**5. Clinical applicability**

#### **5.1. Auditory training**

ear in two different conditions—test and retest [16]). Two studies for children and adolescents will be presented: (i) composed of children between 8 and 12 years of age with normal hearing and with the analysis of waves V, A, C, and F and VA complex in **Table 2** (parametric study [mean and standard deviation] by syllable /da/, 40 ms, [silence] performed in children with normal hearing—Russo et al. [15]—on the right ear [15]) and (ii) composed of children and adolescents between 8 and 16 years of age with normal hearing and examination of all the waves in **Table 3** (parametric study [mean and standard deviation] by syllable /da/, 40 ms [silence] performed in children and adolescent with normal hearing—Sanfins et al. [22]—on

**Source Latência (ms) Amplitude (μv) VA measures**

Slope VA (μv/ms) 0.13 0.05 Area VA (μv × ms) 1.70 1.23

Russo et al. [15] studied 36 and 38 children and adolescent (17 females) with normal hearing (8–12 years old).

**Table 2.** Parametric study (mean and standard deviation) by syllable /da/, 40 ms (silence) performed in children with

The majority of studies about speech ABR assessment was performed with monoaural stimulus on the right ear [13, 24, 29, 39, 49, 50]. The choice for the assessment only on the right ear is related to the advantage of the left hemisphere for processing of language sounds. Associated with this fact, earlier research has shown that there are no statistically significant differences between the responses on the right and left ears in subjects with normal hearing and typical development. However, there are many conditions to be studied through the speech ABR, and it is important to consider whether there are differences in responses between

Thereby, the responses on the right and left ears were presented in the population of children and adolescents with normal hearing and normal development so that it can be used as a

It is noted that the parametric studies provide a direction to the researchers. It is fundamental to know the parameters of collection and analysis of each reference author before the use of

comparison with the responses obtained in subjects with different pathologies.

V 6.61 0.25 0.31 0.15 A 7.51 0.34 0.65 0.19 C 17.69 0.48 0.36 0.09 F 39.73 0.61 0.43 0.19

**Right ear Right ear Right ear**

**Mean SD Mean SD Mean SD**

the right and left ears [22]).

18 Advances in Clinical Audiology

Note: Parametric study in normal children.

the ears.

normal hearing (Russo et al. [15]) on the right ear.

Auditory training is able to induce neurophysiological changes that can be observed by an evaluation of speech ABR. According to Killion et al. [57], an auditory training program promotes gains in both speech perception in quiet environments such as in noisy environments and improves short-term memory skills and attentional processes.

According to Hayes et al. [58] children with learning problems can benefit from an auditory rehabilitation program through auditory training. Research has shown that these children have a delay in responses of speech ABR, more specifically, the values of onset portion—wave A, and the assessment of speech ABR may be able to ascertain whether the auditory training program was effective, monitoring the benefits of rehabilitation in children and in young adults [15, 16].

Further studies are needed in the elderly population to determine if this type of assessment can be effective in monitoring this population. Anderson et al. [49] reported that the elderly usually have a hearing loss, thus an auditory training program should be recommended along the selection and adaptation of hearing aid suitable for need each elderly.

Auditory training and amplification are ideal to improve the auditory function and, especially, to improve the process of speech perception. In this context, the assessment of speech ABR could have an important role to demonstrate quickly, clearly, and objectively what are the real gains of interventions. Researchers have emphasized that the assessment of speech ABR is considered a biological marker of auditory training, being able to identify subjects who will have the benefit of an auditory training program [58, 59].

#### **5.2. The aging process**

The elderly has a reduced neural synchrony in the encoding of speech sounds, especially when the speech sounds are produced in the presence of background noise. The assessment of speech ABR is able to monitor the difficulty in understanding speech in noise reported by the elderly. The fitting process allows speech sounds to be heard more clearly. Thus there has been a change of morphology and the latency values of the speech responses ABR [24, 36, 45].

#### **5.3. Differential diagnosis**

Research shows that the literacy process depends on an efficient functioning of the auditory processing in the brainstem. The assessment of speech ABR could accurately predict early and possible changes in the processes of reading, writing, and literacy in preschool children [41, 60, 61].

Children with learning, speech, and hearing impairments not only suffer from background noise and competitive sounds but also have some difficulty in the perception of speech sounds in quiet environments [62]. This difficulty can be arising from changes in temporal processing that can impact the perception of speech. In this context, the speech ABR is a biological marker of auditory processing disorder, being able to identify children with predisposition to these changes [4].

Children with dyslexia often have impairments in the perception of speech sounds that can affect their reading skills [63]. According Hornickel and Kraus [64] good readers have a stable neural representation of sound and that children who have inconsistent neural responses are likely at a disadvantage when learning to read. Thus, the speech ABR can help identify and separate these children, enabling a more appropriate intervention.

Besides that, another 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, and assessing the effects of central auditory deficits in hearing aid and cochlear implant users [11].

Understanding the neural processing of speech sounds at the brainstem level may provide 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 might have a negative impact on communication and have serious consequences for academic success [8].

#### **5.4. Musician**

Auditory training and amplification are ideal to improve the auditory function and, especially, to improve the process of speech perception. In this context, the assessment of speech ABR could have an important role to demonstrate quickly, clearly, and objectively what are the real gains of interventions. Researchers have emphasized that the assessment of speech ABR is considered a biological marker of auditory training, being able to identify subjects who will

The elderly has a reduced neural synchrony in the encoding of speech sounds, especially when the speech sounds are produced in the presence of background noise. The assessment of speech ABR is able to monitor the difficulty in understanding speech in noise reported by the elderly. The fitting process allows speech sounds to be heard more clearly. Thus there has been a change

Research shows that the literacy process depends on an efficient functioning of the auditory processing in the brainstem. The assessment of speech ABR could accurately predict early and possible changes in the processes of reading, writing, and literacy in preschool children [41,

Children with learning, speech, and hearing impairments not only suffer from background noise and competitive sounds but also have some difficulty in the perception of speech sounds in quiet environments [62]. This difficulty can be arising from changes in temporal processing that can impact the perception of speech. In this context, the speech ABR is a biological marker of auditory processing disorder, being able to identify children with predisposition to these

Children with dyslexia often have impairments in the perception of speech sounds that can affect their reading skills [63]. According Hornickel and Kraus [64] good readers have a stable neural representation of sound and that children who have inconsistent neural responses are likely at a disadvantage when learning to read. Thus, the speech ABR can help identify and

Besides that, another 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, and assessing the effects of central auditory deficits in hearing

Understanding the neural processing of speech sounds at the brainstem level may provide 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 might have a negative impact on

separate these children, enabling a more appropriate intervention.

communication and have serious consequences for academic success [8].

of morphology and the latency values of the speech responses ABR [24, 36, 45].

have the benefit of an auditory training program [58, 59].

**5.2. The aging process**

20 Advances in Clinical Audiology

**5.3. Differential diagnosis**

aid and cochlear implant users [11].

60, 61].

changes [4].

Currently, there is an increasing interest in the influence of musical experience related to language processing. The intense musical training in the long term seems to cause an anatomical and physiological change and improves the working memory in cognitive processes, the control of emotions, and perception of sound stimuli [65].

The brain stem has an important role in the encoding of speech sound stimuli and temporal processing [66]. Temporal processing contributes to the perception of duration of the consonants and the identification of notes and musical scales [66, 67]. The literacy process, including the process of reading, writing, and language, is also influenced by the temporal processing [68]. The detection of small and rapid changes of the sound stimulus is associated with the rhythm, the frequency of the sound stimulus, phonemic discrimination, duration, and discrimination of pitch [69]. Understanding how music influences the encoding of speech sounds can be used for more information about the learning process [64]. One way to analyze this is through the responses of speech ABR.

#### **5.5. History of otitis media**

Otitis media is one of the most common childhood diseases, affecting about two-third of children in the first 5 years of life [70, 71]. This period is important for the development of oral and written language. Otitis media can cause functional sequelae of the middle ear structures and can induce a temporary mild-to-moderate hearing loss. The latter can remain for a few days or for several weeks [72, 73]. Concomitantly, the accumulation of fluid in the middle ear interferes the speech perception, causing a distortion in the perception of acoustic signals and reduces the speed and accuracy of verbal decoding [74]. When hearing fluctuation occurs early in life, that is the critical period for linguistic development, a limited acquisition of speech and language occurs. As a result communication problems may appear, such as language developing impairment, auditory processing deficits, cognitive impairment, and psychosocial development and impairment in the acquisition of literacy skills [75, 76].

Inadequate auditory stimulation in childhood can lead to long-term alterations of the auditory structures in the central auditory nervous system [73]. Research shows that children suffering from secretory otitis media in their first 6 years of age and underwent a surgery for bilateral ventilation tubes placement demonstrates neurophysiological modifications of speech perception when compared with typically developing children and adolescents.
