Handwriting speed in left-handed children with right-sided neonatal brachial plexus palsy

To investigate whether left-handed children with right-sided neonatal brachial plexus palsy (NBPP) exhibited differences in handwriting speed compared to typically developing left-handed children. If differences were identified, potential contributing factors were explored.

In this observational study with comparison groups, 74 left-handed children aged 6 to 21 years, all with right-handed parents, were included: 32 with right-sided NBPP (16 females) and 42 typically developing controls (22 females). Handwriting speed was measured using the 'Vlaamse schrijfsnelheidstest' (Flemish Writing Speed Test) and compared to age- and sex-normed centile scores. Functional assessments included grip strength (E-LINK), fine motor proficiency (Bruininks-Oseretsky Test of Motor Proficiency, Second Edition), and manual dexterity (Purdue Pegboard Test [PPT]). Cognitive ability was assessed via a derived IQ (DIQ). Group comparisons were conducted using general linear models adjusted for age. In the group with NBPP, linear and multiple regression analyses examined associations with handwriting speed.

Children with NBPP showed significantly slower handwriting speed than typically developing controls (mean difference = 25.04 [6.20]; p < 0.001). The score on the PPT performed with the left hand (β = 4.787, 95% confidence interval [CI] = 0.332-9.242; p = 0.036) and the DIQ score (β = 0.730, 95% CI = 0.104-1.355; p = 0.024) were identified as determinants of handwriting speed in the group with NBPP.

Despite writing with the unaffected hand, children with right-sided NBPP demonstrated significantly reduced handwriting speed, best predicted by the manual dexterity of the writing hand and cognitive capacity.