Lecture 6

Question 1

Out of the types of receivers, which will have the higher OE and why?

Answer 1

Supra-aural = more space = higher OE; more space to amplify sound = bigger effect.
Inserts are better/preferable to supra-aural.

Overcome the OE by what is created with the transducer - creating extra problem as a result.

Question 2

When do you mask for BC?

Answer 2

When the air-bone gap of the TE is bigger than 10 dB, masking is needed for BC in the NTW.

Question 3

Why is the gap greater than 10dB?

Answer 3

Figuring out what type of hearing loss, conductive or sensorineural. If it exceeds 10dB - conductive component - is it actually there? MASK to find out

Question 4

How do you establish the starting level for BC masking?

Answer 4

AC of the NTE + 15dB + OE.

This 15dB is to make sure we are masking the ear above the level of the threshold.

Question 5

The OE should be added only if NTE exhibits normal hearing or SNHL. No need to compensate for OE in CHL. Why?

Answer 5

Broken chain where OE is actually being set up, cochlea is receiving the amplified sound.

Question 6

When is it necessary to do interocative test frequencies?

Answer 6

When the threshold obtained at two consecutive test frequencies differ by 20dB or more, test and record subject’s threshold at the relevant inter-octave test frequencies (750Hz, 1500Hz, 3000Hz and 6000Hz)

Question 7

What are the recommended levels for OE in supra-aural and inserts? (for 250Hz, 500Hz, 1000Hz)

Answer 7

Supra-aural: 30, 20, 10

Inserts: 10, 10, 0

Question 8

What is a masking dilemma?

Answer 8

When both ears are equally bad, potential overmasking because you don’t know which ear is picking it up + 15dB above. Subtract 55dB - potential of TE and NTE affected. Rely on on other tests to see if SNHL/CHL/don’t know which ear.

Weber test may confirm lateralization. Hear more in CHL.