Uniform Data Set version 4
UDSv4 - Template

United States

Reference ID

USDv4

Producer(s)

National Alzheimer’s Coordinating Center (NACC) and the NIA-funded ADRC network

Collections

Clinical Trial

Metadata

DDI/XML JSON

Created on

Jul 02, 2026

Last modified

Jul 07, 2026

Page views

16050

Study Description
Data Dictionary

8d1. If present, select one: (ppasynt)

Data file: UDSv4TemplateForXMLD_2026-04-14_0731.REDCap.xml

Overview

Valid: 57

Range: -

Format:

Questions and instructions

Question pretext

[ppasyn] = '1'

Categories

Value	Category	Cases
1	Semantic PPA	15	26.3%
2	Logopenic PPA	9	15.8%
3	Nonfluent/agrammatic PPA	3	5.3%
5	Primary progressive apraxia of speech	12	21.1%
4	PPA other/not otherwise specified	18	31.6%

Warning: these figures indicate the number of cases found in the data file. They cannot be interpreted as summary statistics of the population of interest.

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