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how does vertical gaze center work
"orignates in frontal eye fields or in superior colliculus, requires b/l cortical input, projections travel to rostral interstitial nucleus of the MLF located behind red nucleus in midbrain, fibers travel to nuclei of CN 3 and 4 (upgaze is in lateral portion of riMLF), and downgaze is in media portion of riMLF)"
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what nucleus is responsible for torsional movements
interstitial nucleus of cajal
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what disease has prolonged photostress recovery test and what disease has normal?
"macular has prolonged, optic nerve has normal"
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what color deficiency does acquired macular disease have
blue/yellow in early stages
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what color cones are in the fovea
red/green
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what VEP pattern do you see in toxic or compressive optic neuropathies
reduction of amplitude more pornounced than prolongation of latency (unlike demylienation where latency is prolonged)
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what is cogans dictum
"retrochiasmal disorder causes homonymous hemianopia -> assymetric OKN indicates parietal lobe lesion, symmetric OKN indicates occipital lobe lesion"
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what do you see with downward moving OKN drum in dorsal midbrain syndrome
conergence retraction nystagmus
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what is skew deviation
"vertical misalignment due to imbalance of prenuclear iputs -> vertical tropia where hypodeviated eye is ipsilateral to lesion -> due to brain stem infract, MS, increaesd ICP -> transient"
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what does wipples' disease do to eye
oclomasticatory myorhythmia (vertical eye movements and facial activity similar to myoclonus)
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what os olivopontocerebellar atrophy
"eye movements progresively slow in all directions until complete external ophtalmoplegia -> 2/2 cerebellar and pontine atrophy -> also unseady gait, slurrd speech, dementia, optic atrophy, retinal degeneration"
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"how does kernicterus, wernick'es encelaopathy, maple syrup disease affect eyes"
progressive loss of eye movements
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what is convergence-retraction nystagmus
due to periaquductal gray matter or dorsal midbrain lesion -> co-contraction of lateral recti produces convergence movement on attempted upgaze
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what causes downbeat nystagmus
"cervicomedullary junction lesion (arnold chiari malformation, tumor, syrinx), spinocerebellar degeneration, intoxication, lithium, paraneoplastic cerebellar degerration"
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what causes gaze-evoked nystagmus
"extra-axial mass compressing brain stem (acousti neuroma, cerebellar hemisphere tumor), intoxication"
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what causes seesaw nystagmus
"suprasellar lesion, cva, trauma, congenital"
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what direction is peripheral vestibular disease
"fast phase toward good side, slow phase toward lesion"
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what is opsoclonus
"rapid, chaotic eye movements in all directions, persists in sleep"
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what os ocular motor apraxia
"saccadic palsy with impairment of volutnary eye movements with preservation of reflex movements, acquired form called Balint's syndrome -> b/l cerebral disease (ASSOCIATED WITH GAUCHER'S, SPINOCEREBELLAR DEGENERATION, mr, WILSONS) -> HEAD THRUSTING, ABNORMAL okn, NORMAL PERSUITS"
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what is oculopharyngeal dystorphy
french candian disease with dysphagia followed by ptosis -> CPEO -> 2/2 vacular myopathy
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what chromsome is myoti dystrophy and what makes it worse
"chrom 19; worse with cold, excitement, fatigue"
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what is superior oblique myokymia
"episodic reptitive firing of SO causes intermittent oscillopsia, shimmering vision, and vertical/torsional diplplia -> idiopathic -> tx with carbamazepine or propanolol"
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what are causes of retrobulblar optic neuropathy (rare)
"anemia and hypotension, medicationuse"
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what is pseudo-foster-kennedy syndrome
AION is most frequent cause of unilateral disc edema and contralateral optic atrophy
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what causes pie in the sky visual field defect
"gliioima, vascular lesion of meyer's loop near temporal lobe"
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what is gerstmann's syndrome
"lesion of dominant parietal lobe (inferior homonymous hemianopia, acalculia, agraphia, finger agnosia, left-right confusion)"
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what is foster-kennedy syndrome
"frontal lobe mass causing anosmia, ipsilateral optic atrophy (from tumor compression) and contralateral ON edema (from elevated ICP)"
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what is posterior fossa tumors
most cause severe papilledema because they encroach on cerebral aqueduct and 4th eventricle with rapid rise in ICP
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