Speech Audiometry SPA 4302 Summer 2007
The Diagnostic Audiometer Equipped with • Inputs for microphones, cassette tapes, or CDs • Volume unit (VU) meters • Circuit for masking noise or mixing noise with speech in the same ear • Ability to test __________ or ______________ • Intensity levels ranging from ____ to ____ dB HL • Outputs for __________ amplifiers (to speakers) • Talkback system to allow patient/clinician communication from different rooms/booths
The Patient’s Role in Speech Audiometry • Pt must know and be able to respond to word in the language of the test. • Responses: • ________________________ • ________________________ • ________________________ • ________________________
The Clinician’s Role in Speech Audiometry • Must be able to convey to pt their task, • Keep face from pt’s view • Understand pt responses
Speech-Threshold Testing • Speech Detection Threshold: lowest level at which the listener can tell that something is there (when the signal happens to be speech). Also called the ________________________. • Speech Recognition Threshold: lowest level at which the listener can actual identify what the speech stimulus is. Also called the _________________
SRT Stimuli: Spondees • 2-syllable words with ________________ • can be divided into two monosyllables • e.g., hotdog, baseball, whitewash, mousetrap, birthday, eardrum...
Why spondees? • because their intelligibility curves rise from near chance to _______ performance within a few decibels. (see curve 1 in figure 5.1) • This provides a much more accurate threshold.
Descending Approach Start approx ___dB above expected threshold Drop in __ dB steps 5 words per level Stop when pt misses 5 out of last 6 words Threshold = start level – number correct + correction factor Adaptive Approach Like Pure Tone procedure down in 10 dB steps, up in 5 dB steps Up to __ words per level Threshold = lowest level at which pt correctly id’s at least 2 words (>50%). SRT Methods
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
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 ___ and ___ dB above SRT
Uncomfortable Loudness Level • Begin at ___ , 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.
Range of Comfortable Loudness • (Or the Dynamic Range for Speech) • = UCL – SRT • Normally ___ dB or greater • Unchanged in ____________ losses • Can be much smaller in ____________ hearing loss
Word Recognition Testing • ________ set-client can respond with any word he/she can think of. • ________ set-response options are provided for the client (multiple choice test). • ______ response-client is free to respond or not. • ______ Response-client must say something. • [Forced choice = closed set forced response.]
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 _____ words each.
CNC Word Lists • Consonant-Nucleus-Consonant words • ___________ balanced • Four 50-item lists: the NU-6 Word Lists
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)
Children’s Tests • Word Intelligibility by Picture Identification (WIPI) test – ___ pictures to choose from. • Northwestern University Children’s Perception of Speech (NUCHIPS) test – ____ pictures to choose from • Monosyllable-Spondee-Trochee test – distinguishing word shapes, not identifying particular words; used in ___________ cases.
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 (_________), or • Drops at higher levels (________) • Rollover Index = (PBmax – Pbmin)/PBmax
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 ___________________.
Cross Hearing & the Need to Mask • If Word level (HL)TE – IA > Best BCNTE • Use _______ (Speech) Noise, or _______ noise • EM = PBHL TE – IA + ABGNTE
Predicting WRS from the audiogram: The AI • The __________ Index • __________ Index • “Count the dot” audiogram • If word recognition is poorer than prediction: think neural hearing loss or central disorder.