Brainstem Motility Disorders Flashcards
(24 cards)
When the macula is too high, the eye is ____.
Intorted (higher eye intorts)
When the macula is too low, the eye is _____.
Extorted (lower eye extorts)
Superior muscles _____. Inferior muscles _____.
- Superior = intort
- Inferior = extort
The MVN and LVN tell the eye to move _____. What 2 muscles are yoked for this motion?
- tells eye to move down
- IR and SO
The Superior VN tell the eye to move ____. What 2 muscles are yoked for this motion?
- tells eye to move up
- SR and IO
What usually has a higher deviation magnitude? Skew or CN IV palsy?
Skew
If a skew deviation is worse in downgaze, which VN are lesioned?
MVN and LVN = can’t tell eye to go down
If a skew deviation is worse in upgaze, which VN is lesions?
SVN = can’t tell eye to go up
The higher, intorted eye is ______ to the lesion below the graviceptive pathway crossing?
opposite
The higher, intorted eye is _____ to a lesion above the graviceptive pathway crossing?
ipsilateral
Disconjugate torsion implies a _____ level lesion and conjugate torsion implies ____ level lesion.
- disconjugate = lower
- conjugate = higher
Where are the 4 main areas to localize lesions with a skew deviation?
- Vestibular Nerve
- Medulla
- Midbrain
- MLF/Pons
What is a very common finding with a skew deviation?
INO
An INO is defined by the eye that does not ____.
adduct
For a BNO, if the patient cannot converge where does the lesion localize to?
Midbrain
For a BINO, if the patient can converge where does the lesion localize to?
Pons
What is the convergence centre?
Midbrain
An unilateral INO is found in what type of ppl with what disease?
Older people with a vascular issue (i.e. stroke)
A BINO is found in what type of ppl with what disease?
Younger people with a demyelinating condition (MS)
A lesion of the MLF causes what ocular disease?
Internuclear Ophthalmoplegia (INO)
In a WEBINO, what two areas are lesioned together?
- MLF and CN III nucleus is lesioned
Where is the lesion for a WEBINO?
Midbrain
For one and a half syndrome, is convergence intact?
Yes!
What is the workup for brainstem motility issues?
- MRI with GAD
- if demyelination = FLAIR MRI
- if Infarct = DWI