What are the characteristics of a type A tymp?
Peak Admittance
- Between (and including) 0.3 to 1.4
Peak Pressure
- Greater then or equal to -100 daPa
Canal Volume
- 0.6 - 1.5
What are the characteristics of a type C tymp?
Peak Admittance
- Classified as deep or shallow if it falls outside the normal range
Peak Pressure
- <-100 daPa
Canal Volume
- 0.6 - 1.5
Causes: abnormally negative peak pressure, Eustachian tube dysfunction
What are the characteristics of a type B tymp?
Peak Admittance
- No clear peak
Peak Pressure
- n/a
Canal Volume
- n/a
What are the characteristics of a type B-low tymp?
Peak Admittance
- No clear peak
Peak Pressure
- n/a
Canal Volume
- <1.5
Causes: otitis media, occluding cerumen
What are the characteristics of a type B-high tymp?
Peak Admittance
- No clear peak
Peak Pressure
- n/a
Canal Volume
- > 1.5
Causes: Perforated ear drum, patent grommet
What are the characteristics of a type A-deep tymp?
Peak Admittance
- Greater than 1.4
Peak Pressure
- Greater then or equal to -100 daPa
Canal Volume
- 0.6 - 1.5
Causes: flaccid or hypermobile ear system, ossicular discontinuity
What are the characteristics of a type A-shallow tymp?
Peak Admittance
- Less than 0.3
Peak Pressure
- Greater then or equal to -100 daPa
Canal Volume
- 0.6 - 1.5
Causes: stiffness dominated (otoscelerosis, tympanosclerosis)
What is the passing criteria for DPOAEs?
Present in 4/5 frequencies between 1.5 - 6 kHz
Responses need to be:
~ SNR ≥ 6 dB
~ or 5 dB if adjacent frequency passed at 6 dB
~ Absolute amplitude ≥ -5 dB
What is the step masking rule for air-conduction?
AC (non-test ear) + 30
If threshold shifts by 20 or more, add extra 20 dB of masking
What is the step masking rule for bone conduction?
AC (non-test ear) + 30 + OE
Supra OE Values:
500 = 20
1000 = 10
Insert OE Values:
500 = 10
1000 = 0
If threshold shifts by 20 or more, add extra 20 dB of masking
What is the plateau masking method for air conduction?
AC (non-test ear) + 10
Proceed with the plateau masking method
What is the plateau masking method for bone conduction?
AC (non-test ear) + 10 dB + OE
Supra OE Values:
500 = 20
1000 = 10
Insert OE Values
500 = 10
1000 = 0
Proceed with plateau masking method
What is the IAA values for speech audiometry?
Supra / shallow insert = 40 dB
Deep inserts = 50 dB
What is the process for speech masking?
Mask if:
PL (test ear) - IAA ≥ best BC (non-test ear)
Masking level:
PL (test ear) - IAA + biggest ABG (non-test ear) + 10
