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
The concept of 'resonant frequency' in middle ear mechanics refers to the frequency at which:
Answer: Mass and stiffness reactance are equal, resulting in minimum impedance
At the resonant frequency (~800–1200 Hz for the normal middle ear), mass and stiffness reactance cancel, leaving only resistance and yielding peak energy transmission.
A bone-anchored hearing aid (BAHA) improves auditory transmission in conductive hearing loss primarily by:
Answer: Transmitting vibrations directly through the skull to the cochlea, bypassing the middle ear
A BAHA uses a titanium osseointegrated implant to conduct amplified vibrations through skull bone directly to the cochlea, circumventing a damaged outer or middle ear.
In audiometric testing, the air-bone gap represents:
Answer: The difference between air-conduction and bone-conduction thresholds at the same frequency
The air-bone gap (ABG) is the dB difference between AC and BC thresholds; a significant ABG (≥15 dB) indicates a conductive component in the hearing loss.
Which factor primarily determines the characteristic frequency (place) of maximal basilar membrane displacement in the cochlea?
Answer: Stiffness gradient along the basilar membrane from base to apex
The basilar membrane's graded stiffness (stiff at the base, compliant at the apex) creates a tonotopic map where high frequencies activate the base and low frequencies activate the apex.
Superior semicircular canal dehiscence (SSCD) can produce a false air-bone gap on audiometry because:
Answer: It creates a third mobile window that shunts acoustic energy away from the oval window
The dehiscent canal creates a pathological third window (in addition to the oval and round windows), allowing acoustic energy to escape and artificially lowering bone-conduction thresholds while raising air-conduction thresholds.
When measuring hearing with insert earphones versus supra-aural earphones, which transmission-related advantage do insert earphones provide?
Answer: Increased interaural attenuation (~50–75 dB) and elimination of ear canal collapse
Insert earphones placed in the ear canal increase interaural attenuation (reducing cross-hearing) and prevent collapsible ear canals from artificially elevating thresholds.
Otitis media with effusion (OME) impairs ossicular chain transmission primarily through which mechanism?
Answer: Fluid mass loading and stiffening of the tympanic membrane and ossicular system
Middle ear effusion adds mass and increases stiffness of the middle ear system, reducing the mobility of the tympanic membrane and ossicular chain and causing conductive hearing loss typically of 20–40 dB.