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Dr. Laser,

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this is a 63-year-old man with ataxia and dementia.

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It's a mixed case.

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We'll talk about the specific findings in one

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of the later vignettes.

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For instance,

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there's there's midbrain abnormalities.

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There's abnormalities of the left

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greater than right frontal lobe,

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left greater than right parietal lobe,

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and some other subtle abnormalities that might

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help with the differential diagnosis.

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But we're here to talk about the patterns of

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parietal atrophy and how you would grade them.

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Now, you've mentioned to me that when you're

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looking at these axial images,

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and it's noteworthy that the frontal and

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the parietal areas are involved,

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you said that as soon as you get

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up to the interparietal sulcus,

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the very first cut is where you look

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for that parietal atrophy,

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and that interparietal sulcus goes

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into the postcentral sulcus.

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This is kind of where you play your game

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of assessing the degree of parietal atrophy,

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which is rather pronounced on the left

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and somewhat mild on the right,

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or mild to moderate on the right.

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So what's the grading system for parietal

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atrophy that you might use?

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So, the grading system that I use is called the codom scale.

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Grade 0 being no cortical atrophy.

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So the gyri and the sulci are touching.

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Grade 1 would be mild parietal cortical atrophy,

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which would essentially mean that the sulci start

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to slightly widen in the posterior cingulate

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and the parietal occipital sulci.

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Grade 2 would be substantial parietal atrophy

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with substantial widening of the sulci.

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So you've lost both sulci and gyri.

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You start to lose the gyri.

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So you'll have some gyral thinning,

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and you'll have increased widening of the sulci.

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And then your extreme,

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your last grade would be a grade 3.

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would be extreme widening of the

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posterior cingulate and the

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parieto-occipital sulci,

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which would also lead you into

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the voluminous of the cortex

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with a knife blade type appearance.

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Okay, so I've written that down,

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and you mentioned numerous times the cingulum,

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which is very important in ALZ and other dementias,

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and the parietal occipital area.

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So let's just scroll a little bit.

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Here's the cingulate sulcus turning into the

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super marginal sulcus right here,

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or marginal sulcus right above

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that is the cingulum.

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So, we do have some atrophy here.

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When we get to the parietal occipital area

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in the back, there is atrophy

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but not as profound as some of

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the other distributions.

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Here's the parietal occipital sulcus right here.

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So it is involved.

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The occipital region is involved.

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Now, bear in mind that there is a spectrum of

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neurodegenerative diseases as we exit this case.

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Sometimes you'll have extension of ALZ

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like disease into the frontal region.

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Sometimes it'll be more unilateral

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and cause speech disturbance.

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That's called semantic aphasia with dementia,

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probably an ALZ variation.

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And it can even selectively involve the posterior

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cingulum and the occipital region only.

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That's another Alzheimer's variant

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called Benson Syndrome.

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So, you've given the codom score

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for parietal atrophy.

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Again,

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some subjectivity associated with this.

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Let's move on, shall we?