Clinicians should be aware of the fundamental difference between the 2 disorders and make good use of handwriting assessment as a reference to deliver effective therapies and trainings.

Background/aim: Handwriting difficulties can be detrimental to students' performance in school tests and even in public examinations. It is crucial for school-based occupational therapists to identify students with handwriting difficulties and support them with appropriate adaptive strategies. The purpose of this study is to validate a computerised assessmentthe Computerised Handwriting Speed Test System (CHSTS) of both Chinese and English handwriting for Chinese secondary students and provide an objective reference for extra time allowance in paper-based examinations. Methods: The internal consistency, test-retest reliability, convergent and discriminant validity of CHSTS were examined using the data from 512 typically developing students and 64 students with special educational needs (SEN) in Hong Kong mainstream secondary schools. Results: Handwriting performance of senior students was better than that of junior students. High internal consistency was shown by over 0.80 Cronbach's a in all measurement items and over 0.90 item-total correlations in temporal domain items. Intra-class correlation indicated good to excellent test-retest reliability of CHSTS (all P < 0.0001). Principal Component Analysis revealed that four components in CHSTS accounted for over 80% of the variance. Handwriting performance was positively associated with manual coordination, automaticity and oculomotor control (all P < 0.05) in linear regression analyses. Students with SEN could be effectively differentiated from typically developing students (over 75% sensitivity and specificity) based on the CHSTS items. Conclusion: Validation of CHSTS is the groundwork for identifying students with handwriting difficulties and providing adaptive strategies including fair special examination arrangements for these students.

Impaired sensorimotor control, as a common feature of autism spectrum disorder (ASD), could be a driving factor to handwriting problems. This study examined the Chinese and English handwriting and sensorimotor skills of 15 ASD and 174 typically developing Chinese adolescents. Participants with ASD had lower writing speed and poor manual dexterity (MD) than the typically developing participants. MD was a significant mediator between ASD and handwriting speed. Ground time and airtime represent the length of time when the pen touches the paper and is held in air, respectively. Participants with ASD who had better performance in MD showed shorter ground time in Chinese handwriting and shorter airtime in English handwriting. Training for adolescents with ASD on their MD may improve their handwriting performance.