On videonystagmography (VNG) caloric testing, a patient shows 40% reduced caloric response on the right side compared to the left. This finding is termed canal paresis (CP). At what percentage of asymmetry is this considered clinically significant using Jongkee's formula?
- A Greater than 10% asymmetry
- B Greater than 25% asymmetry ✓
- C Greater than 20% asymmetry
- D Greater than 35% asymmetry
Correct answer: B. Greater than 25% asymmetry
Explanation
Canal paresis (CP) is calculated using Jongkee's formula: CP% = [(RW + RC) − (LW + LC)] / (RW + RC + LW + LC) × 100, where W = warm (44°C) and C = cool (30°C) responses. A CP value of >25% is considered clinically significant and indicates ipsilateral peripheral vestibular hypofunction (e.g., vestibular neuritis, labyrinthitis, or Meniere's disease on the hyporesponsive side). Values up to 25% may reflect normal biological variation.
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.