**1. Introduction**

#### **1.1. Evoked potential**

Evoked potentials (EP) are the electrical signals measured from the scalp after the stimulation rendered by some external stimulus. Corresponding to various stimuli, evoked potentials are distinguished as visual, auditory and somatosensory evoked potentials.

Event related potential (ERP) implies both EP and brain responses prompted by cognitive processes evolved by external stimuli or precursory mechanisms for motor action [1, 2].

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
