The association between infant EEG aperiodic exponent and the trajectory of restricted and repetitive behaviors for toddlers with and without autism.

BACKGROUND

Restricted and repetitive behaviors (RRB) are core features of autism but are also observed in typical development. Our understanding of the neural underpinnings of RRBs is limited. Given that excitation-inhibition (E/I) balance may underlie RRBs, we aimed to evaluate the relationship between aperiodic exponent (as a proxy of E/I balance) and changes in RRBs over time in infants with and without elevated likelihood of autism.

METHODS

Resting-state EEG data were collected from 12-to-14-month-old infants and aperiodic exponent was calculated. Parent-reported RRBs were obtained using the Repetitive Behavior Scale-Revised questionnaire to measure the severity and change in RRBs from 12-to-36 months. Multiple linear regressions were conducted to assess relationships between aperiodic and change in RRBs.

RESULTS

Marginal effects analysis of linear regressions revealed significant associations such that lower aperiodic exponent was associated with elevated RRBs reported over time across the whole sample ([Formula: see text]=0.31, β= -0.21, p = 0.01), which was more prominently observed in the infants who later received an autism diagnosis (δy/δx = -15.57, p < .001).

CONCLUSIONS

Results suggest that early EEG aperiodic activity may serve as a potential correlate of increased manifestation of RRBs. Longitudinal studies are needed to elucidate whether the early trajectory of aperiodic activity in development influences the severity of RRBs in childhood.