title: Normative reflectance and transmittance measurements on healthy newborn and 1-month-old infants.
abstract: 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.
  
  
  METHODS
  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.
authors.affiliation: Smith College, Northampton, Massachusetts 01063, USA.
authors.forename: Gabrielle R
authors.initials: GR
authors.lastname: Merchant
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Horton
authors.forename: Susan E
authors.initials: SE
authors.lastname: Voss
mesh_terms: D001299:Audiometry / Q000379:methods; D002657:Child Development / Q000502:physiology*; D004424:Ear Canal / Q000254:growth & development / Q000502:physiology*; D004432:Ear, Middle / Q000254:growth & development / Q000502:physiology*; D005260:Female; D006309:Hearing / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008954:Models, Biological; D015997:Neonatal Screening / Q000379:methods*; D010034:Otitis Media with Effusion / Q000175:diagnosis / Q000503:physiopathology; D011312:Pressure; D012016:Reference Values; D013017:Sound Localization / Q000502:physiology