The NIH Toolbox includes a cognitive battery that provides an Early Childhood Composite score for children age 3-7. However, very few studies have evaluated feasibility when it is used in the youngest segment of this age range-3-year-olds. The current study evaluated performance on the four cognitive subtests composing the early childhood composite, two of which assess executive function, in a large sample of 3-year-olds enrolled in a Vanguard pilot of the National Children's Study. Results found that in a cohort of 609 3-year-olds (mean age = 39.6 months, SD = 1.6, 53% male, 64% White, 87% Non-Hispanic) who were administered four subtests included in the Early Childhood Composite, up to approximately 30% were unable to pass practice items on the Flanker, Dimensional Change Card Sort, and Picture Sequence Memory, whereas only approximately 3% were unable to pass practice items on the Picture Vocabulary Test. Furthermore, of those that did pass practice and achieve scores on the subtests, approximately 70% and 80% performed at or below chance level on the executive function tasks (Flanker and Dimensional Change Card Sort) and Picture Sequence Memory, respectively. Ultimately, the average 3-year-old has difficulty with three of the four NIH Toolbox tasks composing the Early Childhood Composite and may not yet have developed the requisite skills. These findings indicate that changes compatible with the developmental level of preschoolers are recommended to increase the feasibility and effectiveness of the NIH Toolbox in measuring individual cognition differences in 3-year-old children.
Keywords: NIH Toolbox; assessment; cognition; executive function; preschool.