Bilgehan Tekin Dal, Gülsüm Aydan Genç, Şule Çekiç, Riza Önder Günaydin
Our findings suggest that age-related changes affect middle-ear sound transmission. Although an association between absorbance and DPOAE SNR at 4 kHz was observed, evidence for a conductive contribution to age-related hearing loss remains inconclusive. Further research with larger samples and, ideally, longitudinal designs is needed to clarify the clinical significance of these findings and their potential diagnostic and rehabilitative implications.
OBJECTIVES: This study aimed to investigate age-related changes in middle-ear sound transmission using wideband acoustic immittance (WAI), distortion product otoacoustic emissions (DPOAE), and air-bone gap (ABG) measurements.
DESIGN: A cross-sectional study was conducted with 30 young adults (18 to 25 years) and 34 older adults (65 to 89 years), each meeting strict inclusion criteria for normal middle ear function. WAI measures, including resonant frequency, absorbance at ambient pressure, and at tympanometric peak pressure (TPP), were measured. DPOAE responses were evaluated at six frequencies (1000 to 6000 Hz), and ABG values were calculated from pure-tone audiometry. Correlation analyses were performed to examine associations between WAI parameters, DPOAE outcomes (signal to noise ratio [SNR] and DPOAE amplitude), and ABG values.
RESULTS: Compared with young adults, older adults showed higher absorbance at lower frequencies and lower absorbance at higher frequencies (at both ambient and TPP), together with lower resonant frequency. DPOAE SNRs and DPOAE amplitudes were significantly lower in older adults at all tested frequencies. Absorbance at ambient pressure and TPP was positively associated with DPOAE SNR only at 4 kHz. In addition, ABG values were significantly higher at 4000 Hz in older adults, while absorbance at ambient pressure and at TPP showed no significant correlation with ABG at any frequency.
CONCLUSIONS: Our findings suggest that age-related changes affect middle-ear sound transmission. Although an association between absorbance and DPOAE SNR at 4 kHz was observed, evidence for a conductive contribution to age-related hearing loss remains inconclusive. Further research with larger samples and, ideally, longitudinal designs is needed to clarify the clinical significance of these findings and their potential diagnostic and rehabilitative implications.