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Audiovestibular assessment · Patient guide

Caloric test, the gold-standard test of the horizontal semicircular canal for vestibular dysfunction.

The bithermal caloric test uses warm and cool water or air to stimulate the horizontal semicircular canal and record the resulting nystagmus. The gold-standard test to detect unilateral vestibular weakness — commonly used to investigate vertigo, Ménière’s disease and vestibular schwannoma.

How to prepare

Reviewed by Pulse Atlas Editorial Board, · 6 min read · Last reviewed 2026-07-30 · Next review 2027-07-30

  • Definition

    Bithermal warm and cool irrigation of the horizontal semicircular canal with nystagmus recording.

  • Gold-standard

    The gold-standard test for unilateral vestibular weakness.

  • Part of

    Part of the videonystagmography (VNG) battery.

  • Interpretation

    Interpreted using the Jongkees formula.

  • Complements

    Complements the video head impulse test (vHIT).

  • Requirement

    Requires an intact tympanic membrane.

Preparation and technique

How the caloric test is performed, step by step.

A short, structured protocol — four irrigations in total, with recovery periods between each. Preparation is what makes the recording interpretable.

  1. 01

    Avoid alcohol and sedatives

    For 48 hours before the test — they suppress vestibular responses.

  2. 02

    Withhold vestibular suppressants

    Antihistamines and benzodiazepines are held, on your clinician’s advice.

  3. 03

    Otoscopic examination

    Ears are examined first to confirm an intact tympanic membrane.

  4. 04

    VNG goggles fitted

    Infrared goggles record eye movements throughout the test.

  5. 05

    Bithermal irrigation

    Water at 30°C then 44°C is irrigated in each ear (or air, if the drum is perforated).

  6. 06

    Nystagmus recorded

    The resulting nystagmus is recorded and quantified for each side.

  7. 07

    Jongkees report

    A written report with the Jongkees canal-paresis calculation.

What it shows

What a caloric test can reveal.

The test answers a specific question — is one horizontal semicircular canal weaker than the other — and, from that, points toward a diagnosis.

  • Unilateral vestibular weakness

    Canal paresis on one side — the classic caloric-test finding.

  • Directional preponderance

    A bias in nystagmus direction, seen in peripheral and central disorders.

  • Complete vestibular loss

    Absent responses on one side after severe injury or surgery.

  • Bilateral vestibulopathy

    Reduced or absent responses on both sides.

  • Central vs peripheral vertigo

    Helps differentiate a central lesion from a peripheral one.

  • Vestibular schwannoma — indirect signs

    Asymmetric caloric response raises suspicion for retrocochlear pathology.

  • Post-viral vestibular neuritis

    Characterises the deficit after acute vestibular neuritis.

  • Red flag: severe bilateral vestibulopathy — investigate ototoxicity or autoimmune causes

    A rare but important pattern that changes the work-up entirely.

Next steps

What happens after the result.

The caloric result guides treatment — from vestibular rehabilitation to imaging or a multi-disciplinary vertigo clinic.

  • Vestibular rehabilitation therapy

    Structured exercise programme — the first-line treatment for most vestibular deficits.

  • Betahistine for Ménière’s disease

    A histamine analogue widely used to reduce vertigo frequency in Ménière’s.

  • Low-salt diet and diuretic

    For Ménière’s — reduces endolymphatic pressure.

  • ENT referral for asymmetric loss

    Formal ENT input when the caloric shows unexplained one-sided weakness.

  • MRI IAM for suspected retrocochlear pathology

    Internal auditory meatus MRI to exclude vestibular schwannoma.

  • Anti-migraine therapy for vestibular migraine

    Prophylaxis and trigger management when migraine is the driver.

  • Repeat testing to monitor recovery

    Serial calorics track compensation and rehabilitation progress.

  • Multi-disciplinary vertigo clinic

    Joint ENT, neurology and audiovestibular input for complex cases.

Red flags

When the caloric points to something more.

Patterns that change the plan — from imaging the internal auditory meatus to reviewing ototoxic medication.

  • Vestibular schwannoma (asymmetric loss)

  • Post-meningitis vestibulopathy

  • Ototoxic drug injury (aminoglycosides, chemotherapy)

  • Autoimmune inner-ear disease

  • Central nystagmus (posterior fossa lesion)

  • Post-labyrinthitis dizziness

  • Persistent postural-perceptual dizziness

  • Migraine-associated vertigo

  • Superior canal dehiscence

Frequently asked

Questions patients ask about the caloric test.

Short, patient-facing answers on preparation, the Jongkees formula, comfort, and how the caloric compares to vHIT.

  • What is a caloric test?

    A bithermal caloric test uses warm and cool water (or air) delivered into the ear canal to stimulate the horizontal semicircular canal. The resulting eye movement (nystagmus) is recorded with infrared goggles and quantified. It is the gold-standard test to detect a one-sided vestibular weakness.

  • Does it hurt?

    No. You may briefly feel dizzy or nauseated during each irrigation — that is the expected response, not a complication. The sensation settles within a minute or two.

  • How long does the test take?

    About 30–45 minutes in total, including preparation and rest periods between the four irrigations (warm and cool in each ear).

  • What is the Jongkees formula?

    A standard calculation that compares the slow-phase velocity of nystagmus from each ear to give a canal-paresis percentage. A value above about 25% is generally considered abnormal.

  • How is it different from vHIT?

    The video head impulse test (vHIT) samples all six semicircular canals at high frequency, while the caloric test isolates the horizontal canal at very low frequency. The two tests are complementary — not interchangeable.

  • Do I need to stop my medication?

    Alcohol and vestibular suppressants (antihistamines, benzodiazepines) should be avoided for 48 hours before the test. Do not stop prescribed medication without checking with the referring clinician.

Sources

Guidelines and clinical bodies referenced in this guide.

Reviewed by Pulse Atlas Editorial Board, . Last reviewed 2026-07-30. Next scheduled review 2027-07-30.

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In practice, in London

Why private caloric test moves differently in London

With caloric test, the London question is usually about report turnaround and the radiologist reading it — not whether the scan is available. Public provision for caloric test is competent but constrained by capacity. Private London clinics tend to have shorter diaries and longer appointment slots, so you get the same specialists with more time. For people who’ve been going round in circles with primary care, that first proper conversation is often what shifts things.

A private caloric test pathway in London usually looks like this: an initial consultation, any diagnostics booked at a nearby facility (most within Zone 1 or 2), and a written report sent to you and your GP within a few days. The consultants we work with hold NHS posts alongside their private lists, which keeps the standards consistent across both settings. For caloric test specifically, the difference between a routine report and a sub-speciality read is where private care earns its keep.

There are a lot of consultants in London who can technically handle caloric test. Fewer who do it week in, week out for the exact question you’re bringing. We spend most of our time working out which is which — and being straight when a different test or a different specialist would serve you better. Everything runs to CQC, GMC and Royal College standards; the choice is about fit, not floor.

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