Tympanometry Flashcards
Impedance:
Admittance:
- The opposition of the flow of sound energy
- The ease of sound flow
If sound pressure level is high, admittance is _
If sound pressure level is low, admittance is _
If sound pressure level is high, admittance is low
If sound pressure level is low, admittance is high
What is acoustic immittance measuring?
The mobility of the TM in response to air pressure (tympanometry) or in response to loud sound (acoustic reflex)
What are the 3 components of typanometry?
Static compliance (admittance)
Peak pressure
Ear Canal Volume
Acoustic transmission (sound traveling through TM) is most efficient when:
Air pressure in the middle ear cavity is the same as ambient pressure
If there is an increase or decrease of ear canal pressure relative to ambient pressure, acoustic transmission is:
Less efficient (less compliant)
In tympanometry, initially start with a positive air pressure at:
+200 daPa
The more positive or negative pressure that is introduced, the more _ the TM becomes
Stiff
On a tympanogram, the x-axis is:
Units of air pressure in daPa
On a tympanogram, the y-axis is:
Compliance in mmho
What is the normal range for static compliance?
What is the normal range for peak admittance?
What is the normal range for ear canal volume?
Static compliance: 0.3 - 1.7 mmho
Peak admittance: -100 to +100 daPa
ECV: 0.9 to 2 cc
Peak admittance is when the TM is:
Maximally compliant
Type A tympanogram is when:
Peak admittance is at ambient pressure and the static admittance is normal
Type B tympanogram is when:
What might cause type B?
There is no peak pressure in the tympanogram aka no point when the TM is mobile (completely stiff) Causes: Normal ECV = Otitis media Smal ECV = Impacted cerumen Large BCV = Perforation or open PE tube
Type C tympanogram is when:
What might cause type C?
Peak compliance is negative and the pressure in the middle ear is negative (peak pressure is less than -100 daPa)
Cause: Going up in an airplane
