On videonystagmography (VNG) caloric testing, a patient shows 70% canal paresis on the right side with 30% directional preponderance to the left. This pattern most suggests:
- A Right peripheral vestibular hypofunction — consistent with right vestibular neuritis or labyrinthitis ✓
- B Right central vestibular lesion at the level of the right vestibular nucleus
- C Left labyrinthine hydrops with endolymphatic excess
- D Bilateral vestibulopathy with equal hypofunction
Explanation
Caloric canal paresis (CP) of ≥25% indicates peripheral hypofunction of the horizontal semicircular canal on that side. A 70% right CP means the right labyrinth (horizontal SCC) is significantly underresponsive — hallmark of right peripheral vestibular hypofunction such as vestibular neuritis (which affects the superior division of the vestibular nerve, sparing the saccule). Directional preponderance (DP) toward the left represents asymmetric spontaneous nystagmus, consistent with the rightward labyrinthine tone loss (nystagmus beats away from the affected ear). Central lesions show dissociated or perverted nystagmus, not simple unilateral CP.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.