Developmental coordination disorder (DCD), an umbrella term for motor dysfunctions, which could associate minor neurological dysfunctions

Introduction Developmental Coordination Disorder (DCD) defines a heterogeneous class of children exhibiting marked impairment in motor coordination. Objectives Explore in depth a general group of deficits in fine and gross motricity (subtype mixed group) common to all research subtyping studies. We aimed to highlight discriminant features and specific comorbidities. Methods Data from DCD children aged between 6 and 13years were eligible for inclusion in this study on DSM-5 criteria. All children were assessed with a neuropsychological evaluation of all brain functions and with developmental standardized physical tasks in the neuropsychomotor battery (NP-MOT) which include detection of minor neurological dysfunction (MND) and neurological soft signs (NSS) using tone examination, never considered in most previous studies. Results Findings show in an unexpected way, a high incidence, in 33% of the children, of a motor pathway dysfunction, evidenced by mild spasticity of gastrocnemius muscles in the lower limbs, associated with NSS, for instance failure of standing tone ( P =0.004) and dysdiadochokinesia ( P =0.011) versus salient DCD markers of the mixed subtype as imitation of gestures, fingers digital perception, digital praxia, manual dexterity, and upper and lower limbs coordination. This mild spasticity (MND) appears as a comorbid disorder increasing impairment of coordination between upper and lower limbs and manual dexterity. It could explain why DCD appears as a collection of motor disorders in a heterogeneous groups in numerous studies. Conclusions Our results provide important new evidence to implement an extensive neuro-developmental assessment (mental and physical), including neuromuscular tone examination using appropriate standardized neurodevelopmental tools (common tasks across ages).