---

Background and Aim: One of the non-pathological factors affect otoacoustic emissions is body position. In the present study, the effect of side-lying position on evoked otoacoustic emission properties and related existing assumptions were investigated.

Methods: The cross-sectional study was performed on 42 adults aged 18-25 years. The results of Transient-evoked otoacoustic emissions (TEOAEs) test were recorded and analyzed in sitting, supine, and side-lying (Ipsi and Contra) positions to compare the total response level, whole wave reproducibility, signal to noise ratio in frequencies of 1 to 5 KHz, and the lasting time of the test.

Results: Changing of the body position had a significant effect on total response level, whole wave reproducibility, and lasting time of the test (p<0.010) while this effect on signal to noise ratio was just found at 1 KHz (p<0.001). The highest total response level and lowest lasting time of the test values were observed in side-lying (contra) position (p<0.050).

Conclusion: Side-lying position (contra) is the best position for the TEOAEs test. The results of this study partly confirm intracranial pressure change hypothesis that intracochlear fluid pressure increase in the auditory system although there are contradictions in this field.