Hello,
I have a few related questions about the MSBB array neuropathological variables whose definitions are given below:
**PLQ_Mn**: plaque density mean (average of NP counts in 5 cardinal cortical regions)
**NPrSum**: sum of neuritic plaque density estimates (sum of CERAD semi-quantitative rating scores for all cortical regions examined neuropathologically)
**NTrSum**: sum of neurofibrillary tangles density estimates (sum of semi-quantitative NFT density ratings for all cortical regions examined)
**CERAD**: 1=Normal, 2=Definite AD, 3=probable AD, 4=possible AD
Here are my questions:
1) Given there are values as big as 35 for NPrSum and the maximum possible CERAD score is 4, I think there are at least 9 regions examined for NPrSum. Is that correct? If so, which regions are included in NPrSum calculation in addition to the 5 regions included for PLQ_Mn, which are I believe middle frontal gyrus, orbital frontal cortex, superior temporal gyrus, inferior parietal cortex and calcarine cortex?
2) For the CERAD score, given the adjective "probable" corresponds to a higher likelihood than the adjective "possible", the numbers in the middle of the range (2 and 3) correspond to a worse patient outcome, which looks counter-intuitive, because then neither a high nor a low NPrSum value would necessarily mean a worse patient outcome. Am I missing something?
3) For NTrSum, what exactly "sum of semi-quantitative NFT density rating" means? What are the possible different ratings? Is it the same as the Braak score?
I would really appreciate a quick response. Thanks!
Created by safiye celik safiye From Harry, the neuropath PI at MSSM:
"1. Given there are values as big as 35 for NPrSum and the maximum possible CERAD score is 4, I think there are at least 9 regions examined for NPrSum. Is that correct? If so, which regions are included in NPrSum calculation in addition to the 5 regions included for PLQ_Mn, which are I believe middle frontal gyrus, orbital frontal cortex, superior temporal gyrus, inferior parietal cortex and calcarine cortex?
CERAD density ratings are 0=none, 1=sparse, 3=moderate, 5=frequent. The NPrSum is the sum of the ratings from: Hippocampus, entorhinal cortex, amygdala, middle frontal gyrus, superior temporal gyrus, interior parietal lobule, occipital cortex (BM-17)
2. For the CERAD score, given the adjective "probable" corresponds to a higher likelihood than the adjective "possible", the numbers in the middle of the range (2 and 3) correspond to a worse patient outcome, which looks counter-intuitive, because then neither a high nor a low NPrSum value would necessarily mean a worse patient outcome. Am I missing something?
CERAD diagnostic scores are: 1=normal brain, 2=definite AD, 3=probable AD, 4=possible AD
3. For NTrSum, what exactly "sum of semi-quantitative NFT density rating" means? What are the possible different ratings? Is it the same as the Braak score?
See above" Hi Safiye,
Sorry for the delay in response. We're following up on this.
Ben Hi, any thoughts on that? Thanks!