Transmission & Drivetrain Systems Flashcards
7 cards from real ABA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Transmission & Drivetrain Systems flashcards as text
In tympanometry, a Type Ad (deep) tympanogram pattern most likely indicates which transmission problem?
Answer: Ossicular discontinuity or hypermobile tympanic membrane
A Type Ad tympanogram shows abnormally high compliance (deep peak), indicating a highly mobile system such as ossicular discontinuity or a flaccid tympanic membrane.
Which frequency range is most attenuated by the acoustic reflex's stiffening effect on the ossicular chain?
Answer: Low frequencies (<1000 Hz)
The stiffness introduced by acoustic reflex contraction primarily attenuates low-frequency transmission because stiffness reactance is dominant at lower frequencies.
The Carhart notch, a characteristic audiometric dip around 2000 Hz on bone conduction, is associated with which drivetrain pathology?
Answer: Otosclerosis
The Carhart notch is a mechanical artifact of otosclerosis where stapes fixation reduces the resonant contribution of the ossicular chain to bone conduction testing.
What is the approximate total middle ear transformer gain that compensates for the impedance mismatch at the air-fluid interface?
Answer: 25–30 dB
The combined area ratio and ossicular lever action provides approximately 25–30 dB of gain, offsetting the ~30 dB loss that would otherwise occur at the air-fluid interface.
Cholesteatoma most commonly damages transmission by eroding which ossicle?
Answer: Long process of the incus
The long process of the incus is the most common site of erosion by cholesteatoma due to its relatively poor blood supply, causing ossicular discontinuity.
Which probe tone frequency is recommended by ASHA guidelines for tympanometry in neonates to assess middle ear transmission?
Answer: 1000 Hz
A 1000 Hz probe tone is recommended for neonates because the neonatal ear canal and middle ear are mass-dominated at low frequencies, making 226 Hz unreliable.
The term 'acoustic immittance' encompasses both acoustic impedance and its reciprocal. What is the reciprocal of impedance called?
Answer: Admittance
Acoustic admittance (Y) is the reciprocal of acoustic impedance (Z), and modern tympanometry measures admittance because it is more clinically useful.