Why adult neuropsychological models don't work for neurodevelopmental syndromes

A cross-syndrome comparison between infants with Williams syndrome and those with Down syndrome seems to result in a neat cognitive double dissociation, like in adult neuropsychological patients. However, a more dynamic developmental analysis shows the data to be far more complex and the result of cascading cross-domain effects over ontogenetic time. The atypical brain of children with genetic disorders is not a normal brain with parts intact and parts impaired but a brain that develops differently throughout embryogenesis and ontogenesis. Thus, cognitive deficits may be due to multiple domain-relevant interacting factors early on that result in domain-specificity in the