Face processing in infants at elevated likelihood for autism: A systematic review and meta-analysis

Face processing has been reported to be atypical in Autism Spectrum Condition (ASC). The latency of the N170 event-related potential component in response to faces has been reported to be slower in children and adults with ASC compared to age-matched controls. To explore whether atypical face processing is evident earlier in development, we focused on the developmental precursor of the N170: the N290/P400 complex. We conducted a systematic review and meta-analysis of studies examining infants aged 6–24 months at elevated likelihood (EL) versus average likelihood (AL) for ASC. Using a random-effects multi-level model, we investigated differences in N290, P400 and Nc latency and amplitude in response to face stimuli between EL and AL infants, and whether these differences were associated with ASC outcomes at age 3. Fourteen studies (405 EL, 323 AL) met the inclusion criteria. EL infants showed no significant differences in N290, P400 and Nc latency or amplitude compared to AL infants. However, EL infants who later received an ASC diagnosis showed slightly longer N290 latency (g=0.13, 95% CI [0.00, 0.26]) and smaller P400 amplitudes ( g =-0.23, 95% CI [-0.28,-0.19]). These findings show that subtle differences in face processing may already be present in EL infants who will develop ASC later in life, providing evidence of early atypical face processing in this group. • Meta-analysis and review of infant ERP studies on early face processing in infants at elevated (EL) vs average (AL) likelihood for ASC. • No overall differences between EL and AL groups in N290/P400/Nc latency or amplitude. • EL infants with later ASC diagnosis showed longer N290 latency and smaller P400 amplitude. • N290 and P400 may serve as early markers of atypical face processing in ASC.