What is admittance in tympanometry?

Physics of the Tympanogram The tympanometer measures the “admittance” or “compliance” of the tympanic membrane while different pressures are being applied to the external ear canal. The compliance of the TM is measured in cubic centimeters, and the pressure in the ear canal is measured in decapascals (daPa).

What type of tympanogram is produced when there is ome or cerumen impaction?

If the ear canal volume is abnormally small and a Type B tympanogram is observed, this is suggestive of blockage of the ear canal because of cerumen impaction. If the ear canal volume is abnormally large and the tympanogram is peakless, this is a sign of a perforation in the tympanic membrane.

What does a Type C tympanogram mean?

negative pressure
Type C tympanograms (Figure 3) are still shaped like a teepee, but are shifted negatively on the graph. This indicates negative pressure in the middle ear space, often consistent with sinus or allergy congestion, or the end-stages of a cold or ear infection.

What can causes Type B tympanogram?

Type “B” tympanogram pattern is not diagnostic of middle ear effusion. The same pattern can also be caused when the probe tip hole is occluded by cerumen or by contact with the canal wall. A type “B” pattern will also occur when there is a perforation in the TM, including a tympanostomy tube.

What is admittance in audiology?

Admittance is measuring the ease at which energy (sound) flows through the system (ear). Admittance (Y) is a measurement taken at the plane of the tympanic membrane and is made up of two components: susceptance (B) and conductance (G).

What is admittance testing?

Admittance testing checks for abnormal admit- tance by injecting an audio frequency into the secondary of an in service transformer, and de- tecting the circuit admittance. Admittance (Y) is the inverse of impedance (Z) and is typically shown as mS (miliSiemens).

What are types of tympanogram?

Tympanogram tracings are classified as type A (normal), type B (flat, clearly abnormal), and type C (indicating a significantly negative pressure in the middle ear, possibly indicative of pathology).

How do you describe TM?

A normal TM is a translucent pale gray. An opaque yellow or blue TM is consistent with MEE. Dark red indicates a recent trauma or blood behind the TM. A dark pink or lighter red TM is consistent with AOM or hyperemia of the TM caused by crying, coughing, or nose blowing.

Why is tympanometry 226 Hz?

The most commonly used probe tone has been 226Hz. This probe tone has some definitive advantages when testing the adult ear. That’s because the adult middle ear system is stiffness-dominated (compliance) at this frequency and the effects of mass and friction are minor.

What is presbycusis caused by?

Presbycusis is usually a sensorineural hearing disorder. It is most commonly caused by gradual changes in the inner ear. The cumulative effects of repeated exposure to daily traffic sounds or construction work, noisy offices, equip- ment that produces noise, and loud music can cause sensorineural hearing loss.

What is Hypercompliant tympanic membrane?

Hypercompliant tymp on the left side due to a floppy eardrum. When the eardrum is floppy, perhaps due to overly exhuberant ear popping or a break in the ossicular chain, then less sounds is reflected back and the tympanogram looks “peaked” (see above).