title: Evaluation of middle ear function in young children: clinical guidelines for the use of 226- and 1,000-Hz tympanometry.
abstract: OBJECTIVE
  The aims of the study were to evaluate tympanometry with regard to age and classification system using two probe-tone frequencies and to provide clinical guidelines.
  
  
  METHODS
  Six subject groups were included in the evaluation: (1) neonatal intensive care unit babies, (2) children younger than 3 months, (3) children 3 to 6 months old, (4) children 6 to 9 months old, (5) children 9 to 32 months old, and (6) adults. Hearing of all subjects was screened by means of auditory brainstem responses, transient-evoked otoacoustic emissions, or behavioral audiometry. Tympanograms, recorded with probe-tone frequencies of 226 and 1,000 Hz, were classified according to shape and middle ear pressure. Additionally, 1,000-Hz tympanograms were classified based on the Vanhuyse model of tympanometric shapes. Furthermore, tympanometric parameters equivalent ear canal volume, admittance value at +200 daPa, middle ear admittance, tympanometric peak pressure, and tympanometric width were calculated for each tympanogram.
  
  
  RESULTS
  For clinical purposes, the visual admittance classification system was more suitable than the Vanhuyse model. Furthermore, in children younger than the age of 3 months, 1,000-Hz tympanometry was easier to interpret and more reliable than 226-Hz tympanometry. From the age of 9 months, 226-Hz tympanometry was more appropriate. In children between 3 and 9 months, the reliability of tympanometry was independent of probe-tone frequency. A two-stage evaluation with a 1,000- to 226-Hz tympanometry sequence was preferred because this reduced the total number of tests.
  
  
  CONCLUSIONS
  The current study provides normative data and age-related guidelines for the use of tympanometry in clinical practice. These results have led to a successful implementation of 1,000-Hz tympanometry in neonatal hearing assessment.
authors.affiliation: ExpORL, Department Neurosciences, K.U.Leuven, Leuven, Belgium. Jane.Alaerts@med.kuleuven.be
authors.forename: Jane
authors.initials: J
authors.lastname: Alaerts
authors.forename: Heleen
authors.initials: H
authors.lastname: Luts
authors.forename: Jan
authors.initials: J
authors.lastname: Wouters
mesh_terms: D000158:Acoustic Impedance Tests / Q000145:classification / Q000592:standards*; D000161:Acoustic Stimulation; D000328:Adult; D000375:Aging / Q000502:physiology; D000465:Algorithms; D001309:Auditory Threshold / Q000502:physiology; D001519:Behavior; D002675:Child, Preschool; D004424:Ear Canal / Q000033:anatomy & histology; D004432:Ear, Middle / Q000502:physiology*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology; D012016:Reference Values