If the numeric values are greater or less than the 90th percentile of the
normative data for a child or an adult, an asterisk appears under the C(hild)
or A(dult) column. The normative data are listed in Table 1 below.
For some tympanometric results, no data will be printed. These occasions are:
• Peak Ya is greater than 1.5 mmhos. The message “High Peak Ya” will
appear at the top of the tympanogram.
• Peak Ya less than 0.3 mmhos.
• Peak Ya which is incomplete; for example, a negative pressure
tympanogram which is so far negative that the peak has not been
reached and data are incomplete.
• Tympanogram has too much artifact. Artifact is generally caused by
movement of the subject or the instrument.
Table 1 — Normative Tympanometric Data
Tympanometric Child’s Ear Adult’s Ear
Measurement (Under Age 10) (Over Age 10)
90% Range 90% Range
Peak Ya 0.2 to 0.9 mmho 0.3 to 1.4 mmho
Gradient (GR)
(Tympanometric Width) 60 to 150 daPa 50 to 110 daPa
Tympanometric
Peak Pressure (TPP) -139 to +11 daPa -83 to 0 daPa
Equivalent Ear Canal
Volume (Vea) 0.4 to 1.0 cc 0.6 to 1.5 cc
NOTE: For purposes of tympanometric norms, an adult is
defined as a person 10 years of age or older, and a child as
under age 10.
Normative data are taken from a study by Margolis and Heller
(1987), and from the “Guidelines for Screening for Hearing
Impairments and Middle Ear Disorders” ASHA (1990).
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