Investigation of clinical features of dysgraphia related to the subtypes of developmental coordination disorder in children regarding high IQ

Abstract

IntroductionHandwriting disorder is commonly observed in Developmental Coordination Disorder (DCD) (87-88%) and is often noted in children with high Intellectual Quotient (HIQ).Two mainly pure DCD subtypes: ideomotor-DCD (IM), visuospatial/or visuoconstructional-DCD (VSC) and a mixed subtype (MX) were identified in the literature but nothing is known regarding IQ and dysgraphia.ObjectivesTo refine the specific clinical features of dysgraphia related to DCD subtypes regarding IQ levels.Methods Neurovisual, neuropsychological, neuropsychomotor functions, and handwriting performances of 38 children (6-to-12 years-old: mean 9y, SD 2.7) diagnosed with DCD (DSM-5 criteria) were collected. Two matched groups were analyzed according to their IQ: 19 (TC) typical children (IQ=90-110) and 19 HIQ children (IQ> 120).Results IQ scores were not significantly associated with dysgraphia. There isa significant difference between TC vs HIQ with a lower rate of IM-DCD respectively 11% vs 5% (p=.035) and 68% vs 37% for VSC-DCD (p=.03) but 21% vs 58% in MX-DCD (p=.41). Dysgraphia was significantly more present in TC group with MX-DCD and in HIQ with VSC-DCD. A negative correlation between Kho’s’ cubes test failure (p=.006), visual-spatial memory (p=.05) and VSC-DCD was noted in HIQ group. The deficit of visual spatial memory was significantly related to dysgraphia in HIQ children (p=.01) associated to visual gnosis impairment (p=.03).ConclusionsDysgraphia was significantly found with VSC-DCD subgroup in FIQ>120 with specific features of visual perception disorders suggesting more involvement of the right cortex. These results suggest that VSC-DCD in HIQ could be a neurovisual impairment rather than a pure VSC-DCD.