title: Multifrequency tympanometry in infants.
abstract: BACKGROUND
  The use of conventional tympanometry is not sufficiently sensitive to detect all cases of middle ear changes, and this hinders accurate diagnosis.
  
  
  OBJECTIVE
  To characterize acoustic immittance measures of infants from 0 to 3 months of age using multifrequency tympanometry in a prospective study.
  
  
  METHODS
  54 infants from 0 to 3 months of age were evaluated. The inclusion criteria included absence of respiratory infections during the evaluation, presence of transient evoked otoacoustic emissions, and absence of risk indicators for hearing loss. The subjects were evaluated by an audiologic interview, a visual inspection of the ear canal, and measures of acoustic immittance at the frequencies of 226 Hz, 678 Hz, and 1,000 Hz. Tympanometric records of the occlusion effect, tympanometric curve type, tympanometric peak pressure, equivalent ear canal volume, and peak compensated static acoustic admittance were collected.
  
  
  RESULTS
  The results indicated the presence of an occlusion effect (2.88% at 226 Hz, 4.81% at 678 Hz and 3.85% at 1,000 Hz), predominance of a tympanometric curve with a single peak (65.35% at 226 Hz, 81.82% at 678 Hz, and 77.00% at 1,000 Hz), and tympanometric peak pressure ranging from -155 to 180 daPa. Further, the equivalent ear canal volume increased with the frequency of the probe (0.64 mL at 226 Hz, 1.63 mho at 678 Hz, and 2.59 mmho at 1,000 Hz) and the peak compensated static acoustic admittance values increased with an increase in frequency (0.51 mL at 226 Hz, 0.55 mmho at 678 Hz and 1.20 mmho at 1,000 Hz). 93.06% of the tympanograms were classified as normal at 226 Hz, 81.82% at 678 Hz, and 77.00 % at 1,000 Hz, respectively.
  
  
  CONCLUSIONS
  Taken together, these results demonstrated that utilizing these evaluations made it possible to characterize the acoustic immittance measures of infants.
authors.affiliation: Master of Science. Resident Speech Therapist for Multidisciplinary Residency Program of Rehabilitation Craniofacial Anomalies Hospital of Universidade de São Paulo /Sao Paulo University.
authors.forename: Tamyne Ferreira Duarte
authors.initials: TF
authors.lastname: de Moraes
authors.affiliation: Master of Rehabilitation Science.Student for Post-Graduation Program of Rehabilitation Craniofacial Anomalies Hospital of Universidade de São Paulo/Sao Paulo University.
authors.forename: Camila de Cássia
authors.initials: Cde C
authors.lastname: Macedo
authors.affiliation: Entitled Professor. Entitled Professor for Speech Therapy Department FOB/USP.
authors.forename: Mariza Ribeiro
authors.initials: MR
authors.lastname: Feniman
keywords: acoustic impedance tests; hearing; infant; middle ear