Kinematic Features of Handwriting Speed: A Comparative Study of Autistic and Non‐Autistic Youth

ABSTRACT Handwriting has received limited attention in Autism Spectrum Disorder (ASD), making systematic investigation crucial. Digital assessments enable deeper analysis of handwriting characteristics and challenges in autistic children and adolescents. This study examined kinematic predictors of handwriting speed in autistic individuals without intellectual disability compared to non‐autistic peers. Two hundred and four participants (White ethnicity, 8–17 years, autistic = 68 [54 M], M age = 12.08 (2.42); non‐autistic = 136 [96 M], M age = 11.97 (2.00), matched for age, IQ, handedness, and sex, completed a tablet‐based sentence‐copying task under maximum accuracy (MA) and speed (MS) conditions. Completion time and kinematic measures (path length, pressure, pen angle, and writing/total time ratio) were recorded. Autistic participants were slower than non‐autistic peers in both conditions ( p s ≤ 0.006, d s ≥ 0.47), with distinct kinematic profiles. In MA (pseudo R 2 = 0.41, p = 0.017), shorter completion time (CT) was linked to greater writing‐time proportion for all participants ( B = −0.09, p = 0.012), with higher pressure being associated to longer CT only in autism ( B = −0.157, p = 0.021). In MS (pseudo R 2 = 0.40, p = 0.05), shorter CT related to larger handwriting (i.e., longer path length) in autism ( B = 0.20, p < 0.001) and to greater writing‐time proportion in the non‐autistic group ( B = −0.30, p < 0.001). Findings underscore the importance of handwriting in functional assessment and support the need for tailored educational accommodations for autistic students.