Variations of babies vocalizations and maternal speech depending on postpartum depression: Modulations according to infant's age and sex

Abstract

The present work aims to study the influence of postpartum depression (PPD) on the acoustic and melodic characteristics present in the vocal interaction between the mother and her baby. We analyze acoustic qualities of the mother's voice when she is talking to her baby (Infant-Directed Speech) such as fundamental frequency (F0 maximum, medium and minimum values) and intensity (maximum, medium and minimum values). The changes of F0 during a vocalization (intonation contours such as rising, falling, bell-shape, U-shape and sinusoidal and flat contours) were also examined. The same prosodic parameters were investigated in regard to prelinguistic vocalizations. The mothers were healthy, primiparous and native speakers of argentinian spanish. The babies were 3 to 6 month old, and those with congenital diseases or diseases that could affect the assessment of the variables under consideration were excluded. We evaluated 40 dyads of mother and child who attend the University Hospital of Maternity and Neonatology of Cordoba, Argentina. The presence of indicators for PPD was examined through the Edinburgh postpartum depression Scale (Cox, Holden & Sagoysky, 1987). The mother-infant interactions were filmed in unstructured play sessions. The categorization of different contexts in which those interactions occur were taken into account for the acoustic and melodic analysis. The types of interactional contexts were distinguished according the classification made in Papousek, Papousek & Symmes (1991). The results showed that 27 mothers did not present indicators of PPD and 13 did. Acoustically, the infant-directed speech of mothers who exhibit the presence of postpartum depression indicators featured lower values of medium and maximum intensity (p