Transient Visual Loss and Disorders of Higher Cortical Function

Question 1

what is Uhthoff phenomenon

Answer 1

transient blurring of vision precipitated by exercise or increased temperature that is seen in patients with current or previous optic neuritis

Question 2

transient monocular vision loss only elicited by certain gazes?

Answer 2

suggests orbital mass causing gaze-dependent ischemia

Question 3

typical presentation and length of symptoms in amaurosis fugax from retinal embolus

Answer 3

curtain descends over eye, and vision loss generally resolves after 10-15 min (although can take up to 1 hour)

Question 4

what did the CREST study determine?

Answer 4

no significant difference between CEA and stenting on stroke rate in patients with high-grade carotid stenosis ( > 70%)

Question 5

Common source(s) of the following retinal emboli:

1. cholesterol
2. platelet-fibrin
3. calcium

Answer 5

1. carotid artery plaque
2. wall of atherosclerotic vessel; heart valves
3. calcified heart valves; calcified aortic stenosis

Question 6

70 yo smoker w/ multiple DM, HTN, HLD p/w monocular TVOs that occur only in very bright light

Answer 6

ocular ischemic syndrome

Question 7

40 yo otherwise healthy patient w/ family h/o migraines has episodes of painless monocular vision loss. exam normal: diagnosis, workup, and possible treatment

Answer 7

retinal artery vasospasm. CBC, carotid duplex, ECG. diagnosis of exclusion. CCBs may be useful.

Question 8

most common cause of transient binocular vision loss? what specific pattern is most common for this cause?

Answer 8

migraine; usually causes homonymous hemianopsia

Question 9

differentiate transient binocular vision loss in migraine v occipital mass

Answer 9

occipital mass: headache first, then visual loss. also, always occur on the same side
migraine: vision loss precedes (aura) migraine

Question 10

transient, recurrent, bilateral vision blurring in patient with subclavian bypass

Answer 10

vertebrobasilar insufficiency

Question 11

symptoms of occipital lobe seizures, and different associations in adults and kids?

Answer 11

usually produce positive visual phenomena (color lights, whiting out of vision) but less likely blacking out of vision. often benign in kids, but generally indicate structural lesion in adults (tumor, AVM, etc)

Question 12

illusion v hallucination

Answer 12

illusion: misinterpretation of actual visual stimulus; often clears after blinking
hallucination: perception of an image in the absence of visual stimulus; often persists after blinking

Question 13

Name the phenomenon and the associated pathology: an object moving perpendicularly across the field of vision appears that is coming towards the viewer

Answer 13

Pulfrich phenomenon; demyelinating optic neuritis

Question 14

Define micropsia, macropsia, teleopsia, and pelopsia, and what lesions are they associated with?

Answer 14

micropsia: objects appear smaller
macropsia: objects appear larger
teleopsia: objects appear farther
pelopsia: objects appear closer
* *All are associated with parietal lobe abnormalities

Question 15

what is palinopsia and what are etiologies

Answer 15

visual preservation after the removal of the original stimulus. often associated with homonymous hemianopia in which the palinoptic image appears in the blind hemifield. can also be caused by migraines, hallucinogenics and other drugs

Question 16

how long do visual symptoms in migraines generally last, and in what temporal relationship to the headache?

Answer 16

last 10-30 minutes, happen before headache

Question 17

visually impaired patients with preserved cognitive status have unformed hallucinations that they know are not real

Answer 17

Charles Bonnet syndrome

Question 18

1. inability to recognize objects?
2. inability to recognize familiar faces?
3. loss of perception of visual motion?
4. ability to write but not read? (and what structure is damaged?)
5. failure to integrate multiple elements of a scene?
6. perception that environment is flipped, rotated, or inverted?

Answer 18

1. object agnosia
2. prosopagnosia
3. akinetopsia
4. alexia without agraphia. corpus callosum
5. simultagnosia
6. visual allesthesia

Question 19

triad of Balint syndrome?

Answer 19

simultagnosia, optic ataxia, ocular motor apraxia,

Question 20

patient with cortical blindness confabulates that he can see things

Answer 20

Anton syndrome

Question 21

perception of motion in a blind hemifield?

Answer 21

Riddoch phenomenon

Question 22

not seeing objects in an area of vision known to be intact? location of lesion?

Answer 22

hemispatial neglect; right hemisphere