Variable Details
Available Studies
ROS, MAP, MARS, Clinical Core, LATC
Categories
Pathology
A score
Amyloid beta plaque score based on Thal plaque phase (4 levels)
Amyloid-ß (Aß) plaque score (4 levels) is based on a 6-level measure of Aß deposits involving different regions of the brain. Aß deposits are detected using immunohistochemistry. In RADC protocol, all regions are checked for Aß deposits. The Thal plaque phase ranges from 0 to 5 and is determined by Aß deposits in the brain region that corresponds to the highest level. Diagnosis includes algorithm and neuropathologist’s opinion. The categories are then collapsed into 4-levels:
| Value | Coding |
|---|---|
| 0 | No Aß or amyloid plaques |
| 1 | Thal phase 1: neocortex only or phase 2: neocortex + hippocampus |
| 2 | Thal phase 3: neocortex (with or without hippocampus) + basal ganglia |
| 3 | Thal phase 4: neocortex (with or without hippocampus) +basal ganglia + substantia nigra or phase 5: neocortex (with or without hippocampus) + basal ganglia (with or without substantia nigra) + cerebellum |
Note: In older cases, standard data collection in all brain regions was not always completed. When regions were not available, neuropathologists used their judgement to determine the amyloid-ß (Aß) plaque score level. This variable is missing if thal data is missing such that an a_score level is unable to be determined.