Influence of tympanic membrane changes on audiometric and immittance findings in school-aged children

[Influence of tympanic membrane changes on immittance and extended frequency audiometric findings]

INTRODUCTION

The aim of the study is to analyze the relationship between otoscopic tympanic membrane abnormalities, results of impedanace and extended-high-frequency audiometry in subjects with history of treatment of secretory otitis media (SOM) and ventilation tube insertion.

MATERIAL AND METHODS

97 subjects treated because of SOM were examined in years 1999-2000. Videootoscopic examinations, extended-high-frequency audiometry and tympanometry with ispilateral acoustic reflex were performed in each patient. The results were analysed in three groups: no otoscopic abnormalities (BZO), retraction pockets (KR) and atrophy and myringosclerosis (AM). The results were compared to otologicaly healthy control group in the same age.

RESULTS

The most common tympanic membrane abnormality were focal atrophy (64.7%) of ears and myringosclerosis (37.2%). Mean pure-tone audiometric threshold were significantly higher in groups KR and AM than in control and BZO groups. Low degree of positive correlation was found between the presence of myringosclerosis and atrophy and audiometric thresholds above 1 kHz. No such correlation was observed with the presence of retraction pockets. In the BZO group middle ear admittance was observed significantly higher than in control group. The absent ipsilateral stapedial reflex was observed in 10.8% ears in BZO group, 16.9% in AM and 33.3% in KR. No correlation was found between the parameters of tympanometric evaluation and results of extended-high-frequency audiometry.

CONCLUSIONS

In ears treated because of SOM with ventilation tube insertion the middle ear compliance is higher. In the presence of myringosclerosis and atrophy higher audiometric thresholds are observed. Tympanic membrane abnormalities have been more clearly indicated by the absent ipsilateral stapedial reflex than tympanometry.

Stapedial Reflex and Ears With High Static Acoustic Admittance

Purpose

To evaluate modified acoustic reflex diagnostic protocols for a group of individuals ( n = 9) with high peak compensated static acoustic admittance (Y tm ) tympanograms.

Method

A modified procedure designed to improve acoustic stapedius reflex threshold (ASRT) measurements in individuals with high-admittance tympanograms was employed in both an experimental and a control group. ASRTs were measured at 0.5, 1.0, and 2.0 kHz, ipsilateral and contralateral. Measurements were obtained within each condition for 7 ear canal pressures that were set to 0, ±50, ±100, and ±150 daPa (relative to tympanometric peak pressure [TPP]).

Results

Though measuring ASRTs at −50 daPa (relative to TPP) in the high-admittance and normal groups did not result in significantly better thresholds than at TPP, the absent reflex rate was reduced when the ear canal pressure was changed by −50 daPa during ASRT measurements.

Conclusions

Based on this sample, it is suggested that a patient presenting with high peak compensated static acoustic admittance (peak Y tm ≥ 2.1 mmho) undergo ASRT evaluation with the ear canal pressure set to −50 daPa (relative to TPP).