Age effect on wideband absorbance in people with normal middle ear function: a systematic review

OBJECTIVE: To explore the influence of age on wideband energy absorbance (EA), measured via Wideband Acoustic Immittance, by synthesising normative data across a wide age range. DESIGN: A systematic review was conducted to combine normative WAI data from 30 eligible publications. EA values at ambient pressure were analysed across different frequencies for eight age-based groups, spanning neonates to individuals aged 80 years. STUDY SAMPLE: The review collectively analysed data from 6,630 ears with normal middle ear conditions, involving 4196 individuals spanning ages from neonates to 80 years. RESULTS: The combined EA values, averaged across different frequencies at ambient pressure, ranged from 0.403 to 0.581 across the eight age groups. The highest EA level was observed in individuals younger than 6 months, while the 6- and 12-month age groups exhibited the lowest average EA. A trend of increasing EA values was noted as age progressed beyond 12-months, peaking between ages 10-13 years, followed by a decline in individuals older than 13-years. Frequency-specific analyses revealed significant differences in EA values at octave frequencies between 0.25 kHz and 8.0 kHz, particularly at 1.0 and 4.0 kHz. CONCLUSION: These findings highlight the importance of age-specific norms in clinical practice to ensure accurate interpretation and diagnosis.