HAC Hearing Aid Fitting & Adjustment 2 — Questions and Answers
Question 1: Which real-ear measurement verifies that the hearing aid output matches the prescribed target at the eardrum?
- Real-ear aided response (REAR)
- Real-ear unaided response (REUR)
- Real-ear insertion gain (REIG) (Correct answer)
- Real-ear coupler difference (RECD)
Correct answer: Real-ear insertion gain (REIG)
REIG is the difference between REAR and REUR, directly showing how much gain the hearing aid adds at the eardrum compared to the prescribed target.
Question 2: A patient reports their hearing aid whistles when they cup their hand near their ear. What is the most likely cause?
- Feedback due to acoustic leakage (Correct answer)
- Insufficient amplification
- Dead microphone port
- Low battery voltage
Correct answer: Feedback due to acoustic leakage
Feedback occurs when amplified sound leaks out of the ear canal and re-enters the microphone, creating an oscillation loop.
Question 3: When fitting a child with a hearing aid, why is the RECD (real-ear-to-coupler difference) especially important?
- Children have higher thresholds than adults
- Children's ear canals produce more gain than a 2-cc coupler predicts (Correct answer)
- Children require less gain than adults
- Children cannot tolerate probe microphones
Correct answer: Children's ear canals produce more gain than a 2-cc coupler predicts
Smaller ear canals create higher SPL than a standard 2-cc coupler, so RECD corrects coupler-based targets to accurately represent real-ear levels in children.
Question 4: Which fitting formula is specifically designed for children and incorporates loudness normalization?
- NAL-NL2
- DSL v5.0 (Correct answer)
- POGO II
- Berger method
Correct answer: DSL v5.0
Desired Sensation Level (DSL) v5.0 was developed to normalize loudness for children across the speech spectrum and includes pediatric-specific targets.
Question 5: A patient with a precipitous high-frequency hearing loss complains that amplified speech sounds 'tinny.' What adjustment should you consider first?
- Increase low-frequency gain
- Reduce high-frequency gain (Correct answer)
- Increase compression ratio
- Switch to a linear processing mode
Correct answer: Reduce high-frequency gain
Reducing high-frequency gain lowers the perceived brightness/tinny quality that results from over-amplification of high frequencies relative to lows.
Question 6: What is the purpose of the 'first-fit' or manufacturer's default program at the initial hearing aid fitting?
- To provide maximum gain immediately
- To serve as a starting point based on audiogram before real-ear verification (Correct answer)
- To permanently program the device without further adjustment
- To test feedback cancellation only
Correct answer: To serve as a starting point based on audiogram before real-ear verification
The first-fit uses the audiogram and fitting formula to generate an initial gain prescription that will be refined with real-ear measurements and patient feedback.
Question 7: A patient's real-ear measurement shows gain 10 dB above the NAL-NL2 target in the 2000 Hz region. What is the appropriate clinical action?
- Leave settings unchanged; the patient will adapt
- Reduce gain in the 2000 Hz channel to match the target (Correct answer)
- Increase compression threshold to compensate
- Switch to a different fitting formula
Correct answer: Reduce gain in the 2000 Hz channel to match the target
When measured gain exceeds the prescriptive target, the clinician should reduce gain in that frequency channel to prevent over-amplification and potential discomfort.
HAC Hearing Aid Fitting & Adjustment 2
Which real-ear measurement verifies that the hearing aid output matches the prescribed target at the eardrum?