Influence of ear side and gender on Distortion Product of normal hearing Iraqi population of age (21-30) years

Abstract

The goal of this study was to evaluate Distortion Product Otoacoustic emissions in the normal hearing subjects regarding to the following variables; ear side & gender. The purpose of this work is to study the influence of the ear side and gender on the distortion product Otoacoustic emission of normal hearing Iraqi population of age (21-30) years. The decision about whether a Distortion Product Otoacoustic Emission is present often depends on a visual assessment of the response along with certain objective criteria, such as DP1 level (amplitude) and the signal-to-noise ratio of the response compared to the noise. DPOAEs were considered present when the signal was at least 3 dB above the corresponding noise level. In the present study, the overall SNR for each tested ear was more than 3 dB SPL at the overall frequency bands. The findings from this study revealed an ear asymmetry and gender effect on the parameters of the DPOAEs (SNRs dB SPL

&DP1 level dB) in Iraqi subjects. Right ears were found to produce higher DPOAEs- SNRs than left ears and The DPOAEs (DP1 level dB) in the right ears was higher than that

in the left ears .The minimum value of the whole Signal-to-noise ratio (SNRs) recorded for all tested ears was above 3 dB SPL over frequency bands 0.5, 0.75, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0 and 8.0 kHz. The mean value of the whole SNRs in 56 ears was (10.53 dB SPL), ranged from 3.0 to 28.30 dB SPL. In females; the mean value of whole SNRs (11.27 dB SPL) was higher than that in males (9.8 dB SPL). The mean value of SNRs in the right ears female (11.38 dB SPL) was higher than that in the left ears female (11.16 dB SPL), while in male; the mean value of SNRs in the right ears male (10.08 dB SPL) was higher than that in the left ears male (9.52 dB SPL). The results show The minimum and the maximum value of the whole Distortion product (DP1 Level) recorded for all tested ears (56) was -10.7 and 25.6 dB respectively over frequency bands 0.5, 0.75, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0 and 8.0 kHz. The mean value of the whole DP1 level in 56 ears was (6.50 dB), ranged from (-10.7 to 25.6 dB). In females; the mean value of whole DP1 Level (7.72 dB) was higher than that in males (5.28 dB). The mean value of DP1 level in the right ears female (8.22 dB) was higher than that in the left ears female (7.23 dB), while in male; the mean value of DP1 level in the right ears male (5.58 dB) was higher than that in the left ears male (4.98 dB).