Compromised interhemispheric transfer of information partially mediates cognitive function deficits in adolescents with fetal alcohol syndrome

Abstract

Background: Prenatal alcohol exposure (PAE) has been associated with compromised interhemispheric transfer of tactile stimuli in childhood and structural changes to the corpus callosum (CC). In this study, we used a finger localization task (FLT) to investigate whether interhemispheric transfer deficits persist in adolescence; whether effects of PAE on perceptual reasoning, working memory, and executive function are mediated by deficits in interhemispheric transfer of information; and whether CC size in childhood predicts FLT performance in adolescence.Methods: Participants, aged 16 to 17 years, were from the Cape Town Longitudinal Cohort, whose mothers were recruited during pregnancy and interviewed regarding their alcohol use using the timeline follow-back method. Diagnoses of fetal alcohol syndrome (FAS) and partial FAS (PFAS) were determined by two expert dysmorphologists; nonsyndromal exposed children were designated as heavily exposed (HE); those born to abstainers or light drinkers, as controls. The FLT was administered to 74 participants (12 FAS, 16 PFAS, 14 HE and 32 controls). CC size at age 9 to 12 years was available for 35 participants (7 FAS, 13 PFAS, 5 HE and 10 control).Results: Although the degree of PAE was similar in the FAS, PFAS, and HE groups, only the adolescents with FAS showed more transfer-related errors than controls in conditions in which one finger was stimulated. FLT performance mediated the effects of FAS on perceptual reasoning and executive function. In the subsample for which neuroimaging data from childhood were available, there was an association among adolescents with PAE of smaller CC volumes with more transfer-related errors on the one-finger/hand hidden condition, suggesting that CC damage previously seen in childhood continues to impact function through adolescence. Conclusions:This study provides evidence of compromised interhemispheric transfer of information in adolescents with FAS, while those with PFAS or heavy exposed nonsyndromal individuals are apparently spared. It is the first to show that PAE effects

Fetal alcohol spectrum disorders

“…Moreover, studies using diffusion tensor imaging reveal reduced integrity of large white matter tracts, including in the corpus callosum, cerebellar peduncles, cingulum and longitudinal fasciculi 101 . Hypoplasia of the corpus callosum in children with FASD is associated with impaired interhemispheric transfer of information 102 .…”

“…Typical brain development is associated with a large increase in cortical grey matter during early childhood followed by loss of cortical grey matter during late childhood and adolescence via synaptic pruning, a process that reflects cortical plasticity 70 . By contrast, children with FASD show region-specific loss of grey matter and decreased gyrification from early childhood through (2023) 9:11 6 0123456789();: Primer adolescence 70,99,102 . This change may partly explain contradictory findings of increased or decreased grey matter volume in various studies, which sampled different brain regions during distinct developmental periods or evaluated populations with different levels of PAE 69 .…”

Editorial: Perspectives and recent advances in Fetal Alcohol Spectrum Disorders research

“…For example, even when adjusting for confounding factors such as age, sex and brain size, the postcentral callosal parcel and its corresponding cortical region appeared to be persistently affected. Given the importance of the CC in interhemispheric communication in the brain, it is perhaps not surprising that the reduced size of these CC parcels may provide a clinically relevant neuroanatomical marker for FASD diagnosis and at least a partial explanation for the cognitive and motor deficits in individuals with FASD (Biffen et al, 2022). Additionally, Gimbel et al used a combination of MRI tractography with a novel diffusion-weighted Neurite Orientation Dispersion and Density Imaging (NODDI) model to characterize the impact of PAE on longitudinal trajectories of developmental white matter microstructure.…”

Prenatal Alcohol Exposure and Metabolic Disorders in Pediatrics: The Role of the Oxidative Stress—A Review of the Literature

“…This study also found other important alterations: hydrocephalus, corpus callosum defects, holoprosencephaly, lissencephaly, minor subarachnoid heterotopias, and prenatal ischemic lesions [ 29 ]. Other studies revealed an overall reduction in brain volume, especially in the cerebellum, cerebrum, basal ganglia, hippocampus, caudate putamen, and thalamus [ 30 , 31 , 32 , 33 , 34 , 35 ]. Furthermore, studies using diffusion tensor imaging showed reduced integrity of large white matter tracts, including the hypoplastic corpus callosum, posteriorly displaced or absent.…”