Efferent: Internuclear And Supranuclear Disorders

Front 1

True/False: Internuclear and supranuclear defects will cause strabismus.

Back 1

False
horizontal gaze paly instead

Front 2

True/False: Internuclear and supranuclear defects will cause diplopia.

Back 2

False
no diplopia excet with INO or skew deviation

Front 3

Horizontal gaze centers controls LR movement on the __________ side and MR movement on the __________ side through the _____.

Back 3

ipsilateral, contralateral, MLF

Front 4

To look LEFT, a signal goes from the _________ PPRF to the _________ VI nerve nucleus innervating the _________ LR. A signal is also sent to the __________ MR subnucleus innervating the ___________ MR.

Back 4

left
left
left
right
right

Front 5

Name the two vertical gaze centers

Back 5

posterior commisure
rostral interstitial MLF

Front 6

where is the PPRF located

Back 6

ill-defined area somewhere around abducens nerve nucleus

Front 7

where are the posterior commisure and riMLF located

Back 7

upper midbrain (ill-defined areas)
act bilaterally

Front 8

what is the vertical gaze center for upgaze

Back 8

posterior commisure

Front 9

what is the vertical center for downgaze

Back 9

riMLF

Front 10

What is the tectum?

Back 10

area of the brain responsible for auditory and visual responses (inferior and superior colliculi)

Front 11

What is the pretectal area

Back 11

transition zone between midbrain and diencephalon

Front 12

Why are the tectal and pretectal areas important ?????????

Back 12

they contain fibers for vertical saccades, vertical pursuit, and pupillary fibersa

Front 13

a lesion at the PPRF will cause? why is there NO optokinetic nystagmus?

Back 13

gaze palsy affecting all movement systems - saccades, pursuits, vestibular reflexes

no nystag because PPRF is termination point for all movement systems

Front 14

INO is a sign of damage to?

Back 14

brainstem/MLF between CN VI (ipsi) and III (contra)

Front 15

How is an INO defect named

Back 15

by the MR affected, ex. RMR affected is right INO

Front 16

bilateral INO usually indicative of

Back 16

MS

Front 17

limited adduction, one eye can abduct but develops nystagmus on abduction what is this
:

Back 17

INO

Front 18

Name three theories for why nystagmus of the abducting eye develops?

Back 18

- impaired inhibition of the MR in abducting eye
- adaptation to the contralateral MR weakness
- interruption of descending internuclear fibers projecting to abducens nucleus

Front 19

True/False: Stimulation of the MR subnuclei of both III nerves occurs with involvement of MLF.

Back 19

False - without MLF involvement - thoguht to occur in upper brainstem. This is why convergence is sometimes not affected with INO

Front 20

A patient with intact convergence is said to have a _____________ INO.

Back 20

posterior

Front 21

INO without any convergence is called a ___________ INO

Back 21

anterior

Front 22

What causes one and a half syndrome

Back 22

combined lesion of abduens nuc or pprf and mlf on one side of brainstem

Front 23

A patient with one and a half syndrome has a slight RXT in pp. where is the lesion?

Back 23

left side

Front 24

downward bobbing of eyes is a classic sign of what type of lesion?

Back 24

pontine

Front 25

What are the causes of one and a half syndrome?

Back 25

trauma
MS
hemorrhage

Front 26

What is a skew deviation?

Back 26

vertical misalignment caused by disturbance of nuclear input

Front 27

How can you differentiate a skew deviation from EOM palsies?

Back 27

scan - in skew dev there will be CNS dysfunction

Front 28

What type of lesion is associated with Parinaud's syndrome?

Back 28

supranuclear

Front 29

supranuclear paresis of vertical gaze where fast and slow eye movements are variably affected is termed as what syndrome?

Back 29

Parinaud's

Front 30

Where is the damage in Parinaud's syndrome?

Back 30

pretectal area near pupillary fibers and vertical center; lesion at posterior commisure

Front 31

a patien was diagnosed to have Parinaud's syndrome and had loss of their saccades but pursuits were fine. Is this diagnosis questionable? Why or why not?

Back 31

This is not questionable since saccades are afftected first with parinaud's, so the pt could be in early stages

Front 32

Your pt has Parinaud's syndrome. You test them with the OKN drum. Describe what you would see.

Back 32

- no optokinetic nystagmus when drum is rotated downward since they can not saccade back up and re-follow
- normal optokinetic response when drum spin upward

Front 33

Parinaud's pt attempt to saccade upward - what happens?

Back 33

- convergence and globe retraction

Front 34

Any pupillary defects in Parinaud's Syndrome?

Back 34

light-near dissociation

Front 35

Why is it said that a parinaud's pt has a pseudo abducens palsy?

Back 35

upon horizontal saccade, abducting eye moves more slowly that adducting

Front 36

What is PSP?

Back 36

progressive supranuclear palsy

Front 37

Explasin the steps in PSP

Back 37

- degenerative disease later in life
- impaired vertical saccades - downward more than upward
- difficulty reading and eating
- horizontal eye movements affected - impaired saccades/pursuits

Front 38

What is the differential for PSP?

Back 38

Hydrocephalus and Parkinson's

Front 39

What type of symptoms happen with Parkinson's patients?

Back 39

- basal ganglia disease
- saccades in upgaze affected
- eye/head movements abnormal
- obsessive fixation of thgouht - trouble looking downward since eyes deviate upward and laterally

Front 40

What is ocular motor apraxia

Back 40

- absent saccadic refixation in HORIZONTAL plane
- head thrusts - over/.undershoots
- improves with age
- aplasia of corpus callosum

Front 41

WHat is the "mushroom cap" looking structure when looking at a cross -section of the brian

Back 41

corpus callosum

Front 42

corpus callosum function?

Back 42

controls movement and feeling on opposite side of body

Front 43

What are some causes of corpus callosum problems? what can this in turn cause?

Back 43

- prenatal infections or viruses
- chromosomal abnormalities
- toxic metabolic conditions
- cyst or other mass blcoking growth of corpus callosum

* can cause ocular motor apraxia *

Front 44

What happens in agenesis of corpus callosum and how is this problem partially resolved?

Back 44

when nerve fibers dont cross during the critical prenatal time. therefore there is agenesis of the corpus callosum. this is partially resolved because other (smaller) structures such as the superior and posterior commisure

Front 45

What happens in a partial ACC?

Back 45

corpus callosum began to develop but did not finish; develops from front to back so front is usually intact with back portion missing; other smaller commisures are also present

Front 46

Give some characteristics associated with dysgenesis of the corpus callosum?q

Back 46

- delays in developmental milestones
- clumsiness and motor coordination
- abnormal sensitivity to sensory clues
- difficulties in multidimensional tasks
- challeneges with social interaction
- mental and processing problems
- limited insight into ther own behavior

Front 47

What is the function of the cerebellum?

Back 47

maintains equilibrium and posture

Front 48

What is Arnold Chiari Malformation?

Back 48

- elongated cerebellar tonsils
- congenital
- blocks flow of cerebrospinal fluid
- cranial nerves and lower cerebellum may be stretched or compressed

Front 49

what is syringomyelia? what can cause it

Back 49

cyst or tubular cavity that forms within the spional cord, expanding over time and destroying the center of spinal cord. usually caused by arnold chiari malformation

Front 50

What are the ocular signs of Arnold Chiari Malformation?

Back 50

- downbeat nystagmus
- PAN
- strabismus
- gaze evoked nystagmus
- impaired pursuit
- dysmetria
- INO
- abnormal VOR