Nystagmus_Dr. M. Sharma

Question 1

Where is the probable location of a upbeat nystagmus?

Answer 1

Posterior fossa (medulla most common)

Question 2

Where is the probable location of a periodic alternating nystagmus?

Answer 2

Cerebellar nodulus

Question 3

Where is the probable location of a ocular bobbing?

Answer 3

Pontine destructive lesion

Question 4

Where is the probable location of a ocular flutter/opsoclonus?

Answer 4

Pons (pause cells); cerebellum (connections to pons)

Question 5

Where is the probable location of a convergence-retraction nystagmus?

Answer 5

Pretectum (dorsal midbrain)

Question 6

Where is the probable location of a see-saw nystagmus?

Answer 6

Paraellar/diencephalon

Question 7

Where is the probable location of a monocular nystagmus of childhood?

Answer 7

optic nerve/chiasm/hypothalamus

Question 8

central vestublar nystagmus is a mixed __________ trajectory?

Answer 8

horizontal-torsional

Question 9

Central vestibular nystagmus usually beats away or towards the side of the vestibular lesion?

Answer 9

away

Question 10

Does central vestibular nystagmus associates with neurologic signs and symptoms?

Answer 10

Yes

Question 11

How is the VA of the people who has central vestibular nystagmus?

Answer 11

VA may be normal small amplitude outside primary position

Question 12

Which nystagmus is the most common form of central vestibular nystagmus?

Answer 12

downbeat nystagmus

Question 13

What is a downbeat nystagmus look like?

Answer 13

results from lesions that produce defective vertical gaze holding characterized by an upward drift of the eyes, which is then corrected with a downward saccade.

Question 14

Does downbeat nystagmus follow the ALEXANDER’S LAW?

Answer 14

Yes

Question 15

In what position does the downbeat nystagmus usually accentuated?

Answer 15

downgaze, especially to either side.

Question 16

T/F In downbeat nystagmus, the lesion is in vestibulocerebellum and diminish the tonic output from the anterior semicircular canals to the ocular motoneurons.

Answer 16

True

Question 17

What is the most common structural lesion of a downbeat nystagmus?

Answer 17

Arnold-Chiari Type 1 malformation. Lesion of the foramen magnum

Question 18

What are the treatments for downbeat nystagmus?

Answer 18

1. Common treatments are “off label” include Clonazepam, Baclofen and Gabapentin
2. Base-Out prisms (induce convergence)
3. Memantine, 4-Aminopyridine and 3,4-Diaminopyridine

Question 19

where is the probable location of lesion with downbeat nystagmus?

Answer 19

Cervical-medullary junction

Question 20

upbeat nystagmus is caused y lesions in the posterior fossa of which part?

Answer 20

Brainstem (often medulla) and The anterior cerebellar vermis

Question 21

The most common causes of upbeat nystagmus are _______, _______, ________, and ________.

Answer 21

Demyelination
Stroke
Cerebellar degeneration
Tobacco smoking

Question 22

Purely torsional nystagmus indicates a _______ lesion.

Answer 22

central lesion, associates with a medullary lesion (eg. syingobulbia, lateral medullary infarction)

Question 23

Periodic alternating nystagmus oscillates predictably in ________, ______ and ______.

Answer 23

direction, amplitude and frequency

Question 24

Is periodic alternating nystagmus congenital or acquired?

Answer 24

can be both

Question 25

Periodic alternating nystagmus is typically associated with dysfunction of the _______ and _______.

Answer 25

cerebellar nodulus and uvula

Question 26

What is the drug of choice to effectively treat acquired form of nystagmus?

Answer 26

Baclofen

Question 27

Acquired pendular nystagmus with both vertical and horizontal components produces ________ (if the components are in phase) or ________ or ________ nystagmus (if the components are out of phase).

Answer 27

oblique, circular, elliptical

Question 28

The eye movements in acquired pendular nystagmus may be conjugate or disconjugate and are often _________.

Answer 28

dissociated

Question 29

Oculopalatal myoclonus or tremor is an acquired _________ plus ________.

Answer 29

pendular nystagmus, myoclonus

Question 30

Oculopalatal myocolonus usually arises several months after a lesion occus that involves the _________.

Answer 30

Guillain-mollaret triangle

Question 31

Which kind of nystagmus produces an inferior olivary hypertrophy?

Answer 31

Oculopalatal myoclonus. When the lesion is within central tegmental tract, it can disrupt transmission between the cerebellum, specifically the flocculus,, and the inferior olive.

Question 32

See-saw nystagmus is a form of disconjugate nystagmus in which 1 eye _____ and _____ while the other eye ______ and ______.

Answer 32

elevates, intorts | depresses, extorts

Question 33

See-Saw nystagmus is most commonly observed in patients with large tumors of the parasellar region that impinge on the ______ ventricle.

Answer 33

third Craniopha-Ryngioma is a frequent cause Other parasellar-diencephalic tumors and trauma may als produce see-saw nystagmus

Question 34

See-Saw nystagmus may be associated with vision loss and often looks like ________ hemianopia.

Answer 34

bitemporal

Question 35

In dissociated nystagmus, the most common form of this disorder is one that is associated with lesions of the __________, which produce an internuclear ___________.

Answer 35

medial longitudinal fasciculus (MLF) | Ophthalmoplegia (paralysis of the muscles within or surrounding the eye)

Question 36

How does dissociated nystagmus look like?

Answer 36

isolated slowing of adduction of the eye isilateral to an MLF lesion, which create excessive saccadic movements in the contralateral rectus muscle (abduction). That's according to Hering's Law.

Question 37

What are the Gaze-holding deficiency nystagmus (neural integrator)?

Answer 37

1. eccentric gaze nystagmus ( and associated rebound nystagmus) 2. Gaze instability ("Run-away") nystagmus.

Question 38

What is eccentric gaze nystagmus?

Answer 38

It develops becaue of an inability to maintain fixation in eccentric gaze. Eyes drift back to the midline and a corrective saccades reposition the eyes on the eccentric target with a fast phase.

Question 39

What law is Eccentric gaze nystagmus follows?

Answer 39

Alexander's law. Nystagmus increases in intensity (amplitude and frequency) as the eyes are moved in the direction of the fast phase.

Question 40

Eccentric gaze nystagmus is caused by dysfunction of the ________ integrator.

Answer 40

neural - For horizonal gaze, the neural integrator include the nucleus prepositus hypoglossi and the medial vestibular nuclei - For vertical gaze the interstitial nucleus of Cajal serves as the neural integrator - The flocculus and nodulus of the cerebellum also play a role in maintaining an eccentric position of gaze.

Question 41

Rebound nystagmus is often a manifestation of _________ disease.

Answer 41

cerebellar

Question 42

what is gaze instability (run-away) nystagmus look like?

Answer 42

ocillation slow phases are directed away from central position

Question 43

Gaze instability (run-away) nystagmus is associated with ________ signs and symptoms.

Answer 43

neurologic

Question 44

In gaze instability nystagmus, ocular motility recording show slow phase that are accelerating or decelerating?

Answer 44

accelerating

Question 45

What is the treatment for superior oblique myokymia?

Answer 45

Carbamazepine

Question 46

What are the treatment for downbeat and other central vestibular forms of nystagmus?

Answer 46

occasionally be helped by clonazepam, A GABA agonists

Question 47

What would you use that may improve visual acuity in patients with congenital nystagmus?

Answer 47

contact lenses

Question 48

What are the non-medical treatments for nystagmus?

Answer 48

1. Prisms such as base out prisms to induce convergence if nystagmus diminishes with convergence 2. contact lenses to improve VA in patients with congenital nystagmus

Question 49

What are the other eye movement disorders?.

Answer 49

1. voluntary flutter ("nystagmus") 2. convergence-retraction nystagmus 3. superior oblique myokymia 4. oculomasticatory myorhythmia 5. ocular bobbing

Question 50

What is the motion you see with voluntary flutter ("nystagmus")?

Answer 50

rapidly oscillating eye movement (almost always horizontal) that can be induced volitionally. The movement lack slow phases, so it's not a form of nystagmus.

Question 51

Voluntary flutter appear as high-frequency, conjugate, back to back saccades without an ___________.

Answer 51

intersaccadic interval

Question 52

Voluntary flutter is associated with convergence and often with eyelid flutter and ________.

Answer 52

facial grimacing

Question 53

is Convergence-retraction nystagmus a true nystagmus?

Answer 53

no because it doesn't have a slow phase

Question 54

Convergence-retraction nystagmus is often associated with paresis of what gaze?

Answer 54

upgaze

Question 55

What is the Collier sign and which nystagmus has this?

Answer 55

Near dissociation, skew deviation and bilateral eyelid retraction

Question 56

Superior Oblique Myokymia produces ________, _______, ________ bursts of contraction of the superior oblique muscle.

Answer 56

paroxysmal, monocular, high frequency

Question 57

Does Superior Oblique Myokymia shows large or small amplitude?

Answer 57

small amplitude and magnification is usually required.

Question 58

Is Superior Oblique Myokymia malignant or benign?

Answer 58

It is almost always benign, although there are rare reports of its association with MS and posterior fossa tumor

Question 59

What is oculomasticator myorhythmia?

Answer 59

It develops pendular, vergence oscillations that occur with contractions of the masticatory muscles.

Question 60

What is an early neurologic finding in whipple disease?

Answer 60

vertical saccadic palsy

Question 61

What is the eye movements you see with ocular bobbing?

Answer 61

rapid downward movement of both eyes, followed by a slow return of the eyes to the midline position.

Question 62

Where is the lesion that causes ocular bobbing?

Answer 62

Usually in the pons, secondary to infarction or hemorrhage.