Robot trainer for children with cerebral palsy
Cerebral palsy (cerebral palsy) is a chronic disease associated with damage to the central nervous system in the perinatal period and characterized by motor disorders. The symptoms of cerebral palsy most often include gait disorders that eventually lead to joint disease, slow walking speed, limited joint mobility, short steps when walking, shakiness, lack of support on the heel, and others. For such children, semi–squatting is characteristic - the legs are bent at the hip, knee and ankle joints, support on the toes.
The group of Professor Sunil Agrawal from Columbia University conducted a pilot study of a robotic method of training muscle strength and coordination, which improves posture and gait.
Gait disorders with excessive flexion in the knee joints ("squatting" gait) are caused by weakness (hypotension) of the extensor muscles, which are unable to support the body in an upright position, combined with excessive strength (hypertonicity) of the flexor muscles. The flounder muscle is one of the extensor muscles that is located on the lower leg, its insufficient tension plays an important role in the formation of shakiness and instability of the body in an upright position.
Based on the fact that one of the main causes of gait disorders is the weakness of the flounder muscle, the researchers suggested that training walking with a load on the pelvis will strengthen the extensor muscles, including the flounder muscle, and improve coordination when walking. Instead of traditional treadmill workouts with a constant load, they decided to increase the load gradually.
To test their hypothesis, the researchers designed a robotic system "Tethered Pelvic Assist Device" (Tethered Pelvic Assist Device TPAD). The system is a lightweight belt with an electronic "stuffing" that can be programmed to create a load on the pelvis of the desired intensity and in the right direction during training on a treadmill.
The researchers worked with six children suffering from cerebral palsy. There were 15 classes of 16 minutes for 6 weeks. During the training on the treadmill, the children wore a TPAD, to which several wires were connected. The load in each individual case was created in real time by a drive fixed on a fixed frame around the treadmill, based on data received from cameras.
Schematic representation of the operation of the TPAD robotic device during classes of patients with cerebral palsy. Source: Sunil Agrawal/Columbia Engineering.
The researchers programmed the TPAD to create an additional load on the center of the pelvis, directed downward, in order to intensively develop the flounder muscle. The load force was equivalent to 10% of the body weight, which corresponds to the load of a healthy child carrying a school backpack. This was the minimum weight needed to achieve a noticeable improvement in posture and gait.
Training with the TPAD device of a child with gait disorders with cerebral palsy.
Source: Sunil Agrawal/Columbia Engineering.
The TPAD is a unique device of its kind, as it adds only the necessary load during the class, while wearing it does not make the workout heavier.
The researchers compared the strength and coordination of muscles according to electromyography data obtained in the first and last classes of the course, and also constantly monitored the nature of movement (kinematics) and load distribution in a vertical stationary position of the body throughout the course.
It was found that the overall condition of the muscular system has improved markedly. Progress was noted in such indicators as posture, coordination, gait, including step length, amplitude of movements in the joints of the lower limb, load distribution on the foot. In addition, parents of children who participated in the study noted improvements in their motor functions. Classes with the TPAD device are really promising for the rehabilitation of children with cerebral palsy.
The researchers plan to conduct a large study to obtain more reliable data and to be able to check more indicators. In addition, they do not exclude the possibility of using TPAD in children with hemiplegic and tetraplegic forms of cerebral palsy.
Article by J. Kang et al. Robot-driven downward pelvic pull to improve crouch gait in children with cerebral palsy is published in the journal Science Robotics.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on Columbia Engineerig: Robot-driven Device Improves Crouch Gait in Children with Cerebral Palsy.