Caloric reflex test

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

In medicine, the caloric reflex test is a test of the vestibulo-ocular reflex. It is used by audiologists and other trained professionals to validate a diagnosis of asymmetric function in the peripheral vestibular system. Calorics are usually a subtest of the electronystagmography (ENG) test battery.

Technique and results

It involves irrigating cold or warm water or air into the external auditory canal.

  • If the water is cold (30oC) the eyes turn toward the ipsilateral ear, with horizontal nystagmus (quick horizontal eye movements) to the contralateral ear.[1][2]
  • If the water is warm (44oC) the eyes turn toward the contralateral ear, with horizontal nystagmus to the ipsilateral ear.
  • Absent reactive eye movement suggests vestibular weakness of the horizontal semicircular canal of the side being stimulated.


Mnemonics are common in the medical literature. One mnemonic used to remember the direction of nystamgus is COWS.[3]

COWS: Cold water = nystagmus to the Opposite side, Warm water = nystagmus to the Same side.

See also


  1. Bardorf CM, Van Stavern GP. Nystagmus, Acquired. URL: Accessed on: August 17, 2006.
  2. Narenthiran G. Neurosurgery Quiz. Annals of Neurosurgery. URL: Accessed on: August 17, 2006.
  3. Webb C (1985). "COWS caloric test". Ann Emerg Med. 14 (9): 938. PMID 4026002.

External links

  • Essentials of Human Physiology by Thomas M. Nosek. Section 8/8ch7/s8ch7_30.