Effect of ear canal pressure and age on wideband absorbance in young infants
Sreedevi Aithal1,2, Venkatesh Aithal1,2, Joseph Kei2
1a Department of Audiology , The Townsville Hospital , Queensland , Australia and.
Insights
Ear canal pressure significantly impacts wideband absorbance (WBA) in infants. WBA changes with pressure decrease, and ear canal stiffening is observed in infants up to six months old.
Area of Science:
- Audiology
- Infant Hearing Development
- Bioacoustics
Background:
- Wideband absorbance (WBA) measures the ear canal's acoustic impedance.
- Understanding WBA in infants is crucial for early hearing assessments.
- Infant ear canal properties change significantly during the first year of life.
Purpose of the Study:
- To investigate how ear canal pressure affects WBA in healthy infants.
- To determine the influence of infant age on WBA across different ear canal pressures.
- To characterize the developmental changes in infant ear canal acoustics.
Main Methods:
- Cross-sectional study design.
- WBA measurements from 0.25 to 8 kHz.
- Ear canal pressure varied from +200 to -300 daPa.
- Participants: newborns to 6-month-old infants (N=58) who passed DPOAEs.
Main Results:
- Negative ear canal pressure generally reduced WBA across frequencies.
- Positive ear canal pressure altered WBA, with specific increases between 2-3 kHz.
- Infants showed greater WBA variation with pressure at birth, decreasing with age, indicating ear canal stiffening.
Conclusions:
- Significant pressure and age-dependent changes in infant WBA were observed.
- Developmental effects on WBA are prominent within the first six months of life.
- Findings suggest progressive stiffening of the infant ear canal with age.
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.
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