Infant frontal EEG asymmetry across an emotion-eliciting task: Leveraging novel quantitative approaches to discern links with parent-child interactions.

Interest in the impact of parent-child interactions on infant electroencephalography (EEG) has steadily grown, yet research is still relatively limited. Additionally, studies often rely on averages computed across trials or isolated segments, and do not examine infants' neurophysiological responses to longer naturalistic emotion-eliciting situations. Mothers with infants (n = 106, boys = 59) 6-12 months of age were recruited with the goal of examining the effect of parent-child interactions on infant CNS response in the context of repeated trials of the Still Face Paradigm (SFP; Haley & Stansbury, 2003). First, latent growth models (LGM) were estimated to examine infant EEG asymmetry across five trials of the repeated SFP, considering parent-child interaction predictors and controlling for relevant covariates. Second, latent profile analysis (LPA) was conducted to examine groupings of frontal asymmetry trajectories over the course of the task. Overall, a reliable pattern of changes across SFP trials was not observed, however, significant inter-individual variability was noted. Latent profile analysis was thus undertaken, indicating appropriateness of a three-group solution. Because two of the groups demonstrating change were small, these were combined to form a reactive profile. Subsequent analyses demonstrated that infants who experienced more reciprocal play with their caregivers were less likely to display significant frontal asymmetry reactivity to SFP when controlling for infant age and sex, maternal age, and socioeconomic status. This work provides evidence for the utility of LPA in infant EEG research, as well support for the capability model of frontal asymmetry.