Hearing Aid Fitting Formulas
The primary purpose of a prescriptive fitting formula is to:
A. Match manufacturer defaults
B. Reduce programming time
C. Narrow the enormous range of possible frequency responses to an evidence-based starting point
D. Eliminate the need for verification
Answer: C
C. Narrow the enormous range of possible frequency responses to an evidence-based starting point
DNR may reduce gain for speech when:
A. Speech is dominant
B. Speech is mixed with noise
C. Noise is absent
D. Directionality is active
Answer: B
B. Speech is mixed with noise
Feedback with jaw movement may suggest:
A. Mechanical failure
B. Ear canal growth
C. Poor physical fit
D. Phase error
Answer: C
C. Poor physical fit
Occlusion is measured with:
A. Hearing aid on
B. Hearing aid off
C. Coupler only
D. Sound field only
Answer: B
B. Hearing aid off
Attack time refers to:
A. Time to return to linear gain after level decreases
B. Time to reduce gain after an increase in input
C. Time to reach MPO
D. Time to reach kneepoint
Answer: B
B. Time to reduce gain after an increase in input
NAL-NL2 primarily aims to:
A. Maximize audibility at each frequency
B. Normalize loudness at each frequency band
C. Balance speech intelligibility and overall loudness comfort
D. Provide the most gain possible for children
Answer: C
C. Balance speech intelligibility and overall loudness comfort
Even when speech recognition does not improve, users often:
A. Reject DNR
B. Prefer DNR active
C. Disable compression
D. Increase gain
Answer: B
B. Prefer DNR active
Feedback Manager sets:
A. Compression ratios
B. Maximum safe gain values per frequency
C. MPO limits
D. Directional patterns
Answer: B
B. Maximum safe gain values per frequency
Why must you complete the Equalization procedure in open fittings?
A. To measure LDLs
B. To measure occlusion
C. To correct for sound leaking out of ear canal
D. To calibrate the probe tube length
C. To correct for sound leaking out of ear canal
Answer: C
What is the purpose of expansion?
A. Increase gain for soft sounds
B. Reduce gain for very soft sounds
C. Increase MPO
D. Reduce compression ratio
Answer: B
B. Reduce gain for very soft sounds
Compared to NAL-NL1, NAL-NL2:
A. Prescribes more gain for bilateral fittings
B. Ignores gender differences
C. Accounts for hearing aid experience and gender
D. Eliminates compression
Answer: C
C. Accounts for hearing aid experience and gender
Reverberation cancelers:
A. Enhance early reflections
B. Increase modulation depth
C. Reduce gain during echo tails
D. Improve SNR
Answer: C
C. Reduce gain during echo tails
Which is NOT a feedback suppression strategy?
A. Gain reduction
B. Notch filtering
C. Phase cancellation
D. Directional microphones
Answer D.
D. Directional microphones
What must MPO never exceed?
A. Target values
B. REUR
C. LDLs
D. SII
Answer: C
C. LDLs
Why is compression considered distortion?
A. It introduces harmonic distortion
B. It changes amplitude relationships over time
C. It adds noise
D. It delays sound
Answer: B
B. It changes amplitude relationships over time
Which fitting philosophy is most appropriate for pediatric fittings?
A. Manufacturer first fit
B. NAL-NL1
C. DSL v5
D. NAL-NL2
Answer: C
C. DSL v5
DNR is especially prone to classification errors for:
A. Steady noise
B. Single talker in quiet
C. Music
D. Babble
Answer: C
C. Music
A possible negative side effect of more occlusion is:
A. Directional distortion
B. Increased SII
C. Occlusion effect
D. Reduced compression
Answer: C
C. Occlusion effect
A REOG of 0 dB suggests:
A. Closed fitting
B. Severe occlusion
C. Open fitting
D. Feedback
Answer: C
C. Open fitting
Modern hearing aids typically combine:
A. Peak clipping and expansion
B. WDRC and compression limiting
C. Linear gain and expansion only
D. Only WDRC
Answer: B
B. WDRC and compression limiting
Real-ear measures may not match software targets due to:
A. Mathematical errors in the prescription
B. Venting and ear canal acoustics
C. Gender differences
D. Bilateral fitting rules
Answer: B
B. Venting and ear canal acoustics
Typical gain reduction from DNR ranges from:
A. 1–3 dB
B. 3–6 dB
C. 6–20 dB
D. 20–40 dB
Answer: C
C. 6–20 dB
Phase cancellation works by:
A. Reducing gain
B. Increasing attenuation
C. Emitting a signal 180° out of phase
D. Closing the vent
Answer: C
C. Emitting a signal 180° out of phase
If aided SII equals unaided SII, what does this suggest?
A. Excellent fitting
B. Over-amplification
C. Little functional benefit
D. Perfect target match
Answer: C
C. Little functional benefit
A hearing aid has a CR of 3:1.
If the input increases by 15 dB, how much does the output increase?
Answer: 5 dB