Impaired motor imagery in children with developmental coordination disorder: task-specific deficits and links to ADHD and ASD traits.

Motor imagery (MI) ability has traditionally been assessed using the Hand Laterality Recognition (HLR) task; however, no studies have examined MI ability in children with Developmental Coordination Disorder (DCD) using the Bimanual Coupling (BC) task. This study aimed to clarify MI ability in children with DCD by using both BC and HLR tasks. Fifteen children with DCD and fifteen typically developing (TD) children participated. Motor coordination skills were evaluated using the Movement Assessment Battery for Children-2 (MABC-2), and neurodevelopmental traits were assessed using the ADHD Rating Scale-IV (ADHD-RS-IV) and Social Communication Questionnaire (SCQ).In the BC task, TD children showed a significant increase in the Ovalization Index (OI) in the motor imagery (MI) condition compared to the unimanual (UM) condition, whereas DCD children did not show this increase. Furthermore, the Imagery Coupling Effect (ICE) was significantly lower in the DCD group than in the TD group. In the HLR task, the DCD group demonstrated significantly lower accuracy and efficiency compared to the TD group. Evidence of the biomechanical constraints effect and the hand posture effect was also limited in children with DCD. Additionally, significant correlations were found between ICE and SCQ scores in the BC task, and between HLR accuracy, DCDQ scores, and ADHD traits. These findings suggest that children with DCD experience difficulties in generating MI, regardless of the type of task used for assessment.