Effect of the angle of shoulder flexion on the reach trajectory of children with spastic cerebral palsy.
Lifting the shoulder past 90° can block reaching entirely in severe CP, so set targets below that line.
01Research in Context
What this study did
Researchers asked kids to reach for a toy while their shoulder was lifted to three angles: 60°, 90°, or 120°. They used 3-D cameras to watch how straight the reach path stayed.
Children with spastic cerebral palsy and typically developing peers joined the lab test.
What they found
When the shoulder was lifted higher, the reach path curved more for kids with severe CP. At the highest angle, two children could not finish the reach at all.
Typical kids kept a fairly straight path no matter the angle.
How this fits with other research
Jaspers et al. (2011) first showed that kids with hemiplegic CP take longer, slower, and less straight reaches. Furuya et al. (2015) now adds that simply lifting the shoulder higher makes those problems worse.
Wilmut et al. (2013) saw similar curved paths in children with Developmental Coordination Disorder. The pattern repeats in CP: trajectory quality drops when the task gets harder.
Sparaci et al. (2015) found that kids with autism can learn a motor task yet still use odd paths. The CP study echoes this: watch the path, not just success or failure.
Why it matters
Before you place a toy on a high shelf during therapy, check shoulder height. If the child shows severe spasticity, lower the target or give trunk support. A small angle change can turn a doable reach into an impossible one.
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02At a glance
03Original abstract
Many children with cerebral palsy (CP) use a wheelchair during activities of daily living and often extend their hand upward and downward to reach objects in a seated position in a wheelchair. However, the effect of shoulder position on reaching movements of children with CP is not established. The purpose of this study was to determine the effect of the angle of shoulder flexion on the reach trajectory of children with spastic CP. Seven children with mild CP [Manual Ability Classification System (MACS) levels I-II], five children with severe CP (MACS levels III-V) and six typically developing (TD) children participated. We prepared the device to have a top board with variable tilting angle in order to reduce the effect of gravity imposing on reaching movements. By using this device, the subjects could extend their arm by sliding it on the board to push a target button. The reaching movements were performed with the more affected hand at three angles (60°, 90° and 120°) of shoulder flexion and captured using a camera motion analysis system. Subjects in the TD and mild CP groups reached the target at 60°, 90° and 120° of shoulder flexion. Subjects of the severe CP group reached the target at 60° and 90° of shoulder flexion, but two of the subjects could not reach the target at 120° of shoulder flexion. The TD and mild CP groups showed smooth and almost straight trajectories at all three angles of shoulder flexion; however, the reach trajectory in the subjects with severe CP changed with the angle of shoulder flexion. A large angle of shoulder flexion induced great outward deviation in the trajectory. These findings suggest that the difficulty of the reaching task is changed depending on the shoulder joint angle in children with severe CP and that therapeutic interventions for children with severe CP should be provided in a manner appropriate for the shoulder joint angle.
Research in developmental disabilities, 2015 · doi:10.1016/j.ridd.2014.10.037