Safety and Effectiveness of Bambini Kids Robot-Assisted Gait Training (RAGT) in Children With Cerebral Palsy

Safety and Effectiveness of Bambini Kids Robot-Assisted Gait Training in Children With Cerebral Palsy: A Randomized Clinical Trial

Cerebral palsy (CP) is a common cause of gait impairment in children, leading to limitations in mobility and daily activities. Although conventional physical therapy is widely used, it has limitations in delivering consistent and intensive training. Robot-assisted gait training (RAGT) has emerged as a promising approach to provide repetitive, high-intensity, and task-specific training, with potential benefits in gait function and motor performance.

The Bambini Kids exoskeleton is a pediatric robotic device designed to assist lower-limb movements, including hip, knee, and ankle joints, to facilitate more natural gait patterns.

This study aims to evaluate the safety and clinical performance of Bambini Kids in children with cerebral palsy and to generate clinical evidence to support its use in real-world rehabilitation settings.

Cerebral palsy (CP) is one of the most common causes of gait impairment in children, and it's a non-progressive neurodevelopmental disorder that results in permanent impairments in motor function and postural control. The prevalence of cerebral palsy in Korea has been reported to be approximately 2.6 per 1,000 individuals. Patients with CP experience limitations in gait and activities of daily living due to muscle spasticity, muscle weakness, and impairments in balance and coordination, which consequently lead to reduced independence and decreased quality of life.

Physical activity is essential for promoting overall health in children with cerebral palsy, and has been shown to improve stability, balance, overall motor function, and aerobic capacity, while reducing the risk of depression and enhancing key functional domains such as social participation and quality of life. To achieve these benefits, conventional physical therapy approaches, including partial body weight-supported gait training, task-oriented training, and treadmill-based training, have been widely used; however, these approaches are associated with substantial physical burden on therapists and limitations in consistently providing repetitive and high-intensity training.

To address these limitations, robot-assisted gait training (RAGT) is getting attention in the field of rehabilitation. RAGT enables the consistent delivery of high-intensity and high-frequency repetitive training in accordance with physiological gait patterns and allows automatic recording of training parameters for objective analysis and comparison. In addition, some wearable exoskeleton can be applied in non-clinical settings, thereby expanding their potential use beyond hospital environments.

The therapeutic effects of robot-assisted gait training (RAGT) have been demonstrated in adult patients with spinal cord injury (SCI) and stroke through multiple randomized controlled trials and systematic reviews, showing positive impacts on gait ability, muscle strength, balance, and recovery of activities of daily living. Studies in children with cerebral palsy have also reported that RAGT has a beneficial effect on activity-related outcomes such as standing ability, gait speed, and walking distance. Early application of rehabilitation in children during developmental stages is of particular clinical importance, as it may promote neuroplasticity during periods when gait patterns and motor function remain modifiable, thereby potentially preventing long-term progression of disability. In a recent multicenter clinical study, significant improvements in gross motor function, balance control, and gait patterns were observed after 6 weeks of robot-assisted gait training, and these effects were maintained at follow-up. Borggraefe et al. reported that patients with milder impairment (GMFCS Levels I-II) showed significantly greater improvements in Gross Motor Function Measure(GMFM-88) dimensions D and E compared to those with moderate to severe impairment (GMFCS Levels III-IV). However, some studies have suggested that the relatively short duration of interventions may have led to an overestimation of treatment effects, indicating the need for further validation.

Recently, in addition to robot-assisted training in medical institutions, studies have actively investigated the feasibility and effectiveness of using exoskeleton robots in home and community settings for children with cerebral palsy. This approach has gained attention as a novel strategy to improve access to therapy and to support continuous rehabilitation in daily life.

Children with cerebral palsy frequently exhibit limitations in normal movement due to reduced joint range of motion, decreased muscle strength, and abnormal muscle tone. They often present with various gait abnormalities, such as equinus gait and crouch gait. Children with cerebral palsy frequently exhibit limitations in normal movement due to reduced joint range of motion, decreased muscle strength, and abnormal muscle tone. They often present with various gait abnormalities, such as equinus gait and crouch gait. These abnormal gait patterns may lead to secondary deformities over time; therefore, a multidisciplinary approach, in addition to conventional physical therapy, is essential in the rehabilitation of patients with cerebral palsy.

Despite these clinical characteristics, particularly those aged 2-11 years with a height of approximately 100 cm, the evidence on the effectiveness and safety of exoskeleton-based gait training in children with cerebral palsy remains limited. This is also reflected in the current regulatory status both domestically and internationally. Among 22 powered exoskeletons that have received U.S. FDA 510(k) clearance, only one pediatric-specific device-developed by Cyberdyne, Inc. in Japan-has been approved. Similarly, in Korea, only two exoskeletons for pediatric use (Exerciser, orthopaedic, electrically-powered or Robotic-guidance rehabilitation system) have been approved, manufactured by COSMO ROBOTICS CO., Ltd. and ANGEL ROBOTICS Co., Ltd. Among these, Bambini Kids developed by Cosmo Robotics Co., Ltd. is the only device that actively assists not only hip and knee flexion and extension, but also ankle dorsiflexion and plantarflexion, as well as hip abduction and adduction.

To address these clinical limitations, the Bambini Kids exoskeleton has been developed with independent motors at the hip and ankle joints. In addition to the conventional assistance of hip and knee flexion and extension provided by existing exoskeleton systems, the device incorporates four additional motors to actively control ankle dorsiflexion and plantarflexion, as well as hip abduction and adduction. This design enhances joint mobility throughout the gait cycle, ankle propulsion, and pelvic stability. As a result, the device is expected to facilitate the acquisition of more natural and symmetrical gait patterns.

Therefore, this study aims to systematically evaluate the safety and effectiveness of the pediatric exoskeleton Bambini Kids in children with cerebral palsy. Based on the results, it is intended to generate evidence to support regulatory approval and clinical application in overseas markets, and to contribute to the development of strategies for expanding the use of robot-assisted gait training (RAGT) across diverse real-world settings, including home and community environments.

Inclusion Criteria:

Subjects eligible for participation in this clinical investigation shall meet all of the following criteria.

• Patient diagnosed with Cerebral Palsy
• Age from 2 to 10 years old
• Classified as Levels II to IV according to GMFCS
• Manual Muscle Testing, MMT score of 0 to 4
• Modified Ashworth Scale, MAS score of 3 and under
• Subjects with sufficient cognitive function to comply with study procedures
• Subjects with adequate upper limb function required for device use and study procedures
• Subjects who meet the physical requirements for use of the medical device as defined by the manufacturer

Exclusion Criteria:

Subjects meeting any of the following criteria are not eligible for participation in the clinical investigation.

• Subjects who do not meet the criteria of age, height, weight, body dimensions, or joint range of motion
• Subjects with skin lesions, pressure sores, infections, or other conditions at area where device touches and makes difficult to use device
• Classified as Levels V according to GMFCS
• Subjects with severe spasticity (MAS > 3), or those at risk of significant worsening of spasticity after training.
• Subjects unable to maintain an upright standing position for at least 15 minutes (e.g., due to autonomic dysreflexia or orthostatic hypotension)
• Subjects with significant cardiovascular disease or a history of myocardial infarction within the past 6 months
• Subjects with medical conditions that are contraindications for use of the medical device as defined by the manufacturer.
• Subjects for whom weight-bearing, standing, or gait training is medically contraindicated (e.g., fractures, severe osteoporosis, severe joint deformity, or joint instability)
• Subjects who have received treatments affecting muscle tone within the past 4 months, such as botulinum toxin injections or baclofen pump implantation
• Subjects who experience adverse events or undesirable side effects during the clinical investigation that make continued participation difficult
• Subjects whom the investigator judges to be unsuitable for participation or continuation in the clinical investigation.