ABA Emissions Control & Environmental Compliance 2 — Questions and Answers
Question 1: Which otoacoustic emission type is generated by two simultaneous pure-tone stimuli presented at frequencies f1 and f2?
- Transient-evoked OAE (TEOAE)
- Distortion product OAE (DPOAE) (Correct answer)
- Spontaneous OAE (SOAE)
- Stimulus frequency OAE (SFOAE)
Correct answer: Distortion product OAE (DPOAE)
DPOAEs are generated when two pure tones (f1 and f2) interact nonlinearly in the cochlea, producing distortion products at predictable frequencies.
Question 2: TEOAEs are typically absent in ears with hearing sensitivity poorer than approximately:
- 10 dB HL
- 30 dB HL (Correct answer)
- 50 dB HL
- 70 dB HL
Correct answer: 30 dB HL
TEOAEs are reliably present in ears with normal or near-normal hearing but are consistently absent when cochlear hearing loss exceeds approximately 30 dB HL.
Question 3: Spontaneous otoacoustic emissions (SOAEs) are found in approximately what percentage of normal-hearing ears?
- Less than 5%
- Approximately 35–50% (Correct answer)
- Approximately 70–80%
- Nearly 100%
Correct answer: Approximately 35–50%
SOAEs occur without any external stimulus and are present in roughly 35–50% of normal-hearing individuals, more commonly in females.
Question 4: Contralateral suppression of OAEs is used to evaluate the integrity of which pathway?
- Auditory brainstem pathway
- Medial olivocochlear (MOC) efferent reflex (Correct answer)
- Middle ear muscle acoustic reflex
- Auditory cortex descending feedback loop
Correct answer: Medial olivocochlear (MOC) efferent reflex
Contralateral noise activates the medial olivocochlear efferent system, which projects to outer hair cells and suppresses OAE amplitude.
Question 5: In clinical practice, DPOAEs are most commonly measured at a primary tone frequency ratio (f2/f1) of approximately:
- 1.10
- 1.22 (Correct answer)
- 1.50
- 2.00
Correct answer: 1.22
A ratio of f2/f1 ≈ 1.22 produces the largest and most reliable DPOAE responses because it optimizes the nonlinear interaction between the two primary tones.
Question 6: A DP-gram plots DPOAE amplitude as a function of:
- Stimulus intensity at a single fixed frequency
- f2 frequency across the audiometric range (Correct answer)
- Time elapsed after stimulus onset
- Signal-to-noise ratio at 1000 Hz only
Correct answer: f2 frequency across the audiometric range
A DP-gram displays DPOAE amplitude (and noise floor) at each f2 frequency tested, providing a frequency-specific map of outer hair cell function.
Question 7: Which type of OAE is best suited for frequency-specific assessment of cochlear function across the audiometric range?
- Spontaneous OAE (SOAE)
- Transient-evoked OAE (TEOAE)
- Distortion product OAE (DPOAE) (Correct answer)
- Cochlear microphonic (CM)
Correct answer: Distortion product OAE (DPOAE)
DPOAEs allow discrete frequency-by-frequency testing across the audiometric range, making them superior for frequency-specific cochlear assessment compared to broadband click-evoked TEOAEs.
ABA Emissions Control & Environmental Compliance 2
Which otoacoustic emission type is generated by two simultaneous pure-tone stimuli presented at frequencies f1 and f2?