Guy's Newborn Threshold ABR Quiz (Part 2 - see below for Part 1)

[Guy]

Continued from the previous quiz (part 1)

Q 16 No ABR responses have been observed from either ear at the maximum recommended stimulus levels using 4kHz AC and BC stimuli. What is your next step?:
A. Test for CMs using 4kHz stimuli
B. Test for CMs using click stimuli
C. Carry out further ABR assessments using click stimuli and then test for CMs if no clear response obtained to click ABR

Reveal Answer » Answer: C (we need to first assess whether there is any ABR using the stimulus (clicks) and inserts that may be necessary if CM tests are needed)

Q 17 At roughly what latency might one typically expect a PAM response?
A. 7 – 12ms
B. 10 – 17ms
C. 15 – 23ms
D. 19 – 27ms

Reveal Answer » Answer: C

Q 18 True or false: for each frequency / ear you should always perform a control run
A. True
B. False

Reveal Answer » Answer: B (false, control runs are helpful in certain circumstances but are a poor use of time for routine use)

Q19 How is a control run performed with a supra-aural earphone?
A. Turn the stimulus down to <=0dB
B. Block the sound using your thumb or Blu-Tac but otherwise keep in the correct position
C. Take the headphone at least 1m away

Reveal Answer » Answer: B (we need to maintain any stimulus artefact since that might be influencing the waveform, so we must use the same stimulus level and keep the earphone in position)

Q20 What range of response amplitudes would you expect for a 4kHz tone pip ABR in a baby.
A. 1 to 2µV
B. 0.05 to 0.5µV
C. 0.01 to 0.05µV

Reveal Answer » Answer: B

Q21 When no response is observed at the maximum recommended stimulus level what checks should you make to ensure that a “response absent” is the correct result?
(You should think of a list of checks before revealing the suggested answer)

Reveal Answer » Answer:
1. The residual noise (as judged from the gap between replicates) is no more than the 25nV criterion. 2. Perform a listening check to ensure the stimulus was delivered as intended.
3. Exclude technical errors such as incorrect electrode connection.

Q22 When using DSL 5.0 to fit hearing aids based on ABR thresholds, should the measured nHL thresholds or the corrected eHL thresholds be entered into the prescription?
A. Enter the measured nHL values, select ‘nHL’ in DSL 5.0 and allow the DSL software to calculate the eHL values.
B. Enter the eHL values calculated using the NHSP correction factors and select ‘eHL’ in DSL 5.0.
C. Either A or B can be used – the end result will be the same.

Reveal Answer » Answer: B. (If the nHL values were measured with insert earphones, C should also be true, but different manufacturers’ applications may use a slightly different nHL to eHL correction, so the safest option is to use the NHSP-calculated eHL values).

Q23 The NHSP discharge level at 4kHz is 30dBeHL. What is the NHSP discharge level at 1kHz?
A. 30dBeHL
B. 35dBeHL
C. 40dBeHL
D. There isn’t one

Reveal Answer » Answer: D (The NHSP discharge level relates only to 4kHz or clicks; at frequencies other than 4kHz we should exercise clinical judgement).

Q24 Using the abbreviations: CR=clear response; RA = response absent; Inc = inconclusive, the NHSP “gold standard” threshold is to obtain a CR at threshold, a CR at 5dB or 10dB above threshold and an RA at 5dB or 10dB below threshold. Which of the following are examples of an NHSP “other standard” threshold reported as =50dB? There may be more than one.
A. 60dB=CR; 50dB=CR; 40dB=Inc
B. 50dB=CR; 40dB=RA
C. 50dB=CR; 40dB=Inc
D. 50dB=CR; 40dB=Inc; 30dB=RA

Reveal Answer » Answer: Only B (inconclusive responses cannot contribute to a reported result under either gold or other standard).

Q25 Using the four scenarios above, how should each be reported (using =, <= and >)?

Reveal Answer » Answer:
A. <=50dB (other standard, providing a gold standard has been obtained)
B. =50dB (other standard, providing a gold standard has been obtained)
C. <=50dB (other standard, providing a gold standard has been obtained)
D. <=50dB (other standard, providing a gold standard has been obtained) or >30dB

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[andilouuk]

I learnt something new today , thanks Guy

A (sitting in a Saturday clinic waiting for a patient...)