Lag‐sensitive cross‐correlation analysis of mother–infant HF ‐ HRV synchrony during free interaction: An exploratory feasibility study

Abstract

Caregiver–infant interaction involves coordinated behavioral and physiological processes. Heart rate variability (HRV) may provide a physiological index of these interactions. This study preliminarily evaluated an analytical approach for characterizing mother–infant HRV synchrony with temporal lags. Electrocardiograms were simultaneously recorded during free interaction. Thirty sessions were obtained from 15 mother–infant dyads, and 16 analyzable sessions from 10 unique dyads were included in the final analysis. Normalized cross‐correlation analysis of high‐frequency HRV was performed using MATLAB R2022b. Highly correlated intervals accounted for a mean of 75% of the analyzed interaction time, and positive and negative lags occurred in nearly equal proportions. Observed synchrony exceeded the session‐specific surrogate distribution in 13 of 16 sessions based on the empirical p‐value criterion. These findings support the feasibility of a lag‐sensitive, surrogate‐informed approach for preliminarily describing putative mother–infant HRV coordination during free interaction.