Impedance audiometry is an objective and quick test useful in diagnosing conductive deafness and evaluating Eustachian tube function, particularly in pediatric patients. The procedure includes tympanometry and measures changes in middle ear impedance based on air pressure variations at the tympanic membrane. Key metrics include normal ranges for static compliance (0.35 to 1.40 ml) and pressure (-50 to +50 mm of water).

1. Impedance
Audiometry
DR SAFIKA ZAMAN
DEPT OF ENT
RKMSP

2. Advantage
 Objective test
 Quick
 Possible in paediatric patients

3. Uses
 Differential diagnosis in cases of conductive deafness
 Evaluation of ET function
 Identification of site of lesions in facial paralysis

4. Impedance
audiometry
 Tympanometry
 Stapedial test
 Eustachian tube function test

5. Impedance
 Impedance of the medium –Complex mixture of 3 parameters
stiffness, mass , friction .
 Middle ear acts as the impedance matching device
 All middle ear pathologies alter this impedance , results in lesser
sound energy being transmitted to the cochlear fluid.

6. Tympanometer

7. Probe
1.Sound
aperture
2.Microphone
3.Manometer

8. Definition of
Tympanometry
 Change in the impedance of the middle ear at the plane of the
tympanic membrane as a result of changes in air pressure in the
external auditory meatus.
Source – ClinicalAudio-Vestibulometry,Anirban Biswas

9. Tympanogram
example

10. Normal Range
 Normal range of static compliance is – 0.35 to 1.40 ml
 Normal pressure is – 50 to +50 mm of water pressure

11. Positive and
negative tail of
tympanogram
Source – ClinicalAudio-Vestibulometry,Anirban Biswas

12. Source – ClinicalAudio-Vestibulometry,Anirban Biswas

13. Source – ClinicalAudio-Vestibulometry,Anirban Biswas

14. Jerger’s
classification

15. Strain, George & Fernandes, Asia. (2015). Handheld tympanometer measurements in conscious dogs for the
evaluation of the middle ear and auditory tube. Veterinary Dermatology. 26. 10.1111/vde.12195.

16. William`sTest
(Eustacchian
tube function
test)

17. Toynbee`sTest
(Eustachian
tube function
test in
perforated
drum )

18. Acoustic
ReflexTest