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Transcutaneous Microcirculatory Imaging in Preterm Neonates
Published on: December 31, 2015
Normative reflectance and transmittance measurements on healthy newborn and 1-month-old infants
Gabrielle R Merchant1, Nicholas J Horton, Susan E Voss
1Smith College, Northampton, Massachusetts 01063, USA.
Insights
Wideband reflectance (WBR) measurements show minimal differences in middle-ear power reflectance and transmittance between newborn and 1-month-old healthy infants. These objective measures are largely consistent across early infant development and sexes.
Area of Science:
- Audiology
- Pediatric Medicine
- Bioacoustics
Background:
- Objective assessment of middle ear function in infants is crucial for early detection of hearing impairments.
- Ear-canal-based wideband reflectance (WBR) offers a non-invasive method for evaluating middle ear status.
Purpose of the Study:
- To compare power reflectance and transmittance in healthy newborn (3-5 days) and 1-month-old (28-34 days) infants.
- To characterize the range of WBR measures in normal infant populations.
- To determine variations in WBR based on age, gender, and ear side.
Main Methods:
- WBR measurements of power reflectance and transmittance were collected from 12 ears of newborns and 19 ears of 1-month-old infants.
- Statistical analyses included permutation tests, t tests, and random effects regression models.
- Factors analyzed were age, gender, and ear side (left vs. right).
Main Results:
- No significant differences in power reflectance and transmittance were found between newborns and 1-month-olds overall.
- A potential age-related difference was noted near 2000 Hz.
- Small, significant differences were observed between left and right ears in specific frequency bands (500-4000 Hz).
Conclusions:
- Middle ear power reflectance and transmittance are largely indistinguishable between healthy newborns and 1-month-olds.
- Gender does not significantly impact these WBR measures.
- Minor ear-side differences exist, but WBR is a reliable objective measure for infant middle ear assessment across early development.
Objective:
Ear-canal-based wideband reflectance (WBR) measurements may provide objective measures to assess and monitor middle-ear status in young babies. This work presents WBR measurements of power reflectance and transmittance on populations of healthy newborn babies (3 to 5 days) and healthy 1-mo-old babies (28 to 34 days). Thus, this work determines how power reflectance and transmittance vary between newborn and 1-mo-old babies and characterizes the range of these measures in normal populations.
Design:
Power reflectance and transmittance were calculated from pressure measurements made in the ear canals of seven newborn (12 ears) and eleven 1-mo-old (19 ears) babies. Permutation tests, t tests, and regression (random effects) models were used to test the effects of age (newborn versus 1 mo), gender, and ear side (right versus left).
Results:
The power reflectance and transmittance did not differ significantly for the age comparison (newborn versus 1 mo), although the results suggest a possible difference between newborn and 1-mo-old ears near 2000 Hz. There were no differences between the male and female ears. There are small but significant differences between left and right ears in three frequency bands encompassing 500 to 4000 Hz, where the predicted power reflectance mean for the left ear differs from the right ear by 0.02 to -0.07 depending on the frequency band.
Conclusions:
At most frequencies, power reflectance and transmittance are indistinguishable for newborn and 1-mo-old healthy babies, with limited or no differences between the two age groups and the males and females. There were small differences in some frequency bands for left and right ears. The measurements made here are similar to other published results in some frequency ranges but differ in other frequency ranges; differences among other studies from neonatal intensive care unit babies, healthy newborn babies, and healthy 1-mo-old babies are discussed.
