title: Infant's emotional variability associated to interactive stressful situation: a novel analysis approach with Sample Entropy and Lempel-Ziv Complexity.
abstract: This study examined to which extent the lack of the mother's communicative input is associated to the variability of the infant's behavioral and emotional states at a microtemporal level. Two novel non-linear signal-processing metrics were used as regularity indexes during both normal and stressful mother-infant interactions (Face-to-Face Still-Face paradigm): (1) Sample Entropy estimates the presence of epochs of similar states in a data-series, according to a moment-to-moment analysis; (2) Lempel-Ziv Complexity evaluates the occurrence and recurrence of the patterns of analogous states along the data sequence. Fourteen mothers and their healthy full-term 7-month-old infants were videotaped and the infants' socio-emotional behaviors were micro-analytically coded off-line using a .20s time sampling method. During the maternal still-face episodes, when infants were confronted with the perturbation of their caregiver remaining unresponsive, both regularity indexes were lower than in normal interactions. Evidence is provided that non-linear techniques are suitable to detect variability in the infant's states.
authors.affiliation: Department of Child and Adolescent Neurology and Psychiatry, E. Medea Scientific Institute, Bosisio Parini, Lecco, Italy. rosario.montirosso@bp.lnf.it
authors.forename: Rosario
authors.initials: R
authors.lastname: Montirosso
authors.forename: Bruno
authors.initials: B
authors.lastname: Riccardi
authors.forename: Erika
authors.initials: E
authors.lastname: Molteni
authors.forename: Renato
authors.initials: R
authors.lastname: Borgatti
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Reni
mesh_terms: D003627:Data Interpretation, Statistical; D004644:Emotions; D005149:Facial Expression; D005260:Female; D006801:Humans; D007223:Infant; D018730:Infant Behavior / Q000523:psychology*; D008297:Male; D008425:Maternal Behavior; D009034:Mother-Child Relations; D017711:Nonlinear Dynamics; D010988:Play and Playthings; D011581:Psychological Tests; D015203:Reproducibility of Results; D012919:Social Behavior; D013315:Stress, Psychological; D013997:Time Factors; D014741:Video Recording