**5. The benefit of hearing aids**

The adaptation of hearing aids promotes neuronal plasticity. Neural networks are generated and areas of the brain that were not stimulated become stimulated, favoring the adaptation of the hearing aid and social reintegration of the elderly. In addition, the adaptation of the hear‐ ing aid can contribute to the stabilization of the hearing loss, namely, the reintroduction of certain sounds by the hearing aid can promote a positive plasticity (structural and functional

The longer an individual stays with hearing loss and without the use of hearing aids, the greater the negative effects on the perception of sound and performance in listening skills. The use of hearing aids favors amplification and modification of the sound stimulus so that it reaches the eardrum with quantity increase and quality, and promotes and stimulates the

Due to the improvement of the quality of sound that reaches the central auditory system, it is believed that after auditory stimulation for a certain period of time, the elderly tends to improve his auditory perception because there is a greater stimulation of the auditory cortex. This theory is grounded by the theory of brain plasticity, or because of high stimulation, which happens with the use of hearing aids: the brain region responsible for the understand‐ ing of the function and process the auditory information creates new neural network (plastic‐ ity), thus, generating a better performance of the individual. When this occurs, the elderly has

In some cases, there is indication of auditory training, so that the auditory cortex can be poten‐ tially stimulated and thus there will be an improvement in hearing. Several surveys show that the auditory training is suitable for adults and the elderly with hearing loss, since this therapeutic resource improves perception and hearing in noisy or acoustically unfavorable

Even with those seniors who have mild hearing loss, satisfaction with the use of hearing aids will not be great because of auditory processing disorders. Research claim that therein lies the impor‐ tance of ear training because it will occur with an improvement in electrophysiological response (latency wave III in ABR) in auditory localization and speech understanding in noise [41].

This training becomes complementary to the use of hearing aids. Thus, it will be through training that the individual with hearing loss will be able to hone your listening skills so there

The auditory training can assist in the recognition of sounds that were not already heard and others that can be modified by technology, such as the lowering frequency that seeks to dislo‐

The professional who will make the indication of the treatment must have concepts of neuro‐ science and aging, which should be considered at the time of the hearing aid selection and type of auditory training. Moreover, it is necessary to consider that there is brain reorganization and acclimatization with hearing aids and that these processes are closely related to cognition [43]. All this care and to look further, beyond the peripheral hearing loss, is essential for the individual with hearing aid, and notices an improvement in his understanding of speech.

a better hearing performance, because in fact there were positive brain changes.

reorganization of the central auditory system).

auditory skills.

120 Advances in Clinical Audiology

environments.

is a better understanding of speech [42].

cate a high‐frequency sound to a lower one.

Modification is generated by the use of hearing aid. Benefit is the difference in the audi‐ tory performance of the individual with and without the use of this technological resource. It is expected that whenever the benefit obtained is positive, an improvement in auditory responses occurs. This is possible, as already mentioned above, due to neuronal plasticity, with no improvement in hearing thresholds or in the response of the cochlear hair cells, but with a change in the cortex, with better auditory responses.

The modification of auditory responses does not happen only by the input of the sound stim‐ ulus of higher quality or more audible. Rather, it is this better quality signal entering the hear‐ ing system that makes possible a change in neural networks, generating a better response in auditory sensation.

However, a positive benefit is not always observed. In some cases, the benefit is negative or zero, i.e., the elderly does not perceive changes in hearing with the hearing aid or even refers to a worsening. In these cases, the adaptation of the hearing aid becomes more difficult and the elderly will not make proper use of the device.

The benefit can be measured by objective and subjective tests. Objective tests assess quantita‐ tively the improvement in hearing performance with the use of hearing aid. Usually, speech is used in noise test, functional gain, insertion responses, among other tests [44]. Speech in noise test is conducted in a soundproof booth, with calibration and standardization. It is supposed to get better performance with hearing aid.

Alongside, there are the subjective tests, such as self‐assessment questionnaire, which are answered by individuals and seek to assess the feeling the individual has about the improve‐ ment in their hearing.

For many services, the subjective test has greater influence and relevance than the objective tests, since these show that the elderly are thinking about the hearing aid, as is its perfor‐ mance in communication activities and may differ from the data obtained in objective tests and influence more on whether or not to use the hearing aid.

The main questionnaires are HHIE (Hearing Handicap Inventory for the Elderly) [45], the APHAB (Abbreviated Profile of Hearing Aid Benefit) [46], and the COSI (Client Oriented Scale of Improvement) [47]. These questionnaires can be used alone or in a combined form and should be applied before and after using the device for the measurement of the benefit.

The HHIE seeks to assess the psychosocial effects of hearing deficiency in the elderly. The questionnaire contains 25 questions that are divided into two scales: social and emotional. By means of these scales it is possible to assess how much the situations of difficult listening affect the individual's behavior and emotional response front to these situations. There are three possible answers: yes, no, and sometimes.

APHAB seeks to assess the hearing disability associated with hearing loss and how it was reduced after using the hearing aid. Therefore, this questionnaire should be applied before the use of hearing aid and after adaptation.

COSI focuses on individual listening difficulties. Before the adaptation, the individual must choose five categories in which I would like to hear well. For evaluation, two scales are used, a relative scale, which assesses the degree of change, and an absolute scale, which records the individual's final skill listening situations.

It is known that even being subjective, the benefit is influenced by cognitive issues, as with cognitive issue preserved, a more effective use of hearing aid will be made, and also the understanding of the auditory information, as well as the ability to understand speech in noisy environments [48]. In others, research is possible to see that the cognitive can change with the benefit of hearing aids [49].

The modification in many categories is just possible to be measured after 1 year of the use of hearing aid [48]. After 4 months of use of the hearing aid, it is possible to see a change in the quality of life of the elderly. Nevertheless, bigger modification in other categories is just per‐ ceived after 12 months of the use of this technology [49]. Some research looks for modification in the benefit after this period, like evaluating the benefit after 24 months of use. However, no significant differences have been observed because an acclimatization had occurred [50].

Many researches look for the benefit of the use of hearing aids. All of them show that the elderly have a significant change in their life to return to social activities and trying again new communication activities. In addition, it is possible to see a reduction in the emotional problems or social isolation [51].

One study evaluated the handicap (Hearing Handicap Inventory for Elderly, HHIE) before and after 6 months of use of hearing aids. One hundred and fifteen (115) elderly were divided into two groups according to the result of the dichotic digits test (normal or abnormal result). After 6 months there was a significant improvement only in the group with normal dichotic test dig‐ its. The author also states that the differences observed between the groups are not justified by memory issues, attention, or difficulty in fine motor. However, the central auditory processing, which when altered generates negative influence on the process of adaptation in the elderly [52].

Therefore, measuring the benefit is essential for a correct assessment of the hearing aid gains possible, as well as checking how the use of this technology is favoring a new neural network.
