the “most developed pediatric RAGT devices are treadmill-tethered trajectory-controlled or end-effector robots,” Song and colleagues noted, meta-analyses have shown weak and inconsistent evidence of benefit in children with cerebral palsy in studies largely using these types of robots.

The RAGT device used in the study by Song and colleagues was the Angel Legs M20 (size small) from Angel Robotics. The device is a lower-limb wearable robot designed to help children with disabilities improve their walking and lower limb mobility. It’s a torque-controlled model that “adjusts the amount of force applied at each joint to aid movement based on the user’s effort and motion, requiring active participation from the patient,” Song’s group noted.

Their trial included 90 children (mean age 9.5 years, 54.5% male) who walked with or without assistance at Gross Motor Function Classification System levels II to IV. They were randomized to 30 minutes of either RAGT or standard physical therapy 3 days per week for 6 weeks. While both groups received 18 sessions, or 9 hours total, the RAGT intervention boosted mean steps per session (997.6 vs 212.9, P<0.001).

In addition to benefits for the primary endpoint of GMFM-88 total score compared with the control group, the RAGT group showed significant improvements as measured by the GMFM’s dimension E, which is related to walking, running, and climbing activities (mean difference 2.70 vs controls, 95% CI 0.08-5.33), and the GMFM-66, a subset of the original 88 items that best describe motor function of kids with cerebral palsy (mean difference 2.52 on the 100-point scale, 95% CI 0.42-4.63).

The RAGT group had immediate increases in the GMFM-88 total, dimension E, and GMFM-66 scores of 2.7%, 2.3%, and 1.2%, respectively, which were clinically significant changes. These improvements were maintained out to the 4-week follow-up.

As for balance control, improvements on the Pediatric Balance Scale were significantly greater in the RAGT group compared with the control group at the 4-week follow-up (mean difference 1.48 on the 56-point scale, 95% CI 0.03-2.94). Selective motor control improved in both groups without significant differences.

Regarding gait, step width normalized significantly more in the RAGT group than the control group (mean difference −0.05 m, 95% CI −0.08 to −0.01), indicating improvement. But gait speed and stride length did not significantly change.

At the 4-week follow-up, improvement on the Gait Deviation Index was significantly greater in the RAGT group compared with the control group (mean difference 6.48 on the 100-point scale, 95% CI 2.77-10.19).

As for physical fitness and participation in daily activities, improvement in gait endurance on a 6-minute walk test was observed only in the RAGT group at the 4-week follow-up, but without a significant difference compared with controls. Physical fitness measures, such as oxygen consumption and muscle and fat mass, were similar between groups.

Compared with the control group, changes in the responsibility domain of the Pediatric Evaluation of Disability Inventory Computer Adaptive Test, or PEDI-CAT, were greater in the RAGT group (mean difference 2.52, 95% CI 0.42-4.63). However, changes in the daily activity, mobility, and social cognitive domains did not significantly differ between groups.

There were no safety issues reported, and the RAGT group did not experience any adverse effects, such as skin lesions, pain, or fatigue. A physical therapist attached the RAGT device to all participants.

Limitations were that lower limb movements were assisted only in the sagittal plane, and that only patients who could use a small RAGT device were included, Song and colleagues noted.

“Additional studies are required to delineate the optimal training parameters and the role of the robot device type according to the patient profile,” they wrote.

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