| Identifier |
visual_variant_of_alzheimers_Lee |
| Title |
Visual Variants of Alzheimer's |
| Creator |
Andrew G. Lee, MD; Praneeth Kambhampati |
| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (PK) Class of 2023, Baylor College of Medicine, Houston, Texas |
| Subject |
Alzheimers; Atrophy; MRI; Simultagnosia |
| Description |
Summary: • Visual Variants of Neurodegenerative Disease o Prototype: Visual variant Alzheimer's Disease -Also called Posterior Cortical Atrophy (PCA) • Better term & describes radiographic features • Axial MRI/CT show atrophy o Occipital lobe atrophy o Ex-vacuo dilation of ventricles -Complaints: • "Can't see, can't read" • "can see letters but can't process words • Don't understand what they're reading • Get lost easily • Spouse: "I will not drive with him because he gets lost easily -Eye Exam: • Acuity: 20/20 • NIR Card: Jeager-1, J1 • Pupil, S-lamp, pressure, motility & fundus: normal -Visual Fields • Expect: homonymous hemianopsia or juxtaposed homonymous hemianopsia or cortical visual impairment o MRI: posterior cortical atrophy -Other Tests • Clock Draw (Ask patient to draw a clock) o Multiple misshapen clock possibilities • Ishihara Color Plates o Simultanagnosia o Alexia with or without Agraphia -Summary (Patients with Posterior Cortical Atrophy) • Vague Complaints • Determine cause of seeing/reading deficit • Indicators: multiple glasses, normal structural exams • Do a Clock Draw & Ishihara Color Plate Screen • If homonymous hemianopsia, juxtaposed homonymous hemianopsia or cortical visual impairments with normal MRI -Posterior Cortical Atrophy |
| Transcript |
So today we are going to be talking about visual variants of neurodegenerative disease. The prototype is visual variant Alzheimer's disease because Alzheimer diseases are the most common primary neurodegenerative disorder. Sometimes it's called posterior cortical atrophy. I like that description better because you don't have to say the Alzheimer's word to the patient. Sometimes they don't like to hear the Alzheimer's word. Also it's a very good description of the radiographic features. So here on this axial MRI or CT what we're going to be seeing is atrophy in the posterior cortex. So we're going to see occipital lobe atrophy and ex-vacuo dilation of the ventricle out of proportion to the rest of the brain. The way it presents to us is in very specific ways. In the visual variant of Alzheimer's disease posterior cortical atrophy the patient is just going to complain that they can't see, that's not that helpful, or that they can't read. So one of the most important things is "why can't you read or why can't you see". The typical answers that you will receive in patients [who live in] have neurocognitive deficit as the cause of their complaint is they'll say they can see the letters but they can't process the words. Also they may say that they don't understand what they're reading or they get lost easily. The chief complaint might also say brought in by spouse who says "I won't drive with him because he gets lost so easily". The tricky part is that the acuity can be 20/20 and if you have them read the NIR card they might be Jeager-1 J1. This happens because they can see the letters. Of course the rest of the exam including the pupil, the S-lamp, the pressure, the motility and the fundus might all be normal. What we're looking for on the visual field is either a homonymous hemianopsia with no structural coronal an MRI or a juxtaposed homonymous hemianopsia (homonymous hemianopia on the right next to a homonymous on the left) or a cortical visual impairment. The key in differentiating imaging finding is the atrophy is in the posterior cortex that corresponds with the field. So in patients who have normal acuity and normal structural exams have a field defect that either shows a homonymous hemianopsia or juxtaposed homonymous hemianopsia where there cortically impaired. They have had an MRI which only shows posterior cortical atrophy. One of the great tests that we're going to be using of rapid screening tests is called a clock draw. We just have them draw a clock, we put a circle in the middle and we ask them to put in all the numbers and make the time say 10 minutes after 11. That's a pretty rapid test in a patient who has difficulty with neurocognitive because this is testing multiple spatial domains. They might draw a clock that has you know all the numbers crammed in on one side, one where they're missing half the numbers, one where they might only have one arm, one where they might put the numbers on the outside or one of any number of combinations where this clock is not a normal clock drawing. For simultanagnosia they can see the individual pieces but they can't recognize the forest for the trees. We can use Ishihara color plates. As you know in a patient who has normal acuity and no color dischromotopsia they are not be able to see the little dots that are actually making up the number 12 or the number 2. They can see the numbers but they only see them as a series of dots. In a person who has simultanagnosia, they might be able to see the individual circles but they wouldn't be able to see the number 4 that's embedded in there. That is simultanagnosia. This can also present to us as alexia with or without agraphia. They had 20/20 vision but they can't read, they have visual spatial difficulties where they get lost easily or they can't drive because they can't do multitasking. Really the main things I want you to know is that in patients who have neurocognitive deficit including posterior cortical atrophy, the visual variant of Alzheimer's, their complaints are going to be quite vague. You need to drill down on why they can't see or why they can't read. They've usually have had multiple pairs of glasses and normal structural exams. Do a clock draw and the Ishihara color plates as the screen. If you see a patient who has either a homonymous hemianopsia, juxtaposed homonymous hemianopsia or cortical visual impairment with a normal MRI look for posterior cortical atrophy. |
| Date |
2019-10 |
| Language |
eng |
| Format |
video/mp4 |
| Type |
Image/MovingImage |
| Collection |
Neuro-Ophthalmology Virtual Education Library: Andrew G. Lee Collection: https://novel.utah.edu/Lee/ |
| Publisher |
North American Neuro-Ophthalmology Society |
| Holding Institution |
Spencer S. Eccles Health Sciences Library, University of Utah |
| Rights Management |
Copyright 2019. For further information regarding the rights to this collection, please visit: https://NOVEL.utah.edu/about/copyright |
| ARK |
ark:/87278/s6ng9g7k |
| Setname |
ehsl_novel_lee |
| ID |
1469333 |
| Reference URL |
https://collections.lib.utah.edu/ark:/87278/s6ng9g7k |
