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Sign Explorer

12 ocular-motor signs, each mapped to its localising region, the conditions that produce it, and its bedside diagnostic value. Filter by origin or by urgency, or search for a feature.

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Showing 12 of 12 signs

  • Spontaneous nystagmus

    Either

    Rhythmic jerking of the eyes at rest, with a slow drift and a fast corrective phase.

    Localises
    Peripheral: vestibular nerve/labyrinth. Central (vertical, torsional, or direction-changing): brainstem or cerebellum.
    Conditions
    Vestibular neuritis, Labyrinthitis, Brainstem stroke, Cerebellar lesion
    Bedside value
    Unidirectional, fixation-suppressed, Alexander's-law-obeying nystagmus is peripheral; vertical, purely torsional, or fixation-resistant nystagmus is central.
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  • Gaze-evoked nystagmus

    centralImage now

    Nystagmus that appears or worsens when the eyes are held in an eccentric position.

    Localises
    Neural integrator — cerebellar flocculus, nucleus prepositus hypoglossi, medial vestibular nucleus.
    Conditions
    Cerebellar disease, Wernicke's encephalopathy, Drug toxicity, MS
    Bedside value
    Non-fatiguing and without latency. Bilateral, symmetric GEN points to the cerebellum; direction-changing GEN is a HINTS central flag.
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  • Central positional nystagmus

    centralImage now

    Positional nystagmus with immediate onset, no fatigue, persistence, and often direction change.

    Localises
    Nodulus/uvula of the cerebellum; craniocervical junction.
    Conditions
    Cerebellar stroke, Chiari malformation, MS, Posterior-fossa tumour
    Bedside value
    Distinguished from BPPV by lack of latency, lack of fatigue, persistence, direction change, and failure to respond to repositioning.
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  • Internuclear ophthalmoplegia

    centralImage now

    Failed adduction of one eye with abducting nystagmus of the other on horizontal gaze; convergence spared.

    Localises
    Medial longitudinal fasciculus (dorsal pons/midbrain).
    Conditions
    Multiple sclerosis, Brainstem infarction
    Bedside value
    Nearly pathognomonic for a central (MLF) lesion — MS in the young, stroke in the older patient.
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  • Skew deviation

    centralImage now

    Vertical misalignment of the eyes, shown by a vertical refixation on alternate cover testing.

    Localises
    Otolith-ocular (graviceptive) pathway — brainstem or cerebellum.
    Conditions
    Brainstem/cerebellar stroke, MS
    Bedside value
    The 'S' of HINTS. Present in central but rare in isolated peripheral lesions.
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  • Ocular tilt reaction

    centralImage now

    Triad of head tilt, conjugate ocular torsion, and skew deviation toward the lesion side.

    Localises
    Graviceptive pathway — pontomedullary, interstitial nucleus of Cajal, or thalamus.
    Conditions
    Pontomedullary lesion, Thalamic stroke, Lateral medullary syndrome
    Bedside value
    A strongly localising graviceptive sign; the full triad confirms otolith-pathway involvement.
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  • Saccadic intrusions

    central

    Involuntary saccades interrupting fixation — square-wave jerks, macrosaccadic oscillations, opsoclonus.

    Localises
    Cerebellar fastigial nucleus, omnipause neurons, superior colliculus.
    Conditions
    Cerebellar ataxia, Paraneoplastic degeneration, PSP
    Bedside value
    Signals impaired cerebellar/brainstem fixation control; opsoclonus suggests a paraneoplastic process.
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  • Smooth-pursuit abnormality

    central

    Tracking a slow target becomes a staircase of catch-up saccades (saccadic pursuit).

    Localises
    Cortical eye fields, cerebellar flocculus/vermis, brainstem pursuit nuclei.
    Conditions
    PSP, MS, Cerebellar lesions, Spinocerebellar ataxia
    Bedside value
    Non-specific alone, but with GEN or dysmetric saccades it strongly supports central disease.
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  • Supranuclear gaze palsy

    centralImage now

    Loss of voluntary gaze (often downgaze first) with preserved reflex eye movements (doll's-head intact).

    Localises
    Above the ocular-motor nuclei — riMLF, PPRF, cortical eye fields, thalamus.
    Conditions
    PSP, Thalamic/midbrain stroke, Corticobasal degeneration
    Bedside value
    Preserved VOR with absent voluntary gaze localises the lesion above the cranial-nerve nuclei.
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  • Oscillopsia

    Either

    The stationary world appears to bounce or shimmer, especially on head movement or walking.

    Localises
    Bilateral vestibular loss, or central VOR-modulating structures; or driven by nystagmus.
    Conditions
    Bilateral vestibulopathy, Downbeat nystagmus, MS, CANVAS
    Bedside value
    Reflects failed gaze stabilisation; dynamic visual acuity testing localises and grades it.
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  • Diplopia

    centralImage now

    Double vision — vertical, horizontal, or oblique — from misaligned visual axes.

    Localises
    Brainstem ocular-motor structures or cranial nerves III/IV/VI.
    Conditions
    INO, Skew deviation, CN III/VI palsy, Cerebellar disease
    Bedside value
    Sustained binocular diplopia with vertigo strongly favours a central cause and prompts imaging.
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  • Normal head impulse (with other signs)

    centralImage now

    No corrective catch-up saccade on the head impulse test, despite ongoing vertigo and nystagmus.

    Localises
    Posterior circulation — brainstem or cerebellum (VOR pathway preserved).
    Conditions
    Posterior-circulation stroke, Brainstem infarct
    Bedside value
    The counter-intuitive heart of HINTS: a normal HIT in active AVS is highly specific for a central cause.
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