Enhanced ERPs to visual stimuli in unaffected male siblings of ASD children

Autism spectrum disorders are characterized by deficits in social and communication abilities. While unaffected relatives lack severe deficits, milder impairments have been reported in some first-degree relatives. The present study sought to verify whether mild deficits in face perception are evident among the unaffected younger siblings of children with ASD. Children between 6-9 years of age completed a face-recognition task and a passive viewing ERP task with face and house stimuli. Sixteen children were typically developing with no family history of ASD, and 17 were unaffected children with an older sibling with ASD. Findings indicate that, while unaffected siblings are comparable to controls in their face-recognition abilities, unaffected male siblings in particular show relatively enhanced P100 and P100-N170 peak-to-peak amplitude responses to faces and houses. Enhanced ERPs among unaffected male siblings is discussed in relation to potential differences in neural network recruitment during visual and face processing.