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ENT · Hearing rehabilitation
Sample itemA 3-year-old child with congenital profound bilateral sensorineural hearing loss gets no benefit from well-fitted hearing aids. Cochlear implantation is planned. Which structure must be intact for the implant to work?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
B. Cochlear (auditory) nerve
A cochlear implant bypasses the damaged hair cells and directly stimulates the spiral ganglion neurons and cochlear nerve fibres with an electrode array in the scala tympani. A functioning auditory nerve is therefore essential, and cochlear nerve aplasia on MRI is a contraindication.
Option by option
A. Tympanic membrane
The tympanic membrane is bypassed by the electrode.
B. Cochlear (auditory) nerve (correct)
Correct. The electrode stimulates the auditory nerve, which then carries the signal to the brain.
C. Ossicular chain
The ossicles are not involved in electrical stimulation.
D. Outer hair cells of the organ of Corti
The implant replaces damaged hair cells, so they need not be present.
Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.
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