audiogram and immittance tutorial

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AUDIOGRAM AND IMMITTANCE TUTORIAL Presented by: Candice “Evie” Ortiz, AuD

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Presented by: Candice “Evie” Ortiz, AuD. AUDIOGRAM AND IMMITTANCE TUTORIAL. Conduction of Stimuli. Air Conduction Signals are delivered through the outer, middle and inner ears Further processing in the CANS Bone Conduction Signal delivered to the mastoid bone - PowerPoint PPT Presentation

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Page 1: AUDIOGRAM AND IMMITTANCE TUTORIAL

AUDIOGRAM AND IMMITTANCE TUTORIAL

Presented by: Candice “Evie” Ortiz, AuD

Page 2: AUDIOGRAM AND IMMITTANCE TUTORIAL

Conduction of Stimuli Air Conduction

Signals are delivered through the outer, middle and inner ears

Further processing in the CANS Bone Conduction

Signal delivered to the mastoid bone○ Bypasses the conductive mechanism

Stimulates both cochlea simultaneously

Page 3: AUDIOGRAM AND IMMITTANCE TUTORIAL

Masking

Used to obtain accurate thresholds when cross-hearing is likelyAsymmetrical hearing losses of ≥ 40dB or

≥60dB○ Dependent on transducers

Gaps of ≥ 15dB during BC Non-test ear is kept “busy” by the

introduction of a masking noise

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Basics of the Audiogram

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Classification of Hearing Loss

Normal: -10 to 25 dB Mild: 26 to 40 dB Moderate: 41 to 55 dB Moderately-Severe: 56 to 70 dB Severe: 71 to 90 dB Profound: > 90 dB

Picture Adapted from: Bess, F.H., Humes, L.E., Audiology: The fundamentals, 2003.

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Common Audiometric Configurations

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Type of Hearing Loss Sensorineural

(SNHL)No air-bone gaps

○ ≥15 dB gap between AC and BC thresholds

Conductive (CHL)≥15dB air-bone gapConsistent with middle

ear pathologyMaximum conductive

component is 60dB

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Describing a Hearing Loss

Degree, Configuration, Location, TypeExamples

○ Mild to severe sloping SNHLNo location implies that loss affects all frequecies

○ Severe high frequency SNHL○ Moderate to mild rising low frequency CHL

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ExamplesDescribing Hearing Loss

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Essentially Mild

Profound

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Normal

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Normal Mild to Moderate

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Time for PracticeDescribing Hearing Loss

Turn to Handouts

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What Does It Mean for Speech?

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Familiar Sounds Audiogram

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Not Audible

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Speech TestingSAT, SRT, and WRS

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Speech Audiometry Speech Recognition

Threshold (SRT)Adults

Speech Awareness Threshold (SAT)Infants and

Non-Verbal patients Useful in determining test

reliability Malingering Does not understand task

Page 19: AUDIOGRAM AND IMMITTANCE TUTORIAL

ExamplesReliability Determination

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PTA = 3

PTA = 35

Good SRT-PTA agreement Good SRT-PTA agreement

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PTA = 10

PTA = 35

Good SRT-PTA agreement Poor SRT-PTA agreement

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Clinical Application ofWord Recognition Tests

Determine site of lesionPB Rollover

Surgery candidacy Hearing aid candidacy

If poor WRS, may not be a good candidate

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ExamplesWord Recognition Consideration

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Dx: OtosclerosisTx: Stapedectomy Q: Which side?

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+ Rollover

- Rollover

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Very Poor WRSMay not be a good hearing aid candidateConsider CROS style or additional testing

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Tympanometry

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Tympanometry

Graphic representation of ear compliance in relation to static pressure changes

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Normative Tympanometry Values

Peak Pressure is typically WNL in the range of -150 to +25 daPACompliance refers to mobility of tympanic membrane

EAR CANAL VOLUME (cm3)

COMPLIANCE (ml)

MEAN 0.5 0.7

90% RANGE 0.4 to 1.0 0.2 to 0.9

EAR CANAL VOLUME (cm3)

COMPLIANCE (ml)

MEAN 1.1 0.8

90% RANGE 0.6 to 1.5 0.3 to 1.4

Children Ages 3-5 years Adults

Margolis and Heller (1987)

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ExamplesTympanometric Configurations: Middle Ear Pathology

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Tympanometric Configurations:Middle Ear Pathology

Normal or HypomobilityOtosclerosis

Type A Type As

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Type C

Tympanometric Configurations:Middle Ear Pathology

Negative pressureEustachian Tube

dysfunctionDeveloping otitis

mediaTM retraction

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Type Ad

Tympanometric Configurations:Middle Ear Pathology

HypermobileAgingAtrophic scarsHealed perforationOssicular

discontinuity

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ECV = 7.0

Type B Flat

Perforated TMPatent PE tube

Tympanometric Configurations:Middle Ear Pathology

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ECV = 1.0

Type B Flat

Middle ear fluidSerous Otitis

Blocked PE tube

Tympanometric Configurations:Middle Ear Pathology

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ECV = 0.2

Type B

FlatImpacted cerumen

Tympanometric Configurations:Middle Ear Pathology

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Type B? Type As?

Tympanometric Configurations:Middle Ear Pathology

Middle ear fluid

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Acoustic ReflexesART and AR Decay

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Acoustic Reflexes Acoustic reflex threshold (ART):

Lowest level at which an AR can be obtained

Most sensitive to middle ear pathologyNormative Values

○ Present for SNHL up to 50 dB○ WNL from 70 to 100 dB○ Elevated responses (≥100 dB) for thresholds

< 50 dB

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Stapedial Reflex Arc

Presentation of an intense sound elicits a contraction of the stapedius muscle Changes the ear’s

immittance

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“Probe Right” Acoustic Reflexes

ProbeStimulus (ipsi)

Stimulus (contra)

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ExamplesCommon Acoustic Reflex Patterns

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ART Patterns:Unilateral CHL

CHL, AD WNL, AS

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ART Patterns:VIII CN or CPA outside of brainstem

Mild high frequency SNHL, AD

WNL, AS

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ART Patterns:Lesions within brainstem which involve reflex pathways

Mild high frequency SNHL, AU

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ART Patterns:Facial Nerve Lesion

WNL, AU Absent probe right

Lesion proximal to stapedius nerve

Verticle segment of facial nerve

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ART Patterns:Cochlear Impairment

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Acoustic Reflex Decay

Retrocochlear Test Measure of ability to

maintain reflex contraction during a continuous stimulation Positive Result

Response decays to ≥ ½ its original magnitude

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Pediatric AudiometryTechniques, Age-Appropriate Results, Management

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Testing Techniques:Newborns and Infants Otoacoustic Emissions (OAE)

Measures pre-neural signals produced by outer hair cells

Objective measureQuick and easy Non-invasive Sensitive to:

○ Presence of hearing loss○ Problems affecting integrity of cochlea

Auditory Brainstem Response (ABR)If baby does not pass OAE

Page 51: AUDIOGRAM AND IMMITTANCE TUTORIAL

Testing Techniques:Behavioral Observation Audiometry (BOA)

3 months through 6 monthsParents hold infantObserve natural response to sounds

○ e.g., eye widening or eye shiftsNo reinforcement needed

Page 52: AUDIOGRAM AND IMMITTANCE TUTORIAL

(Developmental) Age Appropriate Response Levels

TONES (dB)

SPEECH (dB)

0 TO 6 WKS 75 50

6 WKS TO 4 MOS

70 45

4 TO 7 MOS 50 20

7 TO 9 MOS 45 15

9 TO 13 MOS 35 10

As age increases, responses to softer sounds increase

Generally more responsive to speech than tones and narrow band noise

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Testing Techniques:Visual Reinforcement Audiometry (VRA)

Age: 6 mos – 3 yrs (developmental) Teach a child to turn their heads in

response to sound, by reinforcing the act with visual stimuli

Requires head control and good vision Can be performed with all transducers

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Testing Techniques:Visual Reinforcement Audiometry Patient on lap Focus held ahead

by a distracting assistant

When sound is heard, child turns toward speaker

Action rewarded by an animated, visual reinforcer

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VRA Video

VRA In Action

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Testing Techniques:Conditioned Play Audiometry Age: 3 – 4 yrs Child reacts in

“game” fashion when a sound is heard

Requires active listening

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Case StudyLongitudinal

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Case Study

Child diagnosed with Trisomy 21 Failed Newborn Infant Hearing Screen No show at 1 month ABR appointment

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Audiogram:3 Months Old

Impacted cerumen removed prior

Tymps were WNL Tolerated

headphones but not BC

Hearing Loss??

Page 60: AUDIOGRAM AND IMMITTANCE TUTORIAL

Age Appropriate Response Levels

TONES (dB)

SPEECH (dB)

0 TO 6 WKS 75 50

6 WKS TO 4 MOS

70 45

4 TO 7 MOS 50 20

7 TO 9 MOS 45 15

9 TO 13 MOS 35 10

Probably not Monitor closely due to

risk factors Every 3 months ME pathologies Impacted cerumen

due to ear canal size

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Audiogram:10 Months Old

Developmental Age: 6 mos

More difficult to testMore activeWon’t tolerate

headphones Responding with

eye shifts only

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Audiogram:18 Months Old

Will not tolerate headphones

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Audiogram:6 Years Old

Play is usually used at 3-4 yr of age

Cerumenectomy 1 wk prior Every 6 months, prior to

audio evaluation. Necessary maintenance

for managing his chronic ME pathology.

And for maintaining good hearing.

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Audiogram:9 Years Old

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Audiogram:10 Years Old

No cerumenectomy priorImpaction ADUnable to rule out ME

pathology

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Pediatric Goals

Verify and/or enable access to speech sounds in order to promote speech and language development