Longitudinal studies have demonstrated that it is important to attend to the stability of mathematical performance over time as a facet of learning disabilities in mathematics (MLD). The manifestation of MLD changes with development, and individual differences in cognitive profiles and learning trajectories observed in children with MLD implicate differences between subgroups of MLD, low achievement (LA) and typically performing (TA) children. Intra-individual differences over time, and external factors related to children's learning environments, also contribute to performance trajectories; moreover, these factors may explain the inconsistent performance profiles observed among many students whose difficulty with mathematics emerges later or diminishes over time. We will review the key findings from longitudinal studies on MLD during the last 20 year (Mazzocco & Räsänen, 2013). In addition we will present further evidence from the longitudinal Early Steps study (Zhang, Koponen, Räsänen et al. 2013; Zhang, Räsänen, Koponen, et al. in prep.) to demonstrate that MLD and LA represent qualitatively distinct categories with differing severity in mathematical difficulty. A latent class growth analysis was used to find subgroups of children (n= 1471) based on their performance level in arithmetic at grade 4 as well as on their developmental path from the 1st to 4th grade. Using a model with five distinct subgroups we proceeded to examine the extent to which in linguistic (phonological awareness, vocabulary, letter knowledge, and serial naming), spatial (spatial visualization), and numerical (counting sequence knowledge) skills measured before formal education would predict the membership in the groups. The results show that there are early signs in linguistic and spatial cognitive skills as well as in domain-specific numerical skills which may help us to identify both MLD and LA children before formal education. Children with MLD, compared to those with LA, need more intense services to effectively remediate their more severe learning difficulties, although both groups are struggling in mathematics and need remediation. An important question for future research is whether early interventions on these skills found to be powerful predictors of MLD would also prevent difficulties in learning at school age. Copyright © 2014 University of Jyväskylä.
|Publication status||Published - Aug 2014|