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

13018

Study Description
Data Dictionary

0d2. If 'A2 Co-Participant Demographics' not submitted, specify reason (a2not)

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

Overview

Valid: 57

Range: -

Format:

Questions and instructions

Question pretext

[modea2]='0'

Categories

Value	Category	Cases
92	No co-participant	3	5.3%
95	Physical problem	26	45.6%
96	Cognitive/behavioral problem	0	0%
97	Other	4	7%
98	Verbal refusal	24	42.1%

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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