Orozimbo Alves Costa Filho

Audiometria de alta freqüência: estudo com indivíduos audiologicamente normais

Recent research studies pointed to High-Frequency Audiometry (HFA) as a tool for early diagnosis of hearing impairment caused by the main etiological agents, such as aging, exposure to ototoxic drugs, and occupational noise. AIM: Although there are already several techniques developed for this assessment, some of them should not be applied to clinical routine, because of their lack of practicability and, sometimes, lack of reliable results. According to the literature, a suitable methodology for such assessment, as well as values indicated as normal reference, are still needed. STUDY DESIGN: Clinical prospective. MATERIAL AND METHOD: The present research study observed auditory thresholds in young and audiologically normal individual with HFA and assessed some variables that could have an influence upon the results. CONCLUSION: Based on the collected data, we were able to established values for mean, standard deviation and median, besides minimum and maximum values for each frequency, for the entire population. Statistical analyses did not identify significant differences between gender and the ears. Moreover, questions related to inter-and intra-individual variability are discussed.

Potencial evocado auditivo de longa latência-P300 em indivíduos normais: valor do registro simultâneo em Fz e Cz

The P300 is and auditory Evoked Potential, called endogenous potential because it reflects the functional use the individual makes of the auditory stimulus, being highly dependent on cognitive skills; among them we list attention and auditory discrimination. It is a procedure of objective evaluation; however, one that depends on the examiners experience to detect wave peaks, and it is important to use recording methods that facilitate the response presence analysis and result interpretation. AIM: to analyze the P300 Long Latency Auditory Evoked Potential obtained through the use of two active electrodes positioned on Fz and Cz. MATERIALS AND METHODS: 330 individuals from both genders and age ranging between 7 and 34 years participated in this study, they all had normal hearing and did not have any risk factor for mental problems. RESULTS: Results show that there was no statistically significant difference for N2 and P3 latency and P3 amplitude as far as gender is concerned, nor correlation with the individuals age. There was a strong correlation of these measures with Fz and Cz electrode positioning. CONCLUSION: Fz and Cz active electrodes positioning can be considered one more resource to help in the P300 clinical analysis.

Maturação do sistema auditivo central em crianças ouvintes normais

BACKGROUND: the long latency auditory evoked potentials (LLAEP) provide objective data about the function of hearing cortical structures. AIM: to characterize the maturation of the central hearing system in normally hearing children. METHOD: record of LLAEP of fifty-six subjects with hearing tresholds within normal limits, of both genders, being 46 children and 10 adults. With the availability of two recording channels, one was directed to register the LLAEP and the other, to record the artifact generated by ocular movement, aiming at its control. The potentials were recorded with subjects in an alert state, through electrodes positioned in Cz (active) and A2 (reference), and the ocular movements, through electrodes in the left supra and infra-orbital positions; the ground electrode was placed in A1. The morphology and the values of latency and of amplitude for components P1, N1 and P2, according to age, were analyzed. In order to verify the reproducibility of the recorded potentials, a double blind study was carried out, by introducing the analysis of another evaluator. RESULTS: the double blind study did not present statistically significant differences between the analyses. With the increase in age there was an improvement in the morphology and a decrease in the latency values of components P1, N1 and P2. Also there was a decrease in the amplitude of component P1 and no variation in the amplitude values was observed for components N1 and P2. No statistically significant difference was observed between genders. CONCLUSION: the maturational process of the central hearing system occurs gradually, being the greatest changes observed when comparing children and adults.

Emissões otoacústicas evocadas - produto de distorção em neonatos audiologicamente normais

Introducao: Considerando que a pesquisa das emissoes otoacusticas evocadas - produto de distorcao (EOAPD) em neonatos - traz novas perspectivas para o diagnostico precoce da deficiencia auditiva sensorial. Forma de estudo: Prospectivo clinico nao randomizado. Objetivo: Este estudo tem, como objetivo, caracterizar as EOAPD em 20 neonatos audiologicamente normais, de ambos os sexos, quanto a ocorrencia, amplitude e tempo de execucao do exame, atraves do PD-grama, utilizando o equipamento ILO 92 OAE System-Otodynamics Analyser. Resultados: Dos 20 neonatos que compareceram, 17 foram avaliados, totalizando 33 ouvidos. As EOAPD ocorreram em 57,5% em 1 kHz; 93,9% em 1,5 kHz e 3 kHz; 96,9% em 2 kHz; e 100% em 4 kHz e 6 kHz. Conclusao: As amplitudes medias das EOAPD variaram de 9,9 a 20,3 dB NPS; e o tempo medio de realizacao do exame foi de 82 segundos.

Habilidades de ordenação temporal em usuários de implante coclear multicanal

O processamento das pistas acusticas dos sons da fala depende da adequada percepcao da frequencia e da duracao dos estimulos enquanto sequencia de eventos. OBJETIVO: Avaliar as habilidades de ordenacao temporal em usuarios de IC multicanal. METODO: 14 individuos com audicao normal, formadores do grupo controle equiparados em idade e genero com 14 usuarios de IC, que formaram o grupo experimental, foram avaliados e comparados quanto ao Teste de Padroes de Frequencia (TPF) e Teste de Padroes de Duracao (TPD). RESULTADOS: Os usuarios de IC apresentaram bom desempenho nas tarefas de ordenacao temporal, com resultados medios de 48,7% no TPF e 59,6% no TPD. Para o grupo controle, o desempenho medio no TPF foi de 63,4% e no TPD de 64,6%. Nao foi obtida diferenca significativa estatisticamente entre os resultados dos grupos controle e experimental. CONCLUSAO: O IC proporcionou desempenho favoravel nas tarefas que exigem habilidades de ordenacao temporal para os individuos avaliados neste estudo.

A resposta auditiva de estado estável na avaliação auditiva: aplicação clínica

TEMA: a resposta auditiva de estado estavel (RAEE) e um procedimento eletrofisiologico que permite avaliar ao mesmo tempo os limiares auditivos de varias frequencias em ambas as orelhas, reduzindo assim o tempo de teste, e permite estimular ate niveis proximos a 125dB HL, caracterizando assim a audicao residual. OBJETIVO: verificar a aplicabilidade da RAEE para determinar os limiares auditivos nos diferentes graus de perda auditiva neurossensorial coclear. METODO: foram avaliados 48 individuos com idade entre sete e trinta anos e diferentes graus de perdas auditivas. A Audiometria Tonal Liminar (ATL) e a RAEE foram avaliadas nas seguintes frequencias portadoras, 0,5; 1; 2 e 4k Hz. As frequencias portadoras na RAEE foram moduladas em amplitude e frequencia, com estimulacao multipla e dicotica nas perdas auditivas de grau leve e moderado. Estimulacao simples foi utilizada nos outros graus de perdas auditivas. RESULTADOS: houve associacao significante (p < 0,01) entre os limiares obtidos na ATL e RAEE para todas as frequencias testadas, principalmente para perdas auditivas de grau profundo. Contudo em alguns pacientes o grau da perda auditiva pode ser super-estimado. CONCLUSAO: a RAEE pode ser utilizada para predizer os limiares auditivos da ATL, porem nao deve ser analisada de forma isolada, mas de forma complementar a avaliacao audiologica comportamental.BACKGROUND the auditory steady state response (ASSR) is an electrophysiological procedure that evaluates, at the same time, the hearing thresholds of both ears at various frequencies. This procedure reduces the time of testing and enables the stimulation of levels close to 125dB HL, characterizing residual hearing. AIM to verify the applicability of the ASSR to determine the hearing thresholds in different levels of sensorineural hearing loss. METHOD 48 individuals aged 7-30 years, with different levels of hearing loss were assessed. The Pure tone Audiometry (PTA) and the ASSR were carried out in following carrier frequencies 0.5; 1; 2 and 4k Hz. The carrier frequencies in the ASSR were modulated in amplitude and frequency, with multiple dicotic stimulation for mild and moderate hearing loss. Simple stimulation was used to test the other hearing deficit levels. RESULTS there was a significant association (p<0.01) between the thresholds obtained in the PTA and in the ASSR for all of the tested frequencies, especially for the severe levels. However, for some patients, the hearing loss level was overestimated in the ASSR. CONCLUSION the ASSR can be used to estimate the PTA threshold; nevertheless, it should not be analyzed in an isolated way, but seen as a complementary procedure to the behavioral auditory assessment.

Potencial evocado auditivo de estado estável em audiologia pediátrica

UNLABELLED The main issue regarding pediatric audiology diagnosis is determining procedures to configure reliable results which can be used to predict frequency-specific hearing thresholds. AIM To investigate the correlation between auditory steady-state response (ASSR) with other tests in children with sensorineural hearing loss. METHODS Prospective cross-sectional contemporary cohort study. Twenty-three children (ages 1 to 7; mean, 3 years old) were submitted to ASSR, behavioral audiometry, click audiometry brain stem response (ABR), tone burst ABR, and predicting hearing level from the acoustic reflex. RESULTS the correlation between behavioral thresholds and ASSR was (0.70- 0.93), for the ABR tone burst it was (0.73 -0.93), for the ABR click it was (0.83-0.89) only at 2k and 4 kHz. The match between the ASSR and the hearing threshold prediction rule was considered moderate. CONCLUSION there was a significant correlation between the ASSR and audiometry, as well as between ABR click (2k and 4 kHz) and for the ABR tone burst. The acoustic reflex can be used to add information to diagnosis in children.

Implantes cocleares em crianças portadoras de deficiência auditiva decorrente de meningite

Meningitis is the main cause of acquired sensorineural hearing loss in children. The patient may also present motor disorders, visual, vestibular, language and attention deficits as well as inability for learning. Characteristically the hearing loss due to meningitis is bilateral profound sensorineural symmetric and descendent and it is more common in males and in children under 5 years old and it brings severe implications in the emotional, social and development. AIM: To compare the performance of two groups of pre-lingually deaf implanted children, with age varying from 1 year and 10 months to 6 years, with hearing loss due to meningitis and other varied causes. STUDY DESIGN: Transversal cohorte. MATERIAL AND METHOD: 63 profoundly deaf implanted children were evaluated, 25 (40%) were male and 38 (60%) were females. In 12 cases (19%) the hearing loss was caused by meningitis and in 51 cases (81%) hearing loss was due to a variety of causes. All participants were submitted to ear nose throat examination and clinical and objective audiological evaluation. CONCLUSIONS: the occurrence of partial insertion was higher in the meningitis group. There were no statically significant differences on word and phoneme recognition as well as in the questionnaire for evaluation of the hearing (MAIS) and language (MUSS) skills between the groups.

Study on suppression of otoacoustic emissions: lateral domain

UNLABELLED A pon stimulation by contralateral, ipsilateral or bilateral noise, the medial olivocochlear efferent tract changes the amplitude of otoacoustic emissions relative to the tested ear, reducing or removing it; this resulted in a reduction/suppression effect of otoacoustic emissions. Differences in patterns of elimination/reduction of otoacoustic emissions between ears have been documented worldwide; there are, however, no Brazilian studies investigating the effect of lateral dominance. AIMS To compare the effect of the presence of deletion/reduction of otoacoustic emissions and their amplitude relative to lateral dominance in normal hearing adults. METHODS A clinical and experimental study. The sample comprised 75 individuals. The methodology was conventional - linear click intensity of 60 dB SPL; white noise was contralateral stimulation at 60 dB SPL. DESCRIPTION OF RESULTS: There were no statistically significant differences between right and left ear results, in terms of asymmetry of the degree of otoacoustic emissions and the presence of suppression/reduction. CONCLUSION There is no lateral dominance in the degree of otoacoustic emissions in the presence of suppression/reduction in the study population.

P300-long-latency auditory evoked potential in normal hearing subjects: simultaneous recording value in Fz and Cz

UNLABELLED The P300 is and auditory Evoked Potential, called endogenous potential because it reflects the functional use the individual makes of the auditory stimulus, being highly dependent on cognitive skills; among them we list attention and auditory discrimination. It is a procedure of objective evaluation; however, one that depends on the examiners experience to detect wave peaks, and it is important to use recording methods that facilitate the response presence analysis and result interpretation. AIM To analyze the P300 Long Latency Auditory Evoked Potential obtained through the use of two active electrodes positioned on Fz and Cz. MATERIALS AND METHODS 330 individuals from both genders and age ranging between 7 and 34 years participated in this study, they all had normal hearing and did not have any risk factor for mental problems. RESULTS Results show that there was no statistically significant difference for N2 and P3 latency and P3 amplitude as far as gender is concerned, nor correlation with the individuals age. There was a strong correlation of these measures with Fz and Cz electrode positioning. CONCLUSION Fz and Cz active electrodes positioning can be considered one more resource to help in the P300 clinical analysis.