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90 Cards in this Set
- Front
- Back
audiometer calibration |
-daily biologic calibration and listening check -acoustic calibration (annual) -exhaustive callibration (every two years) |
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advantages of insert headphones |
1. prevents collapsed canals 2. hygiene (disposable) 3. greater sound separation between ears 4. greater attenuation of background noise |
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transducers |
transfers energy from one format to another -earphones/bone oscillators |
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bone oscillator placement |
forehead- more reliability mastoir- allows more power to test at higher levels -most use mastoid |
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artificial mastoid |
turns vibrations into electrical signals |
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main audiometer components |
-oscillator -attenuator -interrupter switch |
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oscillator |
generates pure tones |
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attenuator |
controls the intensity level of the signal |
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interrupter switch |
controls the duration of the signal that is presented to the patient |
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three modes of bone conduction hearing |
-compressional -osseotympanic -inertial |
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compressional bone conduction |
primarily for high frequencies; skull vibrations sent directly to bony walls of cochlea -skull vibrates segmentally |
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osseotympanic bone conduction |
broad range of frequencies; skull vibrations sent directly to bony walls of ear canal and tympanic membrane -skull vibration segmental and whole |
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inertial bone conduction |
primarily for low frequencies (100Hz and below); skull vibrates as a whole -ossicles mimic the movement as a whole in the opposite direction |
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under normal listening conditions, vibrations from bone conduction hearing send sound |
outwards as well as inwards |
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when ear is occluded, vibrations from bone conduction are |
deflected backwards into the audiory system, causing more acoustic energy to reach the cochea |
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occlusion effect |
articifial enhancement of bone conduction hearing caused by occluding the ear (increased amount of sound reflected back to the cochlea) -NOT an improvement in bone conduction hearing, only artificial |
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occlusion effect is greatest when |
occlusion is at or near the concha; audiometric headphones we use cause this |
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enhancement of bone conduction hearing is caused primarily in the |
low frequencies |
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bone conduction thresholds artificially enhanced by: |
250Hz = 15dB 500Hz = 15dB 1000Hz = 10dB occlusion effect negligible above 1000Hz |
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insert earphones result in |
less occlusion effect depending upon the depth of their insertion -probably from lessening of the effects of osseotympanic bone conduction with further insertion |
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anything that obstructs the conductive mechanism will cause |
an occlusion effect; wax, foreign object, middle ear fluid, ossicular disarticulation, etc. |
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Weber fork tuning test |
-usefull for asymmetric hearing loss -select a 250Hz or 500Hz tuning fork, strike on bony prominence (not hard surface), place on patient forehead or midline of skull |
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Weber - interpretation |
normal: midline sensation of hearing, same in both ears (normal or equal loss) abnormal: tone louder on one side; if conductive loss, louder on affected side, if sensorineural loss louder on contralateral side |
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Why does Weber test lateralize in poorer ear if conductive loss? |
greatest conductive component |
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in Weber test, if tone lateralizes, it does so in ear with |
the greatest conductive component or with the greatest sensorineural reserve |
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masking causes |
an occlusion effect -causes more of vibratory signal to reach the inner ear |
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audiometric techniques should be |
consistent and clear = credible |
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seating |
seat patients so they can't see your face but you can see theirs; 90-degree angle is good |
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instructions |
-listen for tones, will be faint, one ear at a time, respond every time you hear a tone even if you just think you hear it; give instructions before placing ear phones on patient |
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before placing ear phones |
-ask patient to remove hearing aids, glasses, etc. that might interfere with placement -have patient pull hair back -ask not to chew gum, smoke, drink, etc. -phones off |
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which ear to test first |
better ear first- if neither better, either is fine |
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ear phone placement |
-AuD should do, not patient -center ear phones directly over ear canal opening -adjust headband to appropriate height -if patient re-adjusts, check -insert earphones places with outer flange at concha |
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duration of text tone |
-1-2 seconds "on" -interval between tones at least 2 seconds |
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familiarization |
-familiarize patient with test tone at 1000Hz at audible level, if no response raise dB by 20 |
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threshold determination protocol |
-start at 4-dB; if no response, raise by 20dB until first "yes" -for each "yes", go down 10dB until first no -at first no, go up by 5dB until "yes" -repeat and stop when "yes" occurs 2/3 times at same level -retest at 1000Hz- difference more than 5dB, reinstruct patient and start over |
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correct testing method |
ANSI S3.21- standard |
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standard audiogram x axis |
frequency in Hz (~250-8K) |
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standard audiogram y axis |
hearing level in dB (starts from -10) |
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symbols (unmasked) |
x = left unmasked o = right unmasked less than sign = left BC unmasked greater than sign = right BD unmasked |
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symbols (masked) |
square = left masked triangle = right masked ] = left BC masked [ = right BC masked |
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ear symbol colors |
right ear = red ink left ear = blue ink |
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downward arrows show |
no response, shown at limits of equiptment |
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interaural attenuation |
headphones vibrate the head- some sounds reach normal ear so you need to mask |
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crossover |
contralateralization of the signal; signal perceived by other ear |
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cross hearing |
when stimuli presented to the test ear stimulates the cochlea of the non-test ear |
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clinically accepted interaural attenuation values |
supra-aural earphones: 40dB insert earphones: 60dB bone-conduction oscillator: 0dB |
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unmasked shadow curve |
air conduction in good ear and bone conduction in test ear are the same because of interaural attenuation |
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lack of a legitimate shadow curve |
pseudohypacusis |
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masking |
when the sound "covers up" another sound |
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clinical masking |
done to eliminate one ear from the hearing test |
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nontest ear |
ear getting masked and not being tested |
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minimum masking |
just enough masking to shift the NTE |
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under masking |
not enough masking, when the NTE is still participating in the test |
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sufficient masking |
you can STOP with accurate results for the test ear |
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over masking |
too much masking, when the masker crosses over to the test ear |
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effective masking |
refers to the calibration of masking levels, tells exactly how much masking you're using |
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masking dilemma |
when both ears have large air-bone gaps and masking can only be introduced at a level that results in overmasking -minimum is the same as initial |
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Stenger Principle |
-two tones of the same exact frequency and phase are delivered to each other; right ear receives 80dB and left ear 40dB -patient will report that a tone is heard only in the right ear (and vice versa) -if tones the same, hear it in the middle of the head -test unilateral pseudohypacusis -if patient answers "yes" they're it's negative, if "no" they're faking -can use to estimate threshold |
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uses of speech audiometry |
-corroborate the PT audiogram -word recognition -differential diagnosis -auditory processing -estimating communicative function |
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clinical applications of speech audiometry |
1. speech-recognition threshold 2. speech-awareness threshold 3. word-recognition score 4. sensitized-speech measures |
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calibration tone level |
1000Hz |
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two speech test methods |
-monitored live voice -use of recording materials |
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MLV vs. recorded materials |
MLV- faster, just as accurate, more flexible (most clinics use) recorded materials- more precise, accurate, reliable, normed |
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speech recognition threshold |
-measure of speech threshold -typically use spondees -75% right |
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speech recognition ability |
-measure of clarity -supra threshold -typically use monosyllabic or sentence material -recognize words enough to repeat |
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speech threshold |
lowest level at which speech can be recognized or detected |
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spondee threshold |
the lowest level in decibels at which spondees can be recognized correctly -measure of threshold sensitivity for recognizing speech -estimate of hearing sensitivity |
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spondee |
bisyllabic word enunciated with equal stress on both syllables |
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speech recognition threshold |
lowest level in decibels at which speech can be recognized correctly -sentences, spondees, etc. |
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speech detection threshold vs. speech recognition threshold |
lowest level at which listener can detect signal vs. actually understanding speech |
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speech reception threshold |
50% of spondaic words can be identified |
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Why spondees? |
intelligibility curves rise from near chance to 100% performance within a few decibels; more accurate threshold |
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supra-threshold speech recognition ability |
ability to correctly recognize speech at supra-threshold levels -100% at 80dB HL -96% at 40dB SL |
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bone conduction speech recognition thresholds are |
useful in children and malingerers |
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range of comfortable loudness |
uncomfortable loudness level - speech recognition threshold -unchanged in conductive losses, can be much smaller in sensorineural hearing loss |
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word recognition testing |
client responds to words with set or open responses |
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phonetically balanced word lists |
phonemes appear with same frequency as in normal lexicon |
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suprathreshold |
levels above threshold (worse hearing), may indicate retrocochlear disorder |
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pure-tone average (PTA) |
500, 1000, 2000 Hz (should agree with SRT) -sign of presbycousis if not unless high-frequency losses |
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carrier phrase |
used for word-recognition testing (ex. "Say the word...") but not for SRT |
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establishing a speech-recognition threshold (SRT) |
present spondees, ascend by 10dB until patient responds, descend by 15dB; ascend by 5 until 2 correct |
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speech detection threshold |
may be used when patient can't identify the words (ex. babies) |
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word recognition rollover |
a decrease in speech recognition ability with increasing intensity level |
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auditory adaptation |
process by which a constant audible tone becomes inaudible over time |
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WRS list length |
four 50-word lists |
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Word Intelligibility Picture Identification (WIPI) |
-assess speech recognition for pediatric clients, 6 pictures to choose rom |
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performance-intensity functions |
word recognition scores obtained at a range of stimulus levels; may drop at higher levels (rollover) |
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PI rollover |
8th nerve tumor |
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California consonant test |
another speech word test; lists; distinguish initial and final target phonemes |
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directions for speech recognition testing |
giving directions and familiarizing patient with words is good, guessing okay |