%0 Journal Article
%T Developmental Risk: Evidence from Large Nonright-Handed Samples
%A Filippos Vlachos
%A Francois Gaillard
%A Kiriazis Vaitsis
%A Argiris Karapetsas
%J Child Development Research
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/169509
%X The aim of the present study is twofold. First, we tested the view that individuals who do not develop a typically strong behavioral laterality are distributed differentially among the two genders across age. Second, we examined whether left handedness and mixed handedness are associated with an elevated risk of some developmental or cognitive deficits. A special recruitment procedure provided norms of the Rey-Osterrieth Complex Figure (ROCF) copy from large samples of left-handed ( ) and mixed-handed ( ) compared to right-handed ( ) schoolchildren and adults ( ). This graphic task was considered as reflective of the growth of visual-spatial skills and impairment at copying as a developmental risk. Subjects¡¯ hand preference was assessed by the Edinburgh Handedness Inventory. Data analysis indicated that (1) the trend towards consistent right handedness is sex related. Girls are clearly ahead of boys in this lateralization process, and boys are overrepresented in mixed-handed subjects. The greater prevalence of mixed-handed boys compared to girls decreases with age. (2) Performance on drawing the ROCF varies according to age and handedness groups. Mixed-handed subjects scored worse in all age groups. The results are discussed in relation to the hormonal-developmental, neuropathological, and learning theories of lateralization. 1. Introduction Handedness is a significant feature of ontogenetic development. Its consistency and stability provide evidence for brain hemispheric specialization and can be used as an indicator of developmental stages. Lateralization is both cause and consequence of having a brain with two cerebral hemispheres specialized to perform different tasks and work together in order to improve many motor and cognitive tasks. At the first glance, no hand lateralization is observed in young children who have not yet learned to use innate biological asymmetry. However, careful observation of motor behavior in infants already reveals the human specific trend towards dextrality [1, 2]. The study of handedness has been of interest for many years because subtle cognitive and behavioral differences have been demonstrated in relation to various handedness measures [3]. Gender differences in handedness are widely reported. A recent meta-analysis of 144 studies [4] demonstrated that the gender difference in handedness is both significant and robust, indicating that the overall best estimate, albeit not universal, for the male to female odds ratio was 1.23. The purpose of this study is to investigate further the effects of handedness, as a proxy for
%U http://www.hindawi.com/journals/cdr/2013/169509/