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71 Cards in this Set
- Front
- Back
What two factors affect speech perception?
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auditory and visual
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What are the most common causes of auditory distortion?
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-noise
-reverberation -distance |
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Any unwanted auditory disturbances that interfere with what we want to hear, is called???
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noise
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True or false: what is speech/music in one situation, can be noise in another.
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true
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What is S/N (SNR) and define it?
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-Signal to Noise Ratio
-the ratio of speech signal (intended signal) to that of the background noise |
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How is SNR expressed?
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as a decibel value (positive and negative values)
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What do positive decibel values for SNR represent?
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-that the speech is present at a greater intensity than the noise
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What do negative decibel values for SNR represent?
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-that the noise is present at a greater intensity than the signal
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What dB level (SNR) is needed for a normal listener to understand 50%?
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0 to +2 dB above background noise
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What dB level (SNR) is needed for HOH to understand 50%?
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+5 to +8 dB above background noise
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What is signal to noise ratio somtimes referred to as (not SNR or S/N)?
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-Message to Competition Ration (MCR)
-Signal to Babble Ratio (S/B) |
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What is S/B and define it?
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Signal to Babble Ratio
-here the noise is specific-speech babble (noise composed of many speakers talking at once) |
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What is the most typical SNR for adults?
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+8 dB
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What is SNR typically is public areas?
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+5 to +8 dB
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What is SNR for transportion vehicles?
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0 dB or worse
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The distance at which people communicate _________ as the background noise increases.
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decreases
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The average distance for conversation in the home is _____.
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1 meter
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In higher noise environments, the average distance is ______.
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.4 meter
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What is the Lombard Effect?
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-we tend to raise the intensity level of our voices during communication as the level of background noise increases
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True or False: When shouting, the speech signal becomes clearer.
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false (more distorted)
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Why are adults at a lesser disadvantage than children for loss of acoustic cues?
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-differences in cognitive-linguistic background
-affects of redundant cues -better able to fill in missing parts |
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Normal hearing children require an SNR of at least __________ for optimum communication efficiency.
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+6 dB
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Children who are HOH need SNRs no less than ___ to ___ dB.
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+15 to +20
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Studies have consistently shown that SNRs in classrooms are poor. On the order of ___ to ___ dB.
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+5 to 0
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Why did the studies done in the 70's show that children with hearing aids performed worse than the HOH children who did not?
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-materials presented as one-word, single-syllable words
-crappy technology -only had 1 hearing aid |
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What dB level does ASHA say unoccupied noise levels should not exceed in schools? and ANSI?
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30 dB (ASHA)
35 dB (ANSI) |
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The SNR at the student's ear should exceed at minimum of ___ dB.
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15
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Reverberation time should not exceed _____ (ASHA) and _____ (ANSI).
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.4 sec (ASHA)
.6 sec (ANSI) |
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Define reverberation.
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a phenomenon by which direct acoustic waves bounce off reflective surfaces back into the acoustic space
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What effects can reverberation cause?
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-time-masking effect
-overlap with direct signal -time delays in signal reaching ear |
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Why are adults at a lesser disadvantage than children for loss of acoustic cues?
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-differences in cognitive-linguistic background
-affects of redundant cues -better able to fill in missing parts |
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Normal hearing children require an SNR of at least __________ for optimum communication efficiency.
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+6 dB
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Children who are HOH need SNRs no less than ___ to ___ dB.
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+15 to +20
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Studies have consistently shown that SNRs in classrooms are poor. On the order of ___ to ___ dB.
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+5 to 0
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Why did the studies done in the 70's show that children with hearing aids performed worse than the HOH children who did not?
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-materials presented as one-word, single-syllable words
-crappy technology -only had 1 hearing aid |
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What dB level does ASHA say unoccupied noise levels should not exceed in schools? and ANSI?
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30 dB (ASHA)
35 dB (ANSI) |
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The SNR at the student's ear should exceed at minimum of ___ dB.
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15
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Reverberation time should not exceed _____ (ASHA) and _____ (ANSI).
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.4 sec (ASHA)
.6 sec (ANSI) |
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Define reverberation.
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a phenomenon by which direct acoustic waves bounce off reflective surfaces back into the acoustic space
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What effects can reverberation cause?
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-time-masking effect
-overlap with direct signal -time delays in signal reaching ear |
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Rooms with more reflective surfaces have _______ (longer or shorter) reverberation times.
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longer
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The longer the reverberation time, the _______ (more or less) detrimental to speech recognition.
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more
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True or false: Reverberation is always bad.
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false (good for listening to music and adds liveliness to the sound)
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What does Ts stand for?
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Reverberation time
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Many adult environments have Ts (reverberation time) of ___ to ___ seconds.
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.5 to .75
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Sound treated rooms have Ts (reverberation time) of ___ seconds.
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.3
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Many classrooms have Ts (reverberation time) of __ to ___ seconds.
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.6 to 1.2 (not good)
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Adult-like speech recognition performance is not reached until about what age?
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13 years old
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We most often listen in environments with the presence of noise and reverberation. Adding noise and reverberation creates a synergistic effect. What does this mean?
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the overall effect is greater than what we would predict (eg. noise decreases perception by 15% and reverberation decreases perception by 10% = 25% decrease in understanding....however, there is actaully a 35% decrease in understanding)
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What are ways to meet acceptable standards for classroom listening environments?
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-acoustical modification of classrooms
-reduce speaker-listener distance -use classroom amplification systems (free field or FM systems) -locate rooms away from external noise sources -use landscaping -use internal acoustic treatments -use small group instruction |
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Define multimodal perception. and how does this relate to speech?
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-Cues for perception are available simultaneously from more than one sensory modality.
-For speech this is most often auditory and visual modalities. |
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Define speechreading.
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speech recognition using both auditory and visual cues.
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Define lipreading.
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the process of recognizing speech using only the visual signal and other visual cues such as facial expressions.
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True or False: the terms speechreading and lipreading are synonymous.
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False!
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What is the bottom up approach to speechreading?
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-sensory reception of the segmental aspects of speech that are visible (vowels and consonants)
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What is the top down approach to speechreading?
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-cognitive-linguistic component. skills used to attach meaning to the message (facial expressions, gesture, use of contextual information)
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True or false: Everyone speechreads to some extent, not just D/HH.
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True, but D/HH rely more on speechreading when communication than normal hearing persons
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What is the 3 stage process model to speechreading? (bottom up)
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stage 1 - A and V cues are extracted
stage 2 - cues are integrated stage 3 - central mechanism applies semantic/syntactic constraints |
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What factors affect speechreading performance? (4)
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-speaker/sender (talker)
-signal/code (message) -environment -receiver/speechreader |
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What aspects of the speaker/sender/talker affect speechreading? (6)
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-extent of image (viewing angle)
-lip movement -facial expressions/gestures -speaking rate -familiarity of speaker -visual distractions |
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What is the best viewing angle for adaquate speachreading?
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0 to 60 degrees
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What is normal conversation speech rate? and what is slowed, clear speech rate?
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-normal - about 150 words/minute
-slowed, clear - 90 to 100 words/minute |
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What are examples of visual distractions for speechreading?
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-cigars, etc
-facial hair -excessive jewelry -chewing/eating |
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What percent of sounds in English are visibly different?
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30 to 40% (doesn't mean we can only visually interpret 30-40% of what is spoken)
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True or False: Vowels are more difficult to speechread than consonants.
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True (because most changes occur within the oral cavity)
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What are characteristics of front vowels? High front vowels?
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-vary in amount of lip speading or narrowing
-high front vowels have greatest spreading or narrowing |
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What are characteristics of back vowels? High back vowels?
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-vary in degree of lip rounding or pucker
-high back vowels have the greatest lip rounding |
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Consonants produced in the back of the mouth are easier to speechread than those produced in the front of the mouth. True or False?
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False
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What are other issues that affect consonant identification?
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-visemes
-homophenes -homophones |
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What are visemes?
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-In English, this refers to groups of sounds that share common visual (place of articulation) characteristics. That is, they look alike visually.
-experts have used anywhere from 4 to 12 groups to classify them -some people have their own way of producing phonemes -place of articulation changes when we put sounds together |
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What are homophenes?
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-concept related to visemes
-words that look alike visually -grouped into visemes -about 50% of English words are homophenous -egs. mat/bass, bill/pill, hit/hike/hide |