Brain Activations in Siblings of Autistic Children

Language impairments have been found in apparently typically developing children whose siblings have autism spectrum disorder (ASD), especially in multiplex families (JW Psychiatry Nov 1 2010). This finding raises the question of whether apparently unaffected siblings have different brain activations from typically developing children without autistic siblings. To examine this issue, researchers performed functional magnetic resonance imaging on 25 children with ASD, 20 unaffected children whose siblings had autism (UAS group), and 17 typically developing children (age range, 4–18 years) while the children watched point-light animations of human motion and scrambled displays. Eligible UAS and typically developing children met strict exclusion criteria for any developmental delay (e.g., special school placement) or family history of a broader autism spectrum, except for the affected siblings in the UAS group. The ASD group met comprehensive research and clinical criteria.

When watching human motion versus scrambled displays, both ASD and UAS groups had less activation than the typically developing group in multiple regions (e.g., left dorsolateral prefrontal cortex, right inferior temporal gyrus, bilateral fusiform gyri). The UAS group, compared with the other two groups, had increased activation in additional areas.