When children with developmental coordination disorder use finger-counting: behavioral and 3D motion analyses

Children with Developmental Coordination Disorder (DCD) are known to be at increased risk for mathematical difficulties (Gomez et al., 2015; Pieters et al., 2012). While the severity of their numerical impairments appears to vary with the intensity of their symptoms (Pieters et al., 2012), few studies have attempted to understand how motor deficits affect their numerical abilities. The purpose of this study is to explore the functionality of finger counting in children with DCD in solving resource-demanding problems in numerical and non-numerical contexts. Seventeen children with DCD matched with TD children on school level and on fluid reasoning abilities were tested. They were asked to identify the nth item after a target item in numerical and alphabetical ordered sequences. Behavioral measures supplemented by 3D motion analyses synchronized to a voice recording were used to assess children’s performance and finger counting functionality. Results showed that, although performing finger counting gestures comparable to those of their TD peers, children with DCD had more difficulties in solving resource-demanding problems. When added to the model, working memory captures the majority of the variability explaining this group difference. These finding provide evidence that children with DCD do not take advantage of finger counting to reduce working memory processing load and achieve the same level of performance than their peers.