In Brazil, presbycusis has been blamed as the most frequent cause of hearing impairment in the elderly, causing understanding difficulties during verbal communication.24,6

Both the physiological and natural aspects of presbycusis have been approached by many authors in the national literature25-29.

According to Portmann and Portmann30, presbycusis is a biologic phenomenon of which no one can escape, starting at 20/30 years of age, and becoming socially bothersome when the person reaches 40/50 years.

Few studies carried out in Brazil were identified, so far, that tried to estimate the prevalence of presbycusis and even these did not use populational based samples. This fact is leaving a large gap, considering the current longevity and life expectancy of the elderly31, which make the elderly the most growing populational segment of modern times.

The Hearing Impairment Among Adults - HIA32 report, result of a joint work between Nordic countries – Finland, Norway, Denmark, Sweden and Iceland – and the United Kingdom, aimed at assessing the current and estimated rate of presbycusis, evaluating the results of hearing rehabilitation of the individuals affected by it and understand non-invasive treatment modalities. As non-invasive treatment we understand the individual sound amplification devices, ISAD (Hearing Aid).

Studies presented at the HIA showed an increase in presbycusis prevalence with age. It is considered a natural hearing impairment that grows significantly as people age, and this brings adverse effects in social activities and participation, impacting their life quality. This group of researchers concluded that although there are different types of presbycusis, the evidence gathered do not suggest different prevalence rates among the different countries for people of the same age and gender.

In Brazil, data from the Demographic Census33 show that, according to the International Classification of Functionality, Incapacity and Health, from the World Health Organization, there are 24.5 million Brazilians with some kind of disability, which means 14.5% of the total population. Nonetheless, when we classify hearing impaired patients among a population with some type of disability, the Census defined 176,067 people as hearing impaired; 860,889 with high permanent hearing difficulty, and4,713,854 million people with some permanent hearing disability. This classification encompasses a total of 5.7 million people with hearing disability; however it does not inform the type and level of hearing loss, nor the age of these individuals, thus precluding a better understanding of this population. This classification includes school age children, adults and the elderly, in other words, everyone with some kind of hearing impairment.

Hearing assessment in the elderly must encompass not only objective and subjective tests that aim at defining the individual's audiologic thresholds, but it also has a more general task, which is to evaluate the peripheral hearing quality coming from the central information processing; and also consider the patient's own perception of his/her hearing loss, at a functional level in his/her daily family and social activities34,35. It is known that peripheral hearing involves the amplification and conduction of sound waves, as well as the perception of sound vibrations, which are transformed into nervous inputs. Central hearing involves nerve input conduction through the auditory pathway, all the way to the auditory cortex, where they will be coded and recoded, thus gaining linguistic meaning36.

Therefore, in the audiologic evaluation of the elderly, the audiologist must not lose sight of the need to use the tools necessary to evaluate both the peripheral and the central auditory apparatus. According to Rönnberg37, there is a growing consensus that cognitive and sensorial impairments are somehow related. The author considers that the peripheral auditory information will interact with an “aged” cognitive system and, this way, gain meaning. Therefore, the quality of such process is individualized and depends on a number of factors.

Frequency-specific sensibility must be evaluated by subjective and objective tests, according to the need of each patient. Some tests will inform about outer and middle ear functioning, which is fundamental for a proper amplification and conduction of sound waves to the inner ear. Other tests complete this information, by evaluating the inner ear, where sound waves are transformed into sound impulses, broken down into frequency, time and intensity elements, which are then transmitted to the auditory cortex, by means of the auditory pathways.

Therefore, peripheral activities are responsible for sound sensation, while central activities are in charge of decoding the message received and, concurrently, by its recoding, in a new format required by the nervous system.

Primary auditory cortex discriminates sound frequencies and intensities; it bears a temporal pattern and is involved in sound source location. The association areas are functional areas which are directly related to speech sound recognition. Thus, the auditory central nervous system is intimately related to language processing and other cognitive and emotional functions38.

Considering auditory functionality, capacities to detect, locate, discriminate, recognize and understand the sound message are all evoked39. These skills can both interfere and allow oral communication between individuals. Family and social interaction is established and kept by means of oral communication. Therefore, it is not enough to be able to hear, one must understand what is being heard.

During tonal audiometry, it is possible to notice the quality of peripheral hearing central information processing, both in terms of the speech recognition index and in relation to understanding and performing the orders given by the examiner. All such factors should be considered by the audiologist during hearing assessment of an elderly person, taking them as basic parameters used in other investigations related to the central auditory system.

We still have to investigate possible difficulties related to hearing functional use. Self-assessment questionnaires have been broadly recommended by National and International authors.40,41,16,17. They evaluate the individual's self perception about his/her functional and psychosocial losses caused by the hearing loss in their daily routines, and are paramount in order to better understand presbycusis and its diagnosis, especially considering a process of hearing reeducation.

It is not always that tonal audiometry results correspond to the findings from the functional use of hearing by the elderly40. It is not uncommon to find a significant loss in frequency-specific sensitivity and little complaint about the functional use of hearing in the daily routine of the elderly, as it is also possible to find the opposite. Elderly people with mild hearing loss may present a high index of functional challenge perception.

All this information will be fundamental in order to consider patient's education after audiologic evaluation in the elderly. The prescription of a hearing aid and the hearing reeducation process are directly related to these factors.

The hearing apparatus is one of the most important factors related to the development of oral communication. A failure in this system can start a chain reaction, that is, a hearing impairment causes great communication difficulties that in its turn bring about deterioration in life quality.

Early diagnosis and intervention in aging-related hearing loss are paramount in order to provide the elderly with a good life quality. Studies and research in this area point toward a functional change based on brain plasticity, even in the adult population36.

Early prescription, fitting and using of a hearing aid, that is, immediately after the diagnosis of a mild and/or moderate hearing loss, may contribute to preventing an increase in the hearing loss level and other related alterations such as psychosocial issues for the affected individual.

Some constant studies and research on the work of Musiek and Rintelmann42 show that hearing impairment in the elderly is associated with depression and dementia. According to Rönnberg37, there is a growing consensus that both cognitive and sensorial impairments are, somewhat, related.

However, the referral of these patients to acquire a hearing aid is only the starting point, because without hearing reeducation, often times these patients abandon the device43. According to Espmark16, the primary tool to rehabilitate people with hearing loss is the hearing aid. However, there is also the traditional aural rehabilitation, which includes hearing training and instructions for speech understanding. Such training is fundamental in order to bring down communication barriers of people with hearing loss, helping them to better cope with psychosocial, occupational and educational impacts of such impairment.

According to Couto-Lenzi44, when an elderly, used to normal hearing, loses his/her hearing, or has it reduced, the discomfort is immediate. The difficulties start when they try to communicate with family members, close friends and workmates, later on, in stores, grocery stores, and other social activities. Other social implications of the hearing loss in the elderly involve his/her daily routines, such as listening to the radio and watching TV; speaking on the phone; shopping; talking; playing musical instruments; listening to music and singing; working out; doing Yoga and exercises in the water; participating in courses, seminars, classes and talks.

Precursor of the “Perdoncini” method for Hearing and Language challenged population in Brazil; Couto-Lenzi adapted this work in order to be used in the auditory reeducation for the elderly, of which the main goal is to facilitate communications based on the thorough use of residual hearing.

A reduction in information processing speed, commonly seen in the elderly, may significantly affect speech perception performance when added to a specific frequency sensibility deficit, and this worsens the communication difficulties of this population.45 Thus an auditory reeducation work after fitting a hearing aid is paramount.

Linguistic implications are directly related to the degree of hearing loss, which may vary from mild to profound46. Loss goes from a difficulty in understanding spoken messages, especially in noise environments, up to significant communication alterations, which impairs the person's capacity to actively participate in daily conversations, and there are also voice alterations because of the incapacity to have voice feedback and thus control it.

Some aspects pointed out in studies and research has contributed to the development of a proper hearing reeducation work for the elderly. For instance, one has to consider the fact that in noisy environments, words in a context are more intelligible that isolated words or those without the benefit of a phase context and the very situations peculiar to language communication. Moreover, the phrase context imposes a reduction in possible alternatives, and speech intelligibility increases as the number of possible alternatives reduces.47

According to the aforementioned authors, word predictability has a direct impact on the intelligibility of what will be heard. And when a phrase is presented to a listener at a given context which is established by prior expressions and the very situations in which the expressions are presented, phrase understanding is better when compared to a neutral context, or even an unknown context for the listener in that specific situation.

All these information allow the creation of auditory reeducation strategies that will allow the development of the auditory function in a proper way, improving the person's well being in his/her social and family settings, since it enhances this person's hearing skills.

Awareness about hearing difficulties, associated to frequency-specific sensibility, must be clarified and informed to the elderly and the people who live with them. The interruption in this hearing reeducation work must be partial and progressive. Return to it must happen whenever necessary. The family must receive specific guidelines aiming at reintegrating the elderly with hearing loss to their social and family settings.