NBC-HIS EXAM AND STUDY GUIDE
NEWEST 2025 TEST BANK| COMPLETE
100 REAL EXAM QUESTIONS AND
CORRECT VERIFIED ANSWERS/ ALREADY
GRADED A+| NBC HIS CERTIFICATION
EXAM PREP 2025/2026 (MOST RECENT!!)
1. What is the primary function of the outer hair cells?
Answer: Amplify low-level sounds via electromotility
Rationale: Outer hair cells contract and expand in response to
sound, mechanically amplifying the traveling wave in the cochlea.
This provides up to 60 dB of gain for soft sounds, improving
frequency selectivity and sensitivity.
2. Which tympanometry type is most consistent with
otosclerosis?
Answer: Type As
Rationale: Type As (A-shallow) shows normal middle ear volume
but reduced compliance (stiffness), which is characteristic of
stapes fixation in otosclerosis.
3. What is the interaural attenuation (IA) for a standard
supra-aural headphone?
Answer: 40–50 dB (average 45 dB)
Rationale: IA is the reduction in sound level as it crosses the skull
,from the test ear to the non-test ear. For supra-aural headphones,
this average is 45 dB, which determines when masking is needed.
4. A patient reports hearing their own voice as "echoing" or
"talking in a barrel." What is the most likely cause?
Answer: Vent diameter too large
Rationale: A large vent allows low-frequency bone-conducted
self-vocalizations to escape and re-enter the ear canal, creating a
hollow or echoing sound known as the occlusion effect.
5. Which frequency is most commonly affected first in noise-
induced hearing loss (NIHL)?
Answer: 4000 Hz
Rationale: The resonant frequency of the ear canal and the
vulnerability of the basal turn of the cochlea make 4000 Hz the
classic "notch" seen in early NIHL.
6. What does COSI stand for?
Answer: Client Oriented Scale of Improvement
Rationale: COSI is a validation tool that measures patient-
perceived improvement in specific listening situations pre- and
post-fitting, focusing on real-world benefit rather than
electroacoustic verification.
7. What is the most common site of lesion for an acoustic
neuroma?
Answer: Vestibular branch of CN VIII
Rationale: Although acoustic neuromas cause hearing loss, they
typically originate on the superior or inferior vestibular nerve,
compressing the cochlear nerve as they expand.
, 8. Which test specifically assesses a patient's tolerance for
loud sounds?
Answer: Uncomfortable Loudness Level (UCL)
Rationale: UCL measures the level at which sound becomes
uncomfortably loud, which is essential for setting the maximum
power output (MPO) of a hearing aid to prevent recruitment-
related discomfort.
9. A mother develops progressive hearing loss after
childbirth. What is the most likely pathology?
Answer: Otosclerosis
Rationale: Pregnancy-related hormonal changes can accelerate
otosclerosis, leading to rapid conductive hearing loss due to
stapes fixation.
10. Which part of the cochlea processes high-frequency
sounds?
Answer: Base (basal turn)
Rationale: The base of the cochlea is narrow and stiff, resonating
to high frequencies. The apex is wider and more compliant,
resonating to low frequencies (tonotopic organization).
11. What does the SISI test (Short Increment Sensitivity
Index) measure?
Answer: Ability to detect small changes in intensity
Rationale: A high SISI score (70-100%) suggests cochlear
pathology (recruitment). The test measures detection of 1 dB
intensity increments in a continuous tone.
12. In a purely conductive hearing loss, how do bone
conduction thresholds appear?
Answer: Normal (within 25 dB HL)
NEWEST 2025 TEST BANK| COMPLETE
100 REAL EXAM QUESTIONS AND
CORRECT VERIFIED ANSWERS/ ALREADY
GRADED A+| NBC HIS CERTIFICATION
EXAM PREP 2025/2026 (MOST RECENT!!)
1. What is the primary function of the outer hair cells?
Answer: Amplify low-level sounds via electromotility
Rationale: Outer hair cells contract and expand in response to
sound, mechanically amplifying the traveling wave in the cochlea.
This provides up to 60 dB of gain for soft sounds, improving
frequency selectivity and sensitivity.
2. Which tympanometry type is most consistent with
otosclerosis?
Answer: Type As
Rationale: Type As (A-shallow) shows normal middle ear volume
but reduced compliance (stiffness), which is characteristic of
stapes fixation in otosclerosis.
3. What is the interaural attenuation (IA) for a standard
supra-aural headphone?
Answer: 40–50 dB (average 45 dB)
Rationale: IA is the reduction in sound level as it crosses the skull
,from the test ear to the non-test ear. For supra-aural headphones,
this average is 45 dB, which determines when masking is needed.
4. A patient reports hearing their own voice as "echoing" or
"talking in a barrel." What is the most likely cause?
Answer: Vent diameter too large
Rationale: A large vent allows low-frequency bone-conducted
self-vocalizations to escape and re-enter the ear canal, creating a
hollow or echoing sound known as the occlusion effect.
5. Which frequency is most commonly affected first in noise-
induced hearing loss (NIHL)?
Answer: 4000 Hz
Rationale: The resonant frequency of the ear canal and the
vulnerability of the basal turn of the cochlea make 4000 Hz the
classic "notch" seen in early NIHL.
6. What does COSI stand for?
Answer: Client Oriented Scale of Improvement
Rationale: COSI is a validation tool that measures patient-
perceived improvement in specific listening situations pre- and
post-fitting, focusing on real-world benefit rather than
electroacoustic verification.
7. What is the most common site of lesion for an acoustic
neuroma?
Answer: Vestibular branch of CN VIII
Rationale: Although acoustic neuromas cause hearing loss, they
typically originate on the superior or inferior vestibular nerve,
compressing the cochlear nerve as they expand.
, 8. Which test specifically assesses a patient's tolerance for
loud sounds?
Answer: Uncomfortable Loudness Level (UCL)
Rationale: UCL measures the level at which sound becomes
uncomfortably loud, which is essential for setting the maximum
power output (MPO) of a hearing aid to prevent recruitment-
related discomfort.
9. A mother develops progressive hearing loss after
childbirth. What is the most likely pathology?
Answer: Otosclerosis
Rationale: Pregnancy-related hormonal changes can accelerate
otosclerosis, leading to rapid conductive hearing loss due to
stapes fixation.
10. Which part of the cochlea processes high-frequency
sounds?
Answer: Base (basal turn)
Rationale: The base of the cochlea is narrow and stiff, resonating
to high frequencies. The apex is wider and more compliant,
resonating to low frequencies (tonotopic organization).
11. What does the SISI test (Short Increment Sensitivity
Index) measure?
Answer: Ability to detect small changes in intensity
Rationale: A high SISI score (70-100%) suggests cochlear
pathology (recruitment). The test measures detection of 1 dB
intensity increments in a continuous tone.
12. In a purely conductive hearing loss, how do bone
conduction thresholds appear?
Answer: Normal (within 25 dB HL)
