Global/local integration and corpus callosum: Anatomical and behavioural study of case of Allgrove syndrome (triple-A syndrome)

Abstract

Visuospatial perception is a complex ability, with various aspects. We are continuously integrating different information, like when our brain processes visual information from left and right hemisphere, in order to form a single and unitary image. The processing of visuospatial information, and more specifically its global/local aspect, has led to many studies, indicating the active involvement of the corpus callosum. Objective To study the influence of an alteration of the corpus callosum on the integration of global/local information. Methods C.M. presents an Allgrove syndrome [1] , likely a pathology of white matter fibres. This patient, with a singular neuropsychological profile, is partially impaired in global and local information integration and shows a corpus callosum alteration. This research, a case-study with a group of 6 matched control subjects, relied on a two-level approach, anatomical (MRI-DTI) and behavioural, using a hierarchical letter paradigme [2] . Results Despite all the precautions needed regarding the interpretation of our results, some specificities are emphasized: at an anatomical level, we note, for C.M., a microscopic alteration of her corpus callosum; the results from our behavioural protocol show, for C.M., a higher precedence effect, a greater sensibility to interference and a facilitation effect more important. Discussion These different results, never reported before in this pathology, indicates, for C.M., an impairment in global/local integration associated with a corpus callosum alteration. This alteration, probably part of a more global degenerative process linked to her pathology, shows the relevance of an extended neuropsychological assessment coupled to a DTI study, in order to better understand impairments generally appearing in neuropsychological rehabilitation.