Gender Difference in TEOAEs and Contralateral Suppression of TEOAEs in Normal Hearing Adults

Objectives: Otoacoustic emissions (OAEs) are sounds that originate in cochlea and are measured in external auditory canal and provide a simple, efficient and non-invasive objective indicator of healthy cochlear function. Olivo cochlear bundle (OCB) or auditory efferent system is a neural feedback pathway which originated from brain stem and terminated in the inner ear and can be evaluated non-invasively by applying a contralateral acoustic stimulus and simultaneously measuring reduction of OAEs amplitude. In this study gender differences in TEOAE amplitude and suppression of TEOAE were investigated. Methods: This study was performed at Akhavan rehabilitation centre belonging to the University of Social welfare and rehabilitation sciences, Tehran, Iran in 2011. 60 young adults (30 female and 30 male) between 21 and 27 years old (mean=24 years old, SD=1.661) with normal hearing criteria were selected. Right ear of all cases were tested to neutralize side effect if there is any. Results: According to Independent t-test, TEOAE amplitude was significantly greater in females with mean value of 24.98 dB (P<0.001) and TEOAE suppression was significantly greater in males with mean value of 2.07 dB (P<0.001). Discussion: This study shows that there is a significant gender difference in adult’s TEOAE (cochlear mechanisms) and TEOAE suppression (auditory efferent system). The exact reason for these results is not clear. According to this study different norms for males and females might be necessary.