Is Motor Milestone Assessment in Infancy Valid and Scaled Equally Across Sex, Birth Weight, and Gestational Age? Findings From the Millennium Cohort Study

Denise de Almeida Maia; Farid Bardid; Tobias Koch; Paola Okuda; George Ploubidis; Anders Nordahl-Hansen; Michael Eid; Hugo Cogo-Moreira

doi:10.3389/fpsyg.2021.781602

Is Motor Milestone Assessment in Infancy Valid and Scaled Equally Across Sex, Birth Weight, and Gestational Age? Findings From the Millennium Cohort Study

Front Psychol. 2022 Jan 5:12:781602. doi: 10.3389/fpsyg.2021.781602. eCollection 2021.

Authors

Denise de Almeida Maia¹, Farid Bardid², Tobias Koch³, Paola Okuda¹, George Ploubidis⁴, Anders Nordahl-Hansen⁵, Michael Eid⁶, Hugo Cogo-Moreira^{1

5}

Affiliations

¹ Department of Psychiatry and Medical Psychology, Federal University of São Paulo, São Paulo, Brazil.
² School of Education, University of Strathclyde, Glasgow, United Kingdom.
³ Department of Psychology, Friedrich-Schiller-Universität Jena, Jena, Germany.
⁴ Department of Social Science, Centre for Longitudinal Studies, Institute of Education, University College London, London, United Kingdom.
⁵ Department of Education, ICT and Learning, Østfold University College, Halden, Norway.
⁶ Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany.

Abstract

Is the assessment of motor milestones valid and scaled equivalently for all infants? It is not only important to understand if the way we use gross and fine motor scores are appropriate for monitoring motor milestones but also to determine if these scores are confounded by specific infant characteristics. Therefore, the aim of the study is to investigate the latent structure underlying motor milestone assessment in infancy and measurement invariance across sex, birth weight, and gestational age. For this study, the birth cohort data from the United Kingdom Millennium Cohort Study (MCS) was used, which includes the assessment of eight motor milestone tasks from the Denver Developmental Screening Test in 9-month-old infants (N = 18,531), depicting early motor development of the first children of generation Z. Confirmatory factor analyses showed a better model fit for a two-factor structure (i.e., gross and fine motor development) compared to a one-factor structure (i.e., general motor development), and multiple indicators multiple causes modeling revealed no differential item functioning related to sex, birth weight, and gestational age. The study provides support for the use of gross and fine motor scores when assessing motor milestones in infants-both boys and girls with different birth weights and of varying gestational ages. Further investigation into widely adopted assessment tools is recommended to support the use of valid composite scores in early childhood research and practice.

Keywords: assessment; confirmatory factor analysis; differential item functioning; infants; motor development milestones.