SRT
(stimulus type, open vs. closed, word lists, etc)
also when/how to mask
- speech recognition threshold
- spondee
- closed set
- no carrier phrase required
- visual cues are only ok in the familiarization stage
- patient is familiarized with test items
- MLV or recorded presentation
- ## recorded in dB HL
- masking: when the SRT of the test ear, minus the best bone conduction of the non test ear (from 500-4000 hz) is greater than interaural attenuation
- ——SRTte - best BCnte >/= IA
- level: start 15 db above the SRT of the NTE, then find a plateau
SAT or SDT
(stimulus type, open vs. closed, word lists, etc)
- speech detection/awareness threshold
- cold running speech
- open/closed set and carrier phrase don’t apply
- patient not familiarized with test items
- presentation is MLV or recorded
- recorded in dB HL
QuickSin
(stimulus type, open vs. closed, word lists, etc)
- quick signal in noise
- sentences in noise at different SNRs
- open set
- no carrier phrase required
- patient is not familiarized with test items
- recored in SNR loss (the db separation requried bewteen signal and noise)
WRS (or SDS/SRS)
- word recognition score / speech discrimination score (CID-22 or NU-6)
- PB lists monosyllabic words
- open set
- carrier phrase is required
- patient is not faimilarized with test items
- presentation: recorded
- ## recorded with % correct, test, & number present
- masking is always needed if it is for SRT
- mask if the presentation level is more than the interaural attentuation above the best BC of the NTE
- level: set level (no threshold search)
- —-for up to a mild HL: SRT + 40
- —-for anything over a mild HL: UCL - 5
tympanogram type A
normal peak compliance (.2-1.6) and pressure (-125–+125)
- can have sensory/neural loss
tympanogram type As
normal pressure but reduced compliance (<.2)
- s= stiff (small peak)
- can occur with: immobolized ossicles; thick TM; begining or end of an ear infection
type Ad tympanogram
normal pressure but excessive compliance (>1.6)
- can occur with: flaccid ear drums; separation of ossicles
type B tympanogram
no peak at any pressure (check if ecv is normal-> .5-2.0)
- smaller ecv: bony portion blocked with cerumen
- normal ecv: middle ear full of infected fluid
- larger ecv: eardrum with a hole in it
type C tympanogram
normal compliance but negative peak pressure (< -125)
- end of an ear infection
- eustachian tube dysfunction
- allergies, congetsion, ET blocked
reflex arc for right ipsilateral and contralateral ART pathway
- ipsilateral: stimulus in right ear-> RIE (inner ear)-> RVIII (auditory nerve)-> RCN (cochlear nucleus)-> RSOC (superior olivary complex)&VII(facial nerve) nucleus-> RVII-> R acoustic relfex-> probe in right ear
- contralateral: stimulus in right ear-> RIE-> RVIII-> RCN-> LSOC&VII nuclues-> LVII-> left acoustic reflex-> probe in left ear
what may produce an absent/elevated response vs a normal response?
(in an ART)
ie. acoustic reflex threshold
- absent= not present at the highest level (115 dB HL on audsim)
- elevated= 100
- possible causes:
- middle ear problem
- 60 db hl or worse cochlear hearing loss
- damage to auditory nerve or facial nerve
1. the ear with the probe assembly must not have any outer or middle ear pathology
2. the ear with the stimulus must recieve a tone that is loud enough
3. the neural pathway must be adequate to activate the contraction of the stapedius
- normal ART are in the range 70-95 db hl
- we also expect them to be at 70-90 db SL (referencing the pure tone threshold) ->can’t really interpret hem until after we find pta
- possible causes:
mild to moderate cochlear hearing loss (30-60 db hl)-> with cochlear loss, acoustic reflexes occur at reduced sensation levels (<70 db hl)
what are the hearing loss configurations?
flat, sloping, rising, cookie bite, precipitous/steeply sloping, corner, noise notch
always describe from least loss to worst, unless it is rising then worst to least
degrees of hearing loss and dB HL levels they occur at
normal: -10-25
slight (KIDS ONLY): 16-25
mild: 26-40
moderate: 41-55
moderate/severe: 56-70
severe: 71-90
profound: 91+
what does “VT” mean on an audiogram next to a bone conduction threshold?
vibrotactile response (felt rather than heard)
what is an SOAE
spontaneous otoacoustic emission: continuous tonal signals that occur without any stimulation–present in about 50% of normal ears (if they have them they prob have a normal iner ear and middle ear)
- a person may have multiple SOAEs at different frequencies
- not used clinically
what are EOAEs
otoacoustic emissions that are produced in response to an acoustic stimulus
- two kinds that are used by clinical audiologists: transient and distortion product
what is a TEOAE ?
how is it tested/what stimuli is used to evoke it
transient evoked otoacoustic emissions
- 2 choices of evoking stimuli (called transient becuase it is a very short stimulus- but lots of them)
- —-clicks (broad band)
- —-tone pips (very brief pure tones
- in a single test, several hundred stimuli are presented in rapid succession-> what the ear produces in response:
- —–a broadband sound (ie contains energy over a broad frequency range)
what is a DPOAE?
what is the evoking stimuli and how are they measured
what is the response?
distortion product otoacousstic emissions
- evoking stimuli: two steady pure tones, presented simultaneously
- —called primaries with frequencies F1 and F2
- F1 is always taller and F2 is always higher pitched
- relationship between F1 and F2 is preset to maximize test sensitivity
- in a single test, the primaries will sweep through the whole audiometric frequency range
response:
- several pure tones, all mathematically related to the primaries (called distortion products)
- primary levels & frequencies are chosen to maximize the imission at 2F1-F2
example: F1= 1000 Hz; F2=1200 Hz–> F(dp)= 800Hz
what is a DP-gram
plot of DPOAE levels as a function of F2 frequency
- each point on x-axis reflects the functional status of a specific region of the cochlea
- you want a big separation between the nosie floor and the response (should be at least 6dB greater than the noise- ie SNR)
- SNR required to pass: 6 dB or greater for at least 75% of frrequencies
what is eletrocochleography (EcoG)
measurement of the earliest evoked potentials (changes in brain acitvity in response to specific stimuli) that come from the cochlea
what is ABR and what does it test?
the auditory brainstem response is an EEG based waveform with several peaks and troughs that are produced by electrical potentials recorded from neural generators in teh brainstem in response to a click or tone burst
- can tell us funcitoning all the way up to the brainstem
- patient has to be still and the room can’t have lots of electricity (because it could interfere with the test)
what waves to we look at when measuring an ABR
(auditory brainstem response)
- wave I: distal portion of VIII cranial nerve
- wave II: proximal part of VIII cranial nerve
- wave III: superior auditory complex
- wave IV: hits pons and lateral lemniscus
- wave V: midbrain, lateral lemniscus, and inferior colliculus
explain latencies and amplitudes (in relation to ABR) and how we interpret/use them
- latency: the timing of a response relative to the stimulus (in other words: the time at which a particular wave on the response occured)
- —the response that has the widest clinical application is the auditory brainstem response (ABR)
ABR occurs in the first 10 ms after the stimulus
- generated by the auditory nerve and auditory brainstem
- thus, normal ABR implies normal cochlea
- different types of latencies: absolute, interpeak, interaural
- amplitudes: individual wave amplitudes
- —amplitude ration between wave V and wave I -> V/I ratio: wave five should always be bigger
what is EHDI?
early hearing detection & intervention
- OAEs then automated ABR (AABR) if infant does not pass
- AABR is preferred for babies in the NICU
