Ear and audiology: false-negative fistula test: practice question

A ENT question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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ENT · Ear and audiology: false-negative fistula test

Sample item

A man with long-standing cholesteatoma has a negative fistula test, but profound sensorineural loss in that ear with no response to caloric testing. A CT shows erosion of the lateral semicircular canal. What explains the negative test?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Dead labyrinth, so there is no response to pressure changes

A positive fistula test needs a functioning labyrinth to generate nystagmus on pressure change. If the labyrinth is dead, or the fistula is blocked by granulation, the test can be falsely negative. Imaging showing canal erosion then reveals the true state.

Option by option

  • A. Facial nerve dehiscence

    Facial dehiscence affects the nerve, not the response to the fistula test.

  • B. A functioning vestibular system compensates for the pressure

    Compensation does not abolish the response to pressure in a living labyrinth.

  • C. Dead labyrinth, so there is no response to pressure changes (correct)

    Correct. A non-functioning labyrinth gives no nystagmus even with a fistula.

  • D. No fistula is present

    Imaging shows a fistula, so absence is not the explanation.

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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Questions about this ENT question

What is the answer to this ENT question?

The best answer is C, Dead labyrinth, so there is no response to pressure changes. A positive fistula test needs a functioning labyrinth to generate nystagmus on pressure change.

Why is "Facial nerve dehiscence" not the answer?

Facial dehiscence affects the nerve, not the response to the fistula test.

Why is "A functioning vestibular system compensates for the pressure" not the answer?

Compensation does not abolish the response to pressure in a living labyrinth.

Why is "No fistula is present" not the answer?

Imaging shows a fistula, so absence is not the explanation.

What concept does this question test?

It tests Ear and audiology: false-negative fistula test in ENT. If the labyrinth is dead, or the fistula is blocked by granulation, the test can be falsely negative. Imaging showing canal erosion then reveals the true state.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Ear and audiology: false-negative fistula test?

Learn tuning fork results and audiogram patterns by sketching them. Then use the flashcards and the other ENT questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.