Case Conference

Question 1

HL associated with syndromes means…

Answer 1

1. Require complex needs & many appts
2. Will need to work closely with other health professionals
3. May have developmental delay

Question 2

2 occasions for masking in ABR and how much

Answer 2

1. AC - when there’s asymmetry > or equal to 60dB (IAA of inserts)
2. BC- when responses are equivocal
3. White noise flat masking 60-65dB. Anything lower=insufficient masking, anything greater, potential for overmasking

Question 3

Absolute expected latencies in tone burst ABR

Answer 3

500Hz- 12-15ms
2kHz- 8-12ms
4kHz- 6-8ms

Question 4

Why is latency slightly delayed for 500Hz?

Answer 4

Because sound has to travel all the way up to the apex

Question 5

Recording Parameters

Answer 5

1. Epoch
2. Artefacts
3. Averages

Question 6

What’s artifact rejection? Recommendation on the guide line? How does it affect the results? What can you do?

Answer 6

1. Recording that’s rejected due to the presence of noise
2. Guideline recommends 20-25uV
3. High artifact rejection = noisy recording —> unclear wave and could hinder signal—> hard to interpret
4. Can check if the recording is noisy by checking the EEG window. Can wait till the baby settles.

Question 7

When do you do ABR BC:

1. for 2kHz?
2. For 500Hz?
3. For 4kHz?

Answer 7

1. AC> or equal to 40dB for 2kHz
2. AC>or equal to 50dB for 500Hz
3. AC> or equal to 40dB for 4kHz

Question 8

If ABR was found to be normal for the toneburst, baby is still asleep, would you still do high intensity Click?

Answer 8

Yes, because it shows CM and neural synchrony

Question 9

Risk factors for ANSD

Answer 9

Any conditions that affect the development of ANS e.g. jaundice, NICu

Question 10

CI candidacy

Answer 10

Children < or= 19yo with sev-prf HL on both ears funded in both ears

But rather than looking at the audiogram alone, look at the whole picture, i,e. Speech development, parental report, questionnaires, validation

Question 11

Click response representing what region? Where specifically? Why?

Answer 11

1. Broad cochlea response
2. But most sensitive to 2-4kHz region
3. Because it’s got greater synchrony of HF fibre firing

Question 12

EVA diagnosis and causes

Answer 12

Vestibular aqueduct with a diameter larger than 1.5mm from either MRI or CT
Audiologically either stable or progressive or fluctuating
Causes: arrested development in early gestation or other mutations

Question 13

Insert delay

Answer 13

0.8ms

Question 14

How do you know what you see is CM and not artefacts?

Answer 14

1. Occurs within 1ms but after 0.8ms which is insert delay
2. In complete phase cancellation when polarity changes
3. Absent on alternating

Question 15

Why do we run no sound trial

Answer 15

To demonstrate the presence of stimulus artefact and absence of response from the patient

Question 16

CI validation questionnaire

Answer 16

Functional Listening Index- paediatric (FLI-P)

Question 17

Why does toneburst abr become invalid when diagnosed with ANSD?

Answer 17

Because it means the neural synchrony is disrupted and what we see in toneburst does not reflect true thresholds

Question 18

Management of ANSD

Answer 18

Deferred until we have behavioural responses as it tends to be better due to temporal integration. The key management strategy is to increase neural synchrony by amplifying sounds. And increasing SNR is key

Question 19

What do we expect to see on a kid who’s got HF HL on high click ABR

Answer 19

1. Delayed latency because high intensity is elicited mostly from 2-4kHz without much delay as there is no time lag in excitation of neighbouring neurons and good synchrony at the basal region. But if there is HF HL, most responses elicited from LF at the apex and there is time lag in excitation of neighbouring neurons