Question

A 45-year-old woman is diagnosed with right vestibular neuritis. What findings are expected during the head impulse test in this patient?

• A. When the head is turned to the left, the eyeballs move to the left with Nystagmus.
• B. When the head is turned to the left, the eyeballs move to the right with nystagmus.
• C. When the head is turned to the right, the eyeballs move to the left with Nystagmus.
• D. When the head is turned to the right, the eyeballs move to the right with nystagmus.

Hint:

For vestibular neuritis, remember that the head impulse test will show abnormal eye movement toward the unaffected side (opposite of the impaired ear).

Answer 1

The Correct Option is C

Step 1: Understand what the head impulse test probes.
The test challenges the vestibulo-ocular reflex (VOR), whose job is to drive the eyes in the direction opposite to a quick head turn so that the gaze stays locked on a target. A healthy labyrinth on the side you turn toward generates this counter-rotation instantly.

Step 2: Apply the side of the lesion.
The damage is the right vestibular apparatus (right vestibular neuritis). The horizontal canal that should fire during a turn toward its own side is the right canal; with it impaired, the abnormal response will be unmasked when the head is rapidly turned to the right.

Step 3: Predict the eye behaviour during a rightward impulse.
Normally a rightward head turn would whip the eyes smoothly to the left to hold fixation. Because the right VOR is weak, the eyes are dragged off target with the head, then must make a visible corrective (catch-up) saccade back toward the target - i.e. a fast eye movement to the left. This corrective fast phase is what is observed as nystagmus.

Step 4: Match to the options and exclude the rest.
We need: head turned to the right → eyeballs move to the left with nystagmus. Options that turn the head to the left test the healthy left side and are normal, so they are out; turning right but moving the eyes right is the wrong direction for a corrective saccade.

Final answer: Option 3 - When the head is turned to the right, the eyeballs move to the left with nystagmus.