What is the role of the bithermal caloric test in the diagnosis of dizziness, vertigo, and imbalance?

Updated: Mar 13, 2017
  • Author: Hesham M Samy, MD, PhD; Chief Editor: Robert A Egan, MD  more...
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Answer

Since its introduction in 1903, the caloric test has been the time-honored vestibular test in clinical neuro-otology. Although it remains the standard for evaluating unilateral vestibular deficit, it is a limited and nonphysiologic test of the vestibular system. The literature on the caloric test is extensive; therefore, only a brief description of the test and its interpretation are provided here.

Traditionally, the caloric test is performed with the patient lying with the head elevated 30°. Cold (30°C) and warm (44°C) water are used to irrigate one ear at a time. Cold irrigation is an inhibitory stimulus, and warm irrigation is excitatory. The direction of postcaloric nystagmus is determined by the quick-phase direction and is easily remembered by using the mnemonic COWS: c old o pposite, w arm s ame (ie, quick phase away from or toward the irrigated ear).


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