Methods and Materials:This cross - sectional analytical study examines the clinical utility of the external ear resonance (EER) peak amplitude measurement as an index of the possible middle ear effusions. The EER peak amplitude and frequency of 180 ears in 98 children of 7-9 years old were recorded. 120 of them (30 girls & 30 boys) had normal hearing and showed type A tympanograms. The remomder (60 ear of 38 boys) showed type B tymoanograms. These children were examined at the clinic of audiology department, rehabilitation faculty, Tehran University of medical sciences and health services, year 1376 hijri.The tests included: 1) Otoscopy, 2) Pure tone air - condition test, 3)Tympanometry and 4) E.E.R peak amplitude and frequency measurement through test - retest.
Results: 1- The average of E.E.R peak frequency for normal hearing girls, normal hearing boys and hearing impaired boys is 3206 Hz (SD=564), 3202 Hz (SI)- 634) and 2953 (SD=37l) respectively.
2- The average of E.E.R peak amplitude is 16.0 dB SPL (SD=2.6), 16.6 dB SPL (SD= 3.0) and 23.5 dB (SD=3.0) for normal hearing girls, normal hearing boys and hearing impaired boys respectively.
3- The correlation of the mean of E.E.R peak amplitude and frequency for two normal groups, girls and boys, is not significant (p>0.0l).
4- The mean test/retest variability in the E.E.R peak amplitude is 16.0 dB SPL and 3.1 Hz for frequency. These results indicate high validity and consistency of E.E.R characteristics measurements.
5- E.E.R peak amplitude is significantly ccre1ated with the presence of type B tympanogram (p-0.00) we find a 6.9 dB SPL increase in average E.E.R peak amplitude in boys with type B tympanograms in comparison to boys with
type A results but correlation of average E.E.R peak frequency of two groups is significant too (p=0.00).
* The results are valid only within the context of this research.
* The results of this research have been compared with similar studies in abroad.