{ "id": "epm5ve6804", "slug": "video-head-impulse-test", "title": "Video head impulse test", "updated": "2026-10-15", "topic_path": [ { "id": "life", "label": "Life and health", "api_url": "https://www.edgepedia.org/api/v1/topics/life" }, { "id": "life.health", "label": "Human health and medicine", "api_url": "https://www.edgepedia.org/api/v1/topics/life.health" }, { "id": "life.health.clinical", "label": "Clinical assessment and procedures", "api_url": "https://www.edgepedia.org/api/v1/topics/life.health.clinical" }, { "id": "life.health.clinical.clinical-diagnostics", "label": "Diagnosis and clinical assessment", "api_url": "https://www.edgepedia.org/api/v1/topics/life.health.clinical.clinical-diagnostics" }, { "id": "life.health.clinical.clinical-diagnostics.physical-examination-and-clinical-signs", "label": "Physical examination and clinical signs", "api_url": "https://www.edgepedia.org/api/v1/topics/life.health.clinical.clinical-diagnostics.physical-examination-and-clinical-signs" }, { "id": "life.health.clinical.clinical-diagnostics.physical-examination-and-clinical-signs.neurological-examination", "label": "Neurological examination", "api_url": "https://www.edgepedia.org/api/v1/topics/life.health.clinical.clinical-diagnostics.physical-examination-and-clinical-signs.neurological-examination" } ], "geo": [ { "id": "geo.nongeo.t1946.life.health.clinical.clinical-diagnostics.physical-examination-and-clinical-signs", "label": "Non-geographic · 1946 to 2000: Physical examination and clinical signs", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life.health.clinical.clinical-diagnostics.physical-examination-and-clinical-signs", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.t1946", "label": "Non-geographic · 1946 to 2000", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946" }, { "id": "geo.nongeo.t1946.life", "label": "Life and health", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life" }, { "id": "geo.nongeo.t1946.life.health", "label": "Human health and medicine", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life.health" }, { "id": "geo.nongeo.t1946.life.health.clinical", "label": "Clinical assessment and procedures", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life.health.clinical" }, { "id": "geo.nongeo.t1946.life.health.clinical.clinical-diagnostics", "label": "Diagnosis and clinical assessment", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life.health.clinical.clinical-diagnostics" }, { "id": "geo.nongeo.t1946.life.health.clinical.clinical-diagnostics.physical-examination-and-clinical-signs", "label": "Physical examination and clinical signs", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life.health.clinical.clinical-diagnostics.physical-examination-and-clinical-signs" } ] } ], "excerpt": "The video head impulse test (vHIT) is a clinical vestibular test in which video goggles record eye movements during rapid head turns to measure the vestibulo-ocular reflex.", "snippet": "The video head impulse test (vHIT) is a clinical vestibular test in which video goggles record eye movements during rapid head turns to measure the vestibulo-ocular reflex.", "node": "life.health.clinical.clinical-diagnostics.physical-examination-and-clinical-signs.neurological-examination", "markdown": "# Video head impulse test\n\nThe video head impulse test (vHIT) is a clinical vestibular test in which lightweight video goggles record eye movements during brief, rapid, passive head turns, quantifying the vestibulo-ocular reflex (VOR) gain and catch-up saccades for each semicircular canal in a dizzy patient.[1](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00258/full) It answers a practical question: is the vestibulo-ocular reflex of a given canal impaired, and is the lesion likely peripheral rather than central? Because it is easier to use in clinics than search coils, even in patients with acute [vestibular neuritis](https://www.edgepedia.org/vestibular-neuritis), it has supplanted caloric testing as the initial test of choice in many dizzy clinics.[1](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00258/full) • [2](https://pubmed.ncbi.nlm.nih.gov/19805730/)\n\n| Key fact | Value |\n|---|---|\n| What is measured | VOR gain (eye velocity ÷ head velocity) and catch-up saccades, per canal[1](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00258/full) |\n| Normal horizontal gain | Approximately 0.8–1.2; below 0.8 (horizontal) or 0.7 (vertical) generally abnormal[3](https://www.e-rvs.org/journal/view.php?number=1013) |\n| Impulse parameters | Peak velocity 150–300°/s, duration 100–200 ms, amplitude ~15–20°, 10–20 trials per side[4](https://pmc.ncbi.nlm.nih.gov/articles/PMC11204878/) |\n| Frequency range tested | 1–5 Hz, versus about 0.003 Hz for caloric irrigation[4](https://pmc.ncbi.nlm.nih.gov/articles/PMC11204878/) |\n| Acute vestibular neuritis | Low gains in 78–95% of patients in the acute phase[5](https://www.mdpi.com/2039-4349/12/4/43) |\n| Stroke screening | Gain differentiates vestibular neuritis from posterior circulation stroke with 88% sensitivity, 92% specificity[1](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00258/full) |\n| Introduced | 2009, by the Sydney group and, in parallel, a Munich group[6](https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.2008.03730.x) |\n\n## How it works\n\nThe VOR stabilizes gaze by driving eye velocity equal and opposite to head velocity. It is one of the fastest reflexes in the body, with a latency under 8 ms, so during a rapid head turn the eyes are driven by the canals before slower, visually guided eye movements (latency 70–100 ms) can contribute; vHIT therefore evaluates the VOR at high frequencies of 1–5 Hz.[3](https://www.e-rvs.org/journal/view.php?number=1013)\n\nHead impulses reach angular accelerations of 2,000–4,000°/s², about 100 times greater than motorized chair rotations (rarely above 100°/s/s). At these accelerations the contralateral canal of the working pair is silenced, so the response predominantly reflects the target canal, allowing each of the six canals to be assessed separately.[7](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1147253/full)\n\nGain is the central number: the ratio of the area under the eye velocity curve to the area under the head velocity curve during the impulse, written \\( G_{\\mathrm{VOR}} = A_{\\mathrm{eye}} / A_{\\mathrm{head}} \\). Normal gain is close to 1.0; in unilateral vestibular loss, gain during head turns toward the affected ear is usually below 0.7.[1](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00258/full) When gain is low, the eyes fall behind the head and corrective catch-up saccades bring gaze back to target; their presence, timing, and amplitude carry diagnostic information in their own right.[6](https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.2008.03730.x)\n\n## How it is done\n\nThe patient wears tight-fitting goggles carrying a high-speed eye camera (about 250 Hz sampling) and head-velocity sensors, and fixates a target on the wall. After calibration, the examiner stands behind the patient and delivers abrupt, unpredictable, passive head turns in the plane of the canal pair being tested: horizontal (lateral canal) impulses first, then, for vertical canal pairs, impulses after rotating the head 30–40° to the right or left (LARP and RALP planes).[3](https://www.e-rvs.org/journal/view.php?number=1013)\n\nRecommended impulse characteristics are a peak velocity of 150–300°/s, duration of 100–200 ms, and amplitude of roughly 15–20°, with 10–20 acceptable trials per side.[4](https://pmc.ncbi.nlm.nih.gov/articles/PMC11204878/) Ideal impulses are ballistic at approximately 200°/s with no end-of-impulse overshoot.[8](https://www.neurology.org/doi/10.1212/WNL.0000000000002827)\n\nGain is computed with a wide window, from the start of the impulse until head velocity returns to or crosses 0°/s, using the desaccaded eye velocity trace; this position (area) gain best minimizes artifacts from small goggle slips, whose biphasic movements tend to cancel over the full window.[1](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00258/full) Interpretation combines the gain trace with the saccade record: matching head and eye velocity curves with gain in the normal range indicate normal function, while low mean gain with pathological saccades indicates vestibular dysfunction.[9](https://www.jove.com/v/59012/testing-all-six-semicircular-canals-with-video-head-impulse-test)\n\n## Origin\n\nThe underlying clinical sign, the bedside head impulse test, was described by G. M. Halmagyi and I. S. Curthoys in \"A Clinical Sign of Canal Paresis\" (Archives of [Neurology](https://www.edgepedia.org/neurology), 1988): the clinician turns the patient's head abruptly while the patient fixates the clinician's nose and watches for a corrective saccade.[10](https://doi.org/10.1001/archneur.1988.00520310043015) Objective measurement had relied on the scleral search coil method introduced by David A. Robinson in 1963, which was accurate but impractical for routine diagnostic use.[11](https://doi.org/10.1109/tbmel.1963.4322822)\n\nThe video version was reported in 2009 by two groups in the same volume of the [Annals of the New York Academy of Sciences](https://www.edgepedia.org/annals-of-the-new-york-academy-of-sciences). Konrad P. Weber, Hamish G. MacDougall, G. Michael Halmagyi, and Ian S. Curthoys described a lightweight, nonslip, high-speed video-[oculography](https://www.edgepedia.org/oculography) system detecting both overt and covert catch-up saccades,[6](https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.2008.03730.x) and Klaus Bartl, Nadine Lehnen, Stefan Kohlbecher, and Erich Schneider independently showed that head-mounted high-frame-rate video-oculography could assess VOR gain for individual canals at the bedside against search coils.[12](https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.2009.03850.x) MacDougall and colleagues validated the 250 Hz video system against simultaneous search coils in 2009 (concordance correlation coefficient 0.930; sensitivity and specificity 1.0 in the studied groups).[2](https://pubmed.ncbi.nlm.nih.gov/19805730/) Vertical canal testing was added in 2013 by Hamish Gavin MacDougall and colleagues in PLoS ONE.[13](https://doi.org/10.1371/journal.pone.0061488) Based on these papers, Otometrics (Taastrup, Denmark) developed the ICS Impulse goggles.[7](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1147253/full)\n\n## Variants\n\nThe standard paradigm, now called HIMP (head impulse paradigm), uses an earth-fixed target: compensatory catch-up saccades indicate vestibular loss. The suppression head impulse paradigm (SHIMP), introduced by Hamish G. MacDougall and colleagues in Neurology in 2016, reverses this: the patient fixates a head-mounted laser target, so healthy subjects make large anticompensatory saccades while patients with vestibular loss make small ones or none.[8](https://www.neurology.org/doi/10.1212/WNL.0000000000002827) SHIMP removes covert saccades from the gain measurement,[7](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1147253/full) and its gain is unaffected by spontaneous nystagmus.[4](https://pmc.ncbi.nlm.nih.gov/articles/PMC11204878/) HIMP and SHIMP gains correlate closely (\\( R^{2} = 0.97 \\)), with SHIMP gains about 0.06 lower.[8](https://www.neurology.org/doi/10.1212/WNL.0000000000002827)\n\nThe two widely used commercial systems, EyeSeeCam (Interacoustics) and ICS Impulse (Otometrics), agree well for horizontal canals: in patients with acute unilateral vestibular disorders, affected-side horizontal gains correlated significantly (r = 0.80, P < 0.01) with no significant difference between models. For vertical canals, however, gains were significantly higher with EyeSeeCam than with ICS Impulse, so each model needs its own vertical-canal reference values.[14](https://journals.lww.com/onojournal/fulltext/2024/06000/comparing_video_head_impulse_testing_in_patients.2.aspx) In the ICS Impulse approach, vertical testing uses LARP and RALP impulses with gaze directed along the plane of the stimulated canal pair, minimizing torsion.[7](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1147253/full)\n\n## Applications\n\nIn acute vestibular neuritis, 78–95% of patients show low vHIT gains and caloric unilateral hypofunction, with only 5–10% dissociated results.[5](https://www.mdpi.com/2039-4349/12/4/43) Because vHIT gain can differentiate vestibular neuritis from posterior circulation stroke with 88% sensitivity and 92% specificity, it is used to screen potential stroke patients in the emergency room.[1](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00258/full)\n\nFor bilateral vestibulopathy, saccade-based criteria perform strongly: cumulative HIMP saccade amplitude above 0.78°/trial discriminated bilateral vestibular loss from controls with 100% sensitivity and 100% specificity in the SHIMP study cohort.[8](https://www.neurology.org/doi/10.1212/WNL.0000000000002827) vHIT's vertical canal testing also distinguishes superior vestibular neuritis (85% of cases) from inferior neuritis (15%), which calorics cannot.[3](https://www.e-rvs.org/journal/view.php?number=1013)\n\nAgainst caloric testing, the two methods are complementary rather than interchangeable. In chronic dizziness, a meta-analysis of eleven studies (2,670 patients) found caloric testing abnormal in 55% versus 21% for vHIT, with vHIT sensitivity of 0.341 and specificity of 0.939 against calorics, so vHIT cannot replace caloric testing as a screening test in chronic disease.[15](https://www.sciencedirect.com/science/article/pii/S1808869421000082) In one consecutive series of 893 dizzy patients, dissociation occurred in 18.1%, most often abnormal calorics with normal vHIT, mainly [Ménière's disease](https://www.edgepedia.org/menieres-disease) and vestibular neuritis.[16](https://pubmed.ncbi.nlm.nih.gov/32319245/) vHIT is also used to monitor intratympanic gentamicin treatment of Ménière's disease.[1](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00258/full)\n\n## Limitations and alternatives\n\nFalse normals are the main pitfall. In partial lesions and Ménière's disease the high-frequency VOR measured by vHIT can be preserved while low-frequency function is lost: in 172 patients with caloric unilateral weakness ≥25%, pathological vHIT was found in only 41% overall, in 63% of acute versus 33% of non-acute patients.[4](https://pmc.ncbi.nlm.nih.gov/articles/PMC11204878/) Low-velocity impulses also miss deficits; testing at 240°/s is 17–20% more sensitive than at 80°/s in vestibular neuritis.[4](https://pmc.ncbi.nlm.nih.gov/articles/PMC11204878/)\n\nTechnical artifacts matter. Goggle slippage and poor calibration distort the gain calculation, which is why the wide-window position gain is preferred.[1](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00258/full) Head tilt reduces the measured head velocity by the cosine of the tilt angle; at 25° tilt the horizontal head velocity reads 0.906 of the true value, spuriously raising gain.[7](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1147253/full) Monocular right-eye recording systems carry a rightward gain bias, a mean 9.1% difference favoring the right side across 212 healthy subjects.[17](https://pmc.ncbi.nlm.nih.gov/articles/PMC10273913/) Abnormal vHIT with normal calorics can also reflect central lesions, including AICA stroke and flocculus lesions.[18](https://journals.sagepub.com/doi/full/10.1177/01455613221113790)\n\nCompared with the alternatives: the bedside head impulse test is faster but less accurate; in a 2025 cross-sectional study using vHIT as the reference, bedside HIT had 74% diagnostic accuracy (sensitivity 57%, specificity 89%, Cohen's Kappa 0.468).[19](https://journals.lww.com/ijoo/fulltext/2025/04000/comparison_of_video_head_impulse_test_and_bedside.8.aspx) Search coils remain more accurate for stroke differentiation (94–97% sensitivity, 90–100% specificity) but are impractical for routine use.[1](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00258/full) Normative gain cutoffs also vary between laboratories: 0.8 (or 0.79) is commonly used, while one device-specific study found normal ranges of 0.72–1.04 (left) and 0.72–1.28 (right) with gain <0.72 alone giving 80% sensitivity.[17](https://pmc.ncbi.nlm.nih.gov/articles/PMC10273913/)\n\n## References\n\n1. [The Video Head Impulse Test (Halmagyi, Curthoys et al., Frontiers in Neurology 2017)](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00258/full)\n2. [The video head impulse test: diagnostic accuracy in peripheral vestibulopathy (MacDougall et al., Neurology 2009)](https://pubmed.ncbi.nlm.nih.gov/19805730/)\n3. [Clinical usefulness of the video head impulse test: a narrative review (Research in Vestibular Science)](https://www.e-rvs.org/journal/view.php?number=1013)\n4. [Application of a Video Head Impulse Test in the Diagnosis of Vestibular Neuritis (2024 review)](https://pmc.ncbi.nlm.nih.gov/articles/PMC11204878/)\n5. [Dissociation between Caloric and Video Head Impulse Tests in Dizziness Clinics (review)](https://www.mdpi.com/2039-4349/12/4/43)\n6. [Impulsive Testing of Semicircular-Canal Function Using Video-oculography (Weber, MacDougall, Halmagyi, Curthoys, Annals of the New York Academy of Sciences, 2009)](https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.2008.03730.x)\n7. [A review of the geometrical basis and the principles underlying the use and interpretation of the video head impulse test (vHIT) in clinical vestibular testing (Frontiers in Neurology 2023)](https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1147253/full)\n8. [A new saccadic indicator of peripheral vestibular function based on the video head impulse test (MacDougall et al., Neurology 2016;87(4):410-418, SHIMP paper; publisher page, excerpts merged from PMC4977115 copy)](https://www.neurology.org/doi/10.1212/WNL.0000000000002827)\n9. [Testing of all Six Semicircular Canals with Video Head Impulse Test Systems (JoVE, 2019, DOI 10.3791/59012-v)](https://www.jove.com/v/59012/testing-all-six-semicircular-canals-with-video-head-impulse-test)\n10. [G. M. Halmagyi, I. S. Curthoys (1988). A Clinical Sign of Canal Paresis. Archives of Neurology.](https://doi.org/10.1001/archneur.1988.00520310043015)\n11. [David A. Robinson (1963). A Method of Measuring Eye Movemnent Using a Scieral Search Coil in a Magnetic Field. IEEE Transactions on Bio-medical Electronics.](https://doi.org/10.1109/tbmel.1963.4322822)\n12. [Head Impulse Testing Using Video-oculography (Bartl, Lehnen, Kohlbecher, Schneider, Annals of the New York Academy of Sciences, 2009)](https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.2009.03850.x)\n13. [Hamish Gavin MacDougall and colleagues (2013). The Video Head Impulse Test (vHIT) Detects Vertical Semicircular Canal Dysfunction. PLoS ONE.](https://doi.org/10.1371/journal.pone.0061488)\n14. [Comparing Video Head Impulse Testing in Patients With Acute Vestibular Dysfunction (Otology & Neurotology, 2024)](https://journals.lww.com/onojournal/fulltext/2024/06000/comparing_video_head_impulse_testing_in_patients.2.aspx)\n15. [Does the video head impulse test replace caloric testing in the assessment of patients with chronic dizziness? A systematic review and meta-analysis](https://www.sciencedirect.com/science/article/pii/S1808869421000082)\n16. [Dissociated Results between Caloric and Video Head Impulse Tests in Dizziness: Prevalence, Pattern, Lesion Location, and Etiology (Lee et al., PubMed record)](https://pubmed.ncbi.nlm.nih.gov/32319245/)\n17. [Refining the Video Head Impulse Test Diagnostic Accuracy: A Case-Control Study (2023)](https://pmc.ncbi.nlm.nih.gov/articles/PMC10273913/)\n18. [Clinical characteristics of patients with dizziness/vertigo showing a dissociation between caloric and video head impulse test results](https://journals.sagepub.com/doi/full/10.1177/01455613221113790)\n19. [Comparison of Video Head Impulse Test and Bedside Head Impulse Test in Patients of Dizziness: A Cross-sectional Study (2025)](https://journals.lww.com/ijoo/fulltext/2025/04000/comparison_of_video_head_impulse_test_and_bedside.8.aspx)\n\n---\n*Topic: Encyclopedia › Life and health › Human health and medicine › Clinical assessment and procedures › Diagnosis and clinical assessment › Physical examination and clinical signs › Neurological examination*\n\n*Initially written Sep 29, 2026 · Edited: Oct 15, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [], "url": "https://www.edgepedia.org/video-head-impulse-test", "markdown_url": "https://www.edgepedia.org/video-head-impulse-test.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"Video head impulse test\", Edgepedia (EdgeChat), https://www.edgepedia.org/video-head-impulse-test. Edgepedia Community License 1.0.", "credit_md": "\"[Video head impulse test](https://www.edgepedia.org/video-head-impulse-test)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/video-head-impulse-test](https://www.edgepedia.org/video-head-impulse-test). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"Video head impulse test\", Edgepedia (EdgeChat), https://www.edgepedia.org/video-head-impulse-test. Edgepedia Community License 1.0.", "speakable": "The video head impulse test is a clinical vestibular test in which video goggles record eye movements during rapid head turns to measure the vestibulo-ocular reflex." }