Transcript explanation of the 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 likely
 Asymmetrical 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






Picture Adapted from: Bess, F.H., Humes, L.E., Audiology: The fundamentals, 2003.
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
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 gap
 Consistent with middle
ear pathology
 Maximum conductive
component is 60dB
Describing a Hearing Loss

Degree, Configuration, Location, Type
 Examples
○ Mild to severe sloping SNHL
 No location implies that loss affects all frequecies
○ Severe high frequency SNHL
○ Moderate to mild rising low frequency CHL
Describing Hearing Loss
Essentially Mild
Profound
Normal
Normal
Mild to
Moderate
Describing Hearing Loss
Turn to Handouts
Familiar Sounds Audiogram
Not Audible
SAT, 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
Reliability 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 of
Word Recognition Tests

Determine site of lesion
 PB Rollover
Surgery candidacy
 Hearing aid candidacy

 If poor WRS, may not be a good candidate
Word Recognition Consideration
Dx: Otosclerosis
Tx: Stapedectomy
Q: Which side?
+
Rollover Rollover
Very Poor WRS
May not be a good hearing aid candidate
Consider CROS style or additional testing
Tympanometry

Graphic
representation of ear
compliance in
relation to static
pressure changes
Normative Tympanometry Values
Children Ages 3-5 years
EAR CANAL
VOLUME (cm3)
COMPLIANCE
(ml)
MEAN
0.5
0.7
90% RANGE
0.4 to 1.0
0.2 to 0.9
Adults
EAR CANAL
VOLUME (cm3)
COMPLIANCE
(ml)
MEAN
1.1
0.8
90% RANGE
0.6 to 1.5
0.3 to 1.4
Peak Pressure is typically WNL in the range of -150 to +25 daPA
Compliance refers to mobility of tympanic membrane
Margolis and Heller (1987)
Tympanometric Configurations: Middle Ear Pathology
Tympanometric Configurations:
Middle Ear Pathology
Type A
Type As

Normal or Hypomobility
 Otosclerosis
Tympanometric Configurations:
Middle Ear Pathology

Type C
Negative pressure
 Eustachian Tube
dysfunction
 Developing otitis
media
 TM retraction
Tympanometric Configurations:
Middle Ear Pathology
Type Ad

Hypermobile
 Aging
 Atrophic scars
 Healed perforation
 Ossicular
discontinuity
Tympanometric Configurations:
Middle Ear Pathology
Type B

Flat
 Perforated TM
ECV = 7.0
 Patent PE tube
Tympanometric Configurations:
Middle Ear Pathology
Type B

Flat
 Middle ear fluid
ECV = 1.0
 Serous Otitis
 Blocked PE tube
Tympanometric Configurations:
Middle Ear Pathology
Type B

ECV = 0.2
Flat
 Impacted cerumen
Tympanometric Configurations:
Middle Ear Pathology
Type B?
Type As?

Middle ear fluid
ART and AR Decay
Acoustic Reflexes

Acoustic reflex threshold (ART):
 Lowest level at which an AR can be
obtained
 Most sensitive to middle ear pathology
 Normative 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
Probe
Stimulus (ipsi)
Stimulus (contra)
Common 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
Techniques, Age-Appropriate Results, Management
Testing Techniques:
Newborns and Infants

Otoacoustic Emissions (OAE)
 Measures pre-neural signals produced by outer




hair cells
Objective measure
Quick 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 months
 Parents hold infant
 Observe natural response to sounds
○ e.g., eye widening or eye shifts
 No 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
Longitudinal
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)
0 TO 6 WKS
SPEECH
(dB)
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 test
 More active
 Won’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
prior
 Impaction AD
 Unable to rule out ME
pathology
Pediatric Goals

Verify and/or enable
access to speech
sounds in order to
promote speech and
language
development