AC Puretone Testing (6/8/26)

Frequency = ___

Hz

What is the perceptual equivalent of frequency?

Pitch

Intensity = ___

dB

What is dB SPL?

Sound Pressure Level

• The absolute pressure reference level for the decibel

dB HL

Hearing Level

• The reference to average normal hearing

• 0 dB HL represents the dB SPL required to reach threshold sensitivity of the average normal ear at each frequency

T/F: The ear is not sensitive to all frequencies at the same level

True

dB SL

Sensation Level

• Used to specify the intensity of stimuli presented to a patient relative to that specific patient’s threshold

Pt’s threshold is 55 dB HL

• Signal presented at 20 dB SL

• It is 20 dB HL above 55 (20 +55) = signal is presented at 75 dB HL

Say a pt has a threshold of 20 dB HL during SRT

• If you were to check their WRS, and you wanna test at a higher level, say you wanna test a 40 dB SL

• Take 20 + 40…

• Presentation level is 40 dB SL or 60 dB HL

What are the 3 types of transducers?

1. Insert earphones (ER-3A)

2. Supra-aural earphones (TDH-49)

3. Loud speakers

If there’s wax you can’t remove, __________ may be a better option than inserts

Supra-aural headphones

Loud speakers

• Measure sound-field thresholds

• Do not provide ear-specific information

• Can be used w/ aided (hearing aid) testing & VRA (Visual Reinforcement Audiometry) w/ kids

• Orientation of listener matters

  • Can have a large effect on stimulus level presented @ TM → can change by as much as 20 dB by turning head!

What is the Standing Wave Theory? [LOUD SPEAKERS]

When you have direct sound from the speaker hit & reflect off of sound booth walls, it can have a cancelation and/or summation effect

• The sound hitting the wall and bouncing around the booth is what can result in cancelation/summation

Cancelation

The intensity of a sound is decreased

Summation

The intensity of a sound is increased

How can you minimize standing waves? (2)

1. Narrow band noise

   • “shhhhhhhh”

2. Frequency-modulated (FM) / Warbled tones

   • “wowowowowowo”

Instructions for pt ages 5 years and up

“Press the button (or say “yes”) when you hear the series of beeps. We are trying to find the softest level you can hear, so if you barely hear it, or it sounds distant/far away, I still want you to press the button.”

• Ask pt which ear they hear better out of

• You will begin testing in the better ear

• If pt doesn’t have a “better hearing” ear, start on the right ear

• DO NOT TELL PATIENT TO GUESS

Types of Puretone Signals (3)

1. Steady PT

2. Pulsed PT

3. Warbled

Pulsed PT

• Preferred stimulus

• Better for pts with tinnitus

• Reduces number of false positives

Warbled

• Typically used when presented through loud speakers

• Can also be used for pts with tinnitus

False positive

Pt hits button when sound wasn’t produced

*Note when this occurs*

False negative

Pt doesn’t indicate they heard a sound when you know they did

*Note when this occurs*

Modified Hughson-Westlake Procedure

Familiarize pt with task

• Begin at 1000 Hz present at 30 dB HL → familiarization

  • If you suspect a pt has hearing loss, start at 50 or 60 dB HL

• If pt does not respond to initial 30 dB tone, raise stimulus level in 20 dB increments until pt respond → familiarization

  • If they don’t hear it at 50 dB HL, increase 10 dB at a time instead of 20 dB

• If pt does respond at 30 dB HL, decrease by 10 dB step until listener no longer responds → this begins the threshold seeking procedure

Down ___; Up ___

10; 5

• Bracket threshold a few tiems

After every response to a tone, the level of tone is decreased by ___ dB step sizes until there is no response.

10 dB

When there is no response, raise level in ___ dB step sizes until a response is obtained.

5

ASHA recommends that thresholds should correspond to the level at which responses were obtained for…

2 ascending runs

What octave intervals are usually tested?

250-8000 Hz

Generally, what octave(s) are tested first?

1000 Hz

• Continue testing through 8000 Hz

• Go back and recheck 1000 Hz, then go down through 250 Hz

If there is a ___ dB or more difference between octaves, you must test the inter-octave frequency!

20 dB

ASHA recommends testing the inter-octaves of _____ and _____ Hz on all adult patients.

3000 and 6000 Hz

• Don’t forget about 750 and 1500 Hz when a 20 dB difference is found between octaves!

What are 2 common test sequences?

1. Puretone AC → Speech Recognition Threshold → Word Recognition Score → Puretone BC

   • Dr. Barber does SRT → Puretone AC → WRS → Puretone BC

2. Speech Recognition Threshold → Word Recognition Score → Puretone AC → Puretone BC

What 3 factors contribute to Audiometric Interpretation?

1. Degree

2. Type

3. Configuration

**You must test BC to determine type of loss**

Flat configuration

< 5 dB rise or fall per octave

Gradually falling/sloping

5-12 dB increase per octave

Sharply falling/sloping

15-20 dB increase per octave

Precipitously sloping

Flat or gradually sloping, then increase at 25 dB or more per octave

Rising

> 5 dB decrease in threshold per octave

Peaked/saucer

20 dB or > loss at extreme frequencies, but not at mind frequencies

Trough/Cookie Bite

20 dB or > loss in mid frequencies, but not extreme high or low frequencies

• This is very common sensorineural loss for congenital hearing losses

Notched (e.g. noise notch)

20 dB or > loss at one frequency with complete or near-complete recovery at adjacent octave frequencies

Test-Retest Reliability

Generally, there is not going to be more than a 5 dB difference

• The probability of obtaining identical thresholds at each frequency is small.

• If you see a pt after 6 months, and each threshold is 10 dB or more different, that is not test-retest reliability. They should see ENT or PCP to look into that. See them in a month to retest thresholds.

What 4 factors can impact variability?

1. Pt’s decision making process

2. Physiologic/bodily noise

3. Shift in response criterion

4. Differences in transducer placement