Sweep frequency impedance measures in young infants: developmental characteristics from birth to 6 months

Abstract

Objective: International Journal of Audiology To study the developmental characteristics of sweep frequency impedance (SFI) measures in healthy infants from birth to 6 months. Design: All infants were assessed using high-frequency tympanometry (HFT), distortion product otoacoustic emission (DPOAE) and SFI tests. SFI measures consisted of measurement of resonance frequency (RF) and mobility (ΔSPL) of the outer and middle ear. A mixed model analysis of variance was applied to the SFI data to examine the effect of age on RF and ΔSPL. Study sample: Study included 117 ears from 83 infants of different age groups from birth to 6 months. Results: The mean RF of the outer ear increased from 279 Hz at birth to 545 Hz at 4 months, whereas mean ΔSPL of the outer ear decreased from 7.9 dB at birth to 3.7 dB at 4 months of age. In contrast, the mean RF and ΔSPL of the middle ear did not change significantly with age up to 6 months. Conclusions: Developmental characteristics should be considered when evaluating the function of the outer and middle ear of young infants (≤6 months) using the SFI. The preliminary normative SFI data established in this study may be used to assist with the evaluation.

Key Words:

• Electrophysiology
• middle ear
• paediatric
• instrumentation
• sweep frequency impedance

Acknowledgements

The authors are thankful to two anonymous reviewers who critically reviewed the manuscript and provided necessary feedback. The authors are thankful to: Associate Professor Andrew Swanston, Director ENT department, Townsville Hospital and Health Service and Katrina Roberts, Nursing Director, Health and Wellbeing Service Group, Townville Hospital and Health Service for their support. The authors are also thankful to: Marissa Edmondson, Jewelie-Ann Wright, Rowena Lyons, Nicky Audas and Jackie Bunt from Health and Wellbeing Service Group; Sreedevi Aithal and Karen Nielsen from the Audiology Department for their assistance in the data collection; and Ben Mason, Biomedical Technology Service for calibration and maintenance of equipment.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article. This research was funded by the Healthy Hearing program, Private Practice Research and Education Trust fund, and QH Health Practitioners Research & Thesis writing grant. Part of this study has been presented at the Audiology Australia XXII National conference held in Melbourne, Australia from 22–25 May 2016.