Caloric reflex test

Caloric reflex test
Caloric reflex test
ICD-9-CM 95.44

In medicine, the caloric reflex test (sometimes termed 'vestibular caloric stimulation') is a test of the vestibulo-ocular reflex that involves irrigating cold or warm water or air into the external auditory canal.



It is commonly used by physicians, 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) battery of tests. It is one of several tests which can be used to test for brain stem death.

One novel use of this test has been to provide temporary pain relief from phantom limb pains in amputees [1] and paraplegics.[2] It can also induce a temporary remission of anosognosia, the visual and personal aspects of hemispatial neglect, hemianesthesia, and other consequences of right hemispheric damage.[3]

Technique and results

Cold or warm water or air is irrigated into the external auditory canal, usually using a syringe. The temperature difference between the body and the injected water creates a convective current in the endolymph of the nearby horizontal semicircular canal. Hot and cold water produce currents in opposite directions and therefore a horizontal nystagmus in opposite directions.[4] In patients with an intact brainstem:

  • If the water is warm (44°C or above) endolymph in the ipsilateral horizontal canal rises, causing an increased rate of firing in the vestibular afferent nerve. This situation mimics a head turn to the ipsilateral side. Both eyes will turn toward the contralateral ear, with horizontal nystagmus to the ipsilateral ear.
  • If the water is cold, relative to body temperature (30°C or below), the endolymph falls within the semicircular canal, decreasing the rate of vestibular afferent firing. The eyes then turn toward the ipsilateral ear, with horizontal nystagmus (quick horizontal eye movements) to the contralateral ear.[5][6]
  • Absent reactive eye movement suggests vestibular weakness of the horizontal semicircular canal of the side being stimulated.

In comatose patients with cerebral damage, the fast phase of nystagmus will be absent as this is controlled by the cerebrum. As a result, using cold water irrigation will result in deviation of the eyes toward the ear being irrigated. If both phases are absent, this suggests the patient's brainstem reflexes are also damaged and carries a very poor prognosis.[7]


One mnemonic used to remember the FAST direction of nystagmus is COWS.[8]

COWS: Cold Opposite, Warm Same.
Cold water = FAST phase of nystagmus to the side Opposite from the cold water filled ear
Warm water = FAST phase of nystagmus to the Same side as the warm water filled ear
In other words: Contralateral when cold is applied and ipsilateral when warm is applied


  1. ^ André JM, Martinet N, Paysant J, Beis JM, Le Chapelain L (2001). "Temporary phantom limbs evoked by vestibular caloric stimulation in amputees". Neuropsychiatry Neuropsychol Behav Neurol 14 (3): 190–6. PMID 11513103. 
  2. ^ Le Chapelain L, Beis JM, Paysant J, André JM (February 2001). "Vestibular caloric stimulation evokes phantom limb illusions in patients with paraplegia". Spinal Cord 39 (2): 85–7. doi:10.1038/ PMID 11402363. 
  3. ^ Robertson, Ian H.; Marshall, John C. (1993). Unilateral neglect: clinical and experimental studies. pp. 111–113. ISBN 978-0863772085. Retrieved 2010-06-04. 
  4. ^ Purves, D; et al (2004). Neuroscience. Sinauer. 
  5. ^ Nystagmus, Acquired at eMedicine
  6. ^ Narenthiran G. Neurosurgery Quiz. Annals of Neurosurgery. Accessed on: August 17, 2006.
  7. ^ Mueller-Jensen A, Neunzig HP, Emskötter T (April 1987). "Outcome prediction in comatose patients: significance of reflex eye movement analysis". J. Neurol. Neurosurg. Psychiatr. 50 (4): 389–92. doi:10.1136/jnnp.50.4.389. PMC 1031870. PMID 3585347. 
  8. ^ Webb C (1985). "COWS caloric test". Ann Emerg Med 14 (9): 938. doi:10.1016/S0196-0644(85)80671-5. PMID 4026002. 

Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • Reflex — For other uses, see Reflex (disambiguation). A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus.[1] A true reflex is a behavior which is mediated via the reflex arc; this does… …   Wikipedia

  • Vestibulo-ocular reflex — The vestibulo ocular reflex. A rotation of the head is detected, which triggers an inhibitory signal to the extraocular muscles on one side and an excitatory signal to the muscles on the other side. The result is a compensatory movement of the… …   Wikipedia

  • Cushing reflex — (also referred to as the vasopressor response, the Cushing effect, the Cushing reaction, the Cushing phenomenon, the Cushing response, or Cushing s Law) is a physiological nervous system response to increased intracranial pressure (ICP) that… …   Wikipedia

  • Jaw jerk reflex — The jaw jerk reflex or the masseter reflex is a stretch reflex used to test the status of a patient s trigeminal nerve (CN V).[1] The mandible or lower jaw is tapped at a downward angle just below the lips at the chin while the mouth is held… …   Wikipedia

  • Mammalian diving reflex — The mammalian diving reflex is a reflex in mammals which optimizes respiration to allow staying underwater for extended periods of time. It is exhibited strongly in aquatic mammals (seals,[1] otters, dolphins, etc.), but exists in a weaker… …   Wikipedia

  • Withdrawal reflex — The withdrawal reflex (nociceptive or flexor withdrawal reflex) is a spinal reflex intended to protect the body from damaging stimuli.[1] It is polysynaptic, causing stimulation of sensory, association, and motor neurons.[1] Contents 1 Example …   Wikipedia

  • Moro reflex — The Moro reflex in a four day old infant: 1) the reflex is initiated by pulling the infant up from the floor and then releasing him; 2) he spreads his arms; 3) he pulls his arms in; 4) he cries (10 seconds) The Moro reflex, which is distinct from …   Wikipedia

  • Tendon reflex — (or T reflex) may refer to: A stretch reflex, when the stretch is created by a blow upon a muscle tendon. This is the usual definition of the term.[1][2] Deep tendon reflex also usually refers to this sense.[3] The Golgi tendon reflex, motivated… …   Wikipedia

  • Corneal reflex — The corneal reflex, also known as the blink reflex, is an involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body), or bright light, though could result from any peripheral stimulus.… …   Wikipedia

  • Stretch reflex — The stretch reflex (myotatic reflex) is a muscle contraction in response to stretching within the muscle. It is a monosynaptic reflex which provides automatic regulation of skeletal muscle length. When a muscle lengthens, the muscle spindle is… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”