Audiology #3

Impedance is determined by two factors

1. Resistance (R) - The force that opposes motion (friction) -Determined primarily by ligaments that support the ossicles 2. Reactance • A combination of mass (M) and stiffness (S) • Mass (M) is primarily determined by the weight of the ossicles and the TM • Stiffness (S) is primarily determined by the load of fluid pressure from the inner ear at the base of the stapes, also by stiffness of TM and air in the middle ear cavity • Dependent on frequency (resistance is not) • As frequency increases, the contribution of stiffness to reactance diminishes - leaving mass reactance dominant • As frequency decreases, the contribution of stiffness to reactance increases - leaving the system stiffness dominant • In other words, • mass is dominant in the high frequencies • stiffness is dominant in the low frequencies • As the stiffness of the system increases, it becomes less compliant (more difficult to initiate motion) • Therefore, compliance is the inverse of stiffness in the formula

Tympanometry Measurements

1. Static Acoustic Compliance/Static Admittance/Peak Compliance 2. Equivalent Ear Canal Volume 3. Tympanometric Peak Pressure 4. Tympanometric width

Reasons for testing speech perception at suprathreshold levels

1. To diagnose problems about hearing loss - speech recognition testing might inform about function of the auditory nerve and central auditory system - poorer-than-expected speech recognition abilities observed in cases of: CN VIII tumors and Auditory processing disorders (more speech than the audiogram will suspect) 2. To provide information regarding the impact of hearing loss on perception of speech - How much trouble is the listener having? Can aid in counseling, Evaluate function and efficacy of, and candidacy for sensory aids, monitor progress with sensory aids

CID everyday sentences - adults

10-sentence list -open-set

Organ of Corti is anatomically fully developed by

25 weeks gestation

Phonetically balanced kindergarten test (PB-K)

4 50 word lists 1 list is not equally difficult relative to the others Words are supposed to be in the lexicon of Ks Phonetically balanced within a list (difficult test compared to others for kids)

The time of most rapid development of inner ear:

4 weeks through 12 weeks gestation

Suprathreshold tests that are used to assess the cognitive-linguist level -Adults

Adults Open-set - CID W-22 Word Lists (phonetically balanced within a list -Nu-6 Words lists -Isophonemic Word lists -CID Everyday sentences -Hearing in noise test -quick speech in noise test -speech perception in noise test Closed-set -California consonant test -PIT

Selecting an intensity level

Amount of audibility will depend on level of signal, and degree and configuration of hearing loss Recommended levels vary: -5 to 1o dB above MCL -40 dB above SRT - Multiple intensity levels -45 to 50 dB HL to mimic normal conversational levels (counseling)

Northwestern university-children's perception of speech

Closed-set: 4 alternative forced choice picture-pointing task

Word intelligibility by picture identification

Closed-set: 6 alternative forced choice picture-pointing task

Suprathreshold speech testing: Definitions Closed-vs. Open-set Testing

Closed-set: patient chooses what item was heard from a set of options Open-set: patient response from an infinite number of possible items store in her/his lexicon

Ipsilateral vs. Contralateral Reflexes

Convention is to determine ear based on the STIMULUS EAR Sending sound to the right ear if right ipsalateral and recoreded from the right. If right contralateral sound to the right ear but recording from the left. Where are you sending the sound to?

Audiovisual-lexical neighborhood sentence test

Developed from sentences compiled by Eisenberg Video-recorded a professional female speaker who spoke a general american dialect of english Six 8-sentence lists -1/2 on each list contain 3 lexically easy key words and 1/2 contain 3 hard key words -Administered in A-only, V-only, and AV

Immittance

General term that referes to impedance or admittance • Depending on the equipment, we measure either: • Impedance of the ME • Opposition to energy transmission • Admittance of the ME • Ease with which energy is transmitted • Most equipment measures admittance (= compliance)

Genetic Disorders are due to some alteration of the _____ of the individual

Genotype

Non-genetic disorders are not directly related to the ____ of the individual.

Genotype

Branchio-oto-tenal syndrome (BOR)

Genotype: -Autosomal dominant -Variable expressivity -Mapped to a gene on chomosome 8 Phenotype: -Hearing loss in 90% -Pre-auricular pits in 80% -Branchial cysts or fistulas in 60% -Kidney abnormalities in 25% - can be fatal

Treacher Collins Syndrome

Genotype: • Autosomal dominant or sporadic new mutation • Phenotype: • Downward sloping palpebral fissures • Depressed cheekbones • Deformed pinnae and receding chin • Coloboma of lower eye lids • Often have cleft or incomplete soft palate • Often have conductive or mixed loss • Congenital bilateral conductive is most common • Malformations of ossicles (bc conductive hearing loss they usually do well with hearing aids)

Tympanometry

How we measure impedance clinically

Suprathreshold speech testing: Definitions Signal-to-noise ration (S/N or SNR)

Is really a difference, not ratio Difference in intensity between the signal and noise - if the signal is 7dB louder than the noise, the SNR =7dB -if the signal is 7dB softer than the noise, the SNR =-7dB Why add noise? -To simulate everyday listening environments -To make the test more difficult The noise used when testing speech perception is not the narrowband noise used in pure-tone testing because need a broadband signal to mask speech frequencies - Instead we use either: - Speech-shaped masker (white noise shaped to mimic the LTASS - Multi-talker babble (bunch of people talking and then mix it

Lexical neighborhood test & multisyllabic lexical neighborhood test

LNT: 2 50- monosyllabic-word lists MLNT: 2 24-multisyllabic-word lists -Based on the neighborhood activation model of spoken word recognition -Purposes that word recognition accuracy and speed influenced by: - Word frequency -Neighborhood density -Neighborhood words' frequency Lexical access and word recognition -For children, we present an acoustic stimulus that the tester knows is a word -child tries to match the acoustic event with some word in the lexicon -

If you have a disorder causing stiffness of the ME to increase, what frequencies will be effected?

Low

Classification of Tympanograms - Type B

No peak at any pressure • If equivalent EC Volume is normal, indicates fluid • If equivalent EC Volume is very high, indicates perforated TM, patent PE tube or surgically altered ear

Classification of Tympanograms - Type A

Normal compliance and pressure • Abnormal Type A subtypes: • Type AS = normal pressure, but reduced compliance (< .3 mmho) • Type AD = normal pressure, but excessive compliance (> 1.7 mmho)

Classification of Tympanograms - Type C

Normal compliance, but negative peak pressure (< -100 daPa) • Indicates negative pressure in ME • Caused by Eustachian tube dysfunction

OAEs are a by-product of

OHC motility

Suprathreshold tests that are used to assess the cognitive-linguist level -Children

Open-set -Phonetically Balanced- Kindergarten words list -Lexical neighborhood test & multisyllabic lexical neighborhood test -Audiovisual-lexical neighborhood sentence test Closed-set -Word intelligibility by picture identification -Northwestern university-children's perception of speech

Noise-induced Hearing Loss

Postnatal Hearing Loss • Classic "noise notch" around 4 kHz • Damage to cochlea's basal turn • Loss is usually symmetrical • If a rifle shooter, can show more loss opposite the shoulder that

Meniere's disease

Postnatal Hearing Loss • Classic symptoms: • Sudden attacks of vertigo • Vertigo can last 2-4 hours+ • Debilitating • Can be accompanied by nausea and vomiting • Roaring tinnitus • Unilateral hearing loss (later stages can be bilateral) • Aural fullness • Hearing loss characteristics • Fluctuating and progressive sensory/neural HL • Poor speech recognition in affected ear(s) • HL in low frequencies progressing to flat • Cause • Believed to be due to endolymphatic hydrops • Treatment • Vestibular suppressant drugs • Surgery: endolymphatic sac decompression, shunt, cut vestibular n., labyrinthectomy • Non-invasive treatments vary in use and effectiveness

Autoimmune Inn-Ear Disease (AIED)

Postnatal Hearing Loss • Presents similarly to Meniere's Disease • Differential diagnosis is difficult • Relatively rare

Meningitis

Postnatal infection • Bacteria travels from the meninges of the brain to the labyrinth • Causes mild to profound sensory/neural HL • Can have a conductive component due to AOM • HL develops early in the illness • Can lead to ossification of the cochlea • Causes are decreasing due to Haemophilus influenzae type b vaccine

Diabetes mellitus

Postnatal infection • Can present with mild to moderate bilaterally symmetrical progressive sensory/neural HL

Ototoxicity

Postnatal infection • Loss typically starts in the high-frequencies bilaterally • Aminoglycosides (e.g., gentamicin), diuretics (e.g., furosemide), or chemotherapy drugs (e.g., cisplatin)

Autoimmune disease

Postnatal infection • Rapidly progressive bilaterally symmetrical sensory/neural HL

Tympanometry Equipment

Probe contains 3 tubes that connect to: Loudspeaker - 226Hz or 1000Hz at 85 or 90dB SPL Microphone -Measures intensity level in the EC Air Pump -Changes are pressure in EC -1daPa = 1.02mm water - -200-200

Problems with clinical speech recognition testing

Reliability Variability decreases with an increase in the number of test items Not reflective of everyday listening demands

All inner ear disorders result in a

Sensory/neural hearing loss (or mixed)

Sternosis

Severe narrowing of the TM

Quick speech in noise (SIN) test -Adults

Takes less than a minute to complete -6 sentences presented in 4-talker babble -5 scored key words per sentence -Sentences are presented in 5 predetermined SNRs ranging from easy to very hard listening -Scored by determining the increase in dB required by a listener with hearing loss to understand speech like someone with normal hearing in noise -Takes less than 1 minute to complete

Immittance Bridge

Tympanometer

CHARGE Association

We don't know much about the genotype Phenotype: • C = Coloboma (defect of the eye) • Bi- or unilateral • Can affect iris, retina or disc • Degree of visual impairment varies • H = Heart Defects • A = Atresia of choanae (opening of the nasal cavity to the nasopharynx) • R = Retarded growth and development • G = Genital hypoplasia • E = Ear anomalies • Abnormalities of the pinnae • Hearing loss can be conductive or sensory/neural

Picture identification task - Adults

designed for nonverbal adults who have low literacy skills consonant nucleus consonant Response options on each trial are 4 pictured items, all of which rhyme with each other

Tympanometry is an _____ test.

objective

Inner ear develops from the

otic placode

Genesis of the inner ear is earlier than either the

outer or middle ear • Within the inner ear, the cochlea develops before the vestibular system

Contraction of both the Stapedius and Tensor Tympani muscles result in a _____ of the ossicular chain

stiffening • Result: A change in the transmission of sound through the middle ear • Primarily reduces transmission of low frequencies

Embryonic Layers

• 1. Ectoderm - develops into neural tissue, retina, cochlea, olfactory tissue, skin and glands • 2. Mesoderm - develops into connective tissue (cartilage and bone), muscle, kidney, heart, gonads, and spleen • 3. Endoderm - develops into epithelial lining of Eustachian tube, middle ear cavity, digestive system, respiratory system, liver and pancreas

Two Broad Classes of OAEs

• 1. Spontaneous OAEs (SOAEs) • SOAEs are continuous tonal signals that occur without any stimulation • Are present in ~50% of normal ears • If present, can have several SOAEs at multiple frequencies When this was first discovered people hoped that SOAEs meant that if you had them you had health outer ear cells. But only 50% have them so it doesn't represent anything useful clinically. • 2. Evoked OAEs (EOAEs) • EOAEs are produced by the ear in response to an acoustic stimulus • Two types of evoked OAEs are commonly clinically: • 1. Transient Evoked OAEs (TEOAEs) - very fast stimulus • 2. Distortion Product OAEs (DPOAEs) - in response to two different stimuli that come in at a different place

Impedance

• A moving object must overcome a certain amount of resistance to its movement • A sound wave moving through the air will strike surfaces that impede or slow its progress • The impedance of a medium is the opposition it offers to the transmission of acoustic energy • As a surface that is placed in the path of a sound wave is made more dense, it offers greater impedance to the wave. • E.g., a door is much denser than air and therefore will impede much more acoustic energy. The amount of impedance of the door will determine the amplitude of the waves that are transmitted into the room beyond the door.

Acoustic reflex threshold = the lowest....

• Acoustic Reflex Threshold = the lowest level at which the acoustic reflex occurs

Measuring the Acoustic Reflex

• Acoustic reflexes should be measured at the tympanometric peak pressure • Requires a hermetic seal • Measured two ways in each ear: • Ipsilateral: measuring probe and in the same ear • Contralateral: measuring probe and in opposite ears • Measure ipsilaterally and contralaterally at 500, 1000, and 2000 Hz • Present individual pure tones to the stimulus ear • Measure change in admittance in the probe ear • Acoustic Reflex Threshold = the lowest level at which the acoustic reflex occurs

Mastoiditis

• Acute: inflammation of mucosa • Chronic: affects bone structure • Treated with antibiotics, but might require surgery in severe cases

Tympanometric Peak Pressure

• Admittance maximum occurs when there is no difference in pressure across the TM • Indicates pressure of the middle ear and thus Eustachian tube function • Location of the peak on the X-axis • Norms: • -100 - +50 daPa

Congenital rubella syndrome (CRS)

• Also known as German measles • Greatest damage in the first trimester • Can affect hearing, vision, heart, psychomotor development • Defect might not be present at birth, but develop later in life • There was an epidemic in the late 1960s • MMR vaccine • Transmission is unclear in some cases (through placenta or during the birth process or as a result of high fever in mother - causes increased need for oxygen in the fetus - oxygen deprivation of fetus) If the fetus does not have enough oxygen the cochlea is one of the first things to be damaged. The fetus doesn't have rubella, it is a consequence of the mother having rubella.

Acoustic Immittance

• Also known as Impedance Audiometry and Acoustic Immittance • An umbrella term that encompasses: • Tympanometry • Acoustic Reflexes • Acoustic Reflex Decay

Perinatal Assaults

• Anoxia or Hypoxia - reduced oxygen • Alters cell metabolism and results in damage or destruction of the cell • Typical Causes: • Prolapse of the umbilical cord • Premature separation of the placenta • Accumulation of toxic substances in the mother's bloodstream can reduce passage of oxygen across the placenta

Bullous Myringitis

• Blister develops between the layers of the TM • Develops with upper respiratory infection • Rarely results in hearing loss

Tympanosclerosis

• Calcified scar tissue on TM • Related to chronic otitis media • Can cause conductive hearing loss

Non-genetic hearing loss with external and middle ear abnormalities - External Ear

• Collapsed ear canals • Cerumen & foreign bodies • Vernix caseosa • Bony growths - Exostoses or osteoma • Otitis externa

Teratogens

• Drugs, infections, or toxins that cause birth defects • E.g., thalidomide, cytomegalovirus (CMV), rubella • If an embryo is exposed to these early on, embryo death or major anomaly can result

TEOAEs

• Evoking stimuli: • 1. Clicks (very brief broad-band stimuli) • 2. Tone Pips (very brief pure tones) • Ear's Response: • Broadband sound (a sound containing energy over a broad frequency range)

Otoacoustic Emissions (OAEs)

• First reported by David Kemp in 1979 • The sounds emitted by the ear are very low in amplitude • The sounds emitted by the ear are almost always inaudible • But, we can measure them in the ear canal with a small enough microphone • Research has shown that these sounds are generated by the outer hair cells

Inner Ear Disorders • Can be categorized in various ways

• Genetic vs. non-genetic • Acquired vs. congenital • By age at onset • Prenatal: transmitted through placenta or inherited • Perinatal: contracted from mother during the birth process or there was an assault during birth • Postnatal: acquired or inherited

Stickler Syndrom

• Genotype: • Autosomal dominant • Phenotype: • Midfacial flattening • Long, thin extremities • Sometimes cleft palate • Bony enlargement of ankles, knees, joints during first few years of life • Joints may be very loose • Arthritis can worsen in older age • Progressive myopia • Low percentage of sensory/neural or mixed hearing loss • Mild to severe, can be progressive

Apert Syndrom

• Genotype: • Autosomal dominant or sporadic new mutation • Phenotype: • Mental retardation • Ocular hypertelorism • Flat facial profile • Syndactyly of hands and/or feet • Conductive hearing loss

Cholesteatoma

• Growth of skin from external ear than invades the middle ear through a retraction pocket in the TM • Bacteria get trapped in it • Can destroy tissue/structures • Foul-smelling drainage • Conductive hearing loss • Aural fullness • Requires surgery and regular monitoring

Herpes simplex virus (HSV)

• HSV-II (genital herpes) may be transmitted to the fetus during birth (perinatal) • HSV infections in neonates are fatal in 50% of cases • Neonates may show rash, organ dysfunction, neurologic difficulties, and sensory/neural hearing loss

Static admittance (YTM)

• Height from peak to + tail • Higher the height, the more mobile the TM • Norms: • Adults: .3 - 1.7 mmho (or cm3) • Children: .25 - 1.05 mmho (or cm3)

The level (dB) of the probe tone reflected off the TM indirectly indicates the admittance of the middle ear

• High admittance (low impedance) • Most of probe energy (sound) passes through the ME; very little is reflected • Result: LOW probe level recorded • Low admittance (high impedance) • More probe energy (sound) reflected off TM; less passes through ME • Result: HIGH probe level recorded

Embryologic Development

• Human gestation • 40 weeks from woman's last menstrual period (10 lunar months) • Premature = fetus born before the 37th week • Pre-embryonic stage • Fertilization through 3 weeks • Embryonic stage • 4 weeks through 8 weeks • Fetal stage • 9 weeks until term • Blastocyst • Very early mass of cells implanted in the uterus • Embryo • Placenta • Embryonic Layers

Otitis Medai

• Inflammation of the middle ear • May occur with or without middle ear effusion

Tensor Tympani m.

• Innervated by CN V - the Trigeminal n. • Attaches to the manubrium of the malleus via the tympani tendon • Contraction pulls malleus away from the TM • May or may not be involved in the acoustic reflex

Stapedius m.

• Innervated by CN VII - the Facial n. • Attaches to stapes via stapedius tendon • Contraction pulls stapes away from the oval window • **The primary muscle involved in the acoustic reflex

Acoustic Reflex Decay

• Measure how long (up to 10 s) the reflex persists (stapedius m. continues contracting) for a continuous tone presented 10 dB above the reflex threshold • If it can't maintain at least 50% of the contraction for at least 5 seconds, it suggests a lesion on the auditory nerve • Because nerve cannot maintain its continuous firing rate • Tested at 500 or 1000 Hz because it's normal for nerve not to continually fire in the higher frequencies (2000 or 4000 Hz)

Equivalent Ear Canal Volume

• Measure sound level in EC to calculate admittance with maximum positive pressure (+200 daPa) - TM will be immobilized • Reflects the volume of the ear canal in cm3 • Norms: • Children: .3 - .9 cm3 • Adults: .9 - 2.0 cm3

Cytomegalovirus (CMV)

• Member of herpes family of viruses • Not highly contagious among adults • Transmitted through contact with urine • Most people with CMV are asymptomatic, but store the virus • Virus can become "reactivated during pregnancy" • Incidence of congenital CMV infection ranges from .3 to 3% live births • Infection at any stage in gestation affects the fetus • Most infants with congenital CMV are asymptotic at birth; of these, 10-15% will have progressive SNHL and/or developmental delay and CNS sequelae • No treatment available • Pre-, peri- and postnatal transmission

Interpreting the Acoustic Reflex

• Normal acoustic reflex thresholds are recorded between 70 to 90 dB SL (85 to 100 dB SPL) • If acoustic reflexes are elevated or absent, it indicates a problem somewhere along the acoustic reflex arc • Middle Ear • Cochlea • Auditory n. • Facial n. • Consider ipsi- and contralateral reflex results along with tympanometry and pure tone audiometric results • Principles: • If the probe is in an ear with a conductive hearing loss, the reflex will be absent • If tone is in ear with conductive hearing loss and probe is in normal contralateral ear, reflex will be elevated • If tone is in ear with mild-to-moderate cochlear pathology, reflexes will be recorded at reduced SLs regardless of which ear probe is in • Principles: • If tone is in ear with more severe cochlear pathology, reflexes will be absent regardless of which ear probe is in • If probe is on the side of a facial n. lesion, reflex will be absent • If tone is in ear with a mild to moderate loss due to acoustic neuroma, reflex will be elevated or absent (regardless of probe ear), depending on size and specific location of tumor

Non-genetic hearing loss with external and middle ear abnormalities - Middle Ear

• Otitis medai • Bullous myringitis • Cholesteatoma • Mastoiditis • Tympanosclerosis

Postnatal Hearing Loss

• Presbycusis • Sloping HL • Onset and progression • Not dependent on cognitive degeneration • Head Trauma

Toxoplasmosis

• Protozoan parasite • Transmitted by undercooked meat or contact with cat feces • Adults are typically asymptomatic • Neonates can be asymptomatic at birth • Visual problems often develop within weeks • Later development of hearing loss or neurodevelopmental delay • If present at birth, infants can be treated with medication • Transmitted from mother to fetus (prenatal)

Tympanometry

• Requires some cooperation, but no behavioral response • Indirectly measuring how sound is transmitted through the middle ear • Making inferences on TM function

Syphilis

• Sexually transmitted bacterial disease • Transmitted in utero to fetus (prenatal) • Treat infection of mother during pregnancy with antibiotics • Can cause progressive sensory/neural hearing loss and vestibular dysfunction

TORCH Complex: includes factors that could cause hearing loss

• T - toxoplasmosis • O - other bacterial infections, especially syphilis • R - rubella (German measles) • C - cytomegalovirus (CMV) • H - herpes simplex virus

The Acoustic Reflex

• The Stapedius m. contracts bilaterally in response to intense sound (even if the sound is presented to one ear) • Response is not controlled by the listener • It's a REFLEX • Do not know the purpose of the reflex • Proposals • Protection from loud sounds: reduces intensity of sounds below 1000 Hz • Improved sound transmission: smoothes the frequency response of the ME (ME transfer function)

Postnatal Noise

• Very common: 5-20% of the population • Men > Women • Preventable • Damage to (OHC) • Damage to BM • NoTx

CID W-22 (Ross & Huntington, 1962) - Adults

- Based on the phonetically balanced word lists - Each list contains all the phonetic elements of connect English discourse in their normal proportion to one another 4 50 word lists - Lists aren't perfectly equivalent in terms of difficulty, but differences are small

Sensory Primitive Level

- Basic sensory input - Level of simple reception/detection - Perceptual response: detection (do you recognize that speech is present or not) - For speech, measured with the SDT/SAT

Genetic hearing loss with external and middle ear abnormalities

- Branchio-oto-renal syndrome BOR - CHARGE Association -Treacher Collins syndrome -Apert Syndrom -Stickler syndrom

Perceptual Representation Level

- Complex neural encoding of the stimulus - Level of complex perception - Perceptual response: discrimination and categorization - Rarely assessed in audiologic evaluation - Much more common in cochlear implant evaluations and post-op testing (Allows you to tell the difference between speech sounds. Does not carry meaning at this stage. But the sounds themselves are encoded neurally that they sound different. The only clinicians that look at discrimination are people who do cochlear implant work)

Cognitive/Linguistic Level

- Complex neural/acoustic code recognized as words - Phonemes perceived as parts of words - Level of meaning - Perceptual response: verbal repetition, picture-pointing, written or typed response - The vast majority of suprathreshold speech testing assesses this level of perceptual development - (most clinicians will assess this level)

Genetic hearing loss with external and middle ear abnormalities

- May see unilateral or bilateral auricular puts - Can observe thickened earlobes and incudostapedial abnormalities -Can observe microtia or anotia, and stenosis -Will result in conductive or mixed hearing losses

Auditory Perceptual Development (Aslin & Smith, 1988)

- Sensory Primitive Level - Perceptual Representation Level - Cognitive/Linguistic Level

Isophonemic Word Lists - Adults

-15 10-CVC-word lists - 10 CVC words = 30 phonemes/list - Scored by phonemes correct rather than word correct

California Consonant test - Adults

-2 50 monosyllabic-word lists - on each trail the listener picks from 4 written options (closed-set) -designed to test people with high frequency hearing loss

Speech perception in noise (SPIN) Test - Adults

-Assesses a listener's use of context -Low-predictability sentences (there isn't much information provided to tell us what they are talking about) -high-predictability sentences -presented in 12-talker babble at +8 dB SNR

NU-6 Word Lists - Adults

-Based on Lehiste and Peterson's (1959) work demonstrating that word recognition is done on a phonemic basis, rather than phonetic basis -4 50 words lists -High inter-test reliability -In general, a better test than CID W-22 lists because of assumptions about how speech is processed

Hearing in noise test (HINT) - Adults

-present sentences in background noise -Noise level fixed at 65dBA -level of sentences and location vary -Goal: Find the reception threshold for speech (RTS) -RTS =SNR at which listener gets 50% correct

Tympanometry Procedure

1. Insert probe into ear canal 2. Obtain an airtight seal 3. Set immittance bridge to "sweep" the pressure in the ear canal from +200 daPa to -200 daPa 4. Pure-tone generator will emit a 226 or 1000 Hz probe tone throughout test 5. Microphone measures level of sound in EC and calculates admittance as a function of air pressure • Admittance will be greatest at the point where ear-canal and ME pressure are equal (normally ~ 0 daPa)

Static acoustic compliance/static admittance/ peak compliance is determined by calculating the difference between two measurements

1. Measure sound level in EC to calculate admittance with maximum positive pressure (+200 daPa) - TM will be immobilized • This will be the point of maximum sound reflection or maximum impedance/minimum admittance 2. Measure sound level in EC when EC pressure and ME pressure are equal - TM will be maximally mobile • This will be the point of minimum sound reflection or minimum impedance/maximum admittance (At the peak - We take that value and we subtract out the min admittance 1.5cm^3 measurement of how moble to ear drum is)