Objective To observe the electromyography characteristics of children's handwriting with attention deficit hyperactivity disorder(ADHD),and explore its electrophysiological mechanism,so as to provide an objective basis for developing non-pharmacological treatment for such children.Methods Between September 2021 and April 2022,29 ADHD children were recruited from an ordinary public primary school and the psychiatric clinic of a class-3 grade-A hospital in Beijing.Among them,25 were boys and 4 were girls,with an average age of 8.21±1.78 years.Meanwhile,23 male and 5 fe-male healthy counterparts were selected with the age gap no more than 6 months.The Delsys wireless surface EMG system was used to collect the electromyographic signals of the abductor pollicis breve,the first dorsal interosseous muscle,the flexor radial carpi motor and the extensor finger muscles dur-ing their writing tasks such as tracing trajectories,writing Arabic numerals 0-9,26 small and capital English letters,Chinese characters one to ten and"Yong".The percentage of the averaged electromyog-raphy(AEMG)of a muscle in the sum value of all measured muscles,and the coefficient of differ-ence were selected to evaluate the muscle contribution rate and the consistency of exertion,respective-ly.Moreover,the independent sample t-test was employed to compare the two different groups with the significance set at α=0.05.Results There was a significant difference in the muscle contribution of abductor pollicis breve and first dorsal interosseous muscles when writing Arabic numerals and that of abductor pollicis breve muscles when writing Chinese characters between ADHD children(27.29%,25.58%and 27.53%)and their healthy counterparts(42.87%,19.96%and 37.13%)(P<0.05).Most muscle differentiation coefficients of ADHD children were higher than 100%,with that of the domi-nant hand radial wrist flexor muscle reaching 270%in the trajectory tracing task.Conclusion Accord-ing to the characteristics of EMG signals,school-age ADHD children show an immature writing pat-tern,including poor stability of writing-related muscles,insufficient control of small finger muscle groups,poor control of hand coordination,and insufficient muscle inhibition of non-dominant hand.It is recommended to conduct the electromyoelectric assessment of handwriting movements in ADHD chil-dren,so as to carry out targeted intervention at an early stage.

ObjectiveTo investigate the developmental characteristics of gross motor skills and executive functions, and the correlation between them in school-age children with attention deficit hyperactivity disorder (ADHD). MethodsFrom November, 2020 to May, 2021, 90 children with ADHD were recruited from Peking University Sixth Hospital and Beijing Haidian Wanquan Primary School, and other 90 children with normal development from this primary school were recruited matched their age and gender. Gross motor skills were assessed with the Test of Gross Motor Development in Children, Third Edition (TGMD-3), and inhibitory control, working memory, and cognitive flexibility were assessed with Stroop Color Words Test (SCWT), Rey-Osterrich Complex Figure Test (ROCFT) and Trail Making Test (TMT), respectively. ResultsThe TGMD-3 score was significantly lower in children with ADHD than in normal children (t = -6.275, P < 0.001), while the test results of SCWT, ROCFT and TMT were worse (|t| ≥ 1.986, P ≤ 0.05). The TGMD-3 score of children with ADHD was negatively correlated with the word sense reaction time (r = -0.261), the number of word sense errors (r = -0.404) and the number of color errors (r = -0.326) (P < 0.05), positively correlated with the delayed structural memory scores (r = 0.228) (P < 0.05), and negatively correlated with the TMT-A reaction time (r = -0.255), the number of TMT-A errors (r = -0.329), TMT-B reaction time (r = -0.214) and the number of TMT-B errors (r = -0.474) (P < 0.05). Stratified linear regression analyses showed that the TGMD-3 score of children with ADHD was significant only in predicting test results for inhibitory control and cognitive flexibility (P < 0.05), with explanations of 8.7% and 22.5%, respectively. ConclusionDevelopments of both gross motor skills and executive function delay in children with ADHD, and there is a relation between them, especially the level of gross motor skills relating to the developments of inhibitory control and cognitive flexibility.

ObjectiveTo explore the characteristics of fine motor skills of school-age children with attention deficit hyperactivity disorder (ADHD) in different sexes. MethodsFrom April, 2021 to April, 2023, 66 ADHD children from grades one to four in Beijing Haidian Wanquan Primary School were screened by psychiatrists, and other 69 ADHD children were recruited from hospitals and patient groups of WeChat, accounting to 135 ADHD children. Meanwhile, a total of 135 typically developed (TD) children matched with sex and age (< 0.5 year) were recruited from the same primary school as controls. They were assessed with Movement Assessment Battery for Children (MABC-2) four subtests of manual dexterit. ResultsAfter controlling age, the subtest scores and the total score of fine motor of MABC-2 were less in ADHD boys and girls than in the TD boys and girls (P < 0.05). The main effect of sex was significant on the subtest scores and the total score of fine motor for ADHD children (F > 5.133, P < 0.05), and they were less in the boy than in the girls (P < 0.05). ConclusionThe development of fine motor delays in school-aged ADHD children, especially for the boys.