Original Research/StudyAdapting the Ages and Stages Questionnaire to Identify and Quantify Development Among Children With Evidence of Zika InfectionAttell, Jacob E. MPH; Rose, Charles PhD; Bertolli, Jeanne PhD; Kotzky, Kim MPH; Squires, Jane PhD; Krishna, Nevin K. MS; Satterfield-Nash, Ashley DrPH; Peacock, Georgina MD; Ornelas Pereira, Isabela MPH; Faria E. Silva Santelli, Ana Carolina MD; Smith, Camille EdSAuthor Information Eagle Global Scientific, LLC, Atlanta, Georgia (Mr Attell); National Center for Birth Defects and Developmental Disability, U.S. Centers for Disease Control and Prevention, Fort Collins, Colorado (Dr Rose); Division of Human Development and Disability (Drs Bertolli and Peacock), Division of State and Local Readiness (Mr Krishna), and Division of Congenital and Developmental Disorders (Dr Smith), U.S. Centers for Disease Control and Prevention, Atlanta, Georgia; Division of Human Development and Disability, Oak Ridge Institute for Science and Education, Atlanta, Georgia (Ms Kotzky and Dr Satterfield-Nash); College of Education, Center on Human Development, University of Oregon, Eugene (Dr Squires); Transmissible Diseases Department, Ministry of Health of Brazil (Ms Ornelas Pereira); and Overseas Strategy and Management Branch Brazil, Division of Global HIV & Tuberculosis, U.S. Centers for Disease Control and Prevention, Brasilia, Brazil (Dr Faria E Silva Santelli). Mr Attell is now with Booz Allen Hamilton, LLC, McLean, Northern Virginia. Correspondence: Jacob E. Attell, MPH, Civil Services Group, Booz Allen Hamilton, 1349 W Peachtree St NW #1400, Atlanta, GA 30309 (email@example.com). The authors give special thanks to Dr. Lara Robinson, all ZODIAC participants, and investigation staff.This research was made possible through support provided by the Office of Infectious Diseases, Bureau of Global Health, U.S. Agency for International Development (USAID), under the terms of an Interagency Agreement with the Centers for Disease Control and Prevention (CDC) and Cooperative Agreement number NU2G GH001152.The findings and conclusions in this report and those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.Supplemental digital content is available for this article. Direct URL citation appears in the printed text and is provided in the HTML and PDF versions of this article on the journal's Web site (www.iycjournal.com). Infants & Young Children: April/June 2020 - Volume 33 - Issue 2 - p 95-107 doi: 10.1097/IYC.0000000000000161 Buy SDC Metrics Abstract This article describes novel methods of applying the Ages and Stages Questionnaire—3rd edition (ASQ-3) to assess and quantify developmental delay among children following the 2015–2016 Zika virus outbreak in Brazil. Many of the children with Zika virus infection were expected to have severe developmental delay. However, administering the ASQ-3 to caregivers of these children according to standard protocol would have screened for the overall presence of delay but not the severity of delay. We adopted an amended protocol for administration of the ASQ-3 to quantify the developmental functioning of children severely affected by Zika virus infection in this investigation. Protocols for administering the ASQ-3 among this population were drafted in consultation with developmental measurement experts and are presented here. Specific developmental estimates are discussed, including developmental age equivalents, developmental quotients, and developmental quotient z scores. The calculations of these estimates are presented with examples in the context of the 2015–2016 Zika virus outbreak and associated microcephaly among prenatally infected children from 2 states in northeastern Brazil. Potential applications of these methods for estimating developmental ability among similar pediatric populations are discussed. © 2020 Wolters Kluwer Health, Inc. All rights reserved.