Early electrophysiological differentiation of faces and face-like stimuli in pediatric traumatic brain injury

Pediatric traumatic brain injury (PTBI) may disrupt neurodevelopmental systems supporting social perception, including the rapid processing of facial information. Although face perception is essential for social interaction, little is known about how children with TBI process ambiguous face-like configurations such as face pareidolia. This study examined early electrophysiological responses to real face and face-like stimuli in PTBI and typically developing peers. We initially included 44 children, including 22 children with TBI and 22 healthy children. After EEG preprocessing and artifact rejection, the final sample consisted of 35 children (13 PTBI, 22 healthy). Participants completed an EEG task including neutral real face images, face-like images, and scrambled non-target stimuli. Event-related potentials were analyzed for P100, N170, and vertex positive potential (VPP) components. Mean amplitudes and latencies were compared between groups and stimulus conditions. The clearest group-related effect was observed for P100 latency, which showed a significant Group × Category × Stimulus Format interaction. Healthy children showed shorter P100 latencies for face and face-like images than for their scrambled counterparts, whereas children with PTBI showed this difference only for faces. P100 latency to face-like images was also longer in the PTBI group than in healthy children. N170 and VPP showed condition-related modulation without significant group effects. These findings suggest that PTBI may be associated with altered early visual-perceptual timing that is most evident during the processing of ambiguous face-like images, rather than with a generalized slowing of P100 responses. By contrast, later face-sensitive N170 and VPP responses remained observable in both groups and showed broadly comparable condition-related modulation. Face-like stimuli may therefore provide a useful probe for examining subtle alterations in early social-perceptual processing after pediatric brain injury, although larger studies integrating behavioural performance and control conditions matched for target status and response requirements are needed.