Nystagmus Flashcards by Elizabeth Pham

Ocular Motor System controls the _____ and _____ of the eyes

Position and Movement

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A dysfunction in the ocular motor system causes…

Diplopia

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True/False: EOMs are innervated by lower motor neurons

TRUE

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EOMs are attached on one end to ____ and the other end to _______, which allows for eye movements

Sclera; bony orbit

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_______ Nucleus corresponds with CN ____ and innervates the Lateral Rectus of the ______ (ipsilateral/contralateral) eye

Abducens Nucleus corresponds with CN 6 and innervates the Lateral Rectus of the ipsilateral eye

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_______ Nucleus corresponds with CN ____ and innervates the Superior Oblique of the ______ (ipsilateral/contralateral) eye

Trochlear Nucleus corresponds with CN 4 and innervates the Superior Oblique of the contralateral eye

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Oculomotor Complex corresponds with CN ____ and innervates:
- Levator of ______ (ipsilateral/contralateral) eye
- IO of ______ (ipsilateral/contralateral) eye
- IR of ______ (ipsilateral/contralateral) eye
- SR of ______ (ipsilateral/contralateral) eye
- MR of ______ (ipsilateral/contralateral) eye
- LR of ______ (ipsilateral/contralateral) eye

Oculomotor Complex corresponds with CN 3 and innervates:
- Levator of both eyes
- IO of ipsilateral eye
- IR of ipsilateral eye
- SR of contralateral eye
- MR of ipsilateral eye

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Interconnections between _______ and ______, via the _______, coordinate vertical movement

Interconnections between Trochlear Nucleus and Oculomotor Nuclear Complex, via the tectospinal tract, coordinate vertical movement

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Fixation requires the suppression of _____

Unwanted saccades

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Vestibulo-ocular reflex compensates for ____

Head movements

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UMN indicates _____ involvement and likely to cause a _____ (unilateral/bilateral) defect

UMN indicates brainstem involvement and likely to cause a bilateral defect

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LMN indicates _____ involvement and likely to cause a _____ (unilateral/bilateral) defect

LMN indicates direct EOM or CN involvement and likely to cause a unilateral defect

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Nystagmus

Rhythmic and repetitive oscillation of the eye(s)

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Direction of nystagmus is defined by the _____ phase

QUICK

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New onset nystagmus indicates a lesion in either the ______ or the ______

Either the inner ear or the brain

requires urgent evaluation

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What is the most common type of nystagmus?

JERK

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Jerk Nystagmus is characterized by…

Slow pathological phase, followed by fast corrective phase in opposite direction

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What type of disorders are indicated if there is a torsional component to the nystagmus?

Inner Ear Disorder

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Gaze-evoked nystagmus occurs in lateral gaze of ____º or more

40º of more

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TRUE/FALSE: In gaze-evoked nystagmus, nystagmus is absent in primary gaze

TRUE
typically

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Intoxication causes what type of nystagmus, and thus testing for this nystagmus is often used in sobriety testing?

Gaze-evoked

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Unilateral gaze-evoked nystagmus may indicate

Ipsilateral cerebellar or brainstem disease

refer to neuro-ophthalmologist

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Gaze-evoked nystagmus in both horizontal and upgaze indicates

Toxic Metabolic Process (aka Intoxication)

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Internuclear Ophthalmoplegia

When looking at the contralateral side, aBducting eye exhibits nystagmus, and ipsilateral eye cannot aDduct

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INO indicates a lesion where?

MLF

How to differentiate if lesion is in pons or midbrain?

Pons — convergence will be intact Midbrain — cannot converge (cannot aDduct ipsilateral eye)

INO in an adolescent or younger adult is likely caused by…

MS (demyelination)

INO in an older adult is likely caused by…

Stroke (brainstem infarction)

What 3 arteries are likely to be indicated in vascular-related INO?

1. Posterior Cerebral Artery 2. Superior Cerebellar Artery 3. Basilar Artery

Associated Signs of INO

1. **Skew Deviation/Ocular Tilt Reaction** (hyper *ipsilateral* to the lesion) 2. **Vertical Torsional Nystagmus** (ipsilateral downbeat and contralateral torsional nystagmus) 3. **Vertical Gaze Palsy or Nystagmus**

In INO, why does the contralateral eye exhibit nystagmus?

Hering’s Law of Innervation

Bilateral INO

Limitation of aDduction with nystagmus of abducting eye in both left and right gaze

TRUE/FALSE: in INO, there will be *vertical* nystagmus on upgaze

TRUE

Wall Eye Bilateral INO (WEBINO)

Large XT + BINO

What causes WEBINO?

Midbrain lesion that also impacts CN 3 (MR)

One and a Half Syndrome

Ipsilateral gaze palsy + Ipsilateral INO

Where is the lesion in One and a Half Syndrome?

MLF, also impacts CN 6

What is the only residual movement in One and a Half Syndrome?

Abducting of contralateral eye (that exhibits nystagmus)

Brun’ Nystagmus is a type of ____ nystagmus

Gaze-evoked

Brun’s Nystagmus is associated with a lesion in _____

The Cerebellopontine Angle (CPA)

Is Brun’s Nystagmus associated with peripheral or central nystagmus? Explain.

BOTH Peripheral due to CN 8 dysfunction and Central due to pons compression

Brun’s nystagmus: *low* frequency and *high* amplitude when looking _____ (to lesion/opposite of lesion)

*low* frequency and *high* amplitude when looking **to lesion**

Brun’s nystagmus: *high* frequency and *low* amplitude when looking _____ (to lesion/opposite of lesion)

*high* frequency and *low* amplitude when looking **opposite of lesion**

What are some clinical findings you might expect in a patient with Brun’s Nystagmus? (4)

1. CN 7 defects: ipsilateral facial palsy 2. Bilateral papilledema 3. CN 5 defects: sensory loss 4. Cerebellar defects: ataxia

The defect in a *peripheral* vestibular pathway dysfunction is likely to be located ____

In labyrinth of the ear or the vestibular nerve

The defect in a *central* vestibular pathway dysfunction is likely to be located ____

In brainstem: 1. Root entry zone of CN 7 2. Vestibular nuclei 3. Oculomotor nuclei

Alexander’s Law

Nystagmus *increases* when looking at direction of *fast* beating

Peripheral or Central Vestibular Nystagmus: May respond to medication (e.g. *clonazepam*)

Central Vestibular Nystagmus

Peripheral or Central Vestibular Nystagmus: Follows Alexander’s Law

Peripheral

Peripheral or Central Vestibular Nystagmus: Associated with severe vertigo and possible hearing loss

Peripheral

Peripheral or Central Vestibular Nystagmus: Unilateral lesions common

Peripheral

Peripheral or Central Vestibular Nystagmus: Does NOT follow Alexander’s Rule

Central

Peripheral or Central Vestibular Nystagmus: Nystagmus dampened by fixation

Peripheral

Peripheral or Central Vestibular Nystagmus: Unidirectional nystagmus (torsional, vertical, *or* horizontal)

Central

Peripheral or Central Vestibular Nystagmus: can have mixed horizontal/vertical/torsional

Peripheral

Peripheral or Central Vestibular Nystagmus: Induced by head movements

Peripheral

Peripheral or Central Vestibular Nystagmus: May have pursuit/saccadic defects

Central

Peripheral or Central Vestibular Nystagmus: Nystagmus does not increase in direction of fast-beat

Central *does NOT follow Alexander’s Rule*

Possible etiologies of Peripheral Vestibular Nystagmus? (4)

1. Acoustic neuroma 2. Labyrinthitis 3. Meniere’s Disease 4. Demyelination

TRUE/FALSE: periodic alternations nystagmus always indicates an acquired nystagmus

FALSE; periodic alternating nystagmus can be congenital *or* acquired

Periodic Alternating Nystagmus is characterized by…

Direction of fast phase changes in cycles of 60-90 seconds, with (often shifting) null period of 5-10 seconds

TRUE/FALSE: Pendular Acquired Nystagmus can be horizontal, vertical, *or* torsional

TRUE

What occurs if Pendular Acquired Nystagmus combines a vertical and horizontal phase?

Circular, Elliptical, or even Oblique nystagmus

What is the most common pathology associated with Pendular Acquired Nystagmus?

Oculomasticatory Myorhythmia is characterized by

Pendular convergence nystagmus, associated with slow (involuntary) movements of jaw

Oculomasticatory Myorhythmia is strongly associated with…

Whipple Disease

Whipple Disease is strongly associated with which type of nystagmus?

Oculomasticatory Myorhythmia

What is Whipple Disease?

Rare, bilateral infection that affects the GI and *impairs absorption of nutrients*

Whipple Disease TRIAD

1. Dementia 2. Ophthalmoplegia 3. Myoclonus

What is Myoclonus?

Brief, sudden twitching of a muscle/group of muscles

Oculopalatal Myoclonus is characterized by…

Pendular nystagmus in combination with palatal tremor

Likely etiology for Oculopalatal Myoclonus?

Brainstem infarction or hemorrhage

TRUE/FALSE: See-Saw Nystagmus responds well to medication

FALSE; responds very poorly to treatment in general

See-Saw Nystagmus is characterized by

Pendular nystagmus with elevations/intorsion of one eye and depression/extorsion of the other

What type of nystagmus is an example of a Dissociated Nystagmus?

INO

Disassociated Nystagmus is commonly caused by…

MS or brainstem stoke

Dissociated Nystagmus is characterized by…

Movement of right and left eye in the same direction but with asymmetrical amplitudes

Two examples of Monocular Nystagmus

1. Spasmus Nutans 2. Hienmann-Bielschowsky Phenomenon

TRUE/FALSE: Spasmus Nutans can be self-limiting

TRUE, usually by age 5!

TRUE/FALSE: Spasmus Nutans can cause amblyopia and strabimus

TRUE

Spasmus Nutans Triad

1. Torticollis 2. Head nodding 3. Monocular or Asymmetric nystagmus

With monocular nystagmus, why are we concerned and generally should order an MRI?

Potential Optic Pathway/Chiasmal Glioma

Spasmus Nutans: Onset — ? Resolves by —?

Onset: 4-14 months Resolves by: 5 yrs

Hienmann-Bielschowsky Phenomenon is characterized by…

Infantile Monocular (slow) Pendular Nystagmus, secondary to severe monocular visual loss

TRUE/FALSE: even after vision is restored, nystagmus usually persists in Hienmann-Bielschowsky

FALSE: usually resolves when vision is restored

With downbeat nystagmus, the typical head posture is chin-_____ (up/down)

Chin-down (brings eyes up)

With upbeat nystagmus, the typical head posture is chin-_____ (up/down)

Chin-up (brings eyes down)

Downbeat or Upbeat Nystagmus: Associated with Metastatic Breast Cancer

Downbeat

Downbeat or Upbeat Nystagmus: Obeys Alexander’s Law

BOTH

Downbeat or Upbeat Nystagmus: More difficult to locate

Upbeat

Downbeat or Upbeat Nystagmus: Typically caused by lesion in cervicomedullary junction

Downbeat

Downbeat or Upbeat Nystagmus: Minimal nystagmus seen in primary gaze

BOTH

Downbeat or Upbeat Nystagmus: Associated with anticonvulsants (e.g. phenytoin)

Upbeat

Downbeat or Upbeat Nystagmus: More commonly associated with cerebellar lesion

Upbeat

Nystagmus associated with Wernicke’s Encephalopathy

ANY

TRUE/FALSE: Wernicke’s Encephalopathy can be self-limiting

Not really; it’s disabling/life-threatening and requires immediate treatment

Etiology of Wernicke’s Encephalopathy?

Severe B1 deficiency, usually secondary to bariatric surgery or alcoholism

Clinical signs of Wernicke’s

1. Nystagmus 2. Cerebellar dysfunction 3. Confusion

When examining nystagmus, what should be noted? (3)

1. Nystagmus with near and far target 2. Nystagmus in different gazes 3. Nystagmus during fixation

All children with nystagmus should undergo ________ to r/o any _____ etiologies

Careful fundus exam to r/o any retinal or ON etiologies

What is the etiology for congenital nystagmus?

Unknown

TRUE/FALSE: congenital nystagmus is often not noted in the child until days after birth

FALSE; usually *months* after birth

TRUE/FALSE: congenital nystagmus remains present when the child is asleep

FALSE; not present during sleep

FUNBLOCS

**Congenital Nystagmus Features:** 1. Fixation increases the nystagmus 2. Upgaze (+ all other gazes) — nystagmus remains horizontal 3. Null point is present (and can manifest as head turn) 4. Bilateral and conjugate 5. Latent component 6. OKN not superimposable 7. Convergence dampens nystagmus 8. Symptomless (generally no oscillopsia)

TRUE/FALSE: Monocular nystagmus is often horizontal in nature

FALSE; vertical

Latent Component of Congenital Nystagmus often seen in what 3 patients?

1. Infantile ET 2. (+) lesion affecting binocular development 3. Down Syndrome

Latent Component of Congenital Nystagmus is characterized by…

When either eye covered, uncovered eye beat away from covered eye

Congenital Nystagmus is classified as either _____ or _____?

Motor or sensory

Sensory Congenital Nystagmus is associated with what ocular conditions? (5)

1. Albinism 2. Congenital Stationary Night Blindness 3. ON Hypoplasia 4. Retinal Dystrophies 5. Cataracts

Congenital Nystagmus — Motor or Sensory: Stable over lifetime

Motor

Congenital Nystagmus — Motor or Sensory: Varying visual prognoses

Sensory

Congenital Nystagmus — Motor or Sensory: Not associated with other neurological anomalies

Motor

Congenital Nystagmus — Motor or Sensory: Can be AD, AR, or X-linked inheritance

Motor

Congenital Nystagmus — Motor or Sensory: Can be progressive or static

Sensory

Surgical Options for Congenital Nystagmus?

1. Detach/reattach EOMS 2. Align eyes to null point 3. Recti recession to decrease tension

Non-surgical options for Congenital Nystagmus?

1. RE correction 2. BO prism (induce convergence) 3. Toked prism (to null point) 4. 7 BO + -1.00 to compensate for accommodation 5. Topical brinzolamide 6. Oral memantine or gabapentin 7. Botox

What is Mollaret’s Triangle and what type of Nystagmus is it associated with?

Nuclei or midbrain, medulla, and cerebellum Associated with *Oculopalatal Myoclonus*

Associated with parasellar lesions or septa-optic dysplasia

Seesaw Nystagmus

Nystagmus Flashcards

(118 cards)