Caloric reflex test

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In medicine, the caloric reflex test is a test of the vestibulo-ocular reflex. It is used by physicians to assess brain stem function and may be part of an evaluation to determine brain death.

Contents

[edit] Technique and results

It involves putting cold or hot water 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 brain death.[3][4]

[edit] Mnemonic

Mnemonics are common in the medical literature. One mnemonic used to remember the direction of nystamgus is COWS.[5]

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

[edit] See also

[edit] References

  1. ^ Bardorf CM, Van Stavern GP. Nystagmus, Acquired. eMedicine.com. URL: http://www.emedicine.com/oph/topic339.htm. Accessed on: August 17, 2006.
  2. ^ Narenthiran G. Neurosurgery Quiz. Annals of Neurosurgery. URL: http://www.annals-neurosurgery.org/quiz/nsq2/#a3. Accessed on: August 17, 2006.
  3. ^ Hicks R, Torda T (1979). "The vestibulo-ocular (caloric) reflex in the diagnosis of cerebral death.". Anaesth Intensive Care 7 (2): 169-73. PMID 507352.
  4. ^ Born J, Albert A, Hans P, Bonnal J (1985). "Relative prognostic value of best motor response and brain stem reflexes in patients with severe head injury.". Neurosurgery 16 (5): 595-601. PMID 4000430.
  5. ^ Webb C (1985). "COWS caloric test.". Ann Emerg Med 14 (9): 938. PMID 4026002.

[edit] External links

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