Audibility & Speech Recognition Chapter 6 Perry C. Hanavan, Au. D.
Speech Test Applications O obtain information for counseling O illustrate benefits of visual cues O determine hearing aid candidacy – or determine candidacy for CI or ALDs O predict hearing aid benefit O determine when binaural aids might NOT be appropriate – 80%, AD and 20% AS O determine amplification characteristics and features – whether high frequency beneficial O demonstrate advantage of special hearing aid features O demonstrate aided performance is better than undaided O determine whether cognitive or APD exists – older person may have cognitive problems, anyone may have APD O demonstrate that understanding of speech is impaired
Audiologic Evaluation Information helpful to providing AR OAudibility ODynamic Range OFrequency Resolution OTemporal Resolution
Audiologic Evaluation Critical consideration in helping to plan AR: OTime of Onset of loss ODegree of Loss OEtiology OType of Loss OAnd wealth of other factors
Audiologic Evaluation OObservations OInterviews OQuestionnaires OOtoscopic examination OPure tone results OSpeech recognition OImmittance OOAE OElectrophysiologic (ECoch. G, ABR, MLR, etc. )
Pure Tone Results ODegree of loss – normal, minimal, mild, moderately severe, profound OType of loss – conductive – sensorineural – mixed
Tactile Only SNR Many Items Stimulus Familiarity Equivalent Lists Audition Plus Vision Stimulus Units Distance/ Intensity Learning Effects Stimulus Context Stimulus Mode Stimulus Elements Within. Subject Statistical Procedure Audition Plus Tactile Vision Only Open Set Speech Test Factors Clinical Significance Audition Only Auditory Skill Response Format Closed Set Paired t-statistic Stimulus Format Listener Variables Cognitive Ability Communication Mode Test-Restest Variability Linguistic Ability Hearing Loss Live Synthesized Speech Test Reliability Test Conditions Altered Speech Recorded
Stimulus Mode Oauditory alone Ovision alone Otactile alone Oauditory and vision Oauditory and tactile Otactile and vision Oauditory, vision and tactile Tactile Only Audition Plus Vision Audition Only Audition Plus Tactile Vision Only
Auditory Alone Ophoneme, syllable, word, phrase, sentence Oopen, closed set Ohigh, low context cues Oquiet, noise – signal to noise ratio (SNR) Orecorded, live
Auditory Plus Vision OSpeechreading enhancement – speechreading enhancement ratio • vision only / auditory plus vision = SE – Children –Craig Sentence and Craig Words and CHIVE – Adults –Iowa Sentence Test and CUNY Sentences – Erber (vision and hearing assessment)
Auditory Plus Visual Information OSumby and Pollack (1954) demonstrated that the addition of visual speech information could significantly improve speech perception performance and that the importance of visual speech information increased as the listening situation became more difficult.
Auditory Plus Vision OTye-Murray – CHIVE (adult) – CAVET (children) – Audition plus vision – Vision only – Audition alone OEber – Sent-Ident
Speechreading Enhancement/ Visual Enhancement O Benefit from adding a visual signal to an auditory signal O Refers to the benefit obtained from seeing and hearing a speaker compared with auditory alone – Difference or ratio between speech recognition performance in an vision-only condition and an audition plus-vision condition – Difference Formula (AV-V) – Normalized Score Formula (AV-V/100 -V) O Patient A (V score=50% AV score = 75%) – 75 -50=25% enhancement (difference score) – (75 -50)/(100 -50)=50% (normalized difference score) O Patient B (V score = 10% AV score = 55%) – 55 -10=45% visual enhancement – (55 -10)/(100 -10)=50% (normalized difference score)
Auditory Enhancement Benefit from adding an auditory signal to a visual only signal ODifference Formula (AV-A) ONormalized Score Formula (AV-A/100 -A) OPatient A (A score=50% AV score = 75%) – 75 -50=25% enhancement (difference score) – (75 -50)/(100 -50)=50% (normalized difference score) OPatient B (A score = 10% AV score = 55%) – 55 -10=45% auditory enhancement – (55 -10)/(100 -10)=50% (normalized difference score)
Integration Enhancement OMeasure of ability to integrate auditory and visual information OAV-[100 -(100 -A)+(100 -V)]/100 -[100 -(100 -V)+(100 -A)]
THE AUDITORY SANDWICH Visual cues: • lip-reading • printed word • cued speech • signs HEAR SEE - SAY HEAR-UNDERSTAND First, listen. Then, if need be, watch or say it. Then, listen again (no visual cues) Always put it back into hearing!
Back to “choices” Auditory -Verbal Auditory Cued -Oral Speech AUDITORY Total Communication Language Communication Cognition ASL VISUAL
Choices reframed Fully Auditory Communicator A Mostly Auditory Communicator Mostly Visual Communicator Av AV VA Fully Visual Communicator V
Flexibility is essential Fully Auditory Communicator A Mostly Auditory Communicator Mostly Visual Communicator Av AV VA Fully Visual Communicator V
Stimulus Elements SNR OUnits: phoneme, syllable, word, phrase, sentence, non-sense Distance/ stimuli Intensity OProximity: distant, near OIntensity: soft, comfortable, loud OContext: high, low context cues, OSNR: quiet, background sounds-signal to noise ratio OFamiliarity: high, low familiarity with material, nonsense material Stimulus Familiarity Stimulus Units Stimulus Context
Learning Effects OLearning effect: familiarity with items, procedures…not change in ability – Repeated Frame Test – Cinderella-Brahman Speech Recognition Test OEquivalent lists: lists that contain items that are presumed to be equally difficult to recognize – PB, sentences – Repeated Frame Sentences Test ONumerous stimuli – Full lists rather than half lists Many Items Equivalent Lists
Stimulus Items OLive vs. Recorded – – – Voicing frequency Intonation Speech rate Clarity of articulation Physical characteristics OSynthesized speech OAltered speech – Time-compressed – Expanded – Filtered Live Synthesized Speech Altered Speech Recorded
Significance Clinical significance OWhen a small change in performance is clinically significant OWhen comparison between two test results is clinically significant Statistical design OPaired t-statistic OWithin subject statistical procedure Within. Subject Statistical Procedure Paired t-statistic
Significant Difference for NU-6 recorded speech tests
Listener Variables ODegree of hearing loss OCognitive abilities – Thinking, reasoning, remembering, imagining, or learning words OLinguistic abilities – Knowledge of language OCommunication mode used OMulticultural Cognitive Ability Communication Mode Linguistic Ability Hearing Loss
Test Reliability O Test reliability: the degree to which a single test score approximates the true score O Test-retest variability: measure of consistency from one test presentation to the next O Test conditions: Variables affecting test-retest variability: – mode of presentation—live vs recorded – location—test booth vs classroom – talker—familiar vs unfamiliar, male vs female – number times item repeated—once, twice, etc. leads to better performance Test Reliability Test Conditions
Response Format OClosed or limited set OOpen set OAuditory skill – Detection – Discrimination – Identification – Comprehension Open Set Auditory Skill Closed Set
Acclimatization and Brain Reorganization
Plasticity OPhysiological changes in the CNS (and PNS – auditory nerve) that occurs from sensory experiences – Brain’s ability to reorganize space – Benefit from HA, CI, HATs may need to be measured at later date – Brain may continue to acclimate for several years following HA, CI, HAT, therapy
Making Connections OA child is born with over 100 billion neurons or brain cells. OThese neurons form connections, called synapses, which make up the wiring of the brain.
Brain Development O EARLY EXPERIENCES At age eight months an infant may have 1, 000 trillion synapses. O By age 10 the number of synapses decrease to about 500 trillion. O The final number of synapses is largely determined by a child's early experiences, which can increase or decrease the number of synapses by as much as 25 percent.
Brain Development O "USE IT OR LOSE IT!" The brain operates on a "use it or lose it" principle: only those connections and pathways that are frequently activated are retained. O Other connections that are not consistently used will be pruned or discarded so the active connections can become stronger.
Brain Development O DEFINING LANGUAGE SKILLS When an infant is three months old, his brain can distinguish several hundred different spoken sounds. O Over the next several months, his brain will organize itself more efficiently so that it only recognizes those sounds that are part of the language he regularly hears. O During early childhood, the brain retains the ability to relearn sounds it has discarded, so young children typically learn new languages easily and without an accent.
Dendrites ODendrites are thin, branching fibers lined with receptors at which the dendrite receives information from other neurons. OThe greater the surface area, the greater the amount of information. OSome dendrites are covered with spines which greatly increase its surface area.
Plasticity, Adaptation, Acclimatization Many researchers think that training techniques sometimes can help those with the reading disability, dyslexia, because they modify brain networks. The images above hint that this is the case. The top images show the brain activity (litup areas) of a 10 year-old boy while he completes a task that requires the ability to identify the sounds of words. His reading level equaled that of an eight-year-old child. The bottom images show his brain activity while he completes the same task after receiving eight weeks of a type of special training. Following the intervention training, his reading level increased by three years and the images indicate that his brain activity changed as well. Researchers are conducting a very large, ongoing study to confirm this one example.
Auditory Acclimatization Back in the 1940 s, wideband high-fidelity phonograph consoles were just becoming available. Because of his interest in high-quality audio, Harvey Fletcher bought one for his home. Harvey enjoyed listening to this new high-fidelity system, but unfortunately, the enjoyment was not shared by his wife. After listening to a an old 78 rpm record, with the surface noise made particularly prominent by the extended bandwidth of this new high-fidelity system, she said: "That sounds awful. I don't really like having that screechy sound in my home. " Always the creative thinker, the next day, when his wife was out of the house, Harvey went into the living room and soldered twenty 1 u. F capacitors across the loudspeaker terminals, rolling off the high frequencies. (Remember that amplifiers were high impedance back then, so the trick worked. ) That evening, when the music played, his wife was now happy. One night each week, while his wife was sleeping, Harvey would sneak downstairs and clip one capacitor. After twenty weeks, when the music played, they were both happy.
Acclimatization Adapting to a new environment (in this case, auditory) or as defined by Darwin, the process of inuring to a new climate, or the state of being so inured. This seems to be a reasonable term, as it also is used to describe how the human body acclimates to temperature, altitude, and other environmental conditions. From an auditory standpoint, Gatehouse was one of the first to use the term acclimatization, explaining the speech processing capabilities of a group of people aided monaurally. In later research Gatehouse used the term acclimatization to describe an improvement in speech recognition over time. Today, the term is used widely to explain adaptation to hearing aid use in general, and is not limited to the Gatehouse definition.
Adaptation The process of adapting to something, such as environmental conditions (in this case, auditory); the responsive adjustment of a sense organ. This too is a reasonable term, as it has long been used in reference to the eye—e. g. , adaptation to varying light conditions.
Sensory Reorganization When nerve stimulation changes, as with amputation, the brain reorganizes. In one theory, signals from a finger and thumb of an uninjured person travel independently to separate regions in the brain's thalamus (left). After amputation, however, neurons that formerly responded to signals from the finger respond to signals from the thumb (right).
Auditory Reorganization/Plasticity Cochlear dead regions Brain reorganization will occur with damage to regions of the cochlea
Speech Recognition Tests
WIPI OWord Intelligibility by Picture Identification (WIPI) Oclosed-set picture-pointing (six pictures per plate) Oappropriate for children whose language is between 5 and 10 -11 Ocomprised of four 25 monosyllabic word lists Ocontains 26 color plates (one for practice), six pictures per page. (A, V, AV)
NU-CHIPS ONORTHWESTERN UNIVERSITY-CHILDREN’S PERCEPTION OF SPEECH (NUCHIPS) Oclosed set picture pointing word recognition test Ochildren whose language is as low as three O 50 words familiar to three-year-old children in four randomizations Oincludes two picture books with 50 monochrome plates, four pictures per plate. Book A is used forms A & B, book B for C & D. OThere are two recordings, one male and one female talker.
MAC OThe Minimal Auditory Capabilities (MAC) (2 nd Edition) battery specifically targeted to CI patient OConsists of a series of tasks which are graded in difficulty OMost of the MAC battery sub-tests assume patient’s hearing loss has occurred post-lingual, but can be employed as a means of evaluating the hearing abilities of persons for whom traditional speech materials are too difficult OSecond edition has been standardized. OThe recorded materials include gross sound identification, inflection detection, contrast detection, accent discrimination, and word identification O 14 sub-tests, 13 audio and one video
SERT OSOUND EFFECTS RECOGNITION TEST (SERT) developed for those instances where conventional word recognition measures are not appropriate, such as when language limitations due to hearing impairment OCertain children who are unable to recognize even simple speech can perceive correctly environmental sounds to which they are exposed in their daily lives OUnder these circumstances, the SERT can provide valuable information about the integrity of the auditory system. OClosed set, picture-pointing tasks O 10 sounds plus a practice sound
CID Every Day Sentences OEVERYDAY SPEECH O 10 sets of 10 sentences each with 50 "target" words in each set for word recognition assessment under contextual conditions OCan be employed in auditory training OSentences vary in length and are spoken with minimal inflection ONormative data on recording lacking
BKB Sentences Bench, Koval, & Bamford (BKB) O Open set sentences O Appropriate for linguistic abilities of most 8 -15 years of age with hearing loss O Lists of 16 simple sentences, including 50 key words were devised to include vocabulary, grammar and sentence length for 8 -15 year olds O The sentences are presented in an open-set format and the child imitates as much of the sentence as possible. Responses are recorded word-for-word and scored by percent of key words correctly repeated.
NU-6 ONORTHWESTERN UNIVERSITY AUDITORY TEST NUMBER SIX (NU-6) OPhonetically balanced CNC monosyllabic open set word recognition test OFour lists of 50 words each recorded in four randomizations OTalker has a General American dialect OStandardized
Auditory Numbers Test OANT OTest helps identify tactile from auditory listeners OWord closed set recognition auditory alone test OAppropriate for 3 -8 year old children with severe to profound hearing loss OSimple auditory alone test to measure ability to perceive simple auditory cues – (Erber, 1980)
Iowa Consonant Confusion Test OClosed set consonant (phoneme) recognition test Otest can also be analyzed in terms of the listener's ability to identify phonetic features: – Chance performance for consonant voicing, manner, and place of articulation identification is 50%, 33%, and 20% respectively – Example: Mr. S achieved a total score of 79% correct, 96% on voicing, 94% on manner, and 85% on place O 10 consonants presented 12 times in VCV context – – p, t, k, b, d, g, v, z, n, m Presentation examples: aba, ada, aga, etc Each consonant presented 12 times in random order Presented with carrier phrase “The next word is” • (Tyler et al, 1983)
S t i m i l u s p t k b d g v z n m p 0 0 0 1 1 1 0 0 t 2 3 1 1 0 0 2 2 1 0 k 6 2 3 5 1 0 0 0 Response b d g v 2 1 0 0 1 1 0 0 3 1 2 0 0 1 0 2 0 0 0 3 0 2 2 0 0 3 0 0 0 0 z 0 4 2 0 1 0 0 0 n 0 0 1 1 3 0 2 2 4 4 m 1 0 1 1 0 4 0 2 7 8 Example of Iowa Consonant Confusion Test (example: auditory alone)
Children’s Auditory Test OCAT OAuditory alone limited set test assessing ability to perceive stress patterns and word recognition OConsists of 12 words – Monosyllabic words – Trochees – Spondees
IMSPAC OImitative tests of Speech Pattern Contrast Perception ODeveloped by Arthur Boothroyd OSyllable level, 4 lists randomized OChoose odd one of 3 (forced choice) OPointing, button-press or verbal response OAge 7 years and up
AB Short Word List OIsophonemic Word List ODeveloped in 1968 by Arthur Boothroyd OSpeech recognition open set test OEach list consists of ten words, and each word is constructed as consonant - vowel – consonant O 30 phonemes, 10 vowels and 20 consonants present in each list OCNC words OScore is based on the phonemes correct out of 30
Larsen Recorded Test OAuditory word discrimination test OPairs of phonemes in words – few vs. chew – bill vs. mill – nice vs. vice OLists represent an attempt to present the phone in the initial, medial and final position of a word OLimited choice—select one of two words by drawing line through printed word heard
CAVET Children’s Audiovisual Enhancement Test O Assesses speechreading enhancement in children within the vocabulary level of 7 -9 year olds with profound prelingual hearing loss O Designed to minimize ceiling and floor effects, eliminate syntactic factors, and minimize semantic factors O 3 lists of 20 words each with half of words easy to recognize in a vision-only condition and half are less likely to be recognized in each list but presented in random order O Each list is designated for auditory alone, visual alone, or auditory-visual only mode O Test available in CD-ROM and VHS format – (Tye-Murray & Geers, 2002)
CUNY Sentences Test OThe City University of New York (CUNY) OTopic Related Sentence Sets consist of 25 equivalent sets of 12 sentences of varying length OEach sentence is related to one of 12 topics OOpen set sentence recognition test OListener is presented with sentences in three listening conditions: A, V and AV OThe test is scored with the total number of words correctly identified O(Boothroyd, Hannin, & Hnath, 1985)
Lexical Neighborhood Test (LNT) OLexical neighbors--words that sound similar to a target item. OOften defined as words that differ by a single phoneme from target word OOpen-set test that requires child to imitate stimulus words immediately after they are presented OEach list consists of 50 monosyllabic words, 25 of which are high-frequency words with few lexical neighbors (easy) and 25 of which are lower frequency words with many lexical neighbors (hard) OWords were selected to be familiar to children with limited vocabularies. – Easy Words: juice, good, drive, time, hard, gray, foot, orange, count – Hard Words: thumb, pie, wet, fight, toe, cut, pink, hi, song, fun, use, mine, O Alternate version of test, the Multisyllabic Lexical Neighborhood Test (MLNT) consists of 50 words with two to three syllables. – (Kirk, Pisoni, & Osberger, 1995)
Quick. SIN O Provides a one-minute estimate of SNR loss for adults O A quick method to quantify patient’s ability to hear in noise O Can determine if extended high frequency emphasis improves or degrades understanding of speech in noise O Assist in choosing appropriate amplification and/or other hearing assistance technologies O Demonstrates directional microphones may improve speech intelligibility in noise O Open set test recognition test O Consists of list of six sentences with five key words per sentence presented in four-talker babble noise. O Sentences are presented at pre-recorded signal-to-noise ratios which decrease in 5 d. B steps from 25 (very easy) to 0 (extremely difficult). O The SNR's used are 25, 20, 15, 10, 5, 0, encompassing normal to severely impaired performance in noise.
BKB - SIN OSimilar to Quick-SIN but can be utilize with children OSentence recognition using BKB sentence material OOpen set sentence recognition test OBKB SIN test OTest score sheets
HINT O The HINT is a prerecorded test that measures sentence speech recognition abilities in quiet or in noise accurately, reliably and efficiently O The HINT demonstrated the substantial role that binaural, directional hearing plays in a normal hearing individual's ability to communicate in noise O Any degree of hearing impairment, therefore, reduces the benefits of directional hearing in noise and increases communication inadequacy O Used to evaluate functional hearing capabilities of HI users, CI users and those in listening-critical jobs O Copyrighted by the House Institute and is available for purchase on a compact disc recording to hearing clinics and research laboratories nationwide. O A children's version of the HINT is also available
DICHOTIC SENTENCE IDENTIFICATION (DSI) O Developed in an attempt to conceive a dichotic listening task that would be only minimally affected by peripheral hearing loss O Sentences selected from the Synthetic Sentence Identification (SSI) test presented dichotically O Onsets and offsets of the sentences are aligned with an accuracy of 100 microseconds. O Developers claim DSI less susceptible to hearing loss than SSW test O Viable test of central auditory function with hearing loss O Test applicable for auditory assessment of impaired ears through pure tone averages (PTAs) up to 50 d. B O 2 sets of 30 pairs of sentences (closed set identification test) O Normative data are available
Ling-6 OPhoneme level detection and recognition test Om, s, sh, e, a, u OProcedure ODetection and identification of phonemes
Further Auditory Evaluations OMark C. Flynn—Evaluation of Individuals with hearing loss
Assignment OIf you accept the challenge, assign each test discussed in this section on the following grid, thus, OBe able to correctly indicate on the following template, each of the auditory tests discussed earlier
Speech Paradigm Detection Non-Speech Sounds Phonemes Syllables Suprasegmentals Words Phrases Sentences Connected Speech Discrimination Recognition Comprehension
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