Audiology for Auds Flashcards

Asha
Terms Definitions
OAE Facts
Low intensity sound generated by OHC motilityfreq specific probably not essential for hearing but a by-product of active processing of healthy OHCs
Purpose of OAE assessment?
-indepedent site of lesion test-monitoring OHC function(ototoxicity)-Cross check for other tests-Coroborate SOL with test battery-corroborate audio configuration
OHC facts
2-5 rows12,000150 hair on each celltaller row connect to tectorial membrane5% of afferent fib ers innervate OHCsefferent synapse to dir. to base
Benefits of using OAES in audiological assessment?
a separate look at cochlear function, spec. OHC functionsensitive to HL ~ 30 dBHLif present some feel optional to perform tympanometryMay be more sensitive for detecting changes in ME functexcellent to corroborate behavioral tests
TEOAE VS DPOAE stim?
transient evoked = clickdistortion evoked + 2 eliciting tones evoke a distortion product which is measured
Stimulus level for OAEs
80 dBre SPL65/55 dBSPL for OAEs
DPOAEs occur as a result of?
2 tones presented to cochlea a distortion occurs in the form of another tone that is not present in the eliciting tone f1 &f2 presented 2f 1 minus f2 measured (cubic difference tone
Neither TEOAE nor DPOAe are effective in detecting HL at _______ Hz?
500 Hz
ASHA 2004 guidlines for Aud. assessment of children birth - 5 years (acoustic immittance)
0-4 mos tympanometry 660 w/1000Hz probe tone5-24 mos 226Hz 1000 Hz probe25-60 mos 226 Hz middle ear reflexes do at 5-60 mos500,1k,2k,ipsilaterally,contralaterally if concerns
Why tympanometry so important in testing infants and children?
it's an objective measure of ME function
Acoustic Admittance is?
a measure of ease that energy from a probe tone flows in the systemmmhobest at peak of the tympanogram at pressure extremes admittance decreases (more energy reflected into the ear canal
unexectedly small ear canal volume indicative of?
- probe against canal wall- clogged probe- impacted cerumen- atresia, stenosis
Ear canal volume (vec) is 3 times greater than expected indicative of?
TM perforationpatent PE tubelack of sealnorms = adult 0.6 -1.5 mlchildren 0.4 - 1.0
Peak static admittance norms?
Adults 0.37 - 1.66children 0.35 - 1.25infants 0.26 - 0.92 mmho
What is the prevalance of Middle ear effusion in infants?
in full term well babies 17 per 1000 (w/cond loss)in NICU babies - 36 per 1000if ME effusion present won't get normal ABR won't pass OAEwill get referred
OAE results are influenced by the presence of? TEOAEs are absent in ~ 70% of children with abnormal ____?If OAEs are primary screening tool, significant failures due to?
- Middle ear effusion- tympanometry- middle ear effusion
> 4months 220/226Hz tympanogram valid for detecting____?Why not appropriate for
- middle ear effusion- high freq proe tone of 678 or 1000Hz should be used due to the different resonant characteristics in infants of Middle ear
Present acoustic reflexes means?
- peripheral hearing is adequate to present sensation level- intact afferent auditory nerve- intact crossover cochlear nucleus->SOC- intact efferent motor facial nerve- intact stapedius muscle- ME function WNL to observe slight contraction
What other group may have a need for high frequency immittance?
a subset of 5-7 months olds with Middle ear effusion. They can get false negatives with low frequency probe tones so use 1000 Hz or 660 Hz
Peak Static Acoustic admittance is based on?
the calibrated equivalent ear canal volume- 2cc or 2ml for 226 Hz probe tone- 3 time larger for 678Hz- 4 X larger for 1000Hz tone
The most common abnormal patterns for infant tympanometry are?
- trough shapeleft to right upward slopingabnormal findings are common in infants who had a long NICU stay
Tone specific ABR stimulus parameters?
Transducer - ER3A insertsPolarity - alternatingIntensity - as requiredRate - 39.1/secContra noise - white noise 30 dB below level required to behaviorally mask tone ipsilaterally
what population requires sedated ABR?
children 4 mths to 5 yearschildren at high risk for neurological dysfunctionuse chloral hydrate or Versedphysician present monitor HR and BP crash cart
ASSR parameters
single/multiple frequencyfast rate - 75-110 steady state evoked responses elicited by amp modulated or freq modulated continuous tones
ASHA 2007 position state for confirmation of HL in infants & toddlers 0-6 mos
- child and family histor-OAEs, ABR to confirm type, degree, configuration-Acoustic immittance including reflexes-Behavioral response VRA,CPA Speech detection and recognition- Parental report of auditory and visual behaviors-Screening of infants communication milestones
Auditory Neuropathy/Dis summary
- several underlying mechanisms(IHCs,Synaptic gap,8th nerve)- common characterisics = OHC function present(OAEs) and CM.Absence of neural synchrony, absent MEMR, abnormal or absent ABR
Risk factors for AN/AD
Hyperbilrubinemia,Anoxia,Hyposia, Extreme prematurity, congenital brain anomalies, demyelinating conditions ie MS, syndromes associated with other neuropathies, immune disorders, infectious diseases, viral infections w/fever
Assessment and Referal of children sequence
1. confirm and quantify hearing status2. refer to medical hme, otalaryngology,genetics,opthalmologist 3. referral for early intervention & support early development network
6 stages of fitting process?
Assessmenttreatmentselectionverificationorientation validation
Pediatric Working Group developed professional guidlines for HA fitting of children...
Binaural unless contraindicatedBTe preferredprescriptive approach direct real ear of indirect using RECDvalidation to demonstrate benefits/limitation of HAuse performance outcomes -speech measuresfunctional outcomes (questionaires to teachers parents children)follow 0-2 years every 3 monthsfollow up >2yrs every 6 months
Pediatric amplification Protocal AAA 2003Amplification goal for children with HL?
- make speech audible- comfortable level- provide as many acoustic cues as possible-w/o over amplifying sounds
LTASS =
Long term average speech spectrum
Evidence of Verification of HA efficacy?
-Visual displays of audibilityAided thresholdsaided speech testspaired comparison testingsubjective reports obligatorycortical auditory evoked potential
Real Ear Coupler difference defined?
Real ear levels minus 2cc coupler levels
Effectiveness of amplification is best determined by?
-evaluating aided performanceusing subjective reports & objective electrophysiological measureshome based- ELF,ITMAIS, CHILD, PEACHEducational- SIFTERChild- C-APHAB, COSI-C PEACH
IT-MAIS
(6mos-3 yrs) Infant toddler meaningful integration scale- uses interviewer formatdeveloped for children with profound HLEvaluates childs ability to use sound meaningfully in every day situations
C. H. I. L. D.
(3-12 years)administered by family member or audiologist-HA benefit assesment-ALD needs assessment-monitoring of auditory prescription
S.I.F.T.E.R.
Screening instrument for targeting educational risk- teacher rating, pre academics attention, communication, classroom participation and social behavior
Hearing loss risk factors 2007
Family hist of childhood HLcaregiver concerninterutero infection(TORCH)craniofacial anomaliesNICU >5 daysUse of ventilation,ototox medssyndrome associated with HLhyperbilirubinemaneurodegenerative disorders such as HuntersPost natal infections especially bacterial meningitishead trauma requiring hospitalizationchemotherapy
Behavioral measurement techniques for young children?
Observational Audiometry >6 mos VRA-visual reinforcement w/conditioned head response> 2 1/2 Conditioned Play audiometry
What are some signs of unidentified childhood HL?
Lack of awareness to soundSpeech & lang delayPoor Speech intelligibilityDistractibilityBehavior problems
If OAEs are present what does it mean?
Cochlear (OHC) function and most likely hearing is WNL
If OAEs are absent, what does it mean?
Cochlear (OHC) function is abnormal (provided middle ear function is normal) there is HL present > 20-30 dBHL
If OAEs are present but ABR is absent?
Possibility of AN/AS or other neurological pathology must be ruled out with further testing
Essential components of a successful Early Hearing Detection and Intervention program?
Screening before 1 monthDiagnosis before 3 monthsIntervention before 6 monthsMedical home, Data management and tracking, Program evaluation and quality assurance, family support
In normal individuals: ABR absolute latency of Wave IWave IIWave V
I = 1.6msIII = 3.7msV = 5.6ms at 75dBNHLpeak latencies should replicate within 0.1ms
Amplitude of ABR vave III and V are typically larger at what age>
1st year of lifeamplitude increases up to age 4 then declines with ageadults have up to 2 times smaller amp. than infants and toddlers
Conductive HL has what effect on ABR waves?
- prolongation of all waves but inter peak intervals remain WNLshift in latency due to reduction in level of the signal arriving at the cochlea by the conductive loss
Neural Generators of ABR
Wave I = distal VIII nerveWave II = proximal VIII nerveWave III = Coclear nucleusWave IV = SOC and CN and LLWave V = LL and IC
Before there were Early intervention programs... the average age of identification of HL was?
30 months for severe to profound SNHL school age for mild to moderate HL (2nd or 3rd grade)
Why is early identification so important?
Because research has shown that children identified by age 6months can be expected to attain language development on par with thir normally hearing peers
What is VRA
-An operant discrimination procedure-cues infant that a response will result in a visual reinforcement-the head turn is increased by application of a reinforcement
When unconditioned response procedures are used what occurs quickly?
HabituationSticking rigidly to protocols should be avoided as the state of the baby will change within a test
What can Behavioral Observation audiometry contribute to?
-can give partial information about low frequency hearing-give additional information about hearing of neurologically imature babies where there may be doubts about the accuracy of ABR-partial information about functional benefit of HAs -some indication s of uncomfortable loudness levels aided or unaided
Pro's and con's of using OAEs for NB infant screening
not good if too much background noise in environment or infant is too active- cost of equipment less than ABR-affected by transient MI effusion or presence of vernix in the ear canalfor this reason may have higher false positive rate than ABR
ABR pro's vs cons for NB infant screening
higher cost of equipment-due to placement of electrodes, more time consuming-more specific than OAEs-can over lie ME conditions
NICU babies admitted for > 5 days are to have __________ included as part of their screening so that ________ will not be missed
ABRNeural HL
For children...Screening begins when and continues how throughout their life?
Screening at birth-nursery schools, playschools, childcare centers and headstart programs- at school at initial entry to elementary annually from K-3in 7th grade and 11th grade or as otherwise needed
Current screenings detect Hearing loss of ?
> 30dB HL
According to ASHA 1996...Difference betweenDisorderImpairmentDisability
- identified with anatomic, outer ear, otoscopic, tympanometry- something not functioning as it should- lack of ability to do something because of impairment determined by individual
Audiologist responsibility in school district?
-oversee the school based screening program-plan the protocal to be use-train those who will do the screening-supervise them-plan for follow-up procedures to be implemented
What tests are done in screenings for children?
Pure tone testing 20dB at 1k,2k,4k Hz Pass is 2 of 3 times in all Hz both earsTympanometryotoscopy
Follow up procedure for "refer" in hearing screening for children
Audiologic eval to confirm auditory status optimally within 1 month no later than 3
What documentation si included on forms for hearing screenings of school age children?
Childs identifying infoscreening equip usedvisual otoscopic resultspure tone screening resultstympanometyr resultsreferral recommendations signature and release
During the screening what happens with the "refer"?
We reinstruct and rescreen once if a child referseither at same session or within 2 weeksif child does not pass again refer to audiology as outpatient for an appointment within one months time
Stats of OM, what happens if OM goes unnoticed and untreated for long periods? hence... we screen for ?
-35%of preschool children have recurrent episodes of ear infections-get intermittant HL med problems may develop-can cause long term effects on speech and language learning-tympanometry
A childs behavioral hearing test is complete when thresholds are obtained from what frequencies?
250-4000 Hz
What is the "Cross check" principle?
a way to confirm behavioral results- must cross check with immitance and OAE results
What does a test battery approach accomlish?
-furnishes detailed information-avoids drawing conclusions from a single test-allows for the identification of multiple pathologies-provides a comprehensive foundation for observing a childs auditory behaviors
What is the minimum information needed in order to select pediatric amplification?
ear specific responses at 500 & 2000 Hz
Speech discrimination testing for >5 yrs and
PBK 50-3 lists of phonetically balanced words selected from the spoken vocabulary of Kindergartners-open set
What is WHIPI?
(Word intelligibility by picture identification)-Age >4
What is Nu Chips? used for by whom?
used for speech discrimination- ages >2
What is the purpose of Speech testing?
to determine whether speech when presented at a comfortably intense level, passes through the ear clearly as it should with NH or cond loss or whether it is distorted by the ear as with SNLH
Middle ear screenings refer criteria?
Bilateral cases require immediate referral, unilateral can wait 6 wks/retestTympanometric width >200daPaor compliance 1.9cm plus flat type B tymp
What type of sounds can a fetus hear before birth?
low frequency sounds such as talking and heartbeat of mother
At how many weeks is the inner ear (fetus) able to transmit neural impulses?
22 wks
At what age do children have myaline maturity?
7 to 13 years of age
At what age is the cochlea at adult form?
two years of age
While the human cochlea and middle ear are functional at birth, what is very immature?
The central auditory system
The ABR is not mature until what age?
about 2 years of age
When testing children if a conductive HL is suspected start pure tone testing at what frequency?
higher frequencies
If SNHL is suspected begin pure tone testing with
low frequencies
ASHA - what ages should children be tested over lifetime?
at Birth to 6mos7mos to 2 years3 yrs to 5 years5 yrs -18yrs adult
The lowest level at which speech can be recognized or detected?
Threshold of speech SRT - Any kind of speechST- spondee thresholdSAT - speech awareness thresholdSDT - Speech detection threshold
The Ling sounds are:
ah, oo, ee, ss, sh, mmcan use these for non verbal children in detecting sounds
Stages of speech perception?
detectiondiscriminationidentificationcomprehension
Considerations for testing speech perception in children?
-use language an vocab the child can understand-performance should reflect conversational speech-test should provide analytical info about what speech features are perceived-test/retest reliability should be sufficiently small
ASSR - advantages
-uses sophisticated mathematical detection algorithms to objectively detect responses-can simultaneously test binaurally up to 4 frequency specific stim in each ear-more efficient in detecting down to 500 Hz and detecting severe to profound losses
Purpose of hearing screening?
To detect those who need follow up
challengs to early detection of infants
-shortage of pediatric audiologists for evaluation and intervention-referals for diagnostic audiologic not being made consistantly-inadequate third party reimbursement-lack of early intervention services especially for mild losses-inadequate tracking & management of failed screenings due to data systems.-families inability to understand the advantages of early identification and intervention.
8 principles of JCIH 2007
1.all infants have access to screening before 1 month age2. all who fail initial screen and rescreen have audiological & medical evals to confirm HL by 3 months3. confirmed losses should receive intervention before 6 mths4.early detection system should be family centered ,informed choice,shared decision making & parental consent5. access to high quality technology,HA,CI, FM systems6. all infants & children should be monitored for HL in medical home, with continued assessment of communication7.Appropriate interdisiplinary intervention programs for deaf HOH infants & families should be provided by qualified professionals8. interface information with electronic health records
Changes in JCIH 2007
1. Definition expanded to include neural hearing loss(AN/AD)in infants admitted to neonatal intensive care unit2. separae protocols recommended for NICU & well baby nursuries. >5 days in NICU have ABR, if they don't pass referal to audiologist for rescreening & comprehensive evaluation including ABR3. complete rescreening on both ears even if only 1 ear fails.4.for readmissions to NICU when there are conditions related to potential HL repeat screening recommended before discharge.
More changes in JCIH 2007
- at least 1 ABR recommended as part of a complete aud diagnostic evaluation for children younger than 3 yrs for confirmation of permanant HL-for families who elect amplification, child should be fitted within 1 month of diagnosis-for infants with confirmed HL genetics consultation offered to family-confirmed HL infants be evaluated by otolaryngologist , and opthamologist -all families with infants with any degree of bilateral or unilateral permanant HL should be considered eligible for early intervention services, both home based and center based- for all infants, regular surveillance of developmental milestones, auditory skills, parental concerns & ME status performed periodically according to American Academy of Peds. -all children should have an objective standardized screening of global development with validated assessment tool at 9,18,24,30 mths of age or any time there is a concern-infants who don't pass speech language portion of global testing should be referred to speech language pathologist.
What is the difference betwee behavioral audiometry and auditory evoked potentials?
behavioral audiometry evaluates the conscious level of hearing .AEP is the neural synchronous response to a stimulus & there for not a measure of conscious hearing
What are advantages of using wave V latency values versus I-V interpeak latencies for neurodiagnostic assessment?
For some patients with severe SNHL Wave I is absent. Without Wave I you cannot measure I-V interpeak latency.Having wave V absolute norms can be useful for these patients measureing V&V ILD, can be the best technique for patients with absent wave I. Measureing I_V offers greater comment on neural firing along the neural pathway. I-V is preferable for measurement and can be used to measure IV &I-V interaurally.
What are the generators of the Middle latency response?
Primarily the auditory cortex-thalamocortical activity-subcortical activity in the extralemniscal auditory pathway-early components can be contaminated by myogenic activity susceptable to wakefulness & age-comment on non-organic HLobjectively assess effectiveness of CI -useful in research on functional role of Aud. cortex in auditory processing
What are clinical applications of MMN (mismatched negativity)?
an objective and quantifiable index for evaluating sensory representations in the central auditory nervous system. for investigating:- APD, Parkinsons,applications with amplification
What is signal averaging?
technique of averaging successive samples of electroencephalographic activity time locked to a stimulus inorder to reduce unrelated signals & thus improve the signal-to-noise ratio
What are evoked potentials?
Electrical physiological activity occurring in peripheral& central nervous system in response to stimulation
Strengths of ABR neurological evaluation
-sensitive to space-occupying lesions and neural pathway integrity-high abnormal rate in patients with VIII nerve tumors-noninvasive-normal response well defined-good normal response reliability
What are limitations of ABR neurological evaluation?
not sensitive to central nervous system disorders above the brainstem-affected by peripheral HL-may miss small VIII nerve tumors-some subjectivity in marking waveforms
Why request an evoked potential test?
-can be used to construct an audiogram in patients incapable of voluntary responses.-in adults to rule out retrocochlear or demyelinating process-to identify AN/AS- to assess aided thresholds when behavioral testing is not possible
What does ABR track?
Allows tracking of electrical energy via the auditory neural pathway to the level of the IC
What is neural synchrony?
the ability of a group of neurons to activate simultaneously
Recording factors that affect ABR
-electrode montage-filter settings-time window-number of channels-number of sweeps
ABR electrode montage
placement at vertex & ears/mastoid is optimum .-wave I-III more prominant in ipsilateral wave -IV and V better separated in contralateral
ABR filter settings
100-3000 for neurological30-1500 for tonal
ABR time window
varies with age and intensity & type of stimulus- 10-12 ms for click stim- 15ms for babies-tones require 30 ms
Number of channels for ABR?Number of sweeps for ABR?
2 channel is the preferredusually 1000-2000 sweeps are adequate in quiet patients
Patient factors affecting ABR
-age babies more robust I,III,V-gender, females shorter latencies tend to have shorter intervave latency and higher amplitudes-body temperature:- rise in body temp decrease in latency.-reduction in temp increase latency-muscle artifact can obsure waves as can nystagmus
What stimulus factors can affect ABR?
Intensity-decrease -->increase latencyRate- >30 stim/sec --> all components of ABR increase in latency, amplitude decreasesPolarity-rarefaction slighly shorter latency, ampl higherFrequency-higher freq stim elicit shorter latency than lower (place on basilar membrane)monaural vs binaural-usually reflect response of more normal ear. Will not reveal presence of unilateral disorder
Specific effect of polarity on ABR
Rarefaction- (oval window pulls out) causes upward movement of the basilar membrane causing depolarization. Latency is slighty shorter, ampl higher for early componentsCondensation- stim may produce slightly longer latency & amplitude tends to be largerAlternating - reduce stimulus artifacts
In ABR Testing what does the signal averager do?
converts physiological response to digital response-converts analog electrical activity from amplifiers to a series of numerical values(digital). digital values processed by computer, summed, averaged. Response time period determines window of digital values
(ABR) Improvement of SNR can be aided by use of ?
filtersfiltering is incorporated within the amplifier.band pass filters are use
effects of muscle artifact on ABR
-most myogenic potentials are averaged out-excessive neck & jaw tension can obscure wave detection-spontaneous nystagmus w/eyes closed leads to muscle artifact and can interfere with recordings
Effects of cochlear HL on wave V of the ABR
will be normal with louder presentationsout of normal range with softer
Effects of retrocochlear HL on wave V latency ABR
-not very different from conductive-should use bone conduction to cross check
Earlier waves (I,III) harder to see below what intensity on ABR
50bBnHL
Which transducer used in ABR causes longer latency?
insert earphones because of tubing~.9 ms longer
Peak latency in ABR is determined by?
mechanical & physiologic processes in the cochlea,VIII nerve and BS-cochlear transport time-cochlear filter build up time,filter impulse response time at site of activation-synaptic delay between Inner HCs & VIII nerve-neural conduction time plus synaptic delays to point in BSthere fore cochlear & retrocochlear processes affect latency
Who should be referred for ABR?
- unexplained dizziness-unilateral or assymetrical tinnitus-asymmetric SNHL-progressive SNHL-unexplained, elevated, absent assymetrical MEMRs-unexplained poor speech recognition in noise-PIPB rollover, tone decay, AR decay -SNHL>30dB with present OAEs at impaired frequencies-asymetrical perception & performance
What types of conditions would you likely see abnormal auditory evoked potentials?
-Patients with MS or other demyelinating processes-hyperbilirubinema-at levels that require exchange transfusions-patients with severe high freq HL8th nerve tumors
What is a transient stimulus response? (ABR)
a single response evoked by an acoustic click. Essentially instantanious onset of brief duration (0.1ms)
What is a sustained stimulus response?
Responses that reflect either repeated or continual stimulation
(ABR) What is Amplitude ratio V/I
amplitude of positive peak I or V to the following negative trough (I prime or V prime)
As a child gets older what happens to overall latency of peaks in ABR?
latency decreases - better more efficient processing & increased myelination
What is Interaural Latency difference in ABR?
Compares absolute latencies of wave V collected from stimulation of the right vs left ears at equal intensity levels. Should not be more than 0.2-0.4ms
ABR parameters that are evaluated when looking for otoneurological pathology?
-Interpeak latency between I-V-Interaural wave V latency differences-Absolute latency of wave V
Why recommend tone evoked ABRs over click evoked for threshold assessment?
Research shows that tone evoked ABRs provide information about frequency specific impairment that click evoked ABRs miss.
Tone evoked ABR thresholds in normal hearing adults are typically....
10-20 dBnHL
Tone evoked ABR threshold in adults w/SNHL are typically...
5-15 dB higher than pure tone behavioral thresholds
Tone evoked ABR thresholds in children w/SNHL are typically...
10dB lower to 10dB higher than puretone thresholds
Characteristics of AN/AD
-behavioral thresholds anywhere from normal to profound-poorer thresholds in low frequencies-variable responses from test to test but generally reliable within a single test-reflex may be absent regardless of the degree of HL-speech discrim poorer than behavioral audiogram would suggest-HAs of less benefit than behavioral audiogram would suggest-greater difficulty hearing in competing noise than behavioral audiogram would suggest & other features indicative of auditory processing difficulties
Diagnostic criteria for AN/AD
-OAEs-cochlear microphonic obtained from ABR using specific recording techniques-test of auditory nerve function (ABR)-acoustic reflex-suppression of OAEs by contralateral noise
Assistive hearing intervention for AN/AD
-hearing aids-FM system-cochlear implant-cued speech/signing crucial(auditory verbal therapy is ineffective)
At initial assessment in babies click ABR absence or abnormal could be due to?
-Hearing loss -SN or cond.-delayed maturation-or AN/AD
If OAEs /CM absent suspect?
SNHL/CHL
If OAEs /CM present with abnormal ABR suspect
AN/AD or delayed maturation
What is the trade off that occurs when using tone burst ABR?
-tone burst gies greater frequency specificity-but generates poorer neural synchrony which will affect the quality of the response (greater rise time means less synchronous firing)
For presentation of click stimuli, what length time window is recommended?
10-12 ms is usually sufficient- Wave V occurs in NH ~5-6ms of stim at high intensities-Wave V occurs within 8-9 ms for intensities near threshold-for patient younger than 18 mos 15 ms is recommended- tone bursts use 20ms window
Reason for using simultaneous 2 channel recordings for ABR?
-to avoid electrode misrouting errors that occur in 1 channel when operator forgets to change the ear electrode or incorrectly assigns it.-to determine the presence and location of Wave I by comparison to the contralateral recording (Wave I not present in contralateral)
At what age do ABR responses start to look like adult responses?
18 months or older
Testing parameters for air conduction click ABR for neurological evaluation?
Stim = 100ms clickpolarity= rarefactionrate= fast =61.1 slow 19.1intensity=80dBwindow = 10-12msfilter = 100-3000 Hz2 channel -Cz to A1, Cz to A2sweeps= 1000-2000replications = 2
ABR test parameters for tone burst (500, 1k,2k, 4k, Hz)
polarity = alternatingrate = 41.1/secintensity = start 80-->50 drop by 10db to 30dB if posstime window = 21.33filters = 300-1500 Hzsweeps - 2000Wave V should shift as intensity decreases
To increase Wave I amplitude you should ...?
- increase intensity-decrease ratecompare rarefaction & condensation clicks to distinguish cochlear potential from neural responses
Wave I prolongation reported in what MI condition?
Otitis Media, will return to normal after issue is resolved
Wave V latency intensity functions reported to correlate well with?
ear canal occlusion & ME effusion but not ossicular chain disorders
Click stimuli provide maximal stimulation in what freq range?
2000Hz to 4000 Hz -thus reflect activity primarily from more basal portions of the cochlea
What polarity is recommended for bone conduction ABR?
alternating polarity
Comparing separage averages of both rarefaction and condensation stimuli will aid in identificaton of patients with ?
AN/ADCochlear microphonic will invert and be larger in AN/AD
When either the click or the 500 Hz tone burst responses are not present at expected normal levels (ABR) do what?
ABR using bone conducted clicks-clicks are presented at progressively decreasing intensities via bone conduction to determine whether there is a difference between responses with air vs bone.If diff...conductive or mixed loss
The primary task when interpreting ABR is to ?
determine whether the observed deviation is due to pathologic condition or non pathological reason
What objective test is good to monitor drug ototoxicity and noise exposure?
OAEs are able to track early changes
What is an otoacoustic emission?
Any sound that is produced by the cochlea and detected in the ear canal
How many OHCs do we have?
12,000
How many stereocilia on each OHC?
~150 on each cell
What percent of afferent fibers innervate OHCs?
~5 %
What quality do OHC have?
Electromotility
A by product of electromotility of OHCs is?
generation of replication of the input or-the otoacoustic emissionOAE probably not essential for hearing rather they are a by product of active processing of healthy OHCx
When stimulus rates are increased in ABR testing from slow to fast this has what effect on Wave V latency?
Increases Wave V latency more than 0.6 to 0.8 ms
How do spontaneous OAEs affect the evoked OAEs?
The presence of SOAEs affects both the spectrum and the levels of TEOAEs measured. SOAEs can synchronize to the evoking stimulus resulting in peaks at those frequencies in the TEOAE spectrum. A greater number of peaks can be found in clicked evoked spectra of subjects with SOAEs than in those w/o any measurable SOAEs
Auditory peripheral & central pathway =
cochleaspiral ganglionauditory nerveCNSOC MTB LLIC MGBauditory cortex
What OAE results would you expect with middle ear effusion?With PE tubes?
No OAE with effusionNormal OAEs with PE tubes because the evoked sound is able to get to the inner ear to elicit the responseME neg pressure could keep OAEs from being detected
Problems encountered in collecting OAEs from infants?
-outer ear canal debris from birth-middle ear pathology-noise floor especially at 500Hz & 1k Hz- hospital not quiet-infant cooperation during placement of probe
ABR & OAE not a test of hearing but a test of?
Neural function and neural synchrony
Alcohol has what effect on ABR latency?
Alcohol leads to reduced temperature thus increases latencies
ABR to brief tones cannot distinguish what type of hearing loss?
Severe to profound "no response" for ABR can occur at 85-120 dBHLASSR better for distinguishing severe to profound
What polarity is used for bone conduction ABR and why?
-Use alternating polarity to avoid large electrical artiact emitted from transducer
There are basicaly 4 degrees of hearing loss
-Mild loss 26-45 dB, a little difficulty hearing speech . Even a mild hearing loss can be serious for children learning to speak-Moderate loss 46-65 dB-Severe loss at 66-85dB-Profound loss is anything over 85dB. At this level hearing aids may or may not help
Unilateral hearing loss will make hearing difficult for children or adults in certain situation
-hearing faint or distant speech-difficulty localizing sounds and voices using hearing alone-difficulty with background noiseor in reverberant conditions- a child with unilateral HL may be acused of having selective hearing due to discrepancies in speech understanding in quiet versus noise. -Child may become more fatigued in classroom setting due to greater effort needed to listen-child may appear inattentive distracted or frustrated
Conductive HL may be temporary or permanant. Some causes...
-buildup of earwax-ear infection-disarticulation of ossicular chain
SNHL is almost always permanant and is most often caused by
presbycusa a form of age-related HL that destroys hair cells.
Many areas have been identified as being vulnerable to the aging process... some are
-atrophy of support cells in organ of corti-degeneration of hair cells within the cochlea-loss of neurons throughout the auditory pathway-degeneration or thickening of the capillary walls of the stria vascularis-degeneration of the spiral ganglion-shrinkage of the spiral ligament
Some facts about Presbycusis
-can be sensory, neural, strial, cochlear, conductive, mixed and indeterminate in nature-the cumulative effect of ageing on the ears-affects men more than women-usually bilateral-usually affects the high frequencies-happens gradually-older adults require increased S/N ratio-experience recruitment due to reduced dynamic range
The efferent neural system plays a critical role in audition and is _____ in efficiency with age
decreased in efficiency
Neurons originating in the SOC or (____ ____)innerv ate hair cells within the cochleamedial group -lateral group-
(efferent neurons)-Medial group -large myelinated crossed neurons innervate OHC directly-Lateral group - smaller unmyelinated uncrossed neurons innervate IHCs by way of synapses on afferent fibers
Efferent nerve fibers are thought to ...
-alter membrane potential-improve detection of signals in noise-offer protection from loud noise-help control the mechanical state of the cochlea & play a role in attention -decrease in efficiency with age
Type of HL = Severity of HL = Configuration of HL =
-locational (location within the auditory system)-quantitative (in decibles above 0 the normal hearing threshold)-qualitative (as visualized on the audiogram, abnormal in high freq =HFHL, noise induced= notch at 4k, ascending vs decending, gradual vs precipitous
A persons eustachian tube must function normally in order for a
myringoplasty to work
If an examiner finds a patient has a missing or decreased corneal reflex in one eye which of the cranial nerves is affected that could indicate an acoustic neuroma?
Trigeminal nerve- the corneal reflex, involuntary blinking, caused by touching the edge of the cornea, objectively identifies facial sensation. If it is missing in an unconscious patient, it can diagnose brainstem dysfunction - if found missing or diminished in a conscious patient, the nerve affected is either the facial or trigeminal nerve. if a patient has a larger acoustic neuroma affecting the trigeminal nerve it will cause a decrease or absence of corneal reflex on one side.
The US centers for disease control & prevention find that ___ % of all US citizens have had some kind of balance problem at some point in their lives
~ 50 %
The epley maneuver or canalith repositioning procedure involves the audiologist rotating the patients head into different positions while the patient lies on the table with head hanging over the edge. this procedure does what?
moves debris or canaliths backward out of the labyrinth into the vestibule- research finds this maneuver is effective for 50% of patients vs 19% with a placebo treatment
Epley maneuver is contraindicated when?
where there is any unstable heart condition or disease, could trigger cardiovascular incidents, severe carotid arterial stenosis or cervical spondylosis with myelopathy because of the procedures stress on the neck/cervical spine and its blood supply
Which of the following is true regarding myringoplasty?a)ossiculoplasty should be performedb)stapedectomy should not be performedc)neither should be performedd)both may be performed
B) a stapedictomy should not be performed at the same time as a myringoplasty because creating an opening to the inner ear while the ear drum is not intact carries too high a risk for SNHL- okay to do ossiculoplasty
Gradenigo's syndrome is the name for the grouped symptoms of ?can be caused by?
-severe earach, otorrhea, diplopia or double visioncaused by suppurative otitis media
with regard to a symptom, what are vessicles ?
small cysts on the outer ear and or the ear canal -symptoms of herpes Zoster oticus virus also calledRamsey Hunt Syndrome
When indicated a stapedectomy can have what results?
resolve or minimize a conductive HL and/or cause or exacerbate SNHL-it can resolve or minimize a conductive loss by freeing the stapes to move again or by removing an overly compromised stapes & replacing it with a prosthetic
Screening procedures to detect unilateral or bilateral SN and or conductive HL greater than ___ dB are assessed for what frequencies for what age range
20dB 1k, 2k, 4k
What is an ASHA certified Audiologist
professional who has the knowledge, skill and expertise to evaluate hearing impairment
ototoxic chemicals are thought to damage the delicate cochlear structures by...
producing radical oxygen species or free radicals that deplete natural antioxidant substances. What follows is oxidative stress and the beginning of cell death that in the cochlea leads to hearing loss
In some instances, exposure to what will increase ototoxic effects?
exposure to loud noise while taking certain meds
What is interoperative monitoring?
monitoring of the VIIIth nerve during surgery involving this nerve (for acoustic neuroma vestibular schwannoma removal or vestibular neurectomy) This testing continuously monitors how the ear is responding to click stimuli during the entire operation
Disorders of the EAC include
-otitis externaotomycosiseczematoid (psoriatic otitis externa
If you SRT is 5 dB you can understand speech perfectly at ___ ft
21 feet and still catch some words at over 100 feet
An SRT of 30 dB you could only hear perfectly at ___ ft but could still hear some words at ___ ft
1 footsome words at 18 feet
If your SRT is 60 dB (mod severe)you would need the speaker to be only __ __ from your ear in order to hear perfectly and within ___ft to still hear some of the words correctly
1 inch from ear to hear perfectly1 foot to hear some
What is the DSL method described by Seewald 1985 for HA prescription?
-make speech sufficiently audible to alow speech perception, without discomfort , for all degrees of HL
Warble tones commonly used for what?
in real ear measurement as they are not easily influenced by standing waves from reflective surfaces
Ethical considerations in Audiology
the term ethics refers to a group of moral principles or set of values. To act ethically you must conform to professionally endorsed principles and practices
An adult with a perforation will generally notice...
a hearing loss.-water entering the ear when showering or swimming may be painful and cause dizziness. Frequent swimmer ear infections may be a symptom of an undetected perf.-flying with a severe cold can also perforate an eardrum due to changes in pressure-the sudden sensation of severe pain and a bloody discharge from the ear may signal a perf. medical attention should be sought
Wideband measures of reflectance and admittnce may be use to
estimate the ipsilateral acoustic stapedius reflex threshold by separating in frequency the spectral energies of the wideband probe stimulus from the activator stimulus
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