Supranuclear and Internuclear Disorders (F)

Question 1

What are disorders of the ocular motor system that may be caused by lesions of the brainstem, cerebellum, or cerebral hemispheres?

Answer 1

supranuclear

Question 2

Where is the lesion when there is a contralateral horizontal gaze palsy with acute deviation of eyes toward the side of the lesion?

Answer 2

frontal lobe lesion

Question 3

What are the differential diagnoses of Parinaud’s syndrome?

Answer 3

1. pineal region tumors
2. multiple sclerosis
3. stroke
4. hydrocephalus

Question 4

What are the ways to differentiate between a skew deviation and CN IV palsy?

Answer 4

1. subtle saccadic pursuit disorders or nystagmus, other neuro abnormalities
2. Upright-supine test (vert deviation decreases in supine is skew)
3. ocular torsion (hypertropic eye intorted)

Question 5

Where is the nucleus of the abducens (VI) nerve located?

Answer 5

lies immediately ventral to the genu of the facial nerve (facial colliculus in dorsal pons)

Question 6

Where is the nucleus of the trochlear (IV) nerve located?

Answer 6

lies ventral to the aqueduct in the pontomesencephalic junction, caudal to the oculomotor complex

Question 7

What does the MLF connect?

Answer 7

abducens nucleus and contralateral MR subnucleus of CN III

Question 8

Where is the lesion located in an Internuclear Ophthalmoplegia?

Answer 8

MLF of ipsilateral to eye with adduction weakness

Question 9

What is the description of an ocular tilt reaction?

Answer 9

1. pathologic head tilt is ipsilateral to the hypotropic eye
2. ocular torsion is such that the upper poles of both eyes rotate in the same direction as that of the head tilt (hypertropic eye incyclotorted)

Question 10

Where is the lesion when there is a ipsilateral horizontal gaze palsy, acute deviation of eyes away from side of lesion, and overcome by oculocephalic movements?

Answer 10

PPRF lesions

Question 11

What are ocular motor disorders that are caused by disruption of the brainstem pathways that coordinate eye movements?

Answer 11

internuclear

Question 12

Where is the lesion when there is a ipsilateral horizontal gaze palsy, acute deviation of eyes away from side of lesion and not overcome by oculocephalic movements?

Answer 12

abducens nucleus lesions

Question 13

Where is the nucleus of the oculomotor (III) nerve located?

Answer 13

lies in the midbrain, anterior to the cerebral aqueduct

Question 14

What is the eye movement that is maintained in a patient with one-and-a-half syndrome?

Answer 14

only abduction of contralateral eye

Question 15

What is the pathway from the vestibular nuclei for the VOR?

Answer 15

travel rostrally via the medial longitudinal fasiculus, pass through but do not synapse in caudal portion of PPRF, and synapse at the sixth nerve nucleus

Question 16

What is inputed into the vestibular nuclei?

Answer 16

1. labyrinthine semicircular canals and otoliths

2. visual and somatosensory systems

Question 17

What do Parkinson’s and Huntington disease affect ocularly?

Answer 17

1. saccades (first)
2. smooth pursuits
3. fixation

Question 18

What type of eye movements are affected first for supranuclear ocular motor disorders? 1. Last? 2

Answer 18

1. saccades (most severely)

2. VOR (least severely)

Question 19

What are the signs involved in Parinaud’s syndrome?

Answer 19

1. supranuclear upgaze palsy
2. convergence retraction nystagmus on attempted upward saccade
3. mid-position pupils
4. light-near dissociation
5. Collier’s sign (lid retraction)