Pure tone audiometry

Question 1

Reliability is dependent on:

Answer 1

• calibration
• test environment
• pt perfomance
• examiner sophistication

Question 2

What is dB HL?

Answer 2

• The average loudness across frequencies for the average person to JUST detect a sound
• Reference for hearing is changed to the average of a group of normal hearing adults
• softest sounds become 0 dB HL

Question 3

Audiometer

Answer 3

• tests hearing SENSITIVITY by AC and BC
• most test up to 8000 Hz (for speech)
• tones are attenuated

Question 4

On the audiogram, lower down = ______ hearing loss

Answer 4

MORE hearing loss

Question 5

Attenuator

Answer 5

• there is a max electrical force you set a transducer at, and a max output the transducer can give.. so it attenuates the signal to a certain level

Question 6

3 transducers of an audiometer

Answer 6

• earphone
• speaker
• bone

Question 7

Two types of earphones

Answer 7

• TDH (supra-aural)

- ER-3A (insert)

Question 8

What happens if you turn up the AC all the way

Answer 8

• you can cause damage to the patient

Question 9

Can you damage someone’s hearing using BC?

Answer 9

No

Question 10

2 ways around getting rid of background noise

Answer 10

• insert earphones (but if you use w/ BC and inserts still in, you get occlusion effect so take them out first)
• sound-isolated chamber, to keep noise in room below level of masking that would cause a threshold shift

Question 11

Threshold of hearing sensitivity

Answer 11

• the lowest level needed for a person to detect the presence of a signal 50% of the time
• level at which the tone is barely audible

Question 12

What does AC audiometry test?

Answer 12

• what is the patient’s hearing sensitivity across freqs?

- it’s about DETECTION

Question 13

What info do we get from AC audiometry?

Answer 13

• degree of hearing loss (not type) b/c it tests the WHOLE SYSTEM

Question 14

Rule of thumb for Hughson-westlake method

Answer 14

• down 10, up 5

Question 15

Normal hearing dB range for adults

Answer 15

• 10-25 (10-15 for kids) dB

Question 16

Slight hearing loss for kids

Answer 16

• 15-25 dB

Question 17

Mild hearing loss

Answer 17

• 25-40 dB

Question 18

Moderate hearing loss

Answer 18

• 40-55 dB

Question 19

Moderately severe hearing loss

Answer 19

• 55-70 dB

Question 20

Severe hearing loss

Answer 20

• 70-90 dB

Question 21

Profound hearing loss

Answer 21

• 90+ dB

Question 22

What is masking

Answer 22

• controlling for interaural attenuation by putting a range of noise around the centre frequency you’re testing, on the ear you’re NOT testing

Question 23

Why do we mask

Answer 23

• if you keep turning up a sound, eventually it will be loud enough to vibrate the skull and the sound will be picked up by the opposite ear (interaural attenuation)

Question 24

What dB level do we start to mask at

Answer 24

40 dB (AC)
10 dB (BC)

Question 25

Why do we do BC audiometry?

Answer 25

- to determine the hearing levels at the cochlea

Question 26

where do we place the BC

Answer 26

- mastoid

Question 27

What is sensorineural hearing loss?

Answer 27

- no air-bone gap - no conductive component - problem in inner ear or beyond

Question 28

What is conductive hearing loss?

Answer 28

- air-bone gap - BC better than AC - BC w/in normal range - AC outside normal - problem in transmitting signal from outer ear to inner ear

Question 29

What is mixed hearing loss?

Answer 29

- Air-bone gap - BC better than AC - BC outside normal range - AC worse