**1. Introduction**

The auditory processing information can be analyzed by an assessment of the auditory evoked potentials (AEP). Among the different types of AEPs, there is the auditory brainstem response

© 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.

(ABR) The ABR is a clinical tool to assess the neural functionality of the auditory brainstem [1]. Until recently, assessment using clinical ABR protocols was carried out only with nonverbal stimuli, such as clicks, tone-bursts, and chirps. The ABR responses (i) permit the analysis of the integrityofthe auditorypathways and(ii) canestablishelectrophysiologicalthresholds inorder to identify basic neural abnormalities and to evaluate patients who did not provide reliable responses in the standard behavioral audiological assessment [2].

Although the use of the click-evoked ABR has been widely used clinically, it is still necessary to unravel how verbal sounds are coded in the brainstem. Recent technological advances have enabled the inclusion of verbal stimuli in the ABR commercial equipment. The use of verbal stimuli in ABR protocols provided important information of how the speech stimuli are processed by the brainstem structure, which actively participates in the analysis of the complex verbal stimuli [3].

The verbal stimulus most widely used in speech ABR is a syllable composed of a consonant and a vowel (CV) [4]. The consonant perception is performed by the distinction between vocal production times and sound of consonant that guarantees the intelligibility in the process of human communication and the proper development of language.

The perception of speech sounds seems to begin in the brainstem, which has an important role in reading process and phonological acquisition [5–7]. An effective and objective way to investigate this process will be the assessment of speech ABR that allows the identification of fine-grained auditory processing deficits associated with real-world communication, skills which do not appear in click responses, and it also can be used for early identification of auditory processing impairments in very young children [8]. Above all, speech ABR can be used as an objective measure of the hearing function. One of the great advantages of this method is that it is not influenced by environmental issues, which can disrupt the behavioral assessments [2]. Even the best behavioral tests can confound the subject by factors such as attention, motivation, alertness/fatigue, and by co-occurring disorders, such as language impairments, learning impairments, or attention deficits [9].

Understanding the neural processing of speech sounds at the brainstem level provides knowledge regarding the central auditory processes involved in normal hearing subjects and also in clinical populations [10]. Moreover, altered responses of speech ABR may be associated with impaired speech perception in noise. These changes can cause a negative impact on communication and serious consequences for academic success [8]. According to Sinha and Basavaraj [11], the major application of speech ABR can be in diagnosing and categorizing children with learning disability in different subgroups, assessing the effects of aging on central auditory processing of speech, assessing the effects of central auditory deficits in hearing aid, and cochlear implant users.
