| This study examined the effect of middle ear aging in adults using wideband acoustic immittance (WAI) measures. WAI and traditional 226 Hz tympanometry were measured in 25 young adult ears (ages 18-25) and 26 older adult ears (ages 50-71) with normal middle ear status. While minimal differences between older and younger adults were observed with 226 Hz tympanometry, significant age effects were seen with WAI measures. The older adults demonstrated a statistically significant increase in middle ear absorbance at lower frequencies (226-1,260 Hz) and decreased absorbance at higher frequencies (4,000-5,040 Hz) compared to the younger adult group. While the effect of age on WAI was the primary focus of this study, other factors such as ear canal volume and sex influence WAI measures in addition to age. This study also examined the relationship between WAI and distortion product otoacoustic emissions at f2= 1,000, 2,000, and 4,000 Hz in 50 ears from both the age groups. A statistically significant relationship between WAI magnitude and DPOAE magnitude, independent of pure tone threshold sensitivity, was observed at 4,000 Hz. Findings from this study demonstrated an age effect in middle ear transfer function and a potential for WAI to assist with DPOAE interpretation. This study further contributes to the emerging research that suggests a conductive component to the aging auditory system. |
