Motor anticipation in ASD children: the experience of a sequential pointing task

International audienceAutism Spectrum Disorder (ASD) is a neurodevelopmental psychiatric condition characterized by difficulties with social interactions and communication, repeated and stereotypical movements or restricted interests. Altered motor behaviours have also always been observed in ASD children (Kanner, 1943). But, to this day, they are still neglected during rehabilitation. Recent studies on animal models have suggested that ASD could be related with a cerebellum dysfunction (Jaber, 2017). Because the cerebellum is particularly involved in the control of anticipation, we proposed to compare the production of sequential pointing movements in ASD and neurotypical (NT) children. Precisely, we focused on motor anticipation of a second movement which occurs during the production of the first part of the sequence (first pointing).Using a digitizer, 34 NT (18 girls) and 27 ASD children (9 girls), 6-12 years divided into three age groups (6-7 years, 8-9 years, 10-11 years). They’ve had to point to a target first horizontally situated at a 10cm lenght and then, to another one vertically situated at a 17cm height. These two targets were presented ten times on each side. Concerning the second target, two target widths were used (0,5cm and 4cm). A movement endpoint tolerance was used (from the center of the target: radius +0,2mm). The analyses have been concerned with the velocity of the first movement (V P1). One subject of the ASD group was excluded because his results were at +- 2SD of the mean.Results show an effect of the age group (p = .05) and a margin interaction between age group and target width (F (1, 2) = 2.93, p = .06). No interaction effect exists between group, age group and target width (p = .64). Thereby, as NT do, during a sequential pointing task, ASD children can anticipate the difficulty incoming during the production of a current movement and this motor anticipation capacities increase with age. Although their developmental trajectory mimics that of NT children, they stay slower in each of the conditions. Consequently, motor anticipation capacities of ASD children seems preserved but they present global motor slowness. These results will be discussed with the cerebellum dysfunction theory in ASD