Pediatric Fitting: Verification and Validation

Question 1

What is the sequence in the pediatric amplification process?

Answer 1

Assessment
Selection
Verification
Orientation
Outcome evaluation

Question 2

When should amplification be provided?

Answer 2

By 6 months (JCIH, 2007)
By 3 months (JCIH, 2019)
Delay that will compromise that objective must be avoided wherever possible

Question 3

What are some challenges and considerations in pediatric hearing aid fittings?

Answer 3

Anatomical differences (ear canal size is different)
Growth
Environment change (spend most of their lives in quiet environments prior to preschool)
Not well-defined hearing deficit

Question 4

What are the three major reasons why special considerations apply to fitting hearing aids to children?

Answer 4

Rapidly changing ear canal acoustics
Limited ability to provide reliable behavioral and verbal responses
Need for better SNR and sound access for speech and learning

Question 5

What are the main goals of amplifying children?

Answer 5

To provide an amplified speech signal that is consistently audible across levels
To avoid distortion of varying inputs at prescribed settings for the user
To ensure the signal is amplifying sounds in a broad frequency range
To include sufficient electroacoustic flexibility ear growth or changes in the auditory characteristics of the infant

Question 6

When should the fitting our due to JCIH 2007?

Answer 6

One month after diagnosis

Question 7

Should permanent hearing loss fittings be delayed if there is ongoing ME effusion treatment?

Answer 7

No

Question 8

When possible, what should be included in the amplification process?

Answer 8

Audiometric thresholds for both ears
Consultation by an otolaryngologist
RECD, if fitting an air conduction hearing aid
Accurate ear impression(s)
Assessment of non-electroacoustic needs
DSL m[i/o] v5 target ear canal sound pressure levels (SPL)
Parent/caregiver Instruction and counseling sessions
Hearing aid verification
Evaluation of the outcome of the intervention
Appropriate follow-up schedule

Question 9

What happens next for children who fail the newborn hearing screening?

Answer 9

Infants who fail a newborn hearing screening are referred for full diagnostic assessment that includes otoscopy, tympanometry, OAEs, and ABR tests
The information from the diagnostic ABR evaluation will be used for the purpose of fitting hearing aids
Infants have limited ability to provide reliable behavioral and verbal responses to stimuli

Question 10

What are the assessment methods for infants and young children?

Answer 10

Behavioral thresholds (can be limited)
ASSR
ABR (frequency and ear specific)
BOA

Question 11

What is a challenge about testing infants?

Answer 11

Electrophysiological tests
May need sedation

Question 12

What is a challenge about testing toddlers?

Answer 12

Transition to behavioral testing

Question 13

How do you test infants with stenosis or atresia?

Answer 13

Test using bone conduction at 500, 2000, and 4000 Hz for the affected ear(s)
Threshold estimates at other frequencies (e.g., 1000 Hz) are recommended, but not required for the initial provision of amplification

Question 14

Are responses for ASSR in infants lower in amplitude than for adults?

Answer 14

Yes

Question 15

What are some ASSR advantages?

Answer 15

Multiple frequencies can be tested simultaneously
Simultaneous testing of both ears
Faster than ABR
Objective response analysis
Stimuli are easier to calibrate
Potential applications for objective hearing aid evaluation

Question 16

What are some ASSR disadvantages?

Answer 16

Lack of longitudinal data compared to behavioral thresholds for hearing-impaired kids
Artifact responses at high intensity levels
Lack of data on infants

Question 17

What is the ABR assessment protocol in infants?

Answer 17

AC ABR toneburst thresholds at 500, 2000, and 4000 Hz; also, at 1000 Hz when indicated
BC ABR toneburst thresholds at 500 and 2000 Hz; when indicated
Click ABR to assess cochleo-neural status (as needed)
Diagnostic DPOAE for cross check and ANSD
Tympanometry at 1000 Hz
Ipsilateral reflexes at 1000 Hz with a 1000 Hz probe

Question 18

How are ABR thresholds reported?

Answer 18

Results will initially be reported in dB nHL
dB nHL ≠ dB HL; dB nHL < dB HL
Both dB nHL and dB HL are defined with reference to adult norms

Question 19

Do the electrophysiological thresholds need to be converted into the predicted behavioral thresholds?

Answer 19

Yes
By the use of appropriate correction factor
This conversion may be done by the audiologist manually, within the test equipment, or within the hearing fitting software

Question 20

How does DSL implement ABR data?

Answer 20

By allowing threshold entry in normalized HL (nHL)
By allowing a behaviorally equivalent measure (eHL)

Question 21

Do the ABR thresholds tend to be higher than the actual thresholds?

Answer 21

Yes
if you enter the data in nHL without converting it, you will end up overamplifying the child

Question 22

What is the importance of verification?

Answer 22

Essential to avoid over-amplification during periods of rapid growth (regular evaluations)
Objective measurement is essential to ensure amplification supports effectively supports the acquisition of acoustic cues necessary for stimulating neural connections within the auditory system
RECD measurements conducted at regular intervals serve as an objective tool to confirm that amplification is achieving its intended purpose

Question 23

Why do we use RECD?

Answer 23

Small ears; calibration issues
Hearing aid output will be higher in an infant ear canal than in an adult ear canal
RECD measures the difference between a child’s ear canal and an acoustic coupler to estimate accurate amplification levels in the child’s ear canal
Children cannot stay quiet and sit still long enough for REM

Question 24

What is the purpose of RECD?

Answer 24

To correct and convert HL thresholds to the SPL format used by many fitting methods and real ear approaches
To fit the hearing aid in the test box

Question 25

Does the resonant frequency of the unaided ear change with increasing age?

Answer 25

Yes
At birth, the peak is approximately 5 to 6 kHz but, decreases to 3 kHz by the age of 2 to 3 years
The REUG curve affects the insertion gain received by the HA user

Question 26

Is the RECD the greatest for the youngest ages?

Answer 26

Yes
Because the residual volume is smallest for infants
RECD changes very little from 1 month to 3 months of age

Question 27

How often should RECD be measured?

Answer 27

Should be measured each time a new earmold is required

Question 28

Can normative RECDs be used?

Answer 28

Only when absolutely necessary and only until the next opportunity to obtain individual RECDs
Without the actual values, the error could be as large at 5 to 10 dB

Question 29

What is only one RECD can be obtained?

Answer 29

The values obtained can be used for both ears as long as no significant medical conditions are present that might alter the acoustic characteristics of the ear canal or middle ear on one side

Question 30

What is the advantage of using the age appropriate average RECD?

Answer 30

More desirable than using the adult average value for infants

Question 31

What are the limitations of using age appropriate RECD?

Answer 31

Average RECD values were derived from infants and children with normal middle ear status
The predicted values will not reflect any acoustic changes created by middle ear fluid or TM perforation
Large variability in RECDs across healthy infants and young children and errors can be as large at 5 to 10 dB

Question 32

What are the two steps of the RECD measurement?

Answer 32

SPL measurement from a transducer delivered into a 2cc coupler
SPL measurement of the same signal delivered into a patient’s ear

Question 33

Do you need to calibrate the RECD transducer?

Answer 33

Yes
Using a HA-2 coupler in the test box

Question 34

How should you measure how much the probe tube should be inserted?

Answer 34

It should exceed the medial surface of the foam tip or earmold by 3 mm for young infants and 5 mm for older children
0-6 months - 11mm
6-12 months - 15 mm
1-5 years - 20 mm
>5 years - 25 mm
Adults - 27 mm

Question 35

Can the probe tube be pre-attached to the foam tip/earmold of the RECD transducer with a thin strip of plastic wrap?

Answer 35

Yes

Question 36

What is the difference between a foam tip and earmold RECD?

Answer 36

Primarily in the high frequencies (foam tip higher)
The difference is due to increased tubing length and not shallow probe tube insertion

Question 37

Should you use the same coupling method for both the RECD and the hearing threshold measures?

Answer 37

Yes
Small errors can be introduced if you don’t

Question 38

How do you couple insert earphones to personal earmolds?

Answer 38

Can be used during VRA and CPA
Clip the end of an insert tube and attach one end to the insert nubbin and the other to the earmold tubing
A correction factor will be applied by the system when a coupling mismatch is entered

Question 39

If an earmold is used for RECD, should the vents be blocked?

Answer 39

Yes

Question 40

What do negative values
in the low frequencies from the norm RECD mean?

Answer 40

The ear canal is larger than a 2cc coupler

Question 41

What does a difference of >10 from average in the mid to high frequencies from the average RECD mean?

Answer 41

Blockage or shallow probe tube insertion

Question 42

How can you assess auditory development and hearing aid outcomes?

Answer 42

Cannot be measured behaviorally
Questionnaires can be useful in assessing very young children’s auditory development
Assess effectiveness of hearing aids in real-world environments