**5. Conclusion**

This chapter presented an overview on the search of human beings for artificial devices capable of restoring, if not all, at least part of the functionality lost when we are affected by diseases, congenital disorders or trauma that results in the loss of a limb. Focusing on upper limb prosthesis, a series of sophisticated technical solutions have been proposed during the past decade to design devices whose behavior and control approach that of their healthy natural counterparts. However, as described along this chapter, operating a highly complex artificial limb is not a simple task. This is especially true for myoelectric multifunctional prostheses with many degrees of freedom. Since the necessary control commands, in most instances, can be very different from the "natural" commands, learning how to produce them is extremely difficult and time consuming. With the advent of Virtual and Augmented Reality, those technologies have been proposed as relevant tools to address some of the limitations of conventional training techniques. It is possible to design a virtual device very similar, in shape and behavior, to a real one. Also, it is even possible to collect commands from the real world (EMG signals generated by remnant muscles) and use them as inputs to control the actions of a virtual prosthesis in an Augment Reality Environment, according to the training stage of the user, or any other setup defined by the therapist. In so doing, those techniques allow for a considerable reduction of physical and metal efforts usually necessary to master the control of a prosthetic device.
