High frequency immittance for neonates: a normative study

Abstract

Conclusion. High frequency immittance measurements demonstrate promise in clarifying middle ear status for neonates but age-and gender-specific norms should be consulted. Objective. To describe high frequency immittance measurements using a 1000 Hz probe tone for a sample of 278 neonatal ears (0-4 weeks of age) in order to compile normative tympanometric and acoustic reflex criteria. Subjects and methods. Assessment of neonatal ears included 1000 Hz probe tone immittance measurements (tympanograms and ipsilateral acoustic reflexes), and distortion product oto-acoustic emission (DPOAE) screening. Results were compared and normative values were compiled for immittance measures in ears controlled for normal middle ear functioning (n=250). Results. Comparison of immittance results to OAE screening outcome provides estimates of sensitivity and specificity for middle ear fluid with tympanometry of 57% and 95%, and 57% and 90% for acoustic reflex presence, and 58% and 87% for combined tympanogram and acoustic reflex results, respectively. Normative data indicate that static peak admittance values differ significantly across gender and age with the 5th percentile cut-off value for the entire sample at 1.4 mmho. The 90% range of tympanic peak pressure normative values increases with increasing age from 140 daPa for neonates 1 week of age to 210 daPa for neonates 2-4 weeks of age. Acoustic reflexes were elicited at 93±9 dB with a 90% normality range of 80-105 dB.

Acoustic reflex on newborns: the influence of the 226 and 1,000 Hz probes

“…The occurrence of acoustic reflex at 50, 55, or 60 dB was higher with the 1,000 Hz probe. Lower ASRTs were also found (10,21,22) and were justified by the small size of the external auditory canal of newborns by vibration of the wall of the canal after a sound stimulus. However, it is worth to mention that the minimum intensity for the analysis of AR in the equipment is 50 dB NPS.…”

“…With the 1,000 Hz probe, the average was 74.2 dB for the 1,000 Hz frequency and 62.9 dB for 2,000 Hz (Table 1). A study (21) found a mean of 93 dB for the 1,000 Hz and two other studies (10,22) found means of 73.05 and 76.2 dB for 1,000 and 2,000 Hz, respectively. In the these studies, no other frequencies were analyzed.…”

“…In the literature studied, only a few studies focused on analyzing the acoustic reflex threshold with the 1,000 Hz probe. In 2007, authors (21) analyzed the data regarding ASRT in 267 ears, using 1,000 Hz pure tone stimuli, and the acoustic reflex threshold was considered as the lowest intensity in which there was a change in the admittance of at least 0.02 mmho. Based on this criterion, they found out that 94% of the ears had a mean acoustic Minimum 60 65 50 65 55 50 50 50 60 70 70 60 50 65 50 50 Maximum 95 100 100 100 95 95 95 95 100 100 95 90 100 100 100 100 5th percentile 65 65 50 65 60 50 50 50 60 70 70 60 50 65 55 50 95th percentile 95 100 100 100 95 95 85 90 100 100 95 90 100 100 95 reflex threshold of 93 dB and 90% between 80 and 105 dB HL.…”

Timpanometria em lactentes utilizando sonda multifrequencial

“…(19,20,26,28) Como visto na análise das demais variáveis, apenas um estudo(19) utilizando a frequência de 678Hz foi encontrado, indicando valores próximos aos aqui descritos. Na frequência de 1000Hz diversos estudos apresentaram valores de Ymt próximos aos descritos (12,15,25). O estudo mais recente encontrado foi de MAZLAN(41), que ao avaliarem neonatos, encontraram média de Ymt igual a 1,06mmho.…”

“…A avaliação adequada das condições da orelha média no período neonatal resulta em encaminhamentos adequados à equipe médica e audiológica, podendo levar à melhora da eficácia dos programas de triagem auditiva neonatal (15).…”