Neuropathology Data Set (NP)
forms and documentation

(All available in PDF only.)

RDD-np button

 

The Researchers Data Dictionary — Neuropathology Data Set (RDD-NP) is intended to be the first and primary resource for researchers analyzing NACC neuropathology data. The NACC Neuropathology Data Set has undergone several revisions since its inception in 2002, and the RDD-NP brings together information from all of the original data-collection instruments (the Coding Guidebooks and Forms) for all past and current versions of the NACC NP Form.

Our goal in creating the RDD-NP is to provide a comprehensive document describing the data elements available to researchers for analysis of the neuropathology data using versions 1, 7, 8, 9, and 10 of the NP Form.

CONTINUED …

The most substantial revision of the Neuropathology Data Set took place in 2014 with the implementation of version 10 of the Neuropathology Data form.

Several data elements collected in v1-9 of the NP form are not collected in v10, and vice-versa. Version 10 now includes the 2012 NIA-AA criteria for Alzheimer’s disease and the staining methods used, as well as finer detail on vascular, TDP-43, and other pathological features. To clarify the difference between missing data and data not collected due to differences in form versions, codes of -4 = "Not available, NP form version did not collect data this way" were added.

There are also differences in codes for variables that have been continually collected across NP form versions. For example, CERAD neuritic plaque frequency was collected in all versions of the NP form; however, the coding scheme changed in v10: in v1-9, "No neuritic plaques" has a value of 4; in v10, "No neuritic plaques" has a value of 0. In order to provide consistent coding across all versions, derived variables were developed from the original source variables. In analysis files, these derived variables replace the original NP variable. Derived variables are named with the prefix "NACC," while original NP variables begin with the prefix "NP."

When selecting variables for data analysis, be sure to review all data elements in the section of interest. Some variables that differ across forms could not be combined into a single derived variable. For example, the presence of lacunes was slightly different in v9 and v10, so both original source variables are provided. Thus, the investigator will need to decide how to analyze these data keeping in mind the inconsistency.

In addition, original data elements with blank values resulting from skip patterns in v10 of the NP form were recoded to the unknown and missing codes from the gateway question.

Finally, outdated diagnosis variables were removed from this document in order to prioritize newer, more relevant diagnostic criteria and pathologic features; however, all original NP data elements are still available by request.

expand symbol Forms and documentation for current and past NP versions

Version 10

v10 Data form

v10 Coding guidebook

Detailed, annotated explanation of the form on an item-level
basis, with instructions, operational definitions, and references

v9 Data element dictionary

Version 9

v9 Data form

v9 Coding guidebook

Detailed, annotated explanation of the form on an item-level
basis, with instructions, operational definitions, and references

v9 Data element dictionary

Version 8 (July 2006)

Version 7 (July 2006)

Version 1 (December 2001)