**1. Introduction**

Headache is prevalent worldwide and was reported as the sixth most frequent global cause of years lived with disability in 2013 [1]. When limited to migraine, its frequency is 19th place, and when limited to women, its frequency is 12th place [2]. The prevalence rate of tension‐type headache is also high, and it was reported to be 38% in worldwide [3]. However, the diagnosis of tension‐type headache depends on the diagnostic criteria and method. As such, the actual prevalence of patients with headache may be much higher than believed.

© 2017 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. © 2017 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.
