Lecture 6: Suprathreshold Speech Recognition Test (Part II) Flashcards Preview

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Flashcards in Lecture 6: Suprathreshold Speech Recognition Test (Part II) Deck (19):

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

- 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

- 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

-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

- 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

- 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

- 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


What is the WIN (words in noise) test?

- Uses 70 of the original 200 NU-6 words

Presented in MT babble (3 males, 3 females)
- Level of MT babble fixed at 80 dB SPL
- Level of speech varied from 104 dB SPL to 80 dB SPL, in 4 dB decrements (modified method of constants)
- stop presentation when listener misses all words at one SNR

Normative Data

Mean SNR for normal hearing listeners:
- 3.6 dB at 70 dB SPL
- 4.8 dB at 90 dB SPL
- 90th percentile for normal: 6 dB or less

Mean SNR for hearing-impaired listeners
- 12.6 dB at 70 dB SPL
- 12.5 dB at 90 dB SPL


What is the AzBio Sentence Test?

Developed to test listeners with CIs in noise
- Wanted a sentence test with list equivalence in noise
- Wanted a test that was unfamiliar to listeners; multiple lists
- Wanted to avoid floor and ceiling effects with CI listeners

Characteristics of the test:
- 15 lists of 20 sentences each (commercial recording)
- Sentence length: 3-12 words, no proper nouns
- No restrictions on complexity, vocabulary, or phonemic content
- Sentences include contemporary adult topics and social ideas

- Presented in quiet or in noise (10- talker babble; fixed SNR)
- Task: repeat back sentence heard; all words in sentence are scored as correct or incorrect

- 10 lists of the AzBio Sentence Test can be used as a valid, reliable, sensitive measure for clinical and research purposes


What is the Presto?

Goal of test development: need for a test that reveals individual differences among listeners, reflects linguistic and cognitive skills needed to understand speech

Stimuli: TIMIT Sentences (Texas Instruments/MIT)
- Sentence lists (n=19) with 18 sentences/list with 76 keywords/lists
- Keywords varied in familiarity and word frequency, but each list was balanced for these issues
- Sentences differ in length and syntactic structure
- Recorded by multiple talkers

Administration: listener types in sentences on computer; self-paced
- Presented at multiple SNRs in 6-talker babble ( 3 males, 3 females)
- Keywords correct are scored

- Initial study examined test-retest reliability, which was high


What is the computer-aided speech perception assessment (CASPA)?

Stimuli: CVC words (n= 10 items/list; 20 lists)
- 30 most common phonemes in English are used on each list (isophonemic)

Presentation either in Q or N
- Signal level range: 45-75 dB SPL, 5-dB steps (in software); or wider range through audiometer
- Speech noise level fixed at 55 dB SPL (if noise is used)

Tester enters subject's responses on computer
- Computer automatically scores phonemes correct, words correct, consonants and vowels correct
- Program generates PIFs for each of these measures

Advantages to phonemic scoring
- More data points available in short period of time (<5 minutes)
- Less reliance on linguistic knowledge
- But phoneme scores does not equal word scores
- Word score = 100 * (p/100)^2.5

- Use of PIFs for children and adults is clinically feasible; use of phoneme scoring may be especially helpful for those with severe speech understanding problems