Clustering of neuropsychological traits of preschoolers.

Neuropsychological tests (targeting cognitive, linguistic, motor, and executive abilities) are grouped in neuropsychological domains that are thought to be stable through adulthood. However, this assumption does not always hold true, particularly during young children's early developmental phase. Here, we explored how the neuropsychological profile of typical Spanish-speaking preschoolers varied and consolidated with age. We recruited 643 monolingual Latin-American children from Mexico, Colombia, and Guatemala, with ages spanning from 30 to 71 months of age, and applied a novel neuropsychological examination which combined a total of 52 tests covering five classical neuropsychological domains: receptive, expressive, attention/memory, processing, and executive functions. These tests' scores uncovered a correlational structure across neuropsychological functions that could not be explained by chance. Notably, these correlations' overall strength, but not their interdependence across domains, dramatically increased with age. Moreover, by applying conventional clustering techniques to classify the experimental data, we found a stable representation of two clusters of children with distinctive traits, with cultural factors contributing to this classification scheme. We also found that the tasks were well organized in a network of abilities, where nodes with highest highest interconnectedness were those that required multimodal processing. These results contribute to our understanding of children's 'normal' development and could help identify how failure in particular functions forecasts the emergence of neurodevelopmental disorders. Our analytic methods might become useful to characterize individual differences and improve educational practices and interventions.