Table 4.
Main results of included studies.
| Study | Main Results |
|---|---|
| Adi-Japha et al., 2007 [28] | ADHD children made more errors regarding letter insertions, substitutions, transpositions and omissions, produced confusedly shaped letters and replaced the end-of-word letter with its simpler and more common middle-of-the-word version; Speed of handwriting did not differ between groups; No difference considering spatial features; ADHD children displayed poor time utilization, and produced inconsistent and disproportionate writing accompanied by high levels of pressure and multiple corrections; Handwriting problems were associated with attentional problems and reflected an impairment of the graphemic buffer and of kinematic motor production. |
| Åsberg Johnels et al., 2014 [35] | ADHD children obtained lower scores on parental ratings of handwriting. |
| Borella et al., 2011 [36] | ADHD children produced fewer writing sequences than the control groups; ADHD children showed greater IIV than control groups. |
| Capodieci et al., 2018 [37] | No difference between groups considering handwriting speed; In conditions without WM interference, ADHD children produced about 10% fewer graphemes than control groups; In the spatial condition, the difference between groups was slightly greater (−20%), though not statistically significant; In the verbal condition, ADHD children wrote significantly more slowly (−38%) than control groups; The handwriting of ADHD children was generally less legible than the control groups, especially in the verbal and spatial conditions; ADHD group had a higher IIV in the verbal condition than the control groups; High IIV influenced the reduced speed in the case of the verbal condition for both groups. |
| Capodieci et al., 2019 [38] | ADHD children made more spelling mistakes than control groups in all conditions; ADHD children who better coped with a concurrent verbal WM load had better spelling performance; ADHD children obtained lower scores for handwriting quality than control groups; No difference between groups in terms of writing speed. |
| Dirlikov et al., 2017 [39] | ADHD children showed worse letter-form scores compared to control groups across conditions (copy, trace and fast trace); No difference in letter-spacing errors between groups; ADHD children made fewer speed inflections across conditions compared to control groups; Both groups showed a significant correlation between letter form and WM performance in the copy condition only. |
| Farhangnia et al., 2020 [40] | For the copy task, ADHD children had lower global legibility scores compared to control groups; No significant difference between the two groups in terms of space, alignment, size of letters and slant components of writing, as well as for speed of writing; For the dictation task, ADHD children had lower legibility scores compared to control groups, while there was no difference between the groups in terms of space, alignment and slant components and size of letters. |
| Flapper et al., 2006 [41] | ADHD+DCD children showed lower scores for quality of handwriting, but there was no difference in speed of handwriting between groups; When on-state, of the 11 children with ADHD+DCD who could be assessed a second time, 6 improved their handwriting quality on the BHK, 4 did not improve and one child deteriorated When assessed off-state, ADHD+DCD children did not improve their handwriting speed. |
| Frings et al., 2010 [42] | Mean letter height did not differ between groups; Letter height increased during repeated writing of the same sentence in the ADHD group only. |
| Hung and Chang, 2022 [30] | ADHD children had poorer writing performance than the control groups for both character dictation and character copying; ADHD children wrote less fluently and correctly compared to the control groups; Inattention was the stronger predictor of character dictation in ADHD children; Manual dexterity was significantly correlated with character copying in the ADHD group. |
| Johnson et al., 2013 [43] | ADHD children made more total handwriting errors than control groups (i.e., correction and formation errors); No difference between groups in average height or width; No difference in the coefficient of variability of phrase height and width; No difference in average word spacing; ADHD children included additional strokes more often than control groups; There was a trend towards significant difference between the groups in terms of speed of handwriting, yet it was not significant; In the ADHD group, more corrections were associated with slower handwriting speed and maturational processes contributed to handwriting performance. |
| Langmaid et al., 2014 [44] | ADHD children were more variable in terms of stroke length and showed inconsistent stroke height when compared to the control groups; No difference in the other kinematic variables; Symptom severity scores were correlated to variability of stroke height (vertical size); Higher scores on the inattentive and total ADHD subtests were significantly correlated with more variable writing size; Stroke duration was significantly related to hyperactive behavior, such that a more hyperactive child had strokes of shorter duration (faster writing); Ballisticity was significantly associated with hyperactive behavior (more ballistic movement when symptoms of hyperactivity increased). |
| Langmaid et al., 2016 [45] | Despite both groups being significantly more inaccurate on the 40 mm task compared to the 10 mm, ADHD children were unable to maintain the size of their cursive letter at the 40 mm size, contrary to control groups; Groups were comparable on the 10 mm task; ADHD children had more ballistic movements on both tasks; Only pen pressure was positively correlated with inattention scores during the 10 mm task. |
| Laniel et al., 2020 [46] | ADHD children showed poorer performance on quality scores (BHK), lower writing speed and higher writing size than control groups; On the Pen-stroke test, ADHD children displayed poorer motor planning and execution and greater variability in motor control than the control groups; In the ADHD group only, motor planning on the handwriting task correlated with speed of handwriting on the BHK (the faster a child wrote, the shorter the motor production delay); ADHD children showed greater amplitude of movement on the Pen-stroke test, which was associated with faster motor speed; No relationship between inattention and hyperactivity symptoms with motor control skills was measured for the Pen-stroke test. |
| Lofty et al., 2011 [47] | A total of 10% of ADHD children had normal handwriting with no disability, 40% had excellent handwriting with a minimum of disability and 50% of ADHD children showed mild to moderate handwriting disability; ADHD children had poorer performance in respecting lines, spacing between words, letter direction, spelling a sentence and punctuation (item of the DDS); No difference between males and females in the ADHD group only on DDS scores; No correlation between DDS scores and age in the ADHD group only. |
| Okuda et al., 2011 [48] | ADHD children manifested poorer performance regarding flowing lines, descending lines, retouched letters, curvatures and angles of “m”, “n” and “u” letters; They produced more collisions and adherences, sudden movements, irregular sizes and incorrect forms of letters. |
| Rosenblum et al., 2008 [32] | Poorer performance of ADHD children on most handwriting process and product measures when off-state versus on-state; When off-medication, ADHD children showed more total time and more in-air time than when on-medication and compared to control groups; No difference in handwriting speed when on-state and off-state were compared, while on-state and off-state ADHD children wrote faster than control groups; No difference in product handwriting between on-state and off-state, but ADHD children, regardless of on- or off-state, differed in comparison to control groups. |
| Shen et al., 2012 [27] | ADHD children scored lower on THSPC and on BSRWT; Despite the speed of writing per se being no different between the two groups, ADHD children spent more on-paper time on the copy task and, hence, needed more time to finish a copy task. |
| Tucha and Lange, 2001 [49] | When off-state, the quality of handwriting specimens of hyperactive boys was poorer than on-state but more fluent; When off-state, ADHD children did not differ from control groups in handwriting movements; Hyperactive behavior improvement through MPH was associated with increased legibility and greater accuracy of handwriting. |
| Tucha and Lange, 2004 [31] | When on-state, ADHD children displayed significantly more inversions in the direction of their velocity profiles than control groups; When off-state, there was no difference between the groups; The medication resulted in increased dysfluency during handwriting. |
| Yoshimasu et al., 2011 [50] | ADHD girls tended to have a single specific writing difficulty, whereas ADHD boys were more likely to have multiple writing difficulties (e.g., legibility + poor paragraph organization). |
Abbreviations: ADHD: Attention Deficit Hyperactivity Disorder; BHK: Concise Assessment Scale for Children's Handwriting; BRWT: Basic Reading and Writing Comprehensive Test; DCD: Developmental Coordination Disorder; DDS: Dysgraphia Disability Scale; IIV: Intra-Individual Variability; MPH Methylphenidate; THPS: Tseng Handwriting Problem Checklist; WM: Working Memory.