Figure 1

Representative hand trajectories and speed profiles during pointing task paradigm. (A) Schematic of the pointing task. Subjects sat comfortably in front of a touch screen, reaching out their right hands to touch the target (size 5 cm) then retracting their hands spontaneously to their resting positions. Subjects repeated the cycles continuously at their own comfortable pace (human diagram produced by EB Torres using old drawing windows software no longer available. First published in a joint paper (EBT and JVJ ref.²²). (B) Compares the maximum speed magnitude, the average of the speed magnitude and the average cycle temporal durations during ASD and TD group motion cycles: there is no significant distinction among the two groups. (C) shows average speed profiles across cycles, lined up according to the touching points (black dots), including speed profiles in-between touching points at ±1.2 s. Results shown of three representative ASD subjects with decreasing severity (classification given in Table 1) from row 1 to row 3. Row 4 is for a TD adult. (D) Hand positional trajectories during one cycle for each subject defined in (C). (E) Example of velocity profiles along the three orthogonal directions (grey) with their corresponding speed profiles (yellow) during a motion cycle. Highlighted points include the target touch (black dot) and the local speed maxima (s-Peaks, green dots). Notice that the local speed fluctuations, due to the desynchronization along the three velocity directions, do not have a smooth bell shape . Please watch the subjects’ hand motion avatar movie in the Supplementary Material.