CD443- Test 3
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This 18 page Study Guide was uploaded by Leah Larabee on Tuesday January 20, 2015. The Study Guide belongs to CD 443 at University of Alabama - Tuscaloosa taught by Dr. Hay-McCutcheon in Fall2014. Since its upload, it has received 273 views.
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Date Created: 01/20/15
CD 443 Test 3 Study Guide Objective Tests Otoacoustic Emissions and Evoked Potentials Otoacoustic Emnssnons Sounds the ear makes are generated by the outer hair cells OAEs are a byproduct of OHC motility Objective test First started using in 1979 Types of OAEs o Spontaneous OAE Continuous tonal signals that occur without any stimulation Present in about 50 of normal ears A person can have multiple SOAEs at several different frequencies 0 Evoked OAE Otoacoustic emissions that are produced in response to an acoustic stimulus Two kinds of evoked OAEs are commonly used by clinical audiologists 1 Transient evoked OAEs TEOAEs a Evoked by clicks not pure tones b Evoking stimuli two choices i Clicks ii Tone pips brief pure tones c Ear produces broadband sound in response using one signal to measure the responses across a lot of different frequencies 2 Distortion product OAEs DPOAEs when you put 2 frequencies into cochlea and get out more the others we get out are the distortion products a Evoking stimuli i Two steady pure tones 1 Presented simultaneously and referred to as primaries ii Primary frequencies f1 and f2 1 f2 gt f1 2 fl 1st frequency presented to ear 3 f2 2nOI frequency presented to ear iii Primary levels L1 and L2 1 L2 lt L1 b Response i Several pure tones all mathematically related to the primaries 1 Ex 2f1f2 2f2f1 3f22f1 ii Primary levels and frequencies are chosen to maximize the emission at 2f1f2 1 2f1f2 largest amplitude of distortion product emitted and easier to measure so we are most interested in this response 2 Ex f2 2000 Hz fl 1640 Hz a fDP 1280 Hz Measuring OAE 0 Probe is placed in the ear canal takes 15 minutes per ear Interpreting EOAE 0 To get a normal EOAE Cochlea has to generate the emission Ear has to transmit sound two ways 0 Stimulus has to get to the cochlea 0 Emission has to get to the ear canal o Requires normal conductive mechanism Auditory Evoked Potentials Measure the electrical activity from the brain called electroencephalography EEG When we observe changes in the brain activity in response to speci c stimuli we call these changes evoked potentials Measure by averaging 0 Response is always or Latency the timing of a response relative to the stimulus Earliest responses that are recorded are from the cochlea o Referred to as eectrococheography ECoG Latest responses that are recorded are from the auditory cortex 0 Referred to as auditory eventrelated potentials ERPs Auditory Brainstem Response ABR Occurs in the rst 1015 ms after the stimulus Generated by auditory nerve and auditory brainstem 0 Measure ABR 0 Place 34 electrodes on head 0 Test room must be electrically shielded 0 Should use insert earphones o Evoking stimuli use clicks or tone pips Presentation rate usually 331 clicks per second Presentation level depends on purpose of test 0 Response is a set of 5 to 7 small waves Named using Roman numerals lVll 0 Characteristics 0 Latencies latency of response travel time Individual waves typically look at waves l and V lnterpeak latency difference between waves in one ear typically wave l to wave V lnteraural latency difference between ears for a given wave typically wave V Wave V from superior olivary complex larger wave and latency Wave I from auditory nerve earlier latency and less travel time Latencyintensity function to get softest level of a wave and ABR threshold which is lowest level at which a reliable wave V can be measured 0 Amplitudes Individual waves have amplitudes Amplitude ratio between Wave V and Wave quotWI ratioquot Amplitude is highly variable and not typically used diagnostically Audiological purposes to assess hearing sensitivity in difficult to test patients lntraoperative monitoring during surgeries where the cochlea or auditory nerve is at risk for being damaged Neurological purposes 0 Assess health of auditory brainstem 0 Done when audiological evaluation or other symptoms suggest a retrocochlear problem 0 Much less expensive than an MRI and can rule out the need forone Pediatric Audiology Early Attempts at Hearing Loss Identi cation 19905 average age of ID for hearing loss was 3 years old 0 Bene ts of screening screen to provide early intervention APGAR scores 0 Taken at 1 5 and 10 minutes after birth 0 Assess respiratory effect muscle tone heart rate color re ex irritability o A score of 110 is given Startle Re exes o Contraction of muscles around eyes in response to loud sound 0 Problems agreement among technicians that they can miss mild to moderate losses Identifying Hearing Loss in Newborns 2007 approximately 915 of all newborns screened for hearing loss at birth 0 Goal of Healthy People 2010 to increase number of infants screened Approximately 12000 children each year have hearing loss as newborn Up to 3 per 1000 births each year have hearing loss 0 Prior to Universal Newborn Hearing Screening UNHS 0 Average age 30 months 0 Severe to profound hearing losses were identi ed earlier than 30 months of age 0 Mild to moderate hearing loss not identi ed until school age in many cases 0 Impact if you don39t have normal hearing it will affect your ability to develop speech and language Joint Committee on Infant Hearing JCIH Attempt to help improve the way children are identi ed across na on First met in 1969 did not have OAEs yet Came outwith rst position statement says we do not have appropriate techniques to identify infant hearing loss and need more research 0 Second position statement going to identify kids based on high risk register These kids are born with disabling disease or high APGAR scores Need to at least identify these children 0 At this time only had quotcribogramquot crib equipped with motion detectors that measured responses to high sounds not good enough 0 Year 2000 Position Statement all infants need to be screened using objective measures 0 Most recent statement 2007 need to continue to use objective measures to screen for hearing loss Universal Newborn Hearing Screening UNHS Objective test Otoacoustic emissions OAEs used to accomplish UNHS 0 Portable devices used by nurses and technicians and supervised by audiologist 0 Issues to consider May miss some mild to moderate osses Good at detecting conductive and cochlear hearing losses moderate to profound Easier than ABR testing less time intensive Less expensive Auditory brainstem response ABR 0 Portable devices used by nurses and technicians and supervised by audiologist 0 Issues to consider More expensive Will catch conductive cochlear and some neural losses may still miss mild losses 0 Typical procedure 0 Screen using OAEs and then do ABR if baby falls 0 2007 Position Statement Babies in NICU more than 5 days must be screened by ABR because ABR is a little more sensitive test and these children could be at higher risk for developing hearing loss 0 Issues impacting UNHS 0 Short hospital stay and technician did not get to them 0 Child failed screening but family failed to followup 0 False positives important to keep low Early Hearing Detection and Intervention EHDI programs UNHS is not just screening must follow up 1 Screening by 1 month 2 Identi cation by 3 months 3 Intervention by 6 months Risk Factors Identi ed in 2007 ICIH Position Statement 1 UN 8 9 10 11 Caregiver concern regarding hearing speech language or development delay refer to ENT immediately if caregiverparent expresses concern Family history of permanent childhood NICU stay of more than 5 days or any length for certain conditions In utero infections such as CMV herpes rubella syphilis and toxoplasmosis Craniofacial anomalies Physical ndings such as forelock associated with a syndrome that has SNHL or permanent CHL as a component Presence of a syndrome associated with hearing loss or progressivelateonset hearing loss Neurodegenerative disorders Certain postnatal infections Head trauma Chemotherapy Tisting a Baby s Hearing Otoacoustic Emissions 0 Screening otoacoustic emissions only tell you pass or fall 0 EvaluationDiagnostic OAEs tell you more frequency speci c information Auditory Brainstem Response ABR 0 Threshold ABR testing look for lowest stimulus level at which wave V is detectable 0 Use shortduration tone pips can get frequency speci c information Tympanometry amp Acoustic Re exes 0 Use a different frequency probe tone than used with adults 0 Adults 226 Hz 0 Infants lt 6 months 1000 Hz Also monitor behavioral responses to sound Why do both OAE and ABR o Auditory neuropathydyssynchrony auditory nerve is present but may not be functioning or may not be processing signals 0 Will get absent ABR but present OAEs 0 Need both to diagnose Behavioral Testing of Young Children Behavioral Audiometry Techniques 0 Behavioral Observation Audiometry Children younger than 6 months Technique 0 Play sound and look for response 0 Response is quotnot conditionedquot looking for any response to sound such as startle or eyes widening Issues 0 May only see response to high sound levels 0 Highly subjective NOT audiometry use as last resort only 0 Visual Reinforcement Audiometry VRA 6 months 2 years of age Technique Conditioned response child turns head in response to sound Conditioned because have paired stimulus response and reinforcement during trainingconditioning phase Pairing signal with reinforcement ex toy dancing bear 0 Use insert earphones Parent wears headphones so the parent does not hear the sound and prompt the child may have white noise playing in headphones Two testers 0 One in booth with child testroom examiner keep child attentive at midline social reinforcement for child don39t compete with stimulus maintain quiet environment maintain rapport with and cooperation of the parent quick assistance with earphones 0 One at audiometer 0 Both testers vitally important to success 0 Stimuli 0 Speech o Tones warbled or pulsed 0 Order of testing Depends on reason Speech or tones rst depends on how you think the child will respond if child is calm start with tones if child is fussy start with speech Order of tones 2000 500 4000 250 1000 8000 Hz Be prepared for session to end at any time Transducers 0 Speakers in booth testing both ears and don39t know which ear we are testing don t get ear speci c information o Headphones inserts are better for infants and more comfortable but supra aural can be used Always try headphones so we know speci c ear information 0 Bone Vibrator How reliable are responsesresults o If conditioned it is reliable 0 Need skilledpracticed audiologist audiologist must be able to do this 0 Get valid threshold information compared to adults and older children within 10 dB of adult thresholds o Conditioned Play Audiometry 2 years to 5 years Technique Conditioned response to sound 0 Do a play activity when hear sound ex drop a block push a button to make a toy light up place peg in pegboard o Conditioned because pairing the behavior with the stimulus during training phase 0 One or two testers 0 Two testers is ideal and more necessary for younger children 0 Tester in booth important role here too Make response fun for child 0 Important to have a variety of activities 0 May use lighted toys as reinforcement Transducers 0 Usually headphones use speakers as last resort 0 Bone vibrators Test Stimuli 0 Speech Stimuli Must be appropriate for language level Choose response understandable to tester Often picture pointing SRT Speechrecognitionword recognition closed set NU CHIPS or WlPl Open set LNT o Tonal stimuli Disorders Outer and Middle Ear Outer Ear Disorders Disorder of the Pinna o Microtia very small pinna o Anotia absent pinna 0 Disorders of the Ear Canal 0 Stenosis narrowing of the ear canal o Atresia cartilaginous or bony portion or the entire ear canal has not formed at all Have pinna and have middle ear but do not have an external auditory meatus leading up to middle ear Seen in Treacher Collins syndrome 0 CHARGE syndrome abnormalities of the pinna and external auditory meatus 0 External Otitis lnfection that occurs in the skin of the external auditory canal Swimmer s ear Can occur from allergic reaction to earplugs hearing aid ear molds soaps etc o Growths in the canal Osteomas bony tumors in the EAC and not a problem unless they cause a hearing loss or lead to external otitis and can lead to a conductive hearing loss Exostoses bony protrusionsstalagmites in the bony wall of the EAC Will have to use headphones and not insert earphones Middle Ear Disorderi Otitis Media OM o In ammation of the middle ear oTypes Acute Otitis Media Otitis Media with Effusion Effusion uid that accumulates in the middle earspace o Approximately 90 of children have otitis media before school age most frequent between 4 months and 4 years o OM more common in kids because they get more URls and their Eustachian tube is less sloped making it easier for anything to travel from back of throat to middle ear space oYear 2000 16 million doctor s visits for OM 13 million prescriptions for antibiotics o Estimated 3 to 5 billion annual costs 0 Acute Otitis Media AOM lnfection in middle ear when uid is infected it is AOM Secondary to upper respiratory infection URI Symptoms include infected uid middle ear bulging TM red TM otalgia ear pain fever otorrhea drainage rapid onset of symptoms Stages can progress rapidly o Patient has URI o Bacteria associated with URI migrate from back of throat to ME o Bacteria multiple in ME use oxygen create negative pressure in ME Eustachian tube dysfunction due to swelling of mucosa contributes to problem o Cells lining ME secrete uid that becomes infected o Substance uid in middle ear goes to TM and blocks Eustachian tube creating a vacuum in ME space Until Eustachian tube becomes unblocked it will continue to build up TM is bulging and red because uid is built up and has nowhere to go eventually will burst TM and TM will be perforated This can happen pretty rapidly Treatment watch and wait or treat with antibiotics Children younger than 6 months always go straight to antibiotics 0 Otitis Media with Effusion OME Persists beyond 8 weeks Chronic effusion nut no active infection Since uid is not infected child is not sick Fluid may cause hearing loss Fluid does not go away or drain cannot drain middle ear space Chronic negative middle ear pressure creates a vacuum Fluid present during AOM never clears Causes conductive hearing loss may be moderately severe but not more than that maximum of mod mod severe loss Audiogram at audiogram AC scores will have a loss BC scores will be normal and masked Reactance mass and stiffness increased increased mass affects high frequencies and increased stiffness affects low frequencies Speechrecognition suprathreshold test resuts will be around 6070 correct ability to understand speech will be affected if made loud enough should understand some Tympanogram Type B tympanogram volume will be high and above 20 ml Treatments 0 Watch and wait to see if it goes away on its own 0 NO antibiotics because there is no infection o Pressureequalizing PE tubes allows uid to drain 0 Cholesteatoma Pseudotumor in middle ear composed of skin keratin fats starts when skin cells enter middle ear through perforation Very destructive O 0 May erode ossicles Can erode bone and spread into pharynx or brain Can cause hearing loss conductive hearing loss Can cause pain facial nerve symptoms Can be severe if it affects cochlea Treatment 0 Surgery serious problem hearing issues secondary until treated 0 Must remove all cells and cholesteatoma or it will grow back 0 May have permanent conductive hearing loss post surgery 0 Otosclerosis Abnormal growth of spongy bone tissue over the stapes footplate most notable anatomical feature Mass increased so higher frequencies are affected Hereditary in 5070 of cases More frequent in women than men Usually first noticed in 205 and will worsen in pregnancy Symptoms o Progressive conductive hearing loss starts in low frequencies and eventually see at moderate CHL o Carhart s notch most unique audiological feature depressed bone conduction threshold at 2000 Hz results from disruption of inertial bone conduction from build up of calcium Treatment o Stapedectomy Surgery stapes is removed graft is used to seal the oval window stapedial prosthesis is placed o Hearing aids people with conductive hearing loss tend to be extremely successful with hearing aids because hearing aids amplify sounds Disorders Cochlear and Retrocochlear Issues Rubella jerman Measles Concern if caught during 1st trimester Epidemic during 1964 and 1965 0 Babies tend to be born smaller and develop more slowly Brain damage blindness heart defects SNHL Vaccine in 1969 reduced number of cases but still concern among poorer populations Cytomegalovirus CMV Typically harmless illness if not associated with pregnant mother When fetus is affected a number of devastating symptoms can be present in addition to hearing loss Can be contracted before birth through placenta during birth via cervix and after birth via mother s milk Mothers may not know they have it and may seem like an ordinary infection or virus Perhaps screening after birth might help with preventionintervention program Meniere s Disease Classic symptoms 0 O O Sudden attacks of vertigo very debilitating can last 24 hours or more may be accompanied by nausea and vomiting Roaring tinnitus Unilateral sensorineural hearing loss later stages may be bilateral Aural fullness Hearing loss characteristics uctuating and progressive sensorineural hearing loss very poor speech recognition Varies from being very mild to very severe Cause root cause believed to be endolymphatic hydrops over production or under absorption of endolymph Treatment 0 O 0 Low salt diet and diuretics Vestibular suppressant drugs Surgery Endolymphatic sac decompression Shunt Cut vestibular nerve Labyrinthectomy Tympanogram and Acoustic Re exes unilateral hearing loss right ear affected O 0000 Type A tympanogram Right ipsi present at reduced sensation levels Left ipsi present Right contra present at reduced sensation levels Left contra present Noiseinduced hearing loss NIHL Sensorineural hearing loss 0 Noise an acoustic signal which can negatively affect the physiological or psychological well being of an individual can be any sound 0 Excessive noise exposure is one of the most common causes of SNHL o TI39S temporary threshold shift 0 PTS permanent threshold shift 0 Anything over 85 dB can cause gradual hearing loss 0 OSHA expects some hearing loss after many years of exposure 0 Greater than 120 dB may cause sudden hearing loss 0 OSHA Guidelines for Time of Exposure with 5 dB gain starting at 90 dBA the amount of time of exposure is cut in half 0 90 dBA 8 hours 0 95 dBA 4 hours 0 100 dBA 2 hours 0 105 dBA 1 hour NIHL is preventable through education noise reduction or avoidance and hearing protection Stereocillia become oppy and lose contact with tectorial membrane 0 Loss of stereocillia and disarray Loss of OHCs Loss of lHCs When we lose hair cells they aren t sending information to the auditory nerve and we lose function of auditory nerve When sufficient numbers of hair cells are lost cochlear nerve bers degenerate and may then see structural and functional changes in central system 0 Hearing characteristics 0 Sensorineural loss with poorest thresholds at 30006000 Hz recovery at 8000 Hz 0 quotNoise Notchquot or quot4k Notchquot normal hearing at lower frequencies and then drop off around 4000 Hz 0 Tymps Type A tympanogram 0 Acoustic re exes both ears affected L ipsi present at reduced sensation levels R ipsi present at reduced sensation levels L contra present at reduced sensation levels R contra present at reduced sensation levels Ototoxicity Hearing loss acquired due to medications Certain medications can damage the cochlea andor the vestibular system Aminoglycoside antibiotics o The quotmycinsquot are ototoxic 0 Used for drugresistant bacteria or very severe infections Chemotherapy drugs 0 Cisplatin widely used chemotherapy drug Loop diuretics widely used medications for patients with heart failure uid retention problems pneumonia kidney problems 0 Two most common Furosemide Lasix and Ethacrynic acid Salicylates o Aspirin o Ototoxic in large doses may be reversible Quinine 0 Treatment of malaria nocturnal leg cramps o Tinnitus hearing loss vertigo 0 Symptoms generally temporary 0 With high doses hearing loss and tinnitus may be permanent Monitoring hearing status for ototoxic effects and while on ototoxic drugs 0 High frequencies usually affected rst 0 DPOAEs used in some monitoring programs Outer hair cells affected rst and then eventually inner hair cells Progression of damage on hair cells from ototoxic drugs Presbycusis Hearing loss and aging o 30 of adults over the age of 65 have signi cant hearing loss 0 Primary causes of hearing loss in elderly Noise exposure Ototoxicity Affects around 37 of population over 75 years old More prevalent in men than women 0 Audiogram o Sloping high frequency hearing loss 0 Gradual onset and progression progresses more rapidly in men 0 Chief dif culty understanding speech in noise May have poorer than expected word recognition Sensorineural hearing loss Tymps Type A tympanogram OO Acoustic Neuroma Retrocochlear tumor Tumor on the Vlllth cranial nerve Vestibular Schwanomma usually benign and slow growing very treatable if caught early Audiogram typically there is a difference in the right and left ear at one frequency or a couple frequency usually a difference of 15 dB or more Signs that may appear during a standard audiological evaluation and case history 0 Unilateral high frequency hearing sensorineural hearing loss most acoustic neuromas are unilateral and high frequency loss is because of the tonotopic arrangement of nerve bers 0 Poorer than expected word recognition especially at high presentation levels and this is called rollover 0 Absent acoustic re exes despite having a normal tympanogram 0 Absent re ex decay have re ex but it fails to persist for 10 seconds 0 Unilateral tinnitus o Dizzinessdisequilibriumvertigo Need to perform special audiometric tests 0 Otoacoustic emissions OAEs Normal OAEs indicate normal OHCs Suggest hearing loss due to retrocochlear problem 0 Auditory Brainstem response ABR Abnormal interpeak latencies and interaural latencies can indicate an acoustic neuroma Refer patient to ENT is suspect they have acoustic neuroma Treatment almost always surgery 0 Can hearing be preserved Depends on size and location of tumor and surgical approach used 0 If hearing preservation attempted audiologist may monitor hearing during surgery using ABR If not a tumor similar audiometric and ABR results can be from 0 Acoustic neuritis in ammation of auditory nerve 0 Multiple sclerosis breakdown of myelin the insulating layer around many neurons and can affect speech in noise especially 0 REFER any time you see retrocochlear signs Tymps Type A tympanogram Acoustic re exes left ear affected 0 R ipsi present o L ipsi absent NR 0 R contra present 0 L contra absent NR Syndromes and Hearing Loss Down Syndrome Chromosomal disorder extra copy of chromosome 21 0 Characteristics 0 Upslanting palebral ssures eye slits Relatively large tongue with tendency to protrude Small chin Small ngers Developmental delay 0 Small ears 0 Health problems 0 Heart disease 0 Dementia 0 Hearing problems 0 Problems with the intestines eyes thyroid and skeleton Hearing issues 0 Typically conductive loss 0 Typically unilateral and mild to moderate o Impacted cerumen o Retracted TM and middle ear effusion 0 Issues with middle ear and back of throat Causes of hearing loss 0 Susceptibility to URI 0 Congenital malformations of the nasopharynx and Eustachian tube 0 Congenital ossicular chain malformations or destruction of ossicles caused by infection OOOO Treacher Collins Syndrome Genetic disorder inherited from parent or spontaneous gene mutation TCOF1 gene is affected and doesn39t produce protein that is responsible for development of bones and tissue in the face Autosomal dominant pattern just one parent has to affected to pass it on to their children 60 of these cases are from this 0 Characteristics 00000 O O Downward slanting eyes Cleft of lower eyelid Small cheekbones Small jaw Malformations of external ear associated with stenosis or atresia of ear canal Stenosis narrowing of ear canal Atresia bony portion hasn39t formed Cleft or incomplete soft palate Dental problems 0 Hearing issues O 0000 O Pinna malformations Stenosis Atresia ME malformations poorly developed or absent Congenital bilateral conductive hearing loss is most common Degree can range from mild to moderate Usher Syndrome Hereditary syndrome 0 Characteristics 0 O O O Retinitis pigmentosa a degeneration of retina and progressive Congenital hearing loss ranges from moderate to profound typically not progressive sensorineural hearing loss Hearing and vision affected vision is progressive Sensorineural hearing loss not progressive moderate to profound Recessive disorder both parents must be carriers to pass it on o 36 of children who are deaf have this 0 36 of children who are hard of hearing have this 0 Hearing issues 0 O O Incomplete development or atrophy of basal end of organ of corti in the cochlea Atrophy of stria vascularis and spiral ganglion cells Typically have greater hearing loss in the high frequencies compared to low frequencies Some researches have reported 90 of cases have severe to profound hearing loss
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