Virtual body representation for rehabilitation influences on motor performance of cerebral palsy children

Game-based virtual reality systems have been shown to enhance motor function, motivation and therapy adherence in cerebral palsy (CP) children. In these systems, several types of virtual body representations have been implemented, however without conclusive support of guidelines nor the most appropriate choice for enhancing motor performance. Thus, the purpose of this study is to examine how the subjective experience of seeing and controlling a half-body avatar, or an abstract hand representation in a moderate immersion virtual environment (VE), for training upper limb movements may affect CP children’s motor performance. To achieve that purpose, a game-like VE for training the reaching-releasing of objects was designed. Unlike previous studies, relevant task performance and cost function metrics were obtained from the analysis of kinematic and kinetic parameters of movement. Results show that visualizing the hand movement through an abstract object makes children perform faster, correct less to produce smoother movements, and use less mechanical energy than visualizing the arm movement through a realistic Avatar. These effects were more noticeable in the reaching than in the releasing phase of the task. Based on these findings, some recommendations are provided for the effective design and use of VE’s for upper limb rehabilitation of CP children.