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Y. neuro ophthalmology > Nystagmus > Flashcards

Nystagmus Flashcards

1
Q

Ocular Motor System controls the _____ and _____ of the eyes

A

Position and Movement

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2
Q

A dysfunction in the ocular motor system causes…

A

Diplopia

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3
Q

True/False: EOMs are innervated by lower motor neurons

A

TRUE

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4
Q

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

A

Sclera; bony orbit

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5
Q

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

A

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

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6
Q

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

A

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

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7
Q

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

A

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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8
Q

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

A

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

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9
Q

Fixation requires the suppression of _____

A

Unwanted saccades

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10
Q

Vestibulo-ocular reflex compensates for ____

A

Head movements

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11
Q

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

A

UMN indicates brainstem involvement and likely to cause a bilateral defect

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12
Q

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

A

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

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13
Q

Nystagmus

A

Rhythmic and repetitive oscillation of the eye(s)

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14
Q

Direction of nystagmus is defined by the _____ phase

A

QUICK

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15
Q

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

A

Either the inner ear or the brain

requires urgent evaluation

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16
Q

What is the most common type of nystagmus?

A

JERK

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17
Q

Jerk Nystagmus is characterized by…

A

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

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18
Q

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

A

Inner Ear Disorder

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19
Q

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

A

40º of more

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20
Q

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

A

TRUE
typically

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21
Q

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

A

Gaze-evoked

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22
Q

Unilateral gaze-evoked nystagmus may indicate

A

Ipsilateral cerebellar or brainstem disease

refer to neuro-ophthalmologist

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23
Q

Gaze-evoked nystagmus in both horizontal and upgaze indicates

A

Toxic Metabolic Process (aka Intoxication)

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24
Q

Internuclear Ophthalmoplegia

A

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

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25
Q

INO indicates a lesion where?

A

MLF

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26
Q

How to differentiate if lesion is in pons or midbrain?

A

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

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27
Q

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

A

MS (demyelination)

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28
Q

INO in an older adult is likely caused by…

A

Stroke (brainstem infarction)

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29
Q

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

A
  1. Posterior Cerebral Artery
  2. Superior Cerebellar Artery
  3. Basilar Artery
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30
Q

Associated Signs of INO

A
  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
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31
Q

In INO, why does the contralateral eye exhibit nystagmus?

A

Hering’s Law of Innervation

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32
Q

Bilateral INO

A

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

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33
Q

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

A

TRUE

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34
Q

Wall Eye Bilateral INO (WEBINO)

A

Large XT + BINO

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35
Q

What causes WEBINO?

A

Midbrain lesion that also impacts CN 3 (MR)

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36
Q

One and a Half Syndrome

A

Ipsilateral gaze palsy + Ipsilateral INO

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37
Q

Where is the lesion in One and a Half Syndrome?

A

MLF, also impacts CN 6

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38
Q

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

A

Abducting of contralateral eye (that exhibits nystagmus)

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39
Q

Brun’ Nystagmus is a type of ____ nystagmus

A

Gaze-evoked

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40
Q

Brun’s Nystagmus is associated with a lesion in _____

A

The Cerebellopontine Angle (CPA)

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41
Q

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

A

BOTH

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

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42
Q

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

A

low frequency and high amplitude when looking to lesion

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43
Q

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

A

high frequency and low amplitude when looking opposite of lesion

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44
Q

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

A
  1. CN 7 defects: ipsilateral facial palsy
  2. Bilateral papilledema
  3. CN 5 defects: sensory loss
  4. Cerebellar defects: ataxia
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45
Q

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

A

In labyrinth of the ear or the vestibular nerve

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46
Q

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

A

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

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47
Q

Alexander’s Law

A

Nystagmus increases when looking at direction of fast beating

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48
Q

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

A

Central Vestibular Nystagmus

49
Q

Peripheral or Central Vestibular Nystagmus:
Follows Alexander’s Law

A

Peripheral

50
Q

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

A

Peripheral

51
Q

Peripheral or Central Vestibular Nystagmus:
Unilateral lesions common

A

Peripheral

52
Q

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

53
Q

Peripheral or Central Vestibular Nystagmus:
Nystagmus dampened by fixation

A

Peripheral

54
Q

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

55
Q

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

A

Peripheral

56
Q

Peripheral or Central Vestibular Nystagmus:
Induced by head movements

A

Peripheral

57
Q

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

58
Q

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

A

Central

does NOT follow Alexander’s Rule

59
Q

Possible etiologies of Peripheral Vestibular Nystagmus? (4)

A
  1. Acoustic neuroma
  2. Labyrinthitis
  3. Meniere’s Disease
  4. Demyelination
60
Q

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

A

FALSE; periodic alternating nystagmus can be congenital or acquired

61
Q

Periodic Alternating Nystagmus is characterized by…

A

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

62
Q

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

63
Q

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

A

Circular, Elliptical, or even Oblique nystagmus

64
Q

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

65
Q

Oculomasticatory Myorhythmia is characterized by

A

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

66
Q

Oculomasticatory Myorhythmia is strongly associated with…

A

Whipple Disease

67
Q

Whipple Disease is strongly associated with which type of nystagmus?

A

Oculomasticatory Myorhythmia

68
Q

What is Whipple Disease?

A

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

69
Q

Whipple Disease TRIAD

A
  1. Dementia
  2. Ophthalmoplegia
  3. Myoclonus
70
Q

What is Myoclonus?

A

Brief, sudden twitching of a muscle/group of muscles

71
Q

Oculopalatal Myoclonus is characterized by…

A

Pendular nystagmus in combination with palatal tremor

72
Q

Likely etiology for Oculopalatal Myoclonus?

A

Brainstem infarction or hemorrhage

73
Q

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

A

FALSE; responds very poorly to treatment in general

74
Q

See-Saw Nystagmus is characterized by

A

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

75
Q

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

76
Q

Disassociated Nystagmus is commonly caused by…

A

MS or brainstem stoke

77
Q

Dissociated Nystagmus is characterized by…

A

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

78
Q

Two examples of Monocular Nystagmus

A
  1. Spasmus Nutans
  2. Hienmann-Bielschowsky Phenomenon
79
Q

TRUE/FALSE: Spasmus Nutans can be self-limiting

A

TRUE, usually by age 5!

80
Q

TRUE/FALSE: Spasmus Nutans can cause amblyopia and strabimus

81
Q

Spasmus Nutans Triad

A
  1. Torticollis
  2. Head nodding
  3. Monocular or Asymmetric nystagmus
82
Q

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

A

Potential Optic Pathway/Chiasmal Glioma

83
Q

Spasmus Nutans:
Onset — ?
Resolves by —?

A

Onset: 4-14 months
Resolves by: 5 yrs

84
Q

Hienmann-Bielschowsky Phenomenon is characterized by…

A

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

85
Q

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

A

FALSE: usually resolves when vision is restored

86
Q

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

A

Chin-down (brings eyes up)

87
Q

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

A

Chin-up (brings eyes down)

88
Q

Downbeat or Upbeat Nystagmus:
Associated with Metastatic Breast Cancer

89
Q

Downbeat or Upbeat Nystagmus:
Obeys Alexander’s Law

90
Q

Downbeat or Upbeat Nystagmus:
More difficult to locate

91
Q

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

92
Q

Downbeat or Upbeat Nystagmus:
Minimal nystagmus seen in primary gaze

93
Q

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

94
Q

Downbeat or Upbeat Nystagmus:
More commonly associated with cerebellar lesion

95
Q

Nystagmus associated with Wernicke’s Encephalopathy

96
Q

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

A

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

97
Q

Etiology of Wernicke’s Encephalopathy?

A

Severe B1 deficiency, usually secondary to bariatric surgery or alcoholism

98
Q

Clinical signs of Wernicke’s

A
  1. Nystagmus
  2. Cerebellar dysfunction
  3. Confusion
99
Q

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

A
  1. Nystagmus with near and far target
  2. Nystagmus in different gazes
  3. Nystagmus during fixation
100
Q

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

A

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

101
Q

What is the etiology for congenital nystagmus?

102
Q

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

A

FALSE; usually months after birth

103
Q

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

A

FALSE; not present during sleep

104
Q

FUNBLOCS

A

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)

105
Q

TRUE/FALSE: Monocular nystagmus is often horizontal in nature

A

FALSE; vertical

106
Q

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

A
  1. Infantile ET
  2. (+) lesion affecting binocular development
  3. Down Syndrome
107
Q

Latent Component of Congenital Nystagmus is characterized by…

A

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

108
Q

Congenital Nystagmus is classified as either _____ or _____?

A

Motor or sensory

109
Q

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

A
  1. Albinism
  2. Congenital Stationary Night Blindness
  3. ON Hypoplasia
  4. Retinal Dystrophies
  5. Cataracts
110
Q

Congenital Nystagmus — Motor or Sensory:
Stable over lifetime

111
Q

Congenital Nystagmus — Motor or Sensory:
Varying visual prognoses

112
Q

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

113
Q

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

114
Q

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

115
Q

Surgical Options for Congenital Nystagmus?

A
  1. Detach/reattach EOMS
  2. Align eyes to null point
  3. Recti recession to decrease tension
116
Q

Non-surgical options for Congenital Nystagmus?

A
  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
117
Q

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

A

Nuclei or midbrain, medulla, and cerebellum

Associated with Oculopalatal Myoclonus

118
Q

Associated with parasellar lesions or septa-optic dysplasia

A

Seesaw Nystagmus

Y. neuro ophthalmology (10 decks)

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