Infant's emotional variability associated to interactive stressful situation: A novel analysis approach with Sample Entropy and Lempel-Ziv Complexity

Rosario Montirosso, Bruno Riccardi, Erika Molteni, Renato Borgatti, Gianluigi Reni

Research output: Contribution to journalArticle


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 .20. s 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.

Original languageEnglish
Pages (from-to)346-356
Number of pages11
JournalInfant Behavior and Development
Issue number3
Publication statusPublished - Jun 2010



  • Face-to-Face Still-Face paradigm
  • Lempel-Ziv Complexity
  • Mother-infant interaction
  • Sample Entropy

ASJC Scopus subject areas

  • Developmental and Educational Psychology

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