What does vestibular evoked myogenic potential testing assess, and what do cVEMP and oVEMP reflect?

• A. VEMP assesses semicircular canal function; cVEMP reflects saccular and inferior vestibular nerve function; oVEMP reflects utricular and superior vestibular nerve function
• B. VEMP assesses auditory pathways; cVEMP reflects cochlear; oVEMP reflects vestibular
• C. VEMP assesses otolithic pathway function; cVEMP reflects saccular and inferior vestibular nerve function; oVEMP reflects utricular and superior vestibular nerve function
• D. VEMP assesses visual pathways; cVEMP reflects optic nerve function; oVEMP reflects oculomotor nerve

Answer: (C)

VEMP testing taps the otolithic pathways of the vestibular system, focusing on how the otolith organs respond to stimulation. The cervical VEMP is recorded from the sternocleidomastoid muscle and primarily reflects saccular input carried by the inferior vestibular nerve, meaning it tells us about saccular function and its brainstem connections that influence neck muscles. The ocular VEMP is recorded from eye muscles and mainly reflects utricular input via the superior vestibular nerve, giving information about utricular function and its vestibulo-ocular pathways.

So, VEMP assesses otolithic function rather than semicircular canal function, and cVEMP points to the saccule and inferior nerve pathway, while oVEMP points to the utricle and superior nerve pathway.