Flashcards in Gaze palsies Deck (22):
What is a gaze palsy?
Limitation of conjugate movement in both eyes aka 1 eye is not following the other eye
Gaze palsies are caused by damage to _____ structures. Pure gaze palsies affect both eyes equally and there is no strabismus present.
In _____ lesions, saccades are affected first and most severely. In _____ lesions, ALL eye movements affected equally - can't to saccades, pursuits, VOR, or OKN
what does it mean if you have internuclear ophthalmoplegia, but your convergence is still intact? where is the lesion?
that the medial rectus nuclei are fine, so the MLF lesion has to be somewhere in the pons
A _____ gland lesion usually affects all 3 structures in the midbrain: rIMLF, nucleus of Cajal, and posterior commissure
supranuclear EOM abnormalities result from:
1. cerebral dysfunction
2. cerebellar dysfunction
3. brainstem dysfunction
brainstem supranculear palsy includes:
1. impaired range and velocity of saccades
2. impaired OKN
3. preserved/slightly impaired smooth pursuit
4. intact vor
in horizontal gaze palsies, a lesion of the _____ is INO. This means that there will be an ____ deficit on the same as the MLF lesion, and and abducting nystagmus of the contralateral eye. A lesion in the PPRF is slowing of horizontal saccades, limitation in range of horizontal saccades ipsilateral to lesion
What is a bilateral INO
lesion in both MLF structures usually due to an ischemic stroke or demyelinating lesion. Neither eye can adduct
what is a wall- eyed BINO
lesion in midbrain; affects both MLF structures and MR sub nuclei of CN III. In primary gaze, the pt will have an exotropia, and neither eye will be able to adduct when doing vergence. The lesion has nicked the medal rectus nucleus.
what is one and one- half syndrome
gaze palsy to side of lesion, (neither eye can make saccades in one direction), ipsilateral adduction deficit on attempted contralateral gaze (can't adduct 1 eye). The lesion is in the pons, both the PPRF and MLF are affected. VOR will still be in tact.
______ lesion in the PPRF results in loss of all ipsilateral rapid eye movements. Located in CN ___ nucleus or in the PPRF. Voluntary and involuntary saccades are lost. Quick phase of OKN is lost. VOR will still be intact.
CN ____ nucleus lesions results in _____ conjugate gaze palsy, and ipsilateral CN ____ palsy
Patient cannot look in one direction with either eye, and will have a facial palsy on that side
where is the lesion if you have an EOM dysfunction with a wobble nystagmus
lesion is in the brainstem
Vertical gaze palsies is usually due to lesion of EBN in ____. Acute vertical gaze palsy is most often due to midbrain stroke. In younger patients we worry about pineal gland tumors
What are clinical signs of dorsal midbrain syndrome aka parinaud/ pretectal syndrome
1. supranuclear vertical gaze paresis
2. pupillary light near dissociation
3. colliers lid retraction
4. convergence retraction nystagmus
5. intact VOR
6. +/- optic nerve swelling: due to pineal gland tumor and increased ICP.
where is the lesion in dorsal midbrain syndrome
not well defined but in projecting fibers from vertical supranuclear control centers to dorsal midbrain.
what are causes of dorsal midbrain syndrome
1. pineal gland tumors
skew deviation is vertical misalignment of the eyes caused by ____ lesion that is not nuclear/fascicular. usually due to disruption of ____ input to CN III and IV nuclei. May result from cerebellar or peripheral vestibular lesions, but rare.
skew deviation can mimic CN ____ palsy. To tell the difference, in a fourth nerve palsy, the hypertropic eye will be _____ while in skew deviation the hypertropic eye will be _____. Also in skew deviation, pt will have alternating hypertropia, while in CN 4 palsy, only one eye will be hyper
IV; extorted; intorted
also patients with SD will almost always present with additional brainstem signs such as vertigo or oscilopsia from nystagmus because all motor pathways from cortex pass through the midbrain.
What is seen in progressive supra nuclear palsy?
neurodegenerative disorder, more common in elderly men. vertical gaze affected, then horizontal gaze affected second. pts present with dysarthria, rigidity of neck and upper trunk, gait difficulty, and memory problems