Cognitive process-based subtypes of developmental coordination disorder (DCD)

The purpose of the study was to identify the cognitive subtypes demonstrated by children with developmental coordination disorder (DCD) using the Planning-Attention-Simultaneous-Successive Processing (PASS) theory and the Cognitive Assessment System (D-N CAS). Participants were 108 children aged 5- and 6-years old, 54 with DCD and 54 without DCD, all attending typical kindergartens. They were examined on 31 cognitive-motor variables. Hierarchical-agglomerative and iterative partitioning cluster analyses including 9 motor and 7 cognitive variables revealed the following six subtypes: o C1 = children at risk (having considerable difficulty with jumping and minor difficulty with manual dexterity and simultaneous coding); o C2 = children on the mean (all cognitive-motor scores close to the mean); o C3 = free from cognitive-motor problems (all scores above average); o C4 = manual dexterity, planning and simultaneous coding difficulties; o C5 = manual dexterity, dynamic balance, and planning difficulties; o C6 = generalized cognitive-motor dysfunction (all scores considerably below average). It is well known that DCD is a heterogeneous condition. However, whenever cognitive processes were lower than average, cognitive-motor relationship was evident in subgroups C1, C4, C5 and C6. Early identification of task-specific cognitive-motor difficulties may be essential for early educational intervention practices in order to anticipate and improve learning, academic and performing difficulties.