Brainstem Motility Disorders

Question 1

When the macula is too high, the eye is ____.

Answer 1

Intorted (higher eye intorts)

Question 2

When the macula is too low, the eye is _____.

Answer 2

Extorted (lower eye extorts)

Question 3

Superior muscles _____. Inferior muscles _____.

Answer 3

• Superior = intort

- Inferior = extort

Question 4

The MVN and LVN tell the eye to move _____. What 2 muscles are yoked for this motion?

Answer 4

• tells eye to move down

- IR and SO

Question 5

The Superior VN tell the eye to move ____. What 2 muscles are yoked for this motion?

Answer 5

• tells eye to move up

- SR and IO

Question 6

What usually has a higher deviation magnitude? Skew or CN IV palsy?

Answer 6

Skew

Question 7

If a skew deviation is worse in downgaze, which VN are lesioned?

Answer 7

MVN and LVN = can’t tell eye to go down

Question 8

If a skew deviation is worse in upgaze, which VN is lesions?

Answer 8

SVN = can’t tell eye to go up

Question 9

The higher, intorted eye is ______ to the lesion below the graviceptive pathway crossing?

Answer 9

opposite

Question 10

The higher, intorted eye is _____ to a lesion above the graviceptive pathway crossing?

Answer 10

ipsilateral

Question 11

Disconjugate torsion implies a _____ level lesion and conjugate torsion implies ____ level lesion.

Answer 11

• disconjugate = lower

- conjugate = higher

Question 12

Where are the 4 main areas to localize lesions with a skew deviation?

Answer 12

1. Vestibular Nerve
2. Medulla
3. Midbrain
4. MLF/Pons

Question 13

What is a very common finding with a skew deviation?

Answer 13

INO

Question 14

An INO is defined by the eye that does not ____.

Answer 14

adduct

Question 15

For a BNO, if the patient cannot converge where does the lesion localize to?

Answer 15

Midbrain

Question 16

For a BINO, if the patient can converge where does the lesion localize to?

Answer 16

Pons

Question 17

What is the convergence centre?

Answer 17

Midbrain

Question 18

An unilateral INO is found in what type of ppl with what disease?

Answer 18

Older people with a vascular issue (i.e. stroke)

Question 19

A BINO is found in what type of ppl with what disease?

Answer 19

Younger people with a demyelinating condition (MS)

Question 20

A lesion of the MLF causes what ocular disease?

Answer 20

Internuclear Ophthalmoplegia (INO)

Question 21

In a WEBINO, what two areas are lesioned together?

Answer 21

• MLF and CN III nucleus is lesioned

Question 22

Where is the lesion for a WEBINO?

Answer 22

Midbrain

Question 23

For one and a half syndrome, is convergence intact?

Answer 23

Yes!

Question 24

What is the workup for brainstem motility issues?

Answer 24

• MRI with GAD
• if demyelination = FLAIR MRI
• if Infarct = DWI