Speech Audiometry Thresholds, Recognition Tests, MCL &UCL
Slide 2 Testing with Recorded Speech 1000 Hz Calibration tone
provided on recording Balance calibration tone on VU meter at 0
Slide 3 Live Voice Testing: Controlled Vocal Effort, Adjust
microphone sensitivity to have the speech balanced at 0 dB on VU
meter Slide 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. Slide 5 SRT Stimuli: Spondees
2-syllable words with equal stress can be divided into two
monosyllables e.g., hotdog, baseball, whitewash, mousetrap,
birthday, eardrum... Slide 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. Slide 7 SRT Methods ASHA: 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. Slide 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. Slide 9 Exception for
steeply-sloped high frequency losses. SRT will be better than PTA
In this case use Fletcher average: 500 Hz + 1000 Hz / 2. Slide 10
Masking for SRT's: IF SRT - IA > best BC THRESH in NTE. WHITE or
PINK NOISE STARTING LEVEL=SRT TE 35 +ABG NTE Slide 11 Long Term
Spectrum of Speech And the variance around it. Slide 12 Bone
Conduction SRT's: useful in children useful in malingerers. Slide
13 Masking for SRT If SRT - IA > best BC Thresh NTE Put in at
least: STARTING LEVEL=SRT TE 35 +ABG NTE But no more than: OVERMASK
= EM NTE -IA> Best BC Thresh TE Slide 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
Slide 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. Slide 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 Slide 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.]
Slide 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. Slide 19 CNC Word Lists
Consonant-Nucleus-Consonant words Phonemically balanced Four
50-item lists: the NU-6 Word Lists Slide 20 Alternative Speech
Choices High Frequency Word Lists Gardners 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) Slide
21 Childrens Tests Word Intelligibility by Picture Identification
(WIPI) test six pictures to choose from. Northwestern University
Childrens 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. Slide 22 WIPI Sample Item Slide 23 NU-CHIPS Sample Item
Slide 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 Slide
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)
Slide 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 Slide 27 Slide 28 Rollover Indices for the preceding
examples Normal: (100 - 100) / 100 = 0.0 Rollover: (44 - 20) / 44 =
0.54 Cochlear: (80 - 70)/80 = 0.125 Rollover Indices of 0.45 or
greater indicate a neural (VIIIth nerve) problem. Slide 29 Cross
Hearing & the Need to Mask If Word level (HL) TE IA > Best
BC NTE Use Pink (Speech) Noise, or white noise Suggested Levels: EM
= PBHL TE IA + ABG NTE + 20 dB PB Test LevelMasker Level 40 dB HL
--- 60 dB HL40 dB EM 80 dB HL60 dB EM Slide 30 Reliability of Word
Recognition Scores Range of possible scores upon retest Thornton
& Raffin (1978) # of Items Initial Score 100502510
9081-9676-9872-10050-100 5037-6332-6828-7610-90 2011-328-364-440-60
Slide 31 Slide 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 Slide 33 Interpreting Word
Recognition Scores Score: General Word Recognition Ability: 90 to
100Within Normal Limits 75 to 90Slight Difficulty 60 to 75Moderate
Difficulty 50 to 60Poor < 50Very poor Slide 34 Expected PB max
by Hearing Loss Dubno, J. et al. JSHR 1995 Slide 35 PTA (dB HL) 2
nd % Score 1 st % Correct Score SPRINT: Speech Recognition
Interpretation Chart by Linda M. Thibodeau, 1999 Abnormally Low
Word Recognition for HL Slide 36 PTA (dB HL) 2 nd % Score 1 st %
Correct Score SPRINT: Speech Recognition Interpretation Chart by
Linda M. Thibodeau, 1999 95% Confidence Limits for Word Recognition
Score Slide 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. Slide 38 ( Mueller & Killion) Counting Dots:
( Mueller & Killion) Each dot = 1% # of dots below HL line on
audiogram = % correct identification for speech.
