A Neuropsychological Profile for Agenesis of the Corpus Callosum? Cognitive, Academic, Executive, Social, and Behavioral Functioning in School-Age Children

Abstract

Re: A neuropsychological profile for agenesis of the corpus callosum? Cognitive, academic, executive, social and behavioral functioning in school-age children JINS#-17- RR-108Thank you for accepting our manuscript for publication with minor revisions.We would like to thank again the reviewers for their positive and constructive comments.Below we provide responses to each reviewer comment. The associated amendments in the manuscript are highlighted in red (and the amendments related to the previous revisions are highlighted in yellow). Best wishes, Dr Vanessa Siffredi and Dr Megan Spencer-Smith Reviewer 1Comment: The authors have been very responsive to feedback provided by the Reviewers and Action Editor. I have no further suggestions for revision.Response: Thank you. Reviewer 2Comment: You have been very diligent in responding to the questions I raised in my earlier review-thank you! Response: Thank you.Comment: My only lingering concern is whether this report will be really useful, and to whom. The heterogeneity of callosal agenesis both behaviorally and genetically makes it difficult to use the data with reference to particular individuals, although suppose the study can at least indicate the likely range of presentation. You suggest that heterogeneity is a positive feature, although even the heterogeneity is limited given the source of the data. Even so, this study is perhaps a useful contrast with the Quebec studies, where there was relative homogeneity, especially genetically.Response: This report provides crucial information for clinicians (neonatologists, neurologists, and neuropsychologists) Comment: From my perspective, the most useful observation was the even distribution of handedness, ignored in the first version and skipped over here. There is quite a lot of evidence that handedness is random in the absence of any congenital bias, and the data now seem to suggest that it is indeed random among those with agenesis of the corpus callosum. Could this mean that handedness itself depends on normal development of the corpus callosum? To me at least, this is something that does need further comment. (Raymond, Pontier, Dufour, Moller, 1996) 56% (e.g., Lábadi & Beke, 2017;Sauerwein & Lassonde, 1994;Chiarello, 1980) Response: In the general population, the percentage of left-handedness is around 10 to 13%

Structural neuroplastic responses preserve functional connectivity and neurobehavioural outcomes in children born without corpus callosum

“…This study used data from the "Paediatric Agenesis of the Corpus Callosum Project" (19), which examined neurobehavioural, neurological and neuroimaging outcomes in children with AgCC…”

“…Individuals with AgCC present with impairments of varying severity across a range of neurobehavioural domains (17,18) . General cognitive ability in individuals with AgCC who come to clinical attention is typically in the low average range (18,19), with difficulties in executive functions commonly observed, including deficits in cognitive control such as selective attention and inhibition, as well as cognitive flexibility (19)(20)(21). Learning and memory difficulties (22,23), cognitive processing speed (20,22), and difficulties in social and emotional cognition (24) may also be present.…”

Understanding Novel Metaphors: A Milestone in the Developmental Trajectory of Children with Agenesis of the Corpus Callosum?

“…The literature reports the finding that adolescents and adults with ACC perform poorly on tasks involving high-level linguistic usages such as idioms, proverbs, and humor [ 7 , 8 , 9 ]. A more limited number of studies has explored these aspects in children with ACC [ 10 ] within their neuropsychological profile, while, to our knowledge, no study has explored novel metaphor comprehension. Novel metaphors differ from conventional or “lexicalized” metaphors inasmuch as they are generated by a spontaneous creative act and, as such, their meaning is not encoded in the repertoire of already known metaphors.…”

A transcallosal fibre system between homotopic inferior frontal regions supports complex linguistic processing

“…In terms of language development, the CC plays an important role for facilitating language lateralization (Hinkley et al., ) as well the interplay between left and right inferior frontal areas for linguistic and paralinguistic aspects of speech processing as discussed above. Pathological changes in CC structure or development, such as congenital agenesis of the CC negatively affect speech and language abilities in later life (Adibpour, Dubois, Moutard, & Dehaene‐Lambertz, ; Siffredi et al., ). Given this importance of the CC as a structure for facilitating language development and speech, comparatively little in vivo studies on interhemispheric language‐related white matter pathways have been performed.…”