Handwriting acquisition in children with and without dysgraphia: a calculated approach

Thomas Gargot, Thibault Asselborn, Hugues Pellerin, Ingrid Zammouri, Salvatore M. Anzalone, Laurence Casteran, Wafa Johal, Pierre Dillenbourg, David Cohen, Caroline Jolly

Handwriting is a complex skill to acquire and it takes years of practice to master. Children with dysgraphia have difficulty automating their writing. This can lead to anxiety and have a negative impact on their education. 280 children were recruited from schools and specialised clinics to perform the BHK (Concise Evaluation Scale for Children's Handwriting) test on digital tablets.

From this data, we identified children with dysgraphia. Twelve digital features describing different aspects of handwriting (static, kinematic, pressure and tilt) were extracted and used to create linear models to study handwriting acquisition throughout education. A K- means grouping was performed to define a new classification of dysgraphia.

Linear models show that only three characteristics (two kinematic and one static) demonstrated a significant association in predicting the change of handwriting quality in children from the control group. Most of the kinematic and static characteristics changed with age. The results suggested that children with dysgraphia do not simply differ from ones without dysgraphia by quantitative differences on the BHK scale, but exhibit different development in terms of static, kinematic, pressure and tilt features. The K- means grouping made it possible to discern 3 groups (Ci). Children in group C1 had mild dysgraphia, usually not detected in schools, while children in groups C2 and C3 had severe dysgraphia. In particular, C2 contained individuals with abnormalities in terms of kinematics and pressure, while C3 included children with mainly tilt problems.

The current results open up new perspectives for the automatic detection of children with dysgraphia in the classroom. We also believe that pressure and incline training in the form of games could open up new therapeutic possibilities.