Acquired Nystagmus Clinical Presentation

Updated: Oct 17, 2018
  • Author: Christopher M Bardorf, MD, MS; Chief Editor: Edsel Ing, MD, MPH, FRCSC  more...
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Presentation

History

A thorough history is important to help determine the etiology of the nystagmus. Important aspects of the history include the following:

  • Age of onset of the nystagmus, whether it is constant or intermittent, the presence of any aggravating or alleviating factors (eg, head position)

  • Presence or absence of vertigo, oscillopsia (an illusory motion of the seen world), [10] and sensation of disequilibration suggest a lesion of the vestibular system.

  • Deafness or tinnitus is present with peripheral lesions of the vestibular system.

  • Presence of diplopia, particularly in certain positions of gaze: Patients with INO may report diplopia only on lateral gaze or intermittent blurring of vision.

  • Ask questions regarding the presence of any associated symptoms, such as symptoms related to demyelinating disease (eg, a history of loss of vision, eye pain, or numbness or weakness of the extremities), symptoms related to cerebrovascular accident (eg, hemiplegia), and predispositions to thiamine deficiency (eg, alcoholism, bariatric surgery)

  • Medications such as anticonvulsants and lithium may be associated with nystagmus

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Physical

A complete neuro-ophthalmic examination is imperative in patients with nystagmus. Aside from a complete ophthalmic examination, including visual acuity, measurement and reactivity of the pupils to light and accommodation, measurement of intraocular pressure, testing the function of extraocular muscles, and anterior and dilated posterior segment examination, other important aspects of the examination include the following:

  • Observing the nystagmus with regard to type (eg, horizontal, vertical), frequency, amplitude, direction, and conjugate/disconjugate is important. Pure vertical, pure horizontal, or pure rotary nystagmus almost always represents central vestibular dysfunction.

  • Note whether the character of the nystagmus changes in certain directions of gaze.

    • Nystagmus due to vestibular disease increases in intensity when the eyes are turned in the direction of the saccade (fast phase), ie, Alexander law.

    • A horizontal nystagmus due to peripheral vestibular imbalance remains horizontal on upward and downward gaze.

  • Note the presence or absence of head nodding or torticollis (spasmus nutans).

  • Note whether the nystagmus dampens with fixation. Fixation inhibits nystagmus and vertigo due to peripheral lesions of the vestibular system.

  • Optokinetic nystagmus (OKN) drum: The optokinetic reflex allows us to follow objects in motion when the head remains stationary (eg, observing individual telephone poles on the side of the road as one travels by them in a car). The reflex develops at about age 6 months. The normal eye movements that one observes depend upon the orientation of the drum in front of the patient. If the drum is held in front of the patient with the bars directed vertically and is spun to the left (the patient's right), one would observe a slow pursuit movement of the eyes to the patient's right as a moving bar is followed, then a quick saccade to the patient's left as the patient searches for the next moving bar to fixate on and again follows that bar with a slow pursuit movement to the patient's right.

    • This reflex is abnormal in patients with congenital nystagmus. One may observe a paradoxical reversal of the optokinetic nystagmus response.

    • Patients with horizontal nystagmus with unilateral hemispheric lesions, especially parietal or parietal-occipital lesions, show impaired optokinetic nystagmus when the drum is rotated toward the side of the lesion.

    • The OKN drum may be used as an estimate of visual acuity. The striped drum is equivalent to a vision of counting fingers when held at a distance of 3-5 feet from the patient. The further the drum is from the patient, the better the visual acuity must be to respond normally to the moving drum.

  • Confrontational visual field testing may reveal gross field defects that may help determine the presence and/or location of an intracranial lesion.

  • For Romberg testing have the patient stand with eyes closed and feet together. If a defect in the vestibular system is present, the patient tends to fall toward the side of the lesion.

  • Oculocephalic reflex (doll's head phenomenon)

    • The oculocephalic reflex develops within the first week of life and essentially represents a vestibulo-ocular reflex normally suppressed in a conscious individual that attempts to turn the head to fixate on an object.

    • This test consists of the rapid rotation of the patient's head in a horizontal or vertical direction. With intact vestibular nuclei and medial longitudinal fasciculi, the eyes move conjugately in the opposite direction of the head turn. Alternatively, the test may be performed by having the patient extend the arm out in front of the body and fixate on the outstretched thumb. Patients should be instructed to rotate their torso back and forth about their longitudinal axis such that the thumb remains in front of the body at all times.

    • Patients with the ability to suppress the oculocephalic reflex should be able to maintain fixation on their thumb while rotating. An abnormal test result would show the patient continuously losing fixation of the thumb.

    • Inability to suppress the oculocephalic reflex is common in patients with vestibular imbalance.

  • Caloric testing

    • Instilling cold or warm water into the external auditory canal can reproduce the same movement of endolymph in the semicircular canals produced by rotations of the head. Instillation of water into the external auditory canal causes endolymph convection currents that in turn induce nystagmus.

    • While sitting erect, the patient tilts the head back 60°. While in supine, the patient elevates the head 30°; this brings the horizontal semicircular canals into the vertical plane.

    • The external auditory canal is irrigated with cold or hot water. Cold water instilled into the right ear causes the endolymph in the right semicircular canal to cool and sink. This movement of endolymph is the same movement induced by a rotation of the head to the left, inducing a horizontal nystagmus directed to the left (ie, to the opposite side the water was placed). Warm water in the same ear produces the opposite effect (ie, a horizontal nystagmus directed to the right or toward the same side the water was placed); ie, cold-opposite, warm-same (COWS).

  • Note whether the character of the nystagmus changes with otolithic stimulation. Failure to respond to otolithic stimuli implies peripheral vestibular disease.

  • A full neurologic examination may reveal the diagnosis. In patients with vertical pendular nystagmus, associated palatal undulation suggests oculopalatal myoclonus.

  • Visual acuity: In patients with latent nystagmus, acuity should be measured by fogging the contralateral eye with a hyperopic lens.

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Causes

See the list below:

  • Seesaw nystagmus

    • Rostral midbrain lesions

    • Parasellar lesions (eg, pituitary tumors)

    • Visual loss secondary to retinitis pigmentosa

  • Downbeat nystagmus

    • Lesions of the vestibulocerebellum and underlying medulla, including the following:

      • Arnold-Chiari malformation

      • Demyelination (eg, multiple sclerosis) [14]

      • Microvascular disease with vertebrobasilar insufficiency

      • Brain stem encephalitis

      • Tumors at the foramen magnum (eg, meningioma, cerebellar hemangioma)

      • Trauma

      • Drugs (eg, alcohol, lithium, antiseizure medications)

      • Nutritional (eg, Wernicke encephalopathy, parenteral feeding, magnesium deficiency)

    • Heat stroke

    • Approximately 50% have no identifiable cause.

  • Upbeat nystagmus

    • Medullary lesions, including perihypoglossal nuclei, the adjacent medial vestibular nucleus, and the nucleus intercalatus (structures important in gaze holding)

    • Lesions of the anterior vermis of the cerebellum

    • Benign paroxysmal positional vertigo

  • Periodic alternating nystagmus

    • Arnold-Chiari malformation

    • Demyelinating disease

    • Spinocerebellar degeneration

    • Lesions of the vestibular nuclei

    • Head trauma

    • Encephalitis

    • Syphilis

    • Posterior fossa tumors

    • Binocular visual deprivation (eg, ocular media opacities)

  • Pendular nystagmus

    • Demyelinating disease

    • Monocular or binocular visual deprivation

    • Oculopalatal myoclonus

    • Internuclear ophthalmoplegia

    • Brain stem or cerebellar dysfunction

  • Spasmus nutans

    • Usually occurs in otherwise healthy children

    • Chiasmal, suprachiasmal, or third ventricle gliomas may cause a condition that mimics spasmus nutans.

  • Torsional - Lateral medullary syndrome (Wallenberg syndrome)

  • Abducting nystagmus of internuclear ophthalmoplegia

    • Demyelinating disease

    • Brain stem stroke

  • Gaze evoked

    • Drugs - Anticonvulsants (eg, phenobarbital, phenytoin, carbamazepine) at therapeutic dosages

    • Alcohol

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