IMPACT of an Instrumented Measurement on a Performance Assessment in Cerebral Palsy Treatment

The goal of this study is to assess the impact of passive reflective markers on bimanual performance assessment scores in children with unilateral cerebral palsy. The main questions it aims to answer are: * Is it possible to instrument performance assessment without changing the functionnal behaviour of the patient ? * How is this behavious modified ? During their usual occupational therpy assessment at the CMCR Massues, participants will do a second bimanual performance assessment with passive reflection markers taped on their trunk, humerus and forearm. The glocal scores and sub items scors of both instrumented and non instrumented assessment will be compared.