Effect of ear canal pressure and age on wideband absorbance in young infants

Abstract

Objective: The study investigated the effect of ear canal pressure and age on wideband absorbance (WBA) in healthy young infants.

Design: Using a cross-sectional design, WBA at 0.25 to 8 kHz was obtained from infants as the ear canal pressure was swept from +200 to −300 daPa. Study sample: The participants included 29 newborns, 9 infants each at 1 and 4 months and 11 infants at 6 months of age who passed distortion product otoacoustic emissions test. Results: In general, negative-ear canal pressures reduced WBA across the frequency range, while positive-ear canal pressures resulted in reduced WBA from 0.25 to 2 kHz and above 4 kHz with an increase in absorbance between 2 and 3 kHz compared to WBA at ambient pressure. The variation in WBA below 0.5 kHz, as the pressure was varied, was the greatest in newborns. But, the variation was progressively reduced in older infants up to the age of 6 months, suggesting stiffening of the ear canal with age. Conclusions: Significant changes in WBA were observed as a function of pressure and age. In particular, developmental effects on WBA were evident during the first six months of life.

Key Words:

• Wideband tympanometry
• wideband absorbance
• tympanometry
• middle ear
• ear canal pressure

Acknowledgements

This study was supported by Healthy Hearing, Queensland Health. The authors thank Private Practice Research and Education Trust Fund and Health Practitioners Research grants; NAHSSS for providing a scholarship to the first author towards travel and presentation at conferences; Dr Andrew Swanston, Shirley Glennon, Healthy Hearing Programme and Institute of Women’s and Children’s Services at The Townsville Hospital, for their support towards the study; Katrina Roberts, Marissa Edmondson, Rowena Lyons, Jewelie-Ann Wright, Nicky Audas and Jackie Bunt for their help in data collection; Karen Nielsen for her help with administrative duties and data entry.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article