**1. Introduction**

Mild cognitive impairment (MCI) represents an intermediate stage of cognitive impairment between the normal cognitive aging and dementia. The development of the concept of MCI was stimulated by the clinical awareness of the existence of an intermediate level of cognitive impairment that was not captured by any clinical definition on the one hand and by the rising awareness of dementia as an important area of public health on the other [1]. The concept of MCI permits timely identification of patients at high risk of developing dementia, thus opening a potential therapeutic window and increasing the significance of controlling modifiable risk factors.

© 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.
