Reduced P300 amplitude in children and adolescents with autism is associated with slowed processing speed, executive difficulties, and social-communication problems
Authors: Lassen Jonathan , Oranje Bob , Vestergaard Martin , Foldager Malene , Kjær Troels W , Aggernæs Bodil , Arnfred Sidse 
Published: August 2024

Compared to their neurotypically developing peers, children and adolescents with autism spectrum disorders tend to have attenuated neural responses in the parietal lobe when attending sensory input, as reflected by a reduced P3b amplitude measured with electroencephalography. However, it is unknown whether a reduced P3b amplitude in autistic children and adolescents is associated with their autism traits, daily functioning, and/or cognitive functions. To address these questions, we assessed 57 children with autism aged 7–14 years and 57 typically developing children with electroencephalography using a binaural auditory oddball paradigm. Participants further underwent cognitive assessment, and parents reported on autistic traits, executive functioning, and adaptive functioning. As expected, children with autism had lower P3b amplitude compared to controls. Across all participants, a lower P3b amplitude was associated with more parent-reported social-communication problems and impairments in daily executive functioning. Children with autism had reduced visual processing speed, which was coupled to a lower P3b amplitude. In conclusion, we found attenuated P3b amplitude in children with autism performing an auditory selective attention task, which generalized to impaired cross-modal processing of visual input and an underlying impairment in allocating attentional resources critical for social and executive functioning. Lay abstract Selective attention to auditory input is reflected in the brain by an electric amplitude called the P3b amplitude, which is measured using electroencephalography. Previous research has shown that children and adolescents with autism have an attenuated P3b amplitude when they have to attend specific sounds while ignoring other sounds. However, it is unknown whether a reduced P3b amplitude in autistic children and adolescents is associated with their autism features, daily functioning and/or cognitive functions. This study aimed to examine these questions. Therefore, we assessed selective attention to auditory input in 57 children with autism aged 7–14 years and 57 neurotypically developing controls while measuring their brain activity with electroencephalography. Participants further underwent cognitive assessment, and parents reported on autistic traits and daily functioning. As expected, children with autism had lower P3b amplitude compared to their neurotypical peers. Importantly, an attenuated P3b amplitude was associated with more parent-reported social-communication problems and difficulties with daily functioning. Children with autism further had reduced processing speed of visual input, which also was coupled to a lower P3b amplitude. In conclusion, we found attenuated P3b amplitude in children with autism performing an auditory selective attention task, which was related to difficulties with processing visual input and allocating attentional resources critical for social and daily functioning. The results suggest that autistic children are more vulnerable to being disturbed when the environment is filled with conflicting sensory input.