Puretone OSCE

Question 1

In air conduction, which ear do you begin with?

Answer 1

The better ear

Question 2

In bone conduction, which ear do you begin with?

Answer 2

The worse ear

Question 3

For air conduction, what is the dB starting level?

Answer 3

• 30 dB if there is no suspected hearing loss
• 50 dB if there is a suspected hearing loss

Question 4

For bone conduction, what is the dB starting level?

Answer 4

10-15dB above the better ear air conduction threshold

Question 5

What frequencies do you test for air conduction?

Answer 5

1000, 2000, 3000, 4000, 6000, 8000, 500, 250

Question 6

What frequencies do you test for bone conduction?

Answer 6

1000, 2000, 4000, 500

Question 7

When and which inter-octave frequencies would you test?

Answer 7

If there is a 20dB or greater difference between two adjacent octave thresholds

Test 750 Hz and 1500 Hz

Question 8

What do you do if there is no response at initial presentation level?

Answer 8

Go up in 20 dB steps

Question 9

When are how do you determine if a response was due to the patient “feeling” it rather than hearing it?

Answer 9

At high intensities, the stimulus can become vibrotactile

• The patient should be asked if they feel or hear the tone (indicate on audiogram with “VT”)

Bone vibrator: (500 Hz: 55), (1000 Hz: 75)

Supra aural: (250 Hz: 80), (500 Hz: 105), (1000 Hz: 120), (2000 Hz: 130)

Question 10

When may you not need to do bone conduction on the “better” ear?

Answer 10

If the bone conduction results are within 10 dB of the AC on the better ear

Question 11

What causes and what should you do when there is a unexpected air bone gap at 3 and 4 kHz?

Answer 11

• May be due to acoustic radiation and calibration issues
• If there is an unexpected air bone gap, occlude both the ear canals and note on audiogram
• We do not occlude at low frequencies as this can cause the occlusion effect

Question 12

When do you mask for air conduction?

Answer 12

1. AC (test ear) - AC (non-test ear) ≥ IAA
2. AC (test ear) - BC (non-test ear) ≥ IAA

Question 13

When do you mask for bone conduction?

Answer 13

A-B gap (test ear) ≥ 15 dB & AC (test ear) > 15 dB HL

Question 14

What is the initial masking level for air conduction?

Answer 14

AC (non-test ear) + 10 dB

Question 15

What is the initial masking level for bone conduction?

Answer 15

AC (non-test ear) + 10 dB + OE*

*
Headphones and shallow inserts:
500 Hz = 20, 1000Hz = 10

Deeply inserted inserts:
500 Hz = 10

Question 16

What is over-masking?

Answer 16

• When the masking noise in the non-test ear affects the hearing thresholds in the test ear
• Likely to occur with good BC thresholds in the test ear when using supra aurals
• Can help to change the transducer to inserts which have higher IAA
• The minimum masking level at which this may occur is BC (test ear) + IAA

Question 17

What is a masking dilemma?

Answer 17

• Occurs in a large bilateral conductive hearing loss
• Impossible to mask either ear without over-masking the test ear

Question 18

How do you explain the puretone test?

Answer 18

“This test is going to find out the quietest sounds that you can hear. I am going to play some beeps into one ear at a time. I want you to press this button whenever you hear a beep, even if it is very faint. If you want to talk to me at any point, there are microphones in the room so just speak normally and I will be able to hear you. I will get set up and let you know when we are going to start.”

Question 19

How do you connect the AC thresholds?

Answer 19

Solid line for right
dashed line for left