Test of Infant Motor Performance for Infants in Brazil: Unidimensional Model, Item Difficulty, and Motor Function

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

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.

Peabody Developmental Motor Scales-2: The Use of Rasch Analysis to Examine the Model Unidimensionality, Motor Function, and Item Difficulty

The Peabody Developmental Motor Scales-Second Edition (PDMS-2) is a valid and reliable instrument used in several countries, including Brazil, to assess gross and fine motor skills and identify motor deficits and eligibility for intervention for children with and without disabilities. However, the analysis of PDMS-2 items regarding the unidimensionality of the model, order of item difficulty, and whether the items portray the children's developmental trajectories still lacks investigation. Therefore, this study aims to: (1) analyze the unidimensionality of PDMS-2, (2) verify the model's capacity to explain the variance in the motor function responses, and (3) identify the level of difficulty of the items for Brazilian children. Children (n = 637; 51% girls) newborn to 71 months (M age = 21.7, SD = 18.6) were assessed using the PDMS-2. The Rasch analysis was conducted; the indexes of infit and outfit, and the point-biserial correlations coefficient were analyzed. The model unidimensionality was investigated using percentages of variance in the Rasch model (40% of variance). Results indicated that (1) for reflexes subscale, 62.5% of the items had correlations with the factor above 0.60, and two items had unadjusted infit and outfit; (2) for stationary subscale, 83.3% of the correlations of the items with the factor were above 0.50, and one item had unadjusted infit and outfit; (3) for locomotion subscale, 80.0% of the correlation of the items with the factor were above 0.50; all items had adequate infit and outfit; (4) for object manipulation subscale, 79.9% of the correlation of the items with the factor were above 0.50, and one item had unadjusted infit and outfit; (5) for grasping subscale, 92.3% of the correlation of the items with the factor were above 0.50, and one item had unadjusted infit and outfit; and (6) for the visual-motor integration subscale, 73.6% of the correlation of the items with the factor were above 0.50, and six items had unadjusted infit and outfit. The items with unadjusted fit were removed for further analysis. No changes in reliability and separation of items and people scores were observed without the unadjusted items; therefore, all items were maintained. A unidimensional model was found, and the reliability and discriminant capability of the items were adequate, and all items should be used to assess children. The PDMS-2 is appropriate for assessing Brazilian children.

Functional movement assessment with the Test of Infant Motor Performance

The purpose of this article is to review research on the Test of Infant Motor Performance, a functional assessment of movement capabilities with age standards for infants from 34 weeks postmenstrual age through 17 weeks post term (corrected age). The Test of Infant Motor Performance was normed on a U.S. population-based sample to support its use as a tool for diagnosing delayed motor development in early infancy. The test is one of the preferred methods for parents of babies in special care nurseries to learn about their infant's development. The test was used in a variety of clinical trials to document effects of early therapy and can be used as a short-term outcome measure for other interventions expected to impact functional motor performance.