The neural basis underlying motor performance in children using a prosthesis has been severely understudied resulting in minimal empirical evidence. The use of functional near-infrared spectroscopy (fNIRS) in conjunction with customized and visually appealing 3D printed prostheses would provide the unique opportunity to quantitatively assess the influence of upper-limb prostheses in the neural activation patterns of the primary motor cortex and motor performance of children. This information would increase the investigators limited knowledge of how prosthesis usage influences the primary motor cortex of growing children and use this information to develop rehabilitation programs aimed at reducing prosthesis rejection and abandonment.