Lecture 6: Suprathreshold Speech Recognition Test (Part II) Flashcards
What is a closed-message test?
- Monosyllabic tests
- Small # of foils
- Foils chosen to be easily confusable with target
- opportunity for guessing
What is the Fairbanks Rhyme Test (1958)?
5 lists drawn from 250 monosyllables
- All rhyming words
- The listener is provided with the word stem
- Not phonetically balanced
- Probes differentiation of initial consonant
- Can be administered to groups
What is the modified Rhyme Test (1963)?
Purpose: to evaluate communication systems with untrained listeners
Structure: 6 lists, 50 words/each, 6 choices/item
- 25 items: varied initial consonant
- 25 items varied final consonant
- Listener has all 6 choices available
- Results with normal-hearing listeners
- For hearing impaired listeners, the final consonant is harder to differentiate (lower in amplitude than the initial consonant)
What is the effect of open vs. closed set tasks on speech perception thresholds?
- Closed set performance > open set
- Lexically easy words > lexically hard words
- # of alternative choices and difficulty of choices incluences performance
Conclusion: lexical knowledge and task of demands influence performance on open and closed-set speech recognition tasks
What is the CID everyday sentences?
Purpose: estimate everyday hearing disability
Structure:
- 100 sentences, everyday speech, familiar vocabulary
Listener’s task: identify all words in the sentence
Scoring: based on keywords in sentence
- Hearing impaired listener’s performance on CID sentences > W-22’s by 28%
What is the synthetic sentence identification test (SSI)?
Purpose: identify patients with N. VIII lesions
- need to vary temporal structure of speech –> sentences
- avoided use of contextual cues by developing synthetic sentences
Structure: used common vocabulary; followed rules of syntax
- Developed 3rd order approximations to sentences
- Developed lists of 10 sentences each
Presentation:
- Closed set, listener identifies sentence heard
- Presented in background of single talker
- Varied message-to-competition ratio (MCR) from -40 dB –> + 20 dB
- Competition goes into ipsilateral ear or contralateral ear (ICM, CCM)
- Listener gets feedback (correct or incorrect)
Diagnostic usefulness - helps distinguish brainstem vs. cortical lesions
What is the dichotic sentence identification (DSI) test?
- 6 SSI sentences, 1 presented to each ear simultaneously, at 50 dB SL
- Participant selects 2 sentences from a list
- 2 modes: directed mode and free
- 10 sentences presented to each ear
- Relatively resistant to the effects of sensorineural hearing loss until the degree of loss exceeds 50 dB HL
- Normal scores are greater than or equal to 80% with REA seen
- Directed mode scores > free report
- Older listeners do poorly on this test, and are often associated with memory problems
Diagnostic usefulness: central auditory system diagnoses
What is a nonsense syllable test?
Purpose: determine absolute recognition ability of individual listeners
Structure:
- 91 different items
- All possible consonants paired with /a,i,u/
- CV or VC format
- 11 subtests with 7-9 syllables per each
Presentation and results
- Closed response format
- No learning effects, high inter-list equivalence
- No possibility of word understanding
Usefulness of test
- Can determine consonant confusions of individual –> developing rehabilitative program, benefit of hearing aids
What is the purpose of testing in noise?
To measure performance in realistic situations.
To identify deficits the person may experience
What are the procedural variations for testing in noise?
1) Fixed signal-to-noise ratio (SPIN, AzBio)
Advantages: easy to interpret % of correct score
Disadvantages: time-consuming, only 1 S/N ratio doesn’t reflect everyday situations
- at the beginning of the test, the level of the noise is set and the speech level is set
2) Adaptive procedures (HINT)
Advantages: quick
Disadvantages: difficult to interpret (SNR)
- you sample the person’s performance at a particular SNR and if they do well, you make the test harder by reducing the SNR
- If the person gets the item wrong, you make the test easier by increasing the SNR
- Have a stopping rule and average the changes to the SNR – that will be the final score that corresponds to a certain level of performance
3) Method of Constants (Q-SIN, WIN)
Advantages: quick
Disadvantages: difficult to interpret (SNR)
- Fixed steps of SNR
- Not adaptive because you’re not looking at how the person does on a test and making a judgement
What is the speech perception in noise (SPIN) test?
Purpose: compare a person’s recognition of acoustic information to additional use of contextual cues
Structure:
- Sentences have low context (LP items) or high context (HP items)
- 50 sentences per list - half are LP and half are HP (target word is last word of the sentence)
- Present at 50 dB SL re: babble threshold in 12-talker babble at +8 dB S/B ratio (simulates average noise conditions)
Standardization results
- Reliability: acceptable (HP: 0.91, LP: 0.85
- List equivalence: 8 forms in R-SpIN are equivalent
- Performance of listeners
Hearing impaired: 92% on HP SPIN, 44% on LP SPIN
Normal: 100% on HP SPIN, >70% on LP SPIN
What are procedural variations for the SPIN?
Adaptive procedure
- fixed signal level, vary noise level
Process
- Start with noise at 30 dB below signal level
- Present 3 words/step in 2-dB steps
- If 2/3 words are correct, increase noise level
- If 2/3 words are incorrect, decrease noise level
Adaptive rule: continue until 6 reversals in direction
- Calculation of S/B for 50% criterion performance: mean of the midpoints of the final 4 excursions
What is the Hearing in Noise Test (HINT)?
Purpose: develop a test of speech recognition that avoids floor and ceiling effects
Requirements for development:
- Produce reliable results
- Multiple lists, equated in difficulty
- No learning effect with materials
- Representative of language
- Sentence-length materials satisfy requirements
Structure of test
- BKB sentences
- Phonetically balanced sentences
- 25 lists with 10 sentences/list, 3 practice lists
- Scoring for keywords
- Recordings: male talker
- Presented in speech spectrum noise
Procedure:
- Measuring S-SRT in quiet and in fixed noise level of 72 dBA under earphones (for SF testing: noise is 65 dBA)
- Listener repeats sentence presented
- Adaptive rule: if sentence is correct, speech level is attenuated by 2 dB, if incorrect increase level by 2 dB
Normative results:
- Mean SRT in quiet = 23.91 dBA
- Mean S/N ratio at threshold in oise: -2.92 dB (i.e. SRT = 69.08; noise fixed at 72 dBA)
- Lists wer equivalent
- Reliability was high
- Very popular test; available in many languages
- Used to assess “functional hearing”
- Evaluate performance for noise in 2 conditions*
- spatially separated noise (speech at 0 degrees and noise at 90 degrees0
- Co-located (speech and noise at 0 degrees azimuth)
What is the SIN (speech in noise) test?
- Modified method of constants
Purpose of development: evaluate effects of compression ratio in hearing aids on speech intelligibility and quality
Structure of test:
- IEEE sentences, multiple lists
- Original SIN presented at two signal levels in noise with 4- talker babble (multiple SNRs)
What is the Quick Sin Test?
- Assesses “SNR loss” in a 1-mnute test
- 12 equivalent lists, each list has 6 sentences ( 5 keywords per sentence)
- Sentences on a list are presented in noise at 6 SNRs: 25, 20, 15,10, 0 (sentences/SNR)
Presentation Level
- Earphones: speech fixed at 70 dB HL, start noise at SNR = +25 dB, increase noise level in 5 dB steps after each sentence
Scoring- based on keywords in each sentence; extrapolate SNR for 50% correct
- Use tillman-Olsen formula for calculating SRT
- Starting SNR - #correct + 2.5 dB
Convert SNR for 50% to “SNR Loss”
- Individual SNR - Normal SNR (2 dB); short-cut 25.5 -# correct
- Compared to normal score to indicate degree of severity
- SNR loss 0-2 = normal to near normal
- SNR loss 2-7 dB = mild
- SNR loss 7-15 dB = moderate
- SNR loss > 15 dB = severe
