Nystagmus (mnemonic)

Last revised by Daniel J Bell on 18 Mar 2019

A helpful mnemonic to remember the expected direction of nystagmus during a caloric test is:

  • COWS


  • Cold-Opposite
  • Warm-Same

Following ear stimulation with water (left ear):

  • cold water (cooler than body temperature), a right-beating nystagmus (directed toward the opposite ear) results
  • warm water (warmer than body temperature), a left-beating nystagmus (directed toward the same left ear) occurs

Similar, but oppositely-directed responses occur for the right ear.

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