Tympanometry and ECV

Question 1

What is tympanometry

Answer 1

A test used to detect disorders of the tympanic membrane and the middle ear

Question 2

Origin of tympanometry

Answer 2

Tympanon- tympanic

Metrein - to measure

Question 3

What does tympanometry measure?

Answer 3

Pressure (the amount in the middle ear)

Compliance (amount of tympanic membrane movement)

Question 4

Type A tympanogram

Answer 4

Normal pressure (+50 to -100 daPa

Normal compliance(within 0.3 to 1.6 mm H2O or ml)

Question 5

When do we see a type A tympanogram?

Answer 5

Patients who have normal middle ear and tympanic membrane functions

Question 6

Type As tympanogram

Answer 6

Normal pressure (+50 to -100 daPa)
Low compliance (less than 0.3 mm H2O)

Question 7

Clinical presentation of As

Answer 7

Otosclerosis - the stapes has become partially or completely fixed or immobilized

Question 8

Type Ad tympanogram

Answer 8

Normal pressure (+50 to -100 daPa)
High compliance
More than 1.6 mm h2o or ml

Question 9

Clinical presentation ofAd

Answer 9

Atrophic scab, ossicular chain disarticulation

Question 10

Type C tympanogram

Answer 10

Negative pressure more negative than -100 daPa 
Normal compliance (0.3 - 1.6 mm h2o

Question 11

Clinical presentation of type C tympanogram

Answer 11

Eustachian tube dysfunction

Question 12

Type B tympanogram

Answer 12

Tracing is flat or with no discernible peak

Question 13

Clinical presentation of type B tympanogram

Answer 13

Otitis media with effusion
Tympanic membrane perforation
Tympanostomy tube
Atelectasis
Earwax
Probe sealed against the external ear canal wall

Question 14

Ear canal volume

Answer 14

Measurement of the volume of air medial to the probe

Volume between probe tip and tympanic membrane

Question 15

Normal Ear canal volumes

Answer 15

Children 0.3 - 0.9

Adult 0.9 -2.0

Question 16

Type B tympanogram + normal ear canal volume

Answer 16

Middle ear with effusion

Question 17

Type B tympanogram + large ear canal volume

Answer 17

Tympanostomy tube or tympanic membrane perforation

Question 18

Why does a perforation lead to a large ECV?

Answer 18

ECV is now an estimate of the volume of air in the external ear canal and the middle ear

Question 19

Type B tympanogram + small ECV

Answer 19

Earwax that blocks the external auditory canal

Question 20

Benefit of tympanometry and ear canal volume

Answer 20

Don’t require behavioural responses

Useful in diagnosis of tympanic membrane and middle ear diseases