Timpanometria em lactentes utilizando sonda multifrequencial

Int. Arch. Otorhinolaryngol. 2012;16(2):186-194. DOI: 10.7162/S1809-97772012000200006 Original Article Multifrequency tympanometry in infants Timpanometria em lactentes utilizando sonda multifrequencial Tamyne Ferreira Duarte de Moraes1, Camila de Cássia Macedo2, Mariza Ribeiro Feniman3. 1) Master of Science. Resident Speech Therapist for Multidisciplinary Residency Program of Rehabilitation Craniofacial Anomalies Hospital of Universidade de São Paulo /Sao Paulo University. 2) Master of Rehabilitation Science.Student for Post-Graduation Program of Rehabilitation Craniofacial Anomalies Hospital of Universidade de São Paulo/Sao Paulo University. 3) Entitled Professor. Entitled Professor for Speech Therapy Department FOB/USP. Institution: Faculdade de Odontologia de Bauru - Universidade de São Paulo. Bauru / SP – Brazil. Mailing address: Tamyne Ferreira Duarte de Moraes - Espírito Santo Street, 4-63 - Vila Coralina – Bauru / SP – Brazil – Zip-code: 17030-030 - E-mail: Finnancial sponsorshio: CAPES Article received in June 27, 2011. Article approved in February 6, 2012. SUMMARY RESUMO Introduction: The use of conventional tympanometry is not sufficiently sensitive to detect all cases of middle ear changes, and this hinders accurate diagnosis. Objective: To characterize acoustic immittance measures of infants from 0 to 3 months of age using multifrequency tympanometry in a prospective study. Method: 54 infants from 0 to 3 months of age were evaluated. The inclusion criteria included absence of respiratory infections during the evaluation, presence of transient evoked otoacoustic emissions, and absence of risk indicators for hearing loss. The subjects were evaluated by an audiologic interview, a visual inspection of the ear canal, and measures of acoustic immittance at the frequencies of 226 Hz, 678 Hz, and 1,000 Hz. Tympanometric records of the occlusion effect, tympanometric curve type, tympanometric peak pressure, equivalent ear canal volume, and peak compensated static acoustic admittance were collected. Results: The results indicated the presence of an occlusion effect (2.88% at 226 Hz, 4.81% at 678 Hz and 3.85% at 1,000 Hz), predominance of a tympanometric curve with a single peak (65.35% at 226 Hz, 81.82% at 678 Hz, and 77.00% at 1,000 Hz), and tympanometric peak pressure ranging from -155 to 180 daPa. Further, the equivalent ear canal volume increased with the frequency of the probe (0.64 mL at 226 Hz, 1.63 mho at 678 Hz, and 2.59 mmho at 1,000 Hz) and the peak compensated static acoustic admittance values increased with an increase in frequency (0.51 mL at 226 Hz, 0.55 mmho at 678 Hz and 1.20 mmho at 1,000 Hz). 93.06% of the tympanograms were classified as normal at 226 Hz, 81.82% at 678 Hz, and 77.00 % at 1,000 Hz, respectively. Conclusion: Taken together, these results demonstrated that utilizing these evaluations made it possible to characterize the acoustic immittance measures of infants. Keywords: hearing, infant, middle ear, acoustic impedance tests. Introdução: O uso de uma única frequência na timpanometria não é sensível na detecção de todos os casos de alteração na orelha média, dificultando o diagnóstico preciso. Objetivo: Caracterização das medidas de imitância acústica de lactentes utilizando três tipos de sonda. Estudo prospectivo. Método: Foram avaliados 54 lactentes, com idade entre zero e três meses. Os critérios de inclusão foram ausência de infecções de vias aéreas, presença de emissões otoacústicas evocadas transientes, ausência de indicadores de risco para perda auditiva. Foi realizada entrevista audiológica, inspeção visual do meato acústico externo e medidas de imitância acústica nas frequências de 226Hz, 678Hz e 1000Hz. Foram coletados os registros timpanométricos de efeito de oclusão, curva e pressão de pico timpanométrico, volume equivalente do meato acústico externo e pico compensado da admitância acústica estática. Resultados: Os resultados indicaram presença de efeito de oclusão (2,88% em 226Hz, 4,81% em 678Hz e 3,85% em 1000Hz); predomínio de curva em pico único (65,35% em 226Hz, 81,82% em 678Hz e 77,00% em 1000Hz); pressão de pico variando de -150 a 180daPa; aumento do volume equivalente do meato acústico externo com aumento da frequência da sonda (0,64ml em 226Hz, 1,63mmho em 678Hz e 2,59mmho em 1000Hz); aumento do pico compensado da admitância acústica estática (0,51ml em 226Hz, 0,55mmho em 678Hz e 1,20mmho em 1000Hz). Foram classificados como normais 93,06% dos timpanogramas com 226Hz, 80,81% em 678Hz e 82,00% em 1000Hz. Conclusão: Por meio destas avaliações e resultados foi possível caracterizar as medidas de imitância acústica dos lactentes. Palavras-chave: audição, lactente, orelha média, testes de impedância acústica. Int. Arch. Otorhinolaryngol., São Paulo - Brazil, v.16, n.2, p. 186-194, Apr/May/June - 2012. 186 Multifrequency tympanometry in infants. Moraes et al. INTRODUCTION Hearing is the main source for speech and language skill acquisition in children with normal hearing ability. Hearing loss can cause delay in these skills, making the communication process more difficult. In infants, it is recommended that a complete hearing evaluation be performed with electrophysiological and electroacoustic measurements as well as behavioral methods. Acoustic immittance measurements are valuable tools for assessing middle ear changes, since detection is quick and objective. Characterized by the mechanical analysis of the auditory system in response to acoustic stimulation, acoustic immittance measures the acoustic energy transfer that occurs when sound pressure is applied to the tympanic membrane, which causes its movement. This type of assessment evaluates the ease or opposition to this sound energy flow within the auditory system. Multifrequency tympanometry emerged as a promising new method for the evaluation of middle ear conditions because it is fast, straightforward, noninvasive, objective, and more sensitive than conventional tympanometry (performed at a frequency of 226 Hz). Multifrequency tympanometry was developed because episodes of acute otitis media were not always detected by conventional tympanometry (1). Middle ear pathologies that are identified by conventional tympanometry are also identifiable by multifrequency tympanometry. However, conventional tympanometry may fail to detect middle ear pathologies that are correctly identified by multifrequency tympanometry, which is able to identify small changes in the middle ear acoustic mechanism. Some authors recommend the combination of conventional and multifrequency tympanometry in neonates, children, and adults (2-5). The tympanic-ossicular system behaves differently in children up to 2 years of age, as mass is the dominating physical feature and can be evaluated more efficiently at high frequencies (probe tones 678 Hz and 1,000 Hz). After this age, there is a change in behavior, reaching the adult stage, which is dominated by stiffness and is better evalu (...truncated)