Lect 7 gaze palsies

Question 1

Excitatory neurons for vertical saccades are located in the:

a) Rostral interstitial MLF (riMLF) and interstitial nucleus of Cajal (NC)
b) dorsal aspect of PONS
c) Ventral aspect of cerebellum
d) caudal interstitial nucleus of Majal

Answer 1

a) Rostral interstitial MLF (riMLF) and interstitial nucleus of Cajal (NC)

Question 2

Which one of the following statements is INCORRECT?

a) In regards to optokinetic response, slow eye movements occur in the direction of the moving stimulus
b) CN 6 sends interconnection signals to the contralateral CN 3 through the MLF
c) a lesion of the nucleus of Cajal (NC) will cause skew deviation
d) All eye movements are effected equally with supranuclear lesions

Answer 2

d) All eye movements are effected equally with supranuclear lesions (FALSE, all eye movements are affected equally with NUCLEAR lesions. SUPRANUCLEAR lesions affect saccades 1st and most severly and affect VOR and OKN last and least severely)

Question 3

Match the following horizontal gaze palsies with their lesions:

1) Bilateral INO (BINO)
2) Wall-eyed (WEBINO)
3) one and a half syndrome

a) lesion in mid-brain that affects both MLF structures and MR subnuclei of CN III
b) lesion in pons that affects MLF and PPRF
c) lesion in both MLF structures

Answer 3

1) Bilateral INO (BINO)–c) lesion in both MLF structures
2) Wall-eyed (WEBINO)–a) lesion in mid-brain that affects both MLF structures and MR subnuclei of CN III
3) one and a half syndrome–b) lesion in pons that affects MLF and PPRF

Question 4

Which one of the following statements is NOT correct?

a) a lesion of the EBN in riMLF would cause a vertical gaze palsy
b) skew deviation can mimic CN 4 palsy, however the hypertropic eye is intorted
c) progressive supranuclear palsy is rare before age 50
d) skew deviation is usually due to brainstem lesion that disrupt supranuclear input to CN III and IV nuclei
e) skew deviation is a horizontal misalignment of the eyes

Answer 4

e) skew deviation is a horizontal misalignment of the eyes (FALSE, it is a vertical misalignment)

Question 5

Which one of the following is NOT a supranuclear opthalmoplegia?

a) dorsal midbrain syndrome
b) vertical saccadic palsy due to midbrain syndrome
c) horizontal saccadic palsy due to pontine disease
d) proggressive supranuclear palsy
e) all of the above are forms of supranuclear ophthalmoplegia

Answer 5

e) all of the above are forms of supranuclear ophthalmoplegia

Question 6

Your patient can look straight, can look to the right, but upon left gaze, the right eye cannot cross the midline and the left eye experiences nystagmus when abducting. What kind of lesion is this?

A) Cranial nerve 3 nucleus
B) Right MLF lesion
C) Left MLF lesion
D) none of the above

Answer 6

B) Right MLF lesion (this is an internuclear ophthalmoplegia)

Question 7

T/F: you will never have an isolated CN 6 palsy because it will always involve the CN 7 fascicle, causing a facial palsy

Answer 7

True

Question 8

T/F: dorsal midbrain syndrome is not a lesion in riMLF but in the projecting fibers from vertical supranuclear control center to dorsal midbrain

Answer 8

True (causes: pineal gland tumors, hydrocephallus, stroke, MS)

Question 9

T/F: dorsal midbrain syndrome is aka perinaud or pretectal syndrome and can cause supranuclear vertical gaze paresis, pupillary light near dissociation, lid retraction, convergence retraction nystagmus, intact VOR reflex

Answer 9

True