RESUMEN
Introduction: Fetal Alcohol Spectrum Disorders (FASD) are characterized by a variety of multiple cognitive and behavioral impairments, with intellectual, attentional, and executive impairments being the most commonly reported. In populations with multiple neurodevelopmental disorders, the Full Scale Intelligence Quotient (FSIQ) may not be a proper measure of intellectual abilities, rarely interpreted in FASD clinical practice because the heterogeneity of the cognitive profile is deemed too strong. We propose a quantitative characterization of this heterogeneity, of the strengths and weaknesses profile, and a differential analysis between global cognitive (FSIQ) and elementary reasoning abilities in a large retrospective monocentric FASD sample. Methods: Using clinical and cognitive data (Wechsler Intelligence Scale for Children) from 107 children with FASD, we characterized subject heterogeneity (variance and scatter of scaled/composite scores), searched for strengths and weaknesses, and specified intellectual functioning in terms of FSIQ and elementary reasoning (General Abilities Index, Highest Reasoning Scaled Score), in comparison with standardization norms and a Monte-Carlo-simulated sample from normalization data. Results: Performance of children with FASD was lower on all subtests, with a significant weakness in working memory and processing speed. We found no increase in the variance and scatter of the scores, but a discordance between the assessment of global cognitive functioning (28% borderline, 23% deficient) and that of global and elementary reasoning abilities (23-9% borderline, 15-14% deficient). Conclusion: Our results question the notion of WISC profile heterogeneity in FASD and point to working memory and processing speed over-impairment, with global repercussions but most often preserved elementary reasoning abilities.
RESUMEN
AIM: To identify easily accessible neuroanatomical abnormalities useful for diagnosing fetal alcohol spectrum disorders (FASD) in fetal alcohol syndrome (FAS) but more importantly for the probabilistic diagnosis of non-syndromic forms (NS-FASD). METHOD: We retrospectively collected monocentric data from 52 individuals with FAS, 37 with NS-FASD, and 94 paired typically developing individuals (6-20 years, 99 males, 84 females). On brain T1-weighted magnetic resonance imaging, we measured brain size, corpus callosum length and thicknesses, vermis height, then evaluated vermis foliation (Likert scale). For each parameter, we established variations with age and brain size in comparison individuals (growth and scaling charts), then identified participants with abnormal measurements (<10th centile). RESULTS: According to growth charts, there was an excess of FAS with abnormally small brain, isthmus, splenium, and vermis. According to scaling charts, this excess remained only for isthmus thickness and vermis height. The vermis foliation was pathological in 18% of those with FASD but in no comparison individual. Overall, 39% of those with FAS, 27% with NS-FASD, but only 2% of comparison individuals presented with two FAS-recurrent abnormalities, and 19% of those with FAS had all three. Considering the number of anomalies, there was a higher likelihood of a causal link with alcohol in 14% of those with NS-FASD. INTERPRETATION: Our results suggest that adding an explicit composite neuroanatomical-radiological criterion for FASD diagnosis may improve its specificity, especially in NS-FASD. WHAT THIS PAPER ADDS: Neuroanatomical anomalies independent of microcephaly can be measured with clinical-imaging tools. Small-for-age brain, small-for-brain-size callosal isthmus or vermian height, and disrupted vermis foliation are fetal alcohol syndrome (FAS)-recurrent anomalies. Associations of these anomalies are frequent in fetal alcohol spectrum disorder (FASD) even without FAS, while exceptional in typically developing individuals. These associations support higher likelihood of causal link with alcohol in some individuals with non-syndromic FASD. A new explicit and composite neuroanatomical-radiological criterion can improve the specificity of FASD diagnosis.
