Way of Objectively Measuring Arm Movement in Children with Unilateral CP Shows Promise in Study

A new way of measuring arm movements, aimed at children with unilateral cerebral palsy (uCP), shows strong reliability in children going through normal development.

This finding was published in the Journal of Electromyography and Kinesiology, in the paper “Proposal of a new 3D bimanual protocol for children with unilateral cerebral palsy: Reliability in typically developing children.”

It is important to be able to measure objectively upper limb range and motion in children with unilateral cerebral palsy (uCP; cerebral palsy that affects only one side of the body) in order to have useful data to inform both research and treatment. Otherwise, movement ability can only be described subjectively by clinicians.

Recently, there has been a push toward using three-dimensional movement analysis (3DMA), where a computer tracks movement in real-time. This requires having subjects do tasks that replicate their everyday activities while hooked up to monitors, which can be particularly challenging when children are the subjects.

Researchers in France developed a 3DMA system in which children are asked to play a game called “Be an Airplane Pilot.” Basically, it’s a video game in which participants need to interact with joysticks and buttons in a variety of ways to complete plane-related tasks (flying past mountains, dropping parachutists, refueling, etc.).

“The playful setting, including the speech of the operator, aims at surrounding the clinical environment and at leading to spontaneous movements of the child,” the researchers said, suggesting this setup may more closely mimic the type of challenges that children with uCP need to accomplish on a daily basis. It also requires the use of both arms; so in children with uCP, both the affected and unaffected side can be monitored simultaneously.

An optoelectronic system with 12 cameras is then used to track the 3D position of several reflective markers placed on both the dominant and non-dominant upper limb and the trunk of the child.

The researchers had 20 normally developing children (11 boys and 9 girls, ages 6 to 18) complete assessments based on this system three separate times. Then, they calculated the reliability of the measurements — that is, the chances that the same child would get the same measurement every time — by calculating the coefficient of multiple correlation (CMC). CMC scores were designated excellent (≥0.90), good (0.80–0.89), moderate (0.60–0.79), and poor (< 0.60).

Reliability was very high (more than 0.90) for every type of arm movement the researchers assessed. There was only one exception; wrist flexion-extension (moving the palm up/down via the wrist joint) had a CMC of approximately 0.75.

Researchers concluded that these results “are very promising and open the door to further tests on children with uCP and to the definition of first normative values based on [typically-developing children].”

They added that this protocol “would aim at supporting clinical decisions by objectively assessing the efficiency of therapeutics,” such as botulinic toxin injections or surgery.