Dysgenesis of the corpus callosum and manual preference

Abstract

Introduction: Dysgenesis of the corpus callosum (CCD) is a neurodevelopmental disorder characterized by the total or partial absence or hypoplasia of the corpus callosum (CC), the structure responsible for connecting both cerebral hemispheres.
CCD is associated with cognitive, social, visual, auditory, motor, somatosensory and language deficits. Considering that the CC seems to play an important role in the establishment of cerebral asymmetries, DCC patients are expected to have an indeterminate handedness than healthy individuals. In literature, there is no consensus on this issue. Objective: This study aimed at investigating the influence of CCD on manual preference. Methods: An observational study was carried out and Nine participants were recruited from the Instituto D’Or de Pesquisa e Ensino (Rio de Janeiro, Brazil). The Edinburgh Handedness Inventory was used to assess manual preference. The inventory has 10 items: writing, drawing, throwing, scissors, toothbrush, knife, spoom, broom, match and open a box. The laterality quotient (LQ) was applied as follows: LQ = [(R-L) / (R+L) X 100], ranging from -100 (strong left-handedness) to +100 (strong right-handedness). The Research Electronic Data Capture (REDcap) program was used to store all data collected. The statistical analysis involves data description by means of number (%) of occurrences or minimum and maximum values. Results:
Regarding the clinical characteristics of the sample, two types of CCD were identified: Total Agenesis (N = 5, 62.5%) and CC Hypoplasia (N = 3, 37.5%). Furthermore, the results showed that the type of CCD was isolated (Total agenesis: N = 3, 37.5%;
Hypoplasia: N = 2, 22.2%) or associated with other nervous system conditions (Total agenesis: N = 2, 22.2%; Hypoplasia: N = 1, 11.1%). For manual preference, all subjects achieved the maximum score of the assessment instrument (strong left-handedness:
N = 3, 37.5%; strong right-handedness: N = 5, 62.5%). Discussion: These results indicate that patients have a strong manual preference, regardless of the type CCD and associations with other nervous system conditions. Conclusion: These findings
can advance knowledge in the clinical condition of CCD and, consequently, influence the treatment and further research.