Atypical handedness and its clinicoradiological predictors in children with focal epilepsy

Purpose: Handedness has been strongly linked to cerebral lateralisation for language. Literature on atypical handedness and its association with focal epilepsy starting from early childhood is limited and needs exploration.

Methods: In this cross-sectional study, the prevalence of atypical handedness (left-handedness and ambidexterity) was compared between children with left/right focal epilepsy aged 3-14 years without any definite motor deficit, between August 2019 and July 2020. Cognition, behavioral abnormalities, working memory, and executive function were also compared between the groups. Various clinical, demographic, and radiological variables were explored to determine any association with the presence of atypical handedness.

Results: Of the total 79 children (45 boys, 57 % mean age 6.5 ± 2.3 years, 41-left focal epilepsy) with focal epilepsy enrolled for the study, the prevalence of atypical handedness was found to be 12.6 % (10/79). No association between atypical handedness and clinical/demographic variables including left/right focal epilepsy was observed in the study excepting neuroimaging abnormality (p = 0.0008 and 0.02 respectively). This increased prevalence of neuroimaging abnormality in patients with atypical handedness was significant in multivariate analysis, after adjusting for confounding variables. Similarly, intelligence quotient (full scale, verbal and non-verbal, as well as sub-domains), behavioral abnormality (internalizing and externalizing score on CBCL), scores on picture memory, simple copying, and missing scan task were not significantly different between children with left and right focal epilepsy or children with atypical handedness and right-handedness.

Conclusion: Atypical handedness is not more frequent in children with left focal epilepsy as compared to right focal epilepsy.