A caloric test shows a left unilateral weakness. Which statement is most accurate?

A caloric test shows a left unilateral weakness. Which statement is most accurate?

• A. It suggests a right peripheral vestibular disorder of the labyrinth
• B. It is of no real interpretive value
• C. It suggests a nonspecific (nonlocalizing) vestibular disorder
• D. It suggests a left peripheral vestibular disorder of either the labyrinth or the VIIIth nerve.

Answer: (D)

A unilateral weakness on caloric testing localizes to reduced function on the side of the weakness, pointing to a left peripheral vestibular lesion. This means the problem could be in the left labyrinth or in the left vestibular (VIIIth nerve) pathway supplying that labyrinth. The test doesn’t point to a right-sided issue, nor does it render the finding nonlocalizing or of no interpretive value. A clear, side-specific deficit like this is one of the ways caloric testing helps differentiate peripheral vestibular dysfunction from other possibilities.

A unilateral weakness on caloric testing localizes to reduced function on the side of the weakness, pointing to a left peripheral vestibular lesion. This means the problem could be in the left labyrinth or in the left vestibular (VIIIth nerve) pathway supplying that labyrinth. The test doesn’t point to a right-sided issue, nor does it render the finding nonlocalizing or of no interpretive value. A clear, side-specific deficit like this is one of the ways caloric testing helps differentiate peripheral vestibular dysfunction from other possibilities.