Supranuclear Pathways

Question 1

What is Balint’s syndrome?

Answer 1

A form of acquired ocular motor apraxia due to b/l posterior parietal lesions.
Simultanagnosia - inability to perceive more than one object at a time.

Question 2

What is Progressive Supranuclear Palsy?

Answer 2

1. Vertical saccades are affected first but eventually all gaze movements lost.
2. Strabismus
3. Reduced blinking
4. Eyelid opening apraxia
5. Gaze evoked nystagmus
6. Dementia, ataxia, axial rigidity

Question 3

What is skew deviation?

Answer 3

Acquired vertical misalignment of eyes resulting from asymmetric disruption of supra nuclear input from the otolithic organs (utricle and saccule)
Both peripheral and central lesions can produce skew deviation.
Produces DIPLOPIA (impt exception to the general rule that supranuclear lesions do not produce double vision)
ALTERNATING Skew deviation - manifest as hypertropia of the abducting eye that switches gaze (distinguish from b/l 4th nerve palsy)
Lesion located in the cerebellum or dorsal midbrain

Question 4

What is ocular tilt reaction?

Answer 4

A combination of a head tilt, skew deviation, and cycltorsional abnl of both eyes.
Similar to CN4 palsy but opposite higher eye is INTORTED IN ocular tilt reaction.

Question 5

In Latent and MLN which way does the fast phase beat?

Answer 5

Toward the viewing eye.

Question 6

The velocity of slow-phase movement increases exponentially with distance from fixation is?

Answer 6

Congenital nystgmus

Question 7

Which nystagmus abolishes in sleep?

Answer 7

Congenital nystagmus

Question 8

DVD and ET is seen in which type of nystagmus?

Answer 8

Latent nystagmus

Question 9

What is Braun’s nystagmus?

Answer 9

Acoustic neuroma cases a combination of central and peripheral vestibular nystagmus.

Question 10

Where is the lesion in downbeat nystagmus?

Answer 10

Cervical medullary, arnold chiari. bad oscillopsia.

Question 11

Where is the lesion in upbeat nystagmus?

Answer 11

Brain stem or the anterior cerebellar vermis

Demylination, stroke, tobbaco smoking

Question 12

Where is the lesion in torsional nystagmus?

Answer 12

Central lesion (also purely vertical lesions)
Medullary lesion

Question 13

How long is the characteristic oscillation cycle of PAN?

Answer 13

2-4 mins

Question 14

Where is the lesion for PAN?

Answer 14

Inferior cerebellar vermis (congenital and acquired)

Question 15

What is the most frequent cause of see-saw nystagmus?

Answer 15

Craniopharyngioma

Question 16

Where is the lesion in dissociated nystagmus?

Answer 16

MLF

Question 17

Burst and horiztonal movements that have small amplitude with very high frequency?

Answer 17

ocular flutter

Question 18

Multidirectional eye movements with high amplitude and high frequency is what?

Answer 18

opsolonus

Question 19

What produces paroxysmal, monocular, high-frequency bursts of contraction with patients chronically bothered by oscilloopsia or intermittent diplopia?

Answer 19

SO myokymia

Question 20

Vertical saccadic palsy may be an early neurologic findings in what dz?

Answer 20

Whipple dz

Question 21

How can you treat the acquired form of PAN?

Answer 21

Baclofen

Question 22

How do you treat downbeat nystagmus?

Answer 22

clonazepam (GABA A agonist)

Question 23

What is the lesion in ocular bobbing?

Answer 23

Pons secondary to infarction or heme. b/l pontine lesions lead to loss of horizontal eye movements
(rapid downward movements of both eyes)

Question 24

An isolated lesion to the MLF causes what?

Answer 24

Skew deviation (hypertropic eye on side of lesion) in addition to an INO