Acquired Nystagmus Clinical Presentation

Updated: Jun 22, 2021
  • Author: Huy D Nguyen, MD, MBA; Chief Editor: Edsel B Ing, MD, MPH, FRCSC, PhD, MA  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 or body positions).
  • Presence or absence of vertigo, oscillopsia (an illusory motion of the seen world; could either be rotary or linear), [36]  and sensation of disequilibration suggest a lesion of the vestibular system.
  • Associated deafness or tinnitus suggest peripheral lesions of the vestibular system.
  • Presence of diplopia, particularly in certain positions of gaze. For example, 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 vision loss, 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, sedatives, barbiturates, lithium may be associated with nystagmus. Gaze evoked nystagmus is associated with alcohol use.  
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Physical

Neuro-ophthalmic examination

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 plane (ie, horizontal, vertical, torsional, relative to the visual axis), frequency, amplitude, direction, and conjugate/disconjugate is important. Isolated rotary nystagmus almost always represents central vestibular dysfunction; vertical-torsional or horizontal-torsional is associated with peripheral vestibular dysfunction. [6]

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 compensatory 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 maintain foveation on a moving object when the head is stationary (ex., observing individual telephone poles on the side of the road as one travels by them in a car). OKN is involuntary but may be suppressed if the patient looks above or below the moving object.  The reflex develops at about age 6 months and is produced as the patient pursues a moving object, while maintaining a stationary head position, and then experiences a corrective saccade in the opposite direction to follow the next moving target. Note the direction of OKN drum if it induces a change in nystagmus magnitude or direction.

Insufficient suppression of the primitive optokinetic response is believed to drive the development of latent and congenital nystagmus. [18]  One may observe a paradoxical reversal of the optokinetic nystagmus response in patients with congenital nystagmus. [18]  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. The intact reflex determines that the infranuclear pathways are intact and therefore helps in localizing the lesion. This test consists of the rapid rotation of the patient’s head in a horizontal or vertical direction while holding their eyelids open to examine their eyes. With intact vestibular nuclei and medial longitudinal fasciculi, the eyes move conjugately in the opposite direction of the head turn. In a patient with a negative oculocephalic reflex, the eyes remain at midline and do not move as the head rotates. A similar test may be performed for vertical head movements. 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.

Caloric testing

Caloric testing is used to assess the function of the peripheral vestibular system and involves up to four irrigations of water or air into the external ear meatus. [36]  Caloric irrigations create a thermal gradient, or a temperature difference, between the external auditory canal and the endolymph in the horizontal semicircular canal of the inner ear, which in turn changes the density of the endolymph causing it to rise or sink (depending on the temperature of the irrigation fluid). [36]  The rising or sinking of the endolymph deflects the cupula and elicits an excitatory or inhibitory neural response, thus inducing nystagmus. Changes in the temperature and density of the endolymph due to the temperature of the irrigation water mimic those caused by rotations of the head. [36]  The nystagmus response to caloric testing peaks 1 minute after the initiation of irrigation, falls to 50% after another 30-60 seconds and becomes minimal or disappears completely after one more minute. [36]  It has been suggested that the nystagmus dampens before the resolution of the thermal gradient caused by irrigation due to central nervous system adaptation. [36]

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).

Otolithic stimulation

Note whether the character of the nystagmus changes with otolithic stimulation. Failure to respond to otolithic stimuli suggests a peripheral vestibular disease or lesion.

Note whether any body position exacerbates the nystagmus due to otolithic modulation. In an acquired downbeat nystagmus, for instance, the nystagmus is made more prominent when the patient is prone or after resting in the supine or prone position for long periods of the day. [37]

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

Seesaw nystagmus may be caused by the following:

  • Parasellar optic chiasm lesions (eg pituitary tumors)
  • Achiasma
  • Tumors in the diencephalon
  • Lesions in the rostral midbrain.
  • Visual loss secondary to retinitis pigmentosa

Downbeat nystagmus may be caused by the following:

  • Disorders of the craniocervical junction (most commonly the Arnold-Chiari malformation)
  • Spinocerebellar degeneration (due to ataxia telangiectasia, for instance)
  • Bilateral lesions of the medial longitudinal fasciculus
  • Lesions of the vestibulocerebellum and underlying medulla, including:
    • 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 may be caused by the following:

  • Lesions of the anterior vermis of the cerebellum
  • Infiltrating tumors
  • Fourth ventricular masses
  • Multiple sclerosis
  • Nutritional cerebellar degeneration.
  • Medullary lesions, including perihypoglossal nuclei, the adjacent medial vestibular nucleus, and the nucleus intercalatus (structures important in gaze holding)
  • Benign paroxysmal positional vertigo

Periodic alternating nystagmus may be caused by the following:

  • Posterior fossa malformations
  • Demyelinating conditions
  • Spinocerebellar degeneration
  • Anticonvulsant drug use
  • Visual or vestibular loss
  • Transient consequence of sensory deprivation, ex. ocular media opacities
  • Lesions of the vestibular nuclei
  • Head trauma
  • Encephalitis
  • Syphilis

Pendular nystagmus may be caused by the following:

  • Disorders of myelin accompanying oculopalatal myoclonus
  • Wipple’s disease
  • Drug toxicities
  • Brainstem or cerebellar dysfunction
  • Monocular or binocular visual deprivation
  • Internuclear ophthalmoplegia

Spasmus nutans may be caused by the following:

  • Usually benign
  • Parasellar and hypothalamic tumors
  • Retinal disorders
  • Chiasmal, suprachiasmal, or third ventricle gliomas may cause a condition that mimics spasmus nutans.

Torsional nystagmus

  • Lesions of the anterior and posterior semicircular canals on the same side (ex. lateral medullary syndrome(Wallenberg syndrome))
  • Lesions of the lateral medulla

Abducting nystagmus of internuclear ophthalmoplegia may be caused by the following:

  • Demyelinating conditions
  • Brain stem stroke

Gaze evoked nystagmus may be caused by the following:

  • Structural lesions that involve the neural integrator network, which is dispersed between the vestibulocerebellum, the medulla (region of the nucleus prepositus hypoglossi and adjacent medial vestibular nucleus [NPH/MVN]), and the interstitial nucleus of Cajal (INC)
  • Recovery from a gaze palsy
  • Brainstem or cerebellar disease
  • Side effect of alcohol or the use of oral sedatives, barbiturates or anticonvulsant drugs
  • Weakness of 1 or more extraocular muscles or the disruption of their innervations
  • Myasthenia gravis or Guillan Barre syndrome

 

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