Gender differences among newborns on a transient otoacoustic emissions test for hearing.

The purpose of this study was to examine gender differences with regard to cochlea sensitivity as measured by the transient evoked otoacoustic emissions hearing screening procedure. During this test, a sudden burst of sound is presented at between 78 and 83 dB SPL which stimulates the entire basilar membrane. This in turn excites the outer hair cells in the cochlea and causes an echo-type response which is recorded by a microphone in a probe placed in the ear canal. This test is used to screen for peripheral hearing loss. Subjects ( N = 350) for this project were healthy, full-term newborns (38-42 weeks gestation) in the first 48 hours of life who had bilaterally passed the transient evoked otoacoustic emissions (TEOAE) screening test. Male (n = 170) and female (n = 180) infants were selected randomly from all babies born during a 3-month period who met the criteria at a large birthing hospital. Responses to TEOAE stimuli were recorded at 1.6 kHz, 2.4 kHz, 3.2 kHz, and 4.0 kHz. The responses were recorded as decibel levels indicating a signal-to-noise ratio. These decibel levels were used in a three-way ANOVA with repeated measures comparing gender, ear, and frequency level. Results indicated significant differences due to gender (female hearing more sensitive than male) and frequency (least sensitive hearing recorded at 1.6 kHz, most sensitive hearing recorded at 3.2 kHz). A significant two-way interaction indicated that differences in hearing sensitivity between genders increased as the frequency increased.