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149 Cards in this Set
- Front
- Back
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Signals delivered to the TE can cross to the NTE by... |
AC, BC, or both |
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Shadow curve? |
Poorer ear presents thresholds reflecting configuration of the BC of better ear, separated by about 50 dB |
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Interaural attenuation? |
loss of energy in dB as sound travels from TE to NTE |
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Formula to mask for AC |
AC (TE) - IA >= BC (NTE) |
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Formula to mask for BC |
ABG (TE) > 10 dB |
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What is IA for BC, headphones and insert phones? |
BC = 0 headphones = 40 insert phones = 70 |
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When should you mask? |
Whenever crossover is a possibility, better to mask than not to mask when in doubt |
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How do you mask? |
Present noise to NTE
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Types of masking noise? |
white noise/broadband narrowband speech noise
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What is effective masking? |
minimum noise required to make a signal inaudible 20dB EM masks 20dB HL at 1000 Hz, etc. |
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What is the unit for effective masking? |
dB EM |
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Over masking? |
Noise is presented so intensely that the noise crosses the skull and produces masking in the TE, causing a threshold shift |
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Central masking? |
When masking is introduced in NTE, causes small shift ~about 5 dB Produced by inhibition Via CENTRAL AUDITORY PATHWAY |
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Under masking? |
Not enough noise in NTE to cover tone |
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Describe plateau method |
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BC masking formula |
EM = AC threshold NTE + OE OE= occlussion effect |
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Why is BC masking difficult? |
Arrangement of headphone/insert and bone conductor TE must remain uncovered while NTE is covered to deliver masking noise |
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What is the occlusion effect at 250, 500, 750, 1000 Hz? |
250-20 500-15 750-10 1000-5dB |
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Why do we have speech testing? |
Gives us better information about auditory function and perception |
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What are four types of speech stimuli? |
Nonsense syllables Words Sentences/phrases Paragraphs |
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What is optimum speech testing level? |
35-40 dB SL |
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What level is avg conversational speech? |
55 dB HL |
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What is considered "loud levels" |
85-90dB |
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What is MLV |
Monitored Live Voice varies, can be very flexible/faster/slower as needed |
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What is the preferred mode of speech testing? |
Recorded presentation Output is calibrated/standardized and same for all testers |
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What is a VU meter? |
Allows you to visually monitor the intensity of speech for MLV speech testing *majority of speech testing is still performed by MLV* |
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What are the test-types for speech testing? |
Open-set (no clue) Closed -set (list of words or pictures) |
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Carrier phrase? Benefits? |
A phrase to prompt testing No research proves it enhances scores |
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How are responses accepted in speech testing |
Oral (preferred) written signed picture pointing |
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What are some reasons oral responses may not be effective in speech testing? |
Misunderstanding/ articulation issues Bilingual/ ESL Young Age |
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What is SAT or SDT |
Speech awareness (detection) threshold lowest level a patient can detect speech is present Stimulus - short running speech (bababa) |
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What is SRT? |
lowest level a patient can recognize a set of words closed set test may be MLV or CD stimulus - spondees |
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What is the stimulus for: -SAT/SDT -SRT -WRS |
- short running speech -spondees -PB word lists |
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What are spondees? |
two-syllable words with equal emphasis |
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PTA SRT Agreement |
PTA and SRT should be +/- 7 dBHL PTA and SAT should be +/- 10 dBHL ensures accuracy |
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Formula for Fletcher Average |
average of the two best (lowest #) frequencies at 500, 1000 or 2000 Hz |
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When do you use a Fletcher average? |
if one of the PTA frequencies is different by 20dB such as in precipitously sloping HL |
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What is WRS? |
Word (speech) recognition score measures % words correct at a set level usually 35-40dB SL and at 85dB HL stimulus - monosyllables PB words |
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What is PB? |
A LIST or words that is balanced to represent elements of a language
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How do you calculate WRS? |
Open Set 50 words, 2% each Half List 25 words, 4% each perfect score is 100% |
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Does WRS predict real world comphrehension? |
NO, especially if the test was conducted at MCL real world is noisier than a testing booth, speech is usually only 8 dB louder than background noise! |
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What can good/bad WRS scores indicate? |
Very good - invalid pure tone results Very bad - possible retrocochlear issue AN/AD |
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Guideline ranges for scoring WRS? |
Excellent = 100 Good = 80-99 Fair = 60-79 Poor = 0-59
differences of >=20% are signification when looking at 50 word lists |
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How do you test for roll-over? At what level? |
WRS repeated at 80-90dB HL normal = WRS is same or better abnormal = WRS decreases *sign of retrocochlear involvment, nerves can't handle increased signal |
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What is MCL? |
Most Comfortable Loudness 40-55 dB SL above threshold use running speech to test |
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What is UCL? What does it tell us about hearing? |
Uncomfortable Loudness Level HL - MCL and UCL are close normal hearing - MCL and UCL 40/50 dB apart |
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What is speech in noise testing? |
Words/sentences presented over varying background noise to stimulate real world hearing |
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How do you calculate Signal to Noise Ratio? |
Difference of speech relative to noise Speech - Noise = SNR 55dB - 35dB = +20dB SNR |
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Formula for masking for speech testing |
SRT (TE) - IA >= best BC (NTE) at 500, 1000, 2000, 4000 Hz |
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Formula for masking for WRS testing |
WRS (TE) - IA >= best BC (NTE) at 500, 1000, 2000, 4000 Hz |
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What is acoustic immittance often called? |
Middle ear measurement Technically you're measuring the TM, to assess ME function |
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What is tympanometry also called? |
Acoustic immittance testing !! more than just tympanogram!! |
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Define: immittance |
generic term that encompasses impedance, admittance, and compliance |
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define: impedance |
total oppostion of the ME to the flow of acoustic energy |
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define: admittance |
opposite of impedance, the amount of acoustic energy that flows through the ME |
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define: compliance |
opposite of stiffness/impedance |
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Features of an immittance tool |
Three tubes attached to metal probe, fitted in EC with seal. Tubes > loudspeaker (220Hz) 1- miniature loudspeaker 2-tiny microphone 3- air pump (create +/- air pressure) NTE= an insert earphone
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What does tympanometry measure? |
Middle ear pressure Mobility of the TM as a function of various amounts of pressure in the ear canal Results in graph |
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What are the 3 measurements of tympanometry? |
1 - equivalent volume 2 - static compliance 3 - middle ear pressure (level where maximum compliance is reached) |
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What are the axis of a tympanogram? |
x-axis = middle ear pressure daPa or mmH20 y-axis = static compliance (amplitude of peak) |
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What is a normal measurement for: compliance ECV MEP |
compliance: .3-1.7 cc ECV: .9-2 ml MEP: -149 to 100 daPa |
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Type A sharp peak MEP, SC, ECV all within normal limits |
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Type As shallow suggests stiffness still has peak normal MEP SC .1-.3 (lower amplitude) ECV normal |
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Type Ad deep suggests flacid eardrum or ossicle disarticulation MEP normal SC > 2 ECV normal |
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Type B no peak no SC or MEP measurable normal ECV - otitis media small ECV - wax/occlusion large ECV - PE tube or perforation |
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Type C significant negative middle ear pressure SC normal MEP <= -150 daPa ECV normal why? eustachian tube, otitis media |
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What is an acoustic reflex? |
Contraction of stapedius muscle always bilateral observed around 85-100 dB SPL with normal H |
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How do you measure acoustic reflex? Starting at what level? At which frequencies? |
Start at 70 dB HL with a pure tone Up 10, down 5 until threshold or limits Measure compliance to see change Test at 500, 1000, 2000 (sometimes 4000) |
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Two (sides) of AR tests |
ipsilateral - sound measurement in same ear contralateral - sound in one ear, compliance recorded in the other |
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Name the ipsilateral reflex pathway |
external auditory meadus middle ear inner ear auditory nerve cochlear nucleus superior olivary complex (then up to brain and down CN VII to other side of head) |
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Contralateral reflex pathway |
EAM middle ear inner ear auditory nerve cochlear nucleus >>trapezoid body >>>>contralateral superior olivary complex |
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How are AR recorded |
Graph or table |
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Acoustic reflexes measured ipsilateral only |
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What do acoustic reflexes indicate? |
absent = ME pathology, VIII nerve damage, damage in brainstem
very low = not understood
elevated = indicates hearing loss >100dB |
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Why test acoustic reflexes? |
cross-check against other tests doesn't tell you extent of hearing loss |
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T/F - all people have acoustic reflexes? |
False - some people don't have AR and yet have normal hearing |
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What is reflex decay? |
When TM is contracted by loud/high frequency, nerve will eventually weaken its hold normal for high frequencies abnormal for low frequencies |
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How do you measure reflex decay? |
Present signal 10 dB about ART Determine # seconds to reduce amplitude by 50%, or document no change after 10 seconds Test at 500/1000 Hz CONTRALATERALLY |
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What might cause abnormal acoustic reflex decay? |
Lesions to the AN (3-5 seconds) Facial nerve damage |
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What are spontaneous OAEs? |
Noise emitted by normal cochlea, occur in over half the population 1000-3000Hz, from -10 to +10dB SPL (not audible to person, not same as tinnitus) |
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What are evoked OAEs |
Evoked OAEs occur during/immediately after an acoustic stimulus in the ear canal Standard practice in pediatric facilities |
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What are the two types of evoked OAEs? |
Transient Distortion Product |
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Why test OAEs? |
Determine cochlear status, specifically OUTER hair cell function. - differentiate between sensory/neural HL -rule out feigned loss |
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Procedure for Transient Evoked OAE test. |
Stimulus: clicks Analyze data and subtract background noise HL > 35-40 dB will show NR normal/mild H will have present TEOAE |
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What is Distortion Product OAE? |
stimulus- two tones of diff Hz and dB, cochlea receives tones and produces a response at a diff frequency you can get diff responses by varying the two tones (freq. specific)
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What type of test? |
Distortion Product OAE |
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What type of test? |
Transient Evoked OAE |
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What are the four limitations of OAEs |
1- do not show where disorder is in pathway 2- require very quiet and still patient 3- results don't distinguish degree of HL 4- conductive pathway must be clear |
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What does AEP stand for? |
Auditory Evoked Potentials
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What do AEPs measure? |
measure/anaylze the electrical responses generated in the cochlea and up through the brainstem/cortex |
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How is an AEP test conducted? |
Electrical responses to auditory stimulus Recorded by surface electrodes Subdivided by where they occur on auditory pathway |
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Define: latency |
time period that elapses between introduction of stimulus and occurrence of response |
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From 0-200ms, what are the three "periods" we meauser AEPs |
1 - early 1-15ms 2- middle 15-60ms 3- late 50-200ms |
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Examples of Early AEPs (2) What is the origin site measured? |
1- Electrocochleography (ECoG) 2- Auditory Brainstem Response (ABR) origin: CN VIII |
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Where do AMLR and ALR tests originate? LR= latency response |
They both originate from the cortex |
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Process of AEP measurement |
1- stimuli are presented at constant rate 2- EEG equipment reads/amplifies electrical activity from the brain 3- Computer sums/avgs response, filters out noise |
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What does ECoG stand for? |
Electrocochleography |
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What is ECoG? |
Auditory evoked potential that examines electrical response WITHIN cochlea INNER hair cell function
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What are the 2 uses of ECoG |
1- monitor cochlea during surgery 2- diagnose inner ear such as Meniere's |
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What type of test is this? |
Electrocochleography ECoG |
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What does ABR stand for? |
Auditory Brainstem Response
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What does ABR measure? |
neurologic responses to auditory stimulation through electrodes on the head
within 10ms of stimulation |
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What do we look for in ABR results? aka ABR is characterized by? |
Latency of waveform response 5 distinct peaks
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Adult ABR set-up |
-awake/asleep or very still -electrodes on mastoid/earlobe, forehead, and/or nape of neck -insert earphone in ears stimulus = rapid click |
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Measuring ABR response |
main, positive peaks are measured, label 1-5 -if present, intensity is lowered til undetectable -if absent, intensity is raised until response seen |
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Where are waves 1-5 generated? |
I - CN VIII exits cochlea II - CH VIII enters Cochlea Nuclei III - contralateral superior olivary complex IV - lateral lemniscus/ inferior colliculus V - " " |
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What are the 2 reasons to give an ABR? |
1 - assess auditory nerve function (neurologic) could indicate retrocochlear tumors
2 - estimate threshold of hearing (audiologic) define type/ estimate severity after failing newborn screening (or in cases where behavioral tests are impossible) |
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What 5 qualities (not peaks) do you measure on an ABR? |
1- absolute latency 2- interpeak latency 3 - wave amplitudes 4 - threshold of wave V 5 - comparison low click rate/ high click rate |
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On ABR, what do absolute latencies indicate? |
Each wave should occur at specific time Latencies are compared to normative data Long latencies indicate pathology |
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As intensity ______________________, wave latency ________________________. |
decreases increases |
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What interpeak latencies do we measure? Why? |
1 to 3 1 to 5 3 to 5 compare to normative data, looking for tumors along brainstem, prolonged interval indicates site of lesion |
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Why measure wave amplitude? |
Best used to compare between ears not diagnostic |
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As intensity _____________________________, wave amplitude _________________________. |
decreases decreases |
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As intensity increases... wave amplitude ________________________ wave latency __________________________ |
WA -increases WL - decreases |
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Why measure threshold of wave 5? |
-most robust wave of ABR - estimate hearing sensitivity (start at 70 and reduce til wave 5 disappears)
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What is the ABR threshold? |
Lowest level where wave 5 is still visible and replicable |
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what is this test? |
Normal Auditory Brainstem Response ABR |
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What does this ABR test show? |
A person with auditory neuropathy AN/AD |
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What ABR results indicate neurologic concerns? (4) |
1- interpeak intervals 2- diff latencies between the ears 3- amplitude ratios are abnormal 4 - wave V is prolonger or disappers at high click rate |
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What ABR results indicate audiologic concerns? (2) |
1- overall latency of all waves shifted (CHL) 2- wave V is not present at normal levels |
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What does ASSR stand for? |
Auditory Steady-State Response |
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When is ASSR used? |
For patients with hearing loss that is so severe there is no ABR response |
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How does ASSR compare to ABR? |
Goes beyond, helps assess moderate to profound, not as accurate for normal-mild *works at louder intensities |
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When are AMLR and ALRs used? |
Not typical some research, may be a tool for assessing neurological development |
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What does positive/negative SNR indicate? |
+X dB SNR indicates signal was XdB louder than background/room noise -X dB SNR indicates signal was X dB quieter than background/room noise |
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What is this test? |
ABR - latency intervals |
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What is this test? |
Acoustic Reflexes |
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What is this test? |
Distortion Product OAEs (present) |
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What is this test? |
Distortion Product OAEs (absent) |
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What type of tympanogram? R? L? |
Type A both sides |
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What does this illustrate? |
Shadow curve |
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What can you tell from this info? |
Patient has perforated left ear drum. Note high ear canal volume. |
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How do you know when you've reached effective masking level? |
When you can raise/lower the masking signal three times without impacting the threshold in the TE. |
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The three tests of acoustic immitance |
1- static acoustic compliance 2 - tympanometry (ME pressure) 3- acoustic reflect |
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Compliance is the _______ of stiffness (impedance). |
inverse |
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Abnormally low static compliance suggests |
fluid accumulation stiffness of ossicles partial healing |
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Abnormally high static compliance suggests... |
interruption in ossicle chain |
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Tympanometry is generally conducted at what frequency? |
220 or 226Hz |
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CN VIII is also called the _______ |
8th cranial AUDITORY nerve |
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CN VII is also called the _______ |
7th cranial FACIAL nerve |
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what do the solid and dashed lines show? |
Solid = ipsilateral response pathway Dash= contralateral response pathway |
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Acoustic reflex delay is normal in __________ frequencies, but sig. decay in ______frequencies is__________. |
high low usually only seen in lesions of the auditory nerve or brain stem aka BAD |
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If a patient with SNHL has normal OAEs where is the pathology? |
Retrocochlear (beyond the cochlea) |
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If a patient with SNHL has absent OAE where is the pathology? |
In the cochlea AND possibly concomittant retrocochlear |
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The electrophysiologic measure of choice is the? ECoG or ABR |
ABR ECoG is considered too invasive |
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The _____ is the most important "site of lesion" test in the audiologists battery. |
ABR |
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T/F The ABR is a direct test of auditory sensitivity |
False |
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The ASSR is a good tool to reliably predict? |
Hearing sensitivity |
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Are the ABR and ASSR affected by a patients consciousness? |
No |
