AUDIOGRAM AND IMMITTANCE TUTORIAL

Presented by: Candice “Evie” Ortiz, AuD

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

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

Basics of the Audiogram

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.

Common Audiometric Configurations

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

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

ExamplesDescribing Hearing Loss

Essentially Mild

Profound

Normal

Normal Mild to Moderate

Time for PracticeDescribing Hearing Loss

Turn to Handouts

What Does It Mean for Speech?

Familiar Sounds Audiogram

Not Audible

Speech TestingSAT, SRT, and WRS

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

ExamplesReliability Determination

PTA = 3

PTA = 35

Good SRT-PTA agreement Good SRT-PTA agreement

PTA = 10

PTA = 35

Good SRT-PTA agreement Poor SRT-PTA agreement

Clinical Application ofWord Recognition Tests

Determine site of lesionPB Rollover

Surgery candidacy Hearing aid candidacy

If poor WRS, may not be a good candidate

ExamplesWord Recognition Consideration

Dx: OtosclerosisTx: Stapedectomy Q: Which side?

+ Rollover

- Rollover

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

Tympanometry

Tympanometry

Graphic representation of ear compliance in relation to static pressure changes

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)

ExamplesTympanometric Configurations: Middle Ear Pathology

Tympanometric Configurations:Middle Ear Pathology

Normal or HypomobilityOtosclerosis

Type A Type As

Type C

Tympanometric Configurations:Middle Ear Pathology

Negative pressureEustachian Tube

dysfunctionDeveloping otitis

mediaTM retraction

Type Ad

Tympanometric Configurations:Middle Ear Pathology

HypermobileAgingAtrophic scarsHealed perforationOssicular

discontinuity

ECV = 7.0

Type B Flat

Perforated TMPatent PE tube

Tympanometric Configurations:Middle Ear Pathology

ECV = 1.0

Type B Flat

Middle ear fluidSerous Otitis

Blocked PE tube

Tympanometric Configurations:Middle Ear Pathology

ECV = 0.2

Type B

FlatImpacted cerumen

Tympanometric Configurations:Middle Ear Pathology

Type B? Type As?

Tympanometric Configurations:Middle Ear Pathology

Middle ear fluid

Acoustic ReflexesART and AR Decay

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

Stapedial Reflex Arc

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

immittance

“Probe Right” Acoustic Reflexes

ProbeStimulus (ipsi)

Stimulus (contra)

ExamplesCommon Acoustic Reflex Patterns

ART Patterns:Unilateral CHL

CHL, AD WNL, AS

ART Patterns:VIII CN or CPA outside of brainstem

Mild high frequency SNHL, AD

WNL, AS

ART Patterns:Lesions within brainstem which involve reflex pathways

Mild high frequency SNHL, AU

ART Patterns:Facial Nerve Lesion

WNL, AU Absent probe right

Lesion proximal to stapedius nerve

Verticle segment of facial nerve

ART Patterns:Cochlear Impairment

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

Pediatric AudiometryTechniques, Age-Appropriate Results, Management

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

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

(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

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

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

VRA Video

VRA In Action

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

“game” fashion when a sound is heard

Requires active listening

Case StudyLongitudinal

Case Study

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

Audiogram:3 Months Old

Impacted cerumen removed prior

Tymps were WNL Tolerated

headphones but not BC

Hearing Loss??

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

Audiogram:10 Months Old

Developmental Age: 6 mos

More difficult to testMore activeWon’t tolerate

headphones Responding with

eye shifts only

Audiogram:18 Months Old

Will not tolerate headphones

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.

Audiogram:9 Years Old

Audiogram:10 Years Old

No cerumenectomy priorImpaction ADUnable to rule out ME

pathology

Pediatric Goals

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