Normative Values for the MicroTymp2
The normative values listed in Table 4 are taken from a study by Margolis
and Heller (1987), and from the “Guidelines for Screening for Hearing
Impairments and Middle Ear Disorders” (1990).
Table 4 — Normative Tympanometric Values
Tympanometric Child’s Ear Adult’s Ear
Measurement (Under Age 10) (Age 10 & Over )
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.
As the altitude above sea level increases, the admittance of a given volume
of air also increases. Therefore, equivalent ear canal volume (+200 Vea)
overestimates actual ear canal volume as noted in Table 5. To estimate
ear canal volume, subtract the appropriate value in Table 5 from the
MicroTymp 2 Vea Reading. Altitude can also affect MicroTest Cavity results.
Refer to Appendix D, “Functional Checks of the MicroTymp2 Handle and
Printer/Charger.”
Table 5 — Altitude Adjustments for Vea Readings
Altitude Adjustment Adjustment Adjustment Adjustment
for 0.5 cc for 1.0 cc for 1.5 cc for 2.0 cc
1280 ft 0.0 cc 0.0 cc 0.0 cc 0.1 cc
(390 m)
2530 ft 0.0 cc 0.1 cc 0.1 cc 0.2 cc
(770 m)
3220 ft 0.0 cc 0.1 cc 0.2 cc 0.3 cc
(980 m)
4757 ft 0.1 cc 0.2 cc 0.3 cc 0.4 cc
(1450 m)
A-28
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