, Volume 43, Issue 8, pp 1758-1772,
Open Access This content is freely available online to anyone, anywhere at any time.

Psychological Correlates of Handedness and Corpus Callosum Asymmetry in Autism: The left Hemisphere Dysfunction Theory Revisited

Abstract

Rightward cerebral lateralization has been suggested to be involved in the neuropathology of autism spectrum conditions. We investigated functional and neuroanatomical asymmetry, in terms of handedness and corpus callosum measurements in male adolescents with autism, their unaffected siblings and controls, and their associations with executive dysfunction and symptom severity. Adolescents with autism did not differ from controls in functional asymmetry, but neuroanatomically showed the expected pattern of stronger rightward lateralization in the posterior and anterior midbody based on their hand-preference. Measures of symptom severity were related to rightward asymmetry in three subregions (splenium, posterior midbody and rostral body). We found the opposite pattern for the isthmus and rostrum with better cognitive and less severe clinical scores associated with rightward lateralization.

In this paper we have adopted the terminology ASC in preference to “Autism Spectrum Disorders (ASD)”, as we consider this terminology to be less burdensome to individuals and families affected. To avoid confusion, however, we would point out that we are using ASC to refer to the same conditions as ASD.