Portuguese Version

Year:  2004  Vol. 70   Ed. 2 - (10º)

Artigo Original

Pages: 209 to 214

PDF PT  

Auditory processing in elderly people: interaction study by means of verbal and nonverbal stimuli

Author(s): Maria Madalena Canina Pinheiro 1,
Liliane Desgualdo Pereira 2

Keywords: hearing, auditory perception, aged, hearing tests.

Abstract:
Presbyacusis is a hearing loss combined with functional auditory decline due to the aging process. Aim: The aim of this study is to characterize verbal and nonverbal sound interaction aspects in elderly individuals with and without hearing loss by means of Binaural Fusion Test, Sound Localization Test at five directions and Pediatric Sentence Identification (PSI), taking into consideration each procedure and hearing loss magnitude. Study design: Clinical study with transversal cohort. Material and Method: A number of 110 elderly individuals, aged between 60 to 85 years, with normal hearing and with symmetric neurossensorial hearing loss up to moderately severe hearing impairment participated in this study. The common auditory behavior for all the selected tests was nominated as interaction. The analysis was performed by means of a single procedure and also based on audiometric magnitude. Results: There were more individuals that failed the Binaural Fusion Test. The procedures that showed significant statistical dependency on the audiometric magnitude groups were Sound Localization Test, Temporal Lateralization Test and PSI-MCI (-10) Test. Conclusion: Elderly individuals present difficulty in the binaural interaction process when the auditory information is not complete. The magnitude of the hearing loss interfered specially in the localization auditory behavior.

INTRODUCTION

One of the most frustrating sensorial deficits that follow aging process is the deterioration of the auditory function, which leads to a significant reduction in interaction and interpersonal contacts.

As years go by, the five senses become less efficient, interfering in safety, daily activities and general wellbeing 1. Among the affected senses, we can include hearing loss, which is a result of aging process, known as presbyacusis.

Presbyacusis is followed by decrease in speech discrimination, complex decrease in central auditory function that is manifested through increase of difficulty in skills such as auditory fusion, figure-background, auditory attention, auditory judgment, varied behaviors and reduction in auditory closing and synthesis speed 2.

There is evidence that suggests the occurrence of cochlear degeneration, structural changes in the auditory nerve, central brainstem and temporal bone pathways, resulting in dysfunction of peripheral and central auditory system, associated with the aging process 3.

In addition to peripheral, cognitive, linguistic, central, and general slowness that follows the elderly in motor activities, there is deficit of temporal processing transmission.

Temporal auditory processing involves competence to process aspects of changes of sound characteristics as a result of time.

The analysis of the correlation between aging and temporal auditory processing has been increasing in past years owing to the existence of elderly that frequently complain of difficulties to understand speech that are not related to the level of hearing loss they have 4.

The changes in neural activity of the auditory system result in the combination of age and hearing loss, being that loss of capacity of sound temporal processing, associated with aging, generate the most frequent complaint reported by the elderly: they can hear but they do not understand.

According to Welsh (1985), one of the main difficulties in the elderly to auditorily process the speech signals received are the result of the deficit of auditory functioning such as central competence, failure in central fusion in the presence of incomplete auditory information and binaural interaction 5.

Binaural interaction is the skill to perceive and organize environmental sounds, which strongly depends on simultaneous use of both ears, on neural interaction that occurs as signals are received by both ears, and on how auditory information is processed. These interactions make subjects localize the sound sources in the space and define figure-background.

The special tests of auditory processing - sound location in five directions, binaural fusion and pediatric sentence identification (PSI) - assess respectively the following auditory skills: localization, binaural synthesis and figure-ground.

These skills are affected in the elderly, according to the specialized literature, and lead to difficulties to deal with auditory information received simultaneously by both ears (binaural interaction), being suggestive of changes at the brainstem level4-8.

For these reasons, we proposed a study aiming at characterizing the aspects of interaction between verbal and non-verbal sounds in the elderly with and without hearing loss using five direction sound location, binaural fusion and pediatric sentence identification tests in monotic hearing situation (Pediatric Sentence Identification - PSI-MCI), taking into account the procedure and level of hearing loss.

MATERIAL AND METHOD

We assessed 110 elderly patients aged 60 to 85 years, at the Outpatient Unit of Hearing Disorders, Department of Speech and Hearing Disorders, Federal University of Sao Paulo (UNIFESP) - Escola Paulista de Medicina (EPM) and at Centro de Saúde Lívio Amato, Vila Mariana.

The study was approved by the Research Ethics Committee of Federal University of Sao Paulo - Hospital Sao Paulo (CEP 0565/02).

All assessed subjects were submitted to audiological clinical history, ENT assessment and basic audiological examination (pure tone audiometry, speech reception thresholds, speech recognition index and immittanciometry).

The audibility thresholds considered to be normal were classified within 25dB HL (ISO 7566) in all assessed sound frequencies 250, 500, 1000, 2000, 3000, 4000, 6000 and 8000 Hz, based on Silman, Silverman (1997)9.

The level of hearing loss was classified according to the criteria set forth by Silman, Silverman (1997)9, which take into account pure tone mean thresholds obtained with sound frequencies of 500, 1000 and 2000 Hz.

Inclusion of patients in the study was based on the results of the basic hearing assessment. We included in the sample patients with normal hearing and sensorineural hearing loss up to moderately severe level. The difference between mean of hearing thresholds of 500, 1000 and 2000Hz on the right and left ears should not exceed 10dB HL. This criterion was included to ensure that asymmetrical hearing loss would not influence the results of the selected procedures.

In addition to selection measures, subjects were expected not to have neurological affections, be Brazilian and speak Brazilian Portuguese as maternal language.

Subjects selected to the study after the audiological basic assessment were submitted to Auditory Processing assessment comprising Five-Direction Sound Location, Binaural Fusion and Pediatric Sentence Identification (PSI) tests.

The five-direction location sound test was conducted as described by Pereira (1996)10. The responses to these behaviors were divided into four different levels of percentage for the qualitative analysis: 100% (5 directions) - very good; 80% (4 directions) - good; 60% (3 directions) - fair, and 20% (2 directions) - poor.

The binaural fusion test was conducted according to the criteria defined by Pereira, Schochat (1997)11. In our study, we decided for using only list D1 with low pass on the right ear.

The responses to the binaural fusion test were divided into hit percentage intervals for qualitative analysis, to wit: 100-80% - good, 79-60% - fair, and below 59% - poor.

Pediatric Sentence Identification (PSI) was conducted according to the description proposed by Ziliotto et al. (1997)12.

We know that this test is indicated for children below the age f 7 years. However, we decided to apply it to the whole population, once the test of Synthetic Sentence Identification (SSI), which would be the most appropriate test for the age range, involved proficiency in writing and reading and absence of visual impairment, which was not the case of elderly patients.

In our study, we decided to conduct a test only with ipsilateral competitive messages (PSI-MCI). We submitted 10 sentences in each condition per assessed ear and defined the correlation message/competition 0 and -10, that is, PSI (0) when the message and competition were at the same level, and PSI (-10) when the competition was 10dB SL above the message.

For PSI (0) condition, the percentage of hits was divided for the qualitative analysis into: 100-80% - good, 79-60% - fair, and below 59% - poor.

For PSI (-10) condition, the percentage of hits was also divided for qualitative analysis in: 100-70% - good, 69-40% - fair, and below 39% - poor.

The equipment used for conduction of pure tone and speech discrimination audiometry was audiometer model MA-41, brand Maico, phones TDH 39 P and pads MX-41 AR.

In order to conduct immittanciometry, we used Immittanciometer model AZ-7R, brand Interacoustics, with 220 Hz probe.

All auditory processing tests were conducted, except for five-direction location test, with two-channel audiometer model PAC 2000, brand Orlandi with phones TDH 39 P and pads MX-41 AR. The audiometer was coupled to a compact disk BS 270 by Britania.

For PSI and binaural fusion tests, respectively, we used the recording of tracks 4 and 3 of CD volume 1 that comes with the book of Auditory Central Processing - Assessment Manual 13.

The statistical analysis was conducted using chi-square test for independence and Anova-Analysis of Variance test. For all used tests, we determined p-value as 0.05 or 5% significance. When p-value was statistically significant, the value was shown in bold with asterisks.

RESULTS

Out of the total of 110 elderly (220 ears), we detected hearing loss in 91 (182 ears). The hearing loss was classified concerning level (Table 1).

In Tables 2 and 3, we present the distribution of subjects according to percentage of hits in sound location (LS) and binaural fusion (FB).

Tables 4 and 5 present distribution of subjects according to percentage of hits in PSI-MCI in conditions PSI (0) and PSI (-10), according to the variable side of ear.

Figure 1 shows descriptive measures of correct responses (in percentage) of PSI-MCI test for conditions PSI (0) and PSI (-10), according to the variable ear side.

Analyzing Figure 1, we detected there was no statistically significant difference in performance of subjects concerning the variable ear side and test conditions PSI (0) and PSI (-10) and level of hearing loss according to variable ear side.

Chart 1 shows p-value calculated to check whether there was dependence between percentage of hits in the different procedures (LS, FB and PSI) and level of hearing loss according to the variable ear side.

Comparing the performance of subjects in the different procedures and level of hearing loss according to ear side, we detected statistically significant dependence between the test of Sound Location and PSI (-10) and level of hearing loss.

DISCUSSION

Auditory behaviors studied in the test of Sound Location (Table 1) and Binaural Fusion (Table 2) isolated and classified as good or very good were observed in 89% of the subjects for location skills and in 29% for synthesis skills. Therefore, we detected that there were many more subjects that had difficulty in binaural synthesis skills.

The results obtained in the Sound Location test of the present study are not in agreement with Amatucci (1998)14 - the author observed 97% of elderly female patients with abnormal results in the test. However, they are very close to the results reported by Silveira (2001)15, who detected 35% of elderly patients locating the five directions proposed by the test.

Most of the elderly in the study presented appropriate mechanisms of discrimination of sound source direction. The mechanism depended on the process of binaural interaction for good perception of sound source direction.

As to test of Binaural Fusion, Musiek et al. (1982)16, Pereira et al. (1993)17 and Wishart et al. (2003)18 observed appropriate performance in approximately 90% of the tested children and young adults who had no hearing impairment.

In the Brazilian and international literature, most of the studies agree that Binaural Fusion test is a slightly difficult test 16-19. However, the reported studies were applied in children and young adults.

Probably our results disagreed from the studies reported because the studied population had different age ranges.

Therefore, we can infer that aging process results in changes of binaural synthesis skills, that is, difficulty in recognizing physically distorted verbal sounds presented in a dichotic task. This difficulty found in elderly patients results in difficulties to deal with elements that do not have complete auditory information and, consequently, they cannot understand the meaning of information.

Upon comparing the percentage of hits of test by PSI-MCI per condition, PSI (0) and PSI (-10), and according to the variable ear side, we detected that there was no statistically significant difference in performance of subjects concerning the condition and variable ear side (Figure 1).

Many studies in the specialized literature applied SSI in elderly patients and noticed similar results concerning the performance of right and left ears 14, 20-23.

In the present study, we detected good performance in the PSI test on the right (Tables 4 and 5) in PSI (0) and PSI (-10), respectively, in 91 subjects (82.7%) and in 78 subjects (70.9%). On the left (Tables 4 and 5), 95 subjects (86.4%) in the condition PSI (0) and 75 subjects (68.2%) in condition PSI (-10) also had good performance.

These data showed ¾ of assessed subjects with good performance in the task, that is to say, appropriate interaction process for the discrimination mechanisms of verbal sounds overlapped in monotic hearing.

This preserved mechanism is very important to understand auditory information in the presence of competitive message.

In Chart 1, we detected there was statistically significant dependence between percentage of correct responses in the Sound Location test in five-directions and PSI (-10) with hearing loss level.

Therefore, we can infer that the milder the hearing loss, the higher the likelihood of having more correct responses in the test of Sound Location, that is, the subjects without severe hearing impairment locate better than subjects with more severe impairment.

In the specialized literature, many authors discussed the interference of hearing loss in performance of the auditory processing tests and some believe that the level of hearing loss worsens the performance of elderly subjects in sound location tasks 24-25.

However, Kubo et al. (1998)26, stated that the effects of hearing loss level in sound location were not very high.

To McCroskey, Keith (1996) the presence of hearing loss causes less activation of number of nervous fibers, less bulk of information to be processed, resulting in greater demand to the auditory central nervous system, which increases the likelihood of causing temporal processing deficit 27.

As to the test of PSI-MCI, we detected that in the condition PSI (-10) there was statistically significant dependence on level of hearing loss, that is, the greater the level of hearing loss, the higher the likelihood of a subjects presenting changes in the PSI-MCI test in condition PSI (-10).

Our findings agreed with those by Pedalini et al. (1997)23, which found an association between level of hearing loss and percentage of hits in SSI-MCI test, but they disagreed from the results by Jerger (1992)28..The author believed that changes in auditory behavior resulting from aging did not reflect in hearing thresholds, but rather in cognitive status and possible interaction between level of auditory sensitivity and cognitive function.

We suggested that elderly subjects with hearing loss should be assessed by PSI-MCI concerning competitive message from zero so that there is no effect of level of hearing loss.

Sound interaction for mechanisms of discrimination of sound source direction (Sound Location test) and discrimination of overlapped verbal sounds in monotic hearing (PSI-MCI) were not difficult at all, since most of the assessed elderly showed good performance. Only the mechanism to recognize physically distorted verbal sounds (Binaural fusion test) was considered difficult to elderly subjects, since most of them presented fair performance.

Thus, we observed that processing of verbal and non-verbal sounds was appropriate for the elderly when auditory information was complete, but when information was distorted, the subjects presented difficulty in conducting binaural synthesis.

We believe that this inability is responsible for most of the complaints of elderly people of not understanding auditory information in noisy environments.

The level of hearing loss interfered in auditory behavior interaction studied by the following tests: Five-Direction Sound Location and PSI (-10).

To Feres, Cairasco (2001), understanding the functioning and plastic potential of the central auditory pathway is essential for the knowledge about how the brain integrates and discriminates complex stimuli, such as speech sounds. Understanding the mechanisms through which the central structures of the auditory system reacts to loss of afferent information, and later to a new input of stimuli, can help in the development of methods that ensure better use of subjects' communication 29.

The study of auditory processing in elderly patients intends to understand the changes that occur in auditory information processing during aging and contributes to improvement in the communication process.

CONCLUSIONS

 Most of the assessed elderly presented good performance in sound interaction for discrimination mechanisms of sound source direction (Sound Location test) and verbal sound discrimination overlapped in monotic hearing (PSI-MCI). Only the recognition mechanisms of physically distorted verbal sounds (Binaural Fusion test) were considered difficult for the elderly, since most of them presented fair performance.

 We also detected that hearing loss level interfered in the interaction of auditory behaviors studied by the following tests: Sound Location in Five-Directions and PSI (-10).

Table 1. Distribution of hearing loss concerning hearing level and side of ear.

NL- subjects with no hearing loss
L- subjects with mild hearing loss
M- subjects with moderate hearing loss
MDS- subjects with moderately severe hearing loss


Table 2. Distribution of subjects according to percentage of hits in the Sound Location Test.



Table 3. Distribution of subjects according to percentage interval of correct responses in the Binaural Fusion Test.



Table 4. Distribution of subjects according to percentage of correct responses in the PSI- MCI test for PSI (0) according to variable side of ear.



Table 5. Distribution of subjects according to percentage of correct responses in the PSI- MCI test for PSI (-10) according to variable side of ear.



Chart 1. Statistically calculated values (p-value) to check the association between performance of subjects in different procedures with level of hearing loss according to variable side of ear.

LS- Test of Sound Location in Five Directions
FB- Test of Binaural Fusion
GOD- Level of hearing loss on the right ear
GOE- Level of hearing loss on the left ear



Figure 1. Percentage of correct responses in mean values per ear and test condition: PSI (0) and PSI (-10).

REFERENCES

1. Ribeiro A. Aspectos biológicos do envelhecimento. In: Russo IP. Intervenção fonoaudiológica na terceira idade. Rio de Janeiro: Revinter; 1999. p. 1-11.
2. Hull RH. Atendimento ao paciente idoso. In: Katz J. Tratado de audiologia clínica. 4a ed. São Paulo: Manole; 1999. p. 783-91.
3. Bess FH, Hedley-Williams A, Lichtenstein. Avaliação audiológica dos idosos. In: Musiek FE, Rintelmann WF. Perspectivas Atuais em Avaliação Auditiva. 1a ed. Barueri-SP: Manole; 2001. p. 343-69.
4. Neves VT, Feitosa MAG. Controvérsias ou complexidade na relação entre processamento temporal auditivo e envelhecimento? Revista Brasileira de Otorrinolaringologia 2003; 69(2):1-11.
5. Welsh J, Welsh L, Healy M. Central presbyacusis. Laryngoscope 1985; 95: 128-36.
6. Durlach NI, Thompson CL, Colburn HS. Binaural Interaction in impaired listeners. Audiology 1981; 20 (3): 181-211.
7. Baran JA, Musiek FE. Avaliação comportamental do sistema nervoso auditivo central. In: Musiek FE, Rintelmann WF. Perspectivas Atuais em Avaliação Auditiva. 1a ed. Barueri-SP: Manole; 2001. p. 371-410.
8. Tremblay KL, Piskosz M, Souza P. Effects of age and age-related hearing loss on the neural representation of speech cues. Clinical Neurophysiology 2003; 114 (7):1332-43.
9. Silman S, Silverman CA. Basic Audiologic Testing. In: Silman S, Silverman CA. Auditory Diagnosis-Principles and applications. San Diego: Singular; 1997. p 38-58.
10. Pereira LD. Identificação de desordens do Processamento Auditivo Central através de observação comportamental: organização de procedimentos padronizados. In: Schochat E. Processamento Auditivo Central - Manual de Avaliação. São Paulo: Lovise; 1996. p. 43-53.
11. Pereira LD, Schochat E. Baixa redundância: fala filtrada e fusão binaural. In: Pereira LD, Schochat E. In: Processamento Auditivo Central - Manual de Avaliação. São Paulo: Lovise; 1997. p. 103-9.
12. Ziliotto KN, Kalil DM, Almeida CIR. PSI em português. In: Pereira LD, Schochat E. Processamento Auditivo Central: manual de avaliação. São Paulo: Lovise; 1997. p. 113-28.
13. Pereira LD, Schochat E. Processamento Auditivo Central - Manual de Avaliação. São Paulo: Lovise; 1997.
14. Amatucci MAFC. Processamento auditivo central: teste SSI (Identificação de Sentenças Sintéticas) e de Localização Sonora em mulheres jovens, adultas e idosas [tese-mestrado. São Paulo: Universidade Federal de São Paulo; 1998.
15. Silveira KMM. Memória, Interação e Integração em adultos e idosos de diferentes níveis ocupacionais [tese-doutorado. São Paulo: Universidade Federal de São Paulo; 2001.
16. Musiek FE, Geurkink NA, Kietel SA. Test battery assessment of auditory perceptual dysfunction in children. Laryngoscope 1982; 92(3): 251-7.
17. Pereira LD, Gentile C, Costa S, Borges ACLC. Considerações preliminares no teste de fala filtrada e fusão binaural. In: VIII Encontro Nacional de Fonoaudiologia. Anais. Santos; 1993.
18. Wishart JMB, Figueiredo LF, Barbosa PJC, Araujo FCRS, Araújo AML. Teste de fala filtrada e fusão Binaural. In: 18º Encontro Internacional de Audiologia. Anais. Curitiba-PR.
19. Câmara CC, Iório MCM, Pereira LD. Análises dos índices percentuais de reconhecimento da fala filtrada e não sensibilizada em crianças com audição normal com e sem queixa de desatenção. Acta Awho 1995; XIV (4): 184-9.
20. Shirinian MJ, Arnst DJ. Patterns in the performance-intensity functions for phonetically balanced word lists and synthetic sentences in aged listeners. Arch Otolaryngol 1982; 108 (1): 15-20.
21. Aquino AMCM, Almeida CIR, Oliveira JA. Teste de identificação de sentenças sintéticas (SSI) em português com mensagem competitiva: uma padronização. Rev Bras de Otorrinolaringologia 1993; 59 (3): 160-3.
22. Gates GA, Karzon RK, Garcia P, Peterein J, Storandt M, Morris JC, Miller JP. Auditory dysfunction in aging and senile dementia of the Alzheimer's type. Arch Neurol 1995; 52 (6): 626-34.
23. Pedalini MEB, Liberman PHP, Pirana S, Jacob Filho W, Câmara J, Miniti A. Análise do perfil audiológico de idosos através de testes de função auditiva periférica e central. Rev Bras de Otorrinolaringologia 1997; 63 (5): 489-96.
24. Hawkins DB, Wightman FL. Interaural time discrimination ability of listeners with sensorineural hearing loss. Audiology 1980; 19 (6): 495-507.
25. Crandford JL, Andres MA, Piatz KK, Reissig KL. Influences of age and hearing loss on the precedence effect in sound localization. Journal of Speech and Hearing Research 1993; 36: 437-41.
26. Mc Croskey R, Keith RW. AFT-R Auditory fusion test revised. San Antonio: Psychological corporation; 1996.
27. Kubo T, Sakashita T, Kusuki M, Kyunai K, Ueno K, Hikawa C, Wada T, Shibata T, Nakai Y. Sound lateralization and speech discrimination in patients with sensorineural hearing loss. Acta Otolaryngol (Stockh) 1998; 538:63-9.
28. Jerger J. Can age-related decline in speech understanding be explained by peripheral hearing loss? J Am Acad Audiology 1992; 3 (1): 33-8.
29. Feres MCLC, Cairasco NG. Plasticidade do Sistema Auditivo. Rev Bras Otorrinolaringol 2001; 67(5): 716-20.

1 Speech and Hearing Therapist, Master studies in Human Communication Disorders under course, Federal University of Sao Paulo- Escola Paulista de Medicina.
2 Speech and Hearing Therapist, Joint Professor, Ph.D. Department of Speech and Hearing Therapy, Federal University of Sao Paulo- Escola Paulista de Medicina.
Study developed in the Ambulatory of Hearing Disorders, Department of Speech and Hearing Therapy, Federal University of Sao Paulo - Escola Paulista de Medicina, and Centro de Saúde Lívio Amato.
Address correspondence to: Rua Três de Maio 154 ap. 113 04044020 Vila Clementino Sao Paulo SP.
Tel (55 11) 5083-9462/ 9530-3846 - E-mail: madapinheiro@hotmail.com -lilianedesgualdo@uol.com.br
Financial support: CAPES.

Print: