1. Thresholds, Recognition Tests, MCL &UCL
Speech Audiometry
Thresholds,
Recognition Tests,
MCL &UCL

2. Testing with Recorded Speech
1000 Hz Calibration tone provided on recording
Balance calibration tone on VU meter at 0

3. Live Voice Testing: Controlled Vocal Effort,
Adjust microphone sensitivity
to have the speech balanced at 0 dB on VU meter

4. Thresholds for Speech:
Speech Detection Threshold: lowest level at which the listener can tell that something is there (when the signal happens to be speech).
Speech Recognition Threshold: lowest level at which the listener can actual identify what the speech stimulus is.

5. SRT Stimuli: Spondees 2-syllable words with equal stress
can be divided into two monosyllables
e.g., hotdog, baseball, whitewash, mousetrap, birthday, eardrum...

6. Why spondees?
because their intelligibility curves rise from near chance to 100% performance within a few decibels.
This provides a much more accurate threshold.

7. SRT Methods ASHA: Adaptive Instruct Instruct Familiarize (16 words)
Find Starting Level
Begin Descending procedure
Thresh = Start Level - # C + Corr. Factor
Adaptive
Instruct
Familiarize
Bracket (2-4 wds/level)
Thresh = lowest level where you get at least 50% correctly repeated.

8. The SRT should agree with the PTA
(-8 to +6 dB of best threshold at these frequencies).
This way we have a double-check on results.

9. Exception for steeply-sloped high frequency losses.
SRT will be better than PTA
In this case use Fletcher average: 500 Hz Hz / 2.

10. Masking for SRT's: IF SRT - IA > best BC THRESH in NTE.
WHITE or PINK NOISE
STARTING LEVEL=SRTTE –35 +ABGNTE

11. Long Term Spectrum of Speech
And the variance around it.

12. Bone Conduction SRT's:
useful in children
useful in malingerers.

13. Masking for SRT If SRT - IA > best BC Thresh NTE Put in at least:
STARTING LEVEL=SRTTE –35 +ABGNTE
But no more than:
OVERMASK = EMNTE-IA> Best BC Thresh TE

14. Most Comfortable Loudness Level
Instructions important: you can strongly influence how a person responds.
"I am going to continue talking to you as I make my voice louder and softer. I will keep asking you to tell me whether my voice is too soft, too loud or comfortably loud."
Do a number of sweeps in level.
normally between 40 and 55 dB above SRT

15. Uncomfortable Loudness Level
Begin at MCL, raise level as you continue to talk.
"I am now going to ask you to tell me how my voice sounds to you as I make it louder. Please tell me if the level is comfortable, a little loud, or uncomfortably loud.”
Uncomfortable = loud enough so you would not want to listen to my voice for a long time.

16. Range of Comfortable Loudness
(Or the Dynamic Range for Speech)
= UCL – SRT
Normally 100 dB or greater
Unchanged in conductive losses
Can be much smaller in sensorineural hearing loss

17. Word Recognition Testing
Open set-client can respond with any word he/she can think of.
Closed set-response options are provided for the client (multiple choice test).
Free response-client is free to respond or not.
Forced Response-client must say something.
[Forced choice = closed set forced response.]

18. Phonetically Balanced Word Lists
selection of a group of words so that each phoneme appears with the same frequency it has in the normal lexicon. Based on Thorndike-Lorge lists of words and word frequencies.
So-called PB word lists-- CID W-22 Lists
Four lists of 50 words each.

19. CNC Word Lists Consonant-Nucleus-Consonant words Phonemically balanced
Four 50-item lists: the NU-6 Word Lists

20. Alternative Speech Choices
High Frequency Word Lists
Gardner’s Hi Frequency Word Lists
California Consonant Test
Nonsense Syllable Lists
The Nonsense Syllable Test (NST)
Sentence Tests
The Synthetic Sentence Identification (SSI) test
Speech Perception in Noise (SPIN) test
Connected Speech Test (CST)
The Hearing In Noise Test (HINT)

21. Children’s Tests
Word Intelligibility by Picture Identification (WIPI) test – six pictures to choose from.
Northwestern University Children’s Perception of Speech (NUCHIPS) test – four pictures to choose from
Monosyllable-Spondee-Trochee test – distinguishing word shapes, not identifying particular words; used in cochlear implant cases.

22. WIPI Sample Item

23. NU-CHIPS Sample Item

24. Administration: once you've chosen materials
transducer: AC, BC, or sound field.
level: at some SL (40)--may be specified by test.
response: repeat, write, or mark on list.
competing noise: what, how loud.
masking: calculate (Test Level - IA) - BC nte

25. Adaptive Testing Finding a threshold, not a % score
Typically in presence of competing noise
Measure has low variance
Not yet common in clinical practice
(although we will talk about the HINT soon)

26. Performance-Intensity Functions
PI function: word recognition scores obtained at a range of stimulus levels.
Curve reaches a peak (Pbmax), and then
Either remains high (normal), or
Drops at higher levels (Rollover)
Rollover Index = (PBmax – Pbmin)/PBmax

28. Rollover Indices for the preceding examples
Normal: ( ) / 100 = 0.0
Rollover: ( ) / 44 = 0.54
Cochlear: ( )/80 = 0.125
Rollover Indices of 0.45 or greater indicate a neural (VIIIth nerve) problem.

29. Cross Hearing & the Need to Mask
If Word level (HL)TE – IA > Best BCNTE
Use Pink (Speech) Noise, or white noise
Suggested Levels:
EM = PBHL TE – IA + ABGNTE + 20 dB
PB Test Level
Masker Level
40 dB HL
---
60 dB HL
40 dB EM
80 dB HL
60 dB EM

30. Reliability of Word Recognition Scores
Range of possible scores upon retest
Thornton & Raffin (1978)
# of Items
Initial Score
100 50 25 10 90
81-96
76-98
72-100
50-100
37-63
32-68
28-76
10-90 20
11-32
8-36
4-44
0-60

32. NU-6 Words Ordered by Difficulty
Present 10 words- stop if 0 or 1 error
If >1 error, present next 15 words
If < 3 errors (out of 25), stop
If > 3 errors administer all 50 words
Hurley & Sells, 2003

33. Interpreting Word Recognition Scores
General Word Recognition Ability:
90 to 100
Within Normal Limits
75 to 90
Slight Difficulty
60 to 75
Moderate Difficulty
50 to 60
Poor
< 50
Very poor

34. Expected PB max by Hearing Loss
Dubno, J. et al. JSHR 1995

35. SPRINT: Speech Recognition Interpretation Chart
Abnormally Low Word Recognition for HL
PTA (dB HL)
2nd % Score
1st % Correct Score
© by Linda M. Thibodeau, 1999

36. 95% Confidence Limits for Word Recognition Score
SPRINT: Speech Recognition Interpretation Chart
95% Confidence Limits for Word Recognition Score
PTA (dB HL)
2nd % Score
1st % Correct Score
© by Linda M. Thibodeau, 1999

37. Predicting WRS from the audiogram: The AI
The Articulation Index
Audibility Index
“Count the dot” audiogram
If word recognition is poorer than prediction: neural hearing loss or central disorder.

38. Counting Dots: (Mueller & Killion)
Each dot = 1%
# of dots below HL line on audiogram = % correct identification for speech.