Glossary

Pontine nucleus housing motor neurons of the ipsilateral lateral rectus and internuclear neurons that cross and ascend in the MLF to the contralateral medial rectus subnucleus. Central node of the horizontal gaze and VOR pathways.

See also: Vestibulo-ocular reflex, Medial longitudinal fasciculus, Internuclear ophthalmoplegia

Also: AVS

Sudden, persistent vertigo lasting hours to days, with nystagmus, head-motion intolerance, gait unsteadiness, and nausea or vomiting. HINTS is validated within this clinical syndrome — not for episodic positional vertigo.

See also: HINTS exam, Vestibular neuritis, Posterior circulation stroke

References: ³

Also: anterior inferior cerebellar artery

Branch of the basilar artery supplying lateral pons, middle cerebellar peduncle, and inner ear (via the labyrinthine artery). AICA stroke may mimic peripheral vestibulopathy and is the rationale for HINTS-plus.

See also: Labyrinthine artery, HINTS-plus, Posterior circulation stroke

References: ^10,1

In peripheral vestibular nystagmus, slow-phase velocity is greatest when the patient looks in the direction of the fast phase, and least when looking away. Violation of Alexander's law (direction reversal with gaze) is a central sign.

See also: Nystagmus, Direction-changing nystagmus

Also: cover-uncover test

Examiner alternates an occluder between the eyes while the patient fixates a target. A vertical movement of the newly uncovered eye is positive for skew deviation.

See also: Skew deviation

Pure-tone hearing assessment plotting threshold (dB HL) against frequency. New unilateral sensorineural loss in acute vestibular syndrome supports HINTS-plus positivity.

See also: HINTS-plus, Labyrinthitis

Also: ICVD

International Classification of Vestibular Disorders consensus criteria published by the Bárány Society for entities including acute unilateral vestibulopathy and vestibular migraine, and the vascular vertigo criteria for stroke-related dizziness.

See also: Vestibular neuritis, Vestibular migraine, Posterior circulation stroke

References: ^11,4,5

Also: benign paroxysmal positional vertigo

Brief positional vertigo from displaced otoconia in a semicircular canal (most often posterior). Provoked by head movement, lasts seconds. HINTS is not the right tool — use Dix-Hallpike and treat with canalith repositioning.

See also: Dix-Hallpike manoeuvre, Epley manoeuvre

References: ¹³

Combination of normal head impulse, direction-changing or vertical nystagmus, and/or skew deviation in acute vestibular syndrome — suggests a brainstem or cerebellar lesion until proven otherwise.

See also: INFARCT mnemonic, Peripheral HINTS pattern, Posterior circulation stroke

Infarction or haemorrhage in cerebellar territory (AICA, PICA, or SCA). May present with isolated vertigo and ataxia and central HINTS pattern; skew is sometimes absent.

See also: Posterior circulation stroke, AICA, PICA

References: ⁹

Calibrates VOR gain (flocculus, nodulus), adjusts gaze holding, and is a common site of posterior circulation strokes that present as acute vertigo. Cerebellar lesions can produce normal head impulse plus central nystagmus features.

See also: Cerebellar stroke, Vestibulo-ocular reflex, PICA, AICA

Also: catch-up saccade, refixation saccade

Rapid eye movement that brings gaze back to the target after the VOR has failed to keep up with head motion. Overt saccades occur after the impulse and are the bedside positive finding; covert saccades occur during the impulse and require vHIT to detect.

See also: Head impulse test, Covert saccade, Video head impulse test

Corrective saccade occurring during the head movement itself, hidden by the head's motion. Missed at the bedside but captured by video head impulse testing.

See also: Corrective saccade, Video head impulse test

References: ⁸

Also: cervical vestibular evoked myogenic potential

EMG response in the sternocleidomastoid evoked by sound or vibration, mediated by saccule → inferior vestibular nerve → vestibular nuclei → spinal accessory pathway. Absent on the affected side in saccular / inferior division disease.

See also: Saccule, Inferior vestibular nerve, oVEMP

Double vision. Subjective diplopia is not part of HINTS but is a red flag suggesting brainstem or cranial-nerve pathology when it accompanies acute vertigo.

See also: Internuclear ophthalmoplegia

Nystagmus whose fast-phase direction reverses with gaze direction. A central red flag in acute vestibular syndrome and the F of the INFARCT mnemonic.

See also: Nystagmus, INFARCT mnemonic, Central HINTS pattern

References: ³

Provocative positioning test for posterior canal BPPV. Patient is moved from sitting to supine with the head turned 45° and extended ~20°; a typical short-latency torsional up-beat nystagmus is the positive finding.

See also: BPPV, Epley manoeuvre

Vertical nystagmus with the fast phase beating downward, typically enhanced by lateral and downward gaze. Common in cerebellar floccular / paraflocculus dysfunction, drug toxicity (lithium, antiepileptics), and craniocervical-junction lesions.

See also: Nystagmus, Cerebellum

Also: canalith repositioning

Sequence of head positions that uses gravity to move displaced otoconia out of the posterior canal back into the utricle. Treatment of posterior canal BPPV.

See also: BPPV, Dix-Hallpike manoeuvre

Visual fixation damps peripheral vestibular nystagmus; central nystagmus is typically not suppressed. Removing fixation (Frenzel lenses, video goggles) brings out peripheral nystagmus that was suppressed during ordinary viewing.

See also: Frenzel lenses, Nystagmus, Central HINTS pattern

Also: Frenzel goggles

High-magnification illuminated goggles worn by the patient that prevent visual fixation while letting the examiner watch the eyes. Modern equivalents use infrared video goggles.

See also: Fixation suppression, Spontaneous nystagmus

Unsteady, wide-based gait. In acute vestibular syndrome, severe truncal ataxia disproportionate to the spinning sensation is a soft sign of cerebellar involvement.

See also: Cerebellum, Cerebellar stroke

Nystagmus appearing or intensifying on eccentric gaze. Bilateral gaze-evoked nystagmus that changes direction with gaze (direction-changing) is a central sign.

See also: Direction-changing nystagmus, Alexander's law

Also: HIT, Halmagyi-Curthoys test

A rapid, small-amplitude, unpredictable head turn while the patient fixates a target. An intact VOR keeps the eyes on target; a deficient VOR produces a visible corrective saccade back to the target at the end of the impulse.

See also: Vestibulo-ocular reflex, Corrective saccade, Video head impulse test, Covert saccade

References: ²

Also: Head Impulse, Nystagmus, Test of Skew

Three-step bedside oculomotor protocol — Head Impulse, Nystagmus, Test of Skew — used to distinguish peripheral from central causes of acute vestibular syndrome. The original validation reported greater sensitivity than early MRI DWI in trained hands.

See also: Head impulse test, Nystagmus, Skew deviation, INFARCT mnemonic, HINTS-plus

References: ³

Also: HINTS+

Extension of HINTS that adds new unilateral hearing loss at the bedside as a fourth central sign. Rationale: AICA-territory infarction with labyrinthine artery involvement can produce peripheral-looking HINTS plus acute sensorineural hearing loss.

See also: HINTS exam, AICA, Labyrinthine artery

References: ^10,1

Also: lateral semicircular canal, HSC

Semicircular canal oriented horizontally (~30° above the orbitomeatal line). Innervated by the superior vestibular nerve. Pitching the head forward 30° brings it into the testing plane for the horizontal head impulse test.

See also: Semicircular canal, Superior vestibular nerve, Head impulse test

Ipsilateral ptosis, miosis, and (variably) anhidrosis from interruption of the sympathetic pathway to the eye. A feature of lateral medullary (Wallenberg) syndrome.

See also: Wallenberg syndrome

Also: INFARCT

Impulse Normal, Fast-phase Alternating, Refixation on Cover Test. Any one of these in acute vestibular syndrome is a central red flag.

See also: HINTS exam, Central HINTS pattern

References: ³

Carries afferents from the posterior canal and saccule. Selective lesions spare the horizontal head impulse test.

See also: Superior vestibular nerve, Vestibular neuritis

Also: INO

Impaired adduction of the ipsilateral eye on contralateral gaze with dissociated abducting-eye nystagmus, due to an MLF lesion. Bilateral INO in a young patient strongly suggests MS.

See also: Medial longitudinal fasciculus, Multiple sclerosis

References: ¹²

Also: internal auditory artery

Branch of AICA supplying the inner ear. Selective occlusion can cause acute hearing loss and peripheral-pattern HINTS in the setting of AICA stroke.

See also: AICA, HINTS-plus

Inflammation of the labyrinth producing both vestibular and auditory symptoms — typically vestibular neuritis pattern HINTS plus acute hearing loss. The auditory feature is the discriminator.

See also: Vestibular neuritis, HINTS-plus

Diagnostic framework for MS requiring dissemination of CNS lesions in space and time, using clinical, MRI, and CSF evidence. 2017 revision currently in use.

See also: Multiple sclerosis, Internuclear ophthalmoplegia

References: ¹²

Also: MLF

Brainstem white-matter tract connecting the abducens nucleus to the contralateral medial rectus subnucleus, coordinating conjugate horizontal gaze and the horizontal VOR. Lesions produce internuclear ophthalmoplegia.

See also: Internuclear ophthalmoplegia, Abducens nucleus, Vestibulo-ocular reflex

Also: Meniere's disease

Recurrent episodes of vertigo with fluctuating low-frequency sensorineural hearing loss, tinnitus, and aural fullness, attributed to endolymphatic hydrops. Peripheral HINTS during an attack; normal between.

See also: Acute vestibular syndrome, Vestibular neuritis

References: ⁷

Also: MS

Demyelinating disease of the CNS that can produce brainstem syndromes including INO, vertical nystagmus, and skew. Diagnosed per the McDonald criteria.

See also: Internuclear ophthalmoplegia, Medial longitudinal fasciculus, McDonald criteria

References: ¹²

Involuntary rhythmic eye movement with a slow phase (drift) and a fast phase (corrective). Nystagmus is named for the direction of the fast phase. Peripheral nystagmus is typically unidirectional and horizontal-torsional; central nystagmus may be direction-changing, vertical, or pure torsional.

See also: Spontaneous nystagmus, Gaze-evoked nystagmus, Direction-changing nystagmus, Alexander's law

Also: OTR

Triad of skew deviation, head tilt, and ocular counter-roll from imbalance in graviceptive pathways. Most commonly central (brainstem) but described in peripheral utricular disease.

See also: Skew deviation, Utricle

Apparent motion of the visual world, often during head movement, due to VOR insufficiency. A common late symptom of bilateral vestibulopathy.

See also: Vestibulo-ocular reflex

Also: ocular vestibular evoked myogenic potential

EMG response over the inferior oblique evoked by sound or vibration, mediated by utricle → superior vestibular nerve → crossed pathway to extraocular muscles. Absent on the affected side in utricular / superior division disease.

See also: Utricle, Superior vestibular nerve, cVEMP

Abnormal head impulse toward the affected side, unidirectional nystagmus beating away from the affected ear, and absent skew. Reassuring of a peripheral lesion when complete and unambiguous in acute vestibular syndrome.

See also: Central HINTS pattern, Vestibular neuritis

Also: posterior inferior cerebellar artery

Branch of the vertebral artery supplying the lateral medulla and inferior cerebellum. Occlusion produces the Wallenberg (lateral medullary) syndrome.

See also: Wallenberg syndrome, Posterior circulation stroke

Ischaemic stroke in the vertebrobasilar territory, including AICA, PICA, SCA, and basilar branches. Commonly misdiagnosed as peripheral vertigo in the ED; HINTS is the bedside discriminator.

See also: AICA, PICA, Wallenberg syndrome, HINTS exam, Central HINTS pattern

References: ^3,4

Eye position when looking straight ahead at a distant target with head erect. The reference position for assessing spontaneous nystagmus.

See also: Spontaneous nystagmus, Gaze-evoked nystagmus

Rapid conjugate eye movement that redirects gaze. Corrective saccades are the bedside positive finding of the head impulse test.

See also: Corrective saccade, Smooth pursuit

Otolith organ sensing vertical linear acceleration. Innervated by the inferior vestibular nerve. Substrate of the cVEMP.

See also: Utricle, Inferior vestibular nerve

One of three fluid-filled curved tubes (horizontal, anterior, posterior) in the inner ear that detect angular acceleration. The horizontal canal is the substrate of the horizontal VOR and the head impulse test.

See also: Vestibulo-ocular reflex, Head impulse test, Horizontal semicircular canal, Utricle, Saccule

Also: SNHL

Hearing loss arising from the cochlea or auditory nerve, as opposed to conductive loss in the middle ear. Acute unilateral SNHL with acute vertigo is the HINTS-plus auditory red flag.

See also: HINTS-plus, Labyrinthitis, Labyrinthine artery

Vertical misalignment of the eyes from a disturbance in the otolith-ocular pathway, revealed by a vertical refixation on alternate cover testing. A central sign in acute vestibular syndrome (the C / R of INFARCT) — though severe peripheral utricular disease can occasionally produce it.

See also: Alternate cover test, Ocular tilt reaction, INFARCT mnemonic

References: ³

Slow conjugate eye movement that tracks a moving target. Distinct from the VOR; abnormal smooth pursuit suggests cerebellar or brainstem dysfunction.

See also: Vestibulo-ocular reflex, Cerebellum

Nystagmus present in primary gaze without provocation, indicating an asymmetry in resting vestibular tone. In acute vestibular syndrome, the direction of the fast phase identifies the side of the lesion (away from it in peripheral disease).

See also: Nystagmus, Fixation suppression, Frenzel lenses

Carries afferents from the horizontal and anterior semicircular canals and the utricle. The most commonly affected division in vestibular neuritis.

See also: Inferior vestibular nerve, Vestibular neuritis

References: ¹¹

Otolith organ sensing horizontal linear acceleration and head tilt. Innervated by the superior vestibular nerve. Part of the pathway underlying the ocular tilt reaction and skew.

See also: Saccule, Superior vestibular nerve, Ocular tilt reaction

The illusion of motion (spinning or tilting) of self or environment. Distinct from non-specific dizziness or pre-syncope.

See also: Acute vestibular syndrome

Also: VM

Recurrent episodes of vertigo lasting 5 minutes to 72 hours with migrainous features, on a background of migraine. Diagnosed by the Bárány Society / IHS criteria. HINTS is not validated outside acute vestibular syndrome.

See also: Acute vestibular syndrome

References: ^5,6

Also: acute unilateral vestibulopathy, AUVP, vestibular neuronitis

Acute peripheral vestibulopathy presenting as acute vestibular syndrome with peripheral HINTS triad and preserved hearing. Often preceded by a viral illness. Diagnosed per the Bárány Society / ICVD criteria.

See also: Peripheral HINTS pattern, Labyrinthitis, Acute vestibular syndrome

References: ¹¹

Group of four nuclei (superior, medial, lateral, inferior) at the pontomedullary junction that receive primary vestibular afferents and project to oculomotor, spinal, and cerebellar circuits.

See also: Vestibulo-ocular reflex, Abducens nucleus, Medial longitudinal fasciculus

Also: VOR

Reflex eye movement that stabilises gaze during head motion. The horizontal VOR is a three-neuron arc: vestibular afferent → vestibular nucleus → contralateral abducens nucleus → lateral rectus (and via MLF, ipsilateral medial rectus).

See also: VOR gain, Head impulse test, Semicircular canal, Abducens nucleus, Medial longitudinal fasciculus

Also: vHIT

Goggle-based device that records head and eye velocity at high frame rate during impulse testing. Quantifies VOR gain (peak eye velocity divided by peak head velocity) and detects both overt and covert corrective saccades.

See also: Head impulse test, VOR gain, Corrective saccade

References: ⁸

Ratio of peak eye velocity to peak head velocity during an impulse. Normal horizontal canal gain is ~0.9–1.0; values below ~0.8 are typically considered abnormal in most laboratories.

See also: Vestibulo-ocular reflex, Video head impulse test, Head impulse test

References: ⁸

Also: lateral medullary syndrome

Classical PICA-territory stroke syndrome: ipsilateral Horner, crossed sensory loss (face / contralateral body), ipsilateral limb ataxia, dysphagia, dysphonia, and central HINTS pattern.

See also: PICA, Posterior circulation stroke, Central HINTS pattern