Effect of intrathecal recombinant human arylsulfatase A enzyme replacement therapy on structural brain MRI in children with metachromatic leukodystrophy

Consistency in parenting infants has positive developmental outcomes. Yet, the role of socioeconomic status (SES) in consistency of maternal behaviors is not well understood. We investigated individual-order continuity of maternal smile and laughter and positive vocalization from 6 to 12 months of age in 82 mother-infant dyads. Overall, individual differences in maternal smile and laughter, and positive vocalization were consistent across time. A multidimensional measure of SES moderated the association of maternal smile and laughter from 6 to 12 months, such that infants from lower SES families were vulnerable to unpredictable parenting - experiencing a lack of consistency in maternal smiles and laughter.