A 38-year-old woman undergoes caloric testing. Cold water irrigation of the right ear produces nystagmus beating to the LEFT. Hot water irrigation of the right ear produces nystagmus beating to the RIGHT. The responses are symmetrical with the left ear. How is this interpreted?

• A Right canal paresis indicating right peripheral vestibular lesion
• B Normal caloric responses bilaterally ✓
• C Directional preponderance to the left indicating a left central lesion
• D Left canal paresis due to labyrinthine fistula

Explanation

The mnemonic COWS (Cold Opposite, Warm Same) describes normal caloric responses: cold water irrigation produces nystagmus beating to the opposite ear, while warm water irrigation produces nystagmus to the same (ipsilateral) ear. In this patient, cold water to the right ear produces left-beating nystagmus (correct — opposite) and warm water produces right-beating nystagmus (correct — same). Symmetrical responses bilaterally indicate intact vestibular function. Canal paresis would be identified by the Jongkees formula comparing responses.

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.