Influence of age on Distortion Product of normal hearing Iraqi subjects

Abstract

The purpose of this work is to study the influence of the age, ear side and gender on the distortion product Otoacoustic emission for normal hearing subjects. 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 dB and SNR dB SPL (signal to Noise Ratio). 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 age, ear asymmetry and gender effect on the DPOAEs (DP1 level dB) for all subjects groups. Right ears were found to produce higher DPOAEs (DPI level dB) than left ears and The DPOAEs (DP1 level dB) in the females was higher than that in males and also (DPI Level dB) in group I (2-10) years was higher than that in other groups, in group II (11-20) years (DPI Level) was higher than in groups III&IV and in groups III (DPI Level dB) was higher than that in group IV. The results show the minimum and the maximum value of the whole Distortion Product (DP1 Level) recorded for all tested (212) ear was (-3.65dB) and (20.39dB) respectively over frequency bands 0.5, 0.75, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0 and 8.0 kHz.