Background: Evidence exists that there are two main underlying cognitive factors in mathematical difficulties: working memory and number sense. It is suggested that real math difficulties appear when both working memory and number sense are weak, here referred to as the double deficit (DD) hypothesis. Aims: The aim of this study was to test the DD…

The strong differences in manifestation, prevalence, and incidence in dyslexia across languages invite studies in specific writing systems. In particular, the question of the role played by emergent literacy in opaque and transparent writing systems remains a fraught one. This research project tested, through a 4-year prospective cohort study, an…

Age-normed tests of listening comprehension, oral expression, reading comprehension, and written expression were administered in Grades 1 (n = 128), 3, and 5, or 3 (n = 113), 5, and 7. Confirmatory factor analyses compared 1- and 4-factor models at each grade level and supported a 4-factor model of language by ear, mouth, eye, and hand. Multiple…