L’espressione facciale di distress nelle primissime fasi dello sviluppo

Distress, described for the first time and very accurately by Charles Darwin in 1872, is the classic facial expression that accompanies the tears in the earliest stages of development. Term newborn manifests complete and mature distress facial expression, through intense muscular contraction of the bilateral type (Izard, Hembree, Dougherty, & Spizzirri, 1983; Izard, Hembree, & Huebner, 1987); in the preterm infant is performed spontaneously already at 30 weeks postconceptional age (Dondi, Costabile, Vacca, Franchin, Agnoli, Lombardi, & Corchia, 2008). This work presents three experimental studies that investigate the presence of the actions that characterize the facial expression of distress in the very early stages of development, through the use of Baby FACS (Oster, 2009), a methodology specifically developed for the analysis of facial expressions of the child. The first study concerns the analysis of spontaneous facial actions that identify the distress in a sample composed of three groups of fetuses with different gestational ages (20-21, 26 and 28 weeks), observed through the recording of 3D and 4D ultrasound. The results obtained have confirmed the presence of AU4 (Brow Knotting ) on the face of all the subjects of the sample. The second study concerns the analysis of spontaneous facial actions that identify the distress in a sample composed of two groups of preterm and one group of a term infants. The results support and reinforce what was stated up to now: distress is a mature facial expression and it is performed by preterm infants with a very low gestational age. In the third study we observed 12 term infants during a routine blood test. The results obtained in the study showed how the AU4 (Brow Knotting ) and the AU20 (Lip Stretcher), characterizing distress, are showed on the faces of infants with differences in terms of frequency of occurrence and duration of total average in the four phases of the sampling procedure from the heel. Key words: distress, pain, facial expressions, foetus, preterm.