Characterization of motor control in handwriting difficulties in children with or without developmental coordination disorder.

AIM: The purpose of this study was to characterize handwriting deficits in children with developmental coordination disorder (DCD) using computerized movement analyses.
METHOD: Seventy-two children (40 females, 32 males; mean age 7 y, SD 7 mo; range 6 y 2 mo to 7 y 11 mo) with handwriting deficits (33 with DCD, 39 without DCD); and 22 age- and sex-matched children without handwriting deficits were asked to perform handwriting tasks on a digital tablet for the collection of kinematic and kinetic data. Practice times required to achieve automation of movement when writing an unfamiliar character were used to assess the motor learning of handwriting. The children were asked to copy three simple and three complex characters, and the velocity and axial pen force used for corresponding strokes were compared.
RESULTS: The attainment of automated handwriting was markedly slower in children with handwriting deficits and DCD, who used a faster stroke velocity to write simple characters (1.22 times those without handwriting deficits), but when writing complex characters, their stroke velocity and pen force were lower (0.85 and 0.89 times those without handwriting deficits, respectively).
INTERPRETATION: By linking the results with neuromotor control theories, it was determined that children with DCD have difficulties performing the open-loop and closed-loop movements required for fluent handwriting.