Effects of Early Vocal Contact (EVC) in the Neonatal Intensive Care Unit

Background: Preterm infants are at risk for developing altered trajectories of cognitive, social, and linguistic competences compared to a term population. This is mainly due to medical and environmental factors, as they are exposed to an atypical auditory environment and, simultaneously, to long periods of early separation from their parents. The short-term effects of Early Vocal Contact (EVC) on an infant's early stability have been investigated, but currently, there is limited evidence of its impact on the infant's autonomic nervous system maturation, as indexed by the heart rate variability, as well as on its long-term impact on infant neurodevelopment. This multi-centric study aims to investigate the effects of EVC on a preterm infant's physiology, neurobehaviour, and development.

Methods: Eighty stable preterm infants, born at 25 to 32 weeks and 6 days gestational age, without specific abnormalities, will be selected and randomized to either an intervention or a control group. The intervention group will receive EVC: mothers talking and singing to their preterm infants for 10 minutes thrice a week for 2 weeks. Mothers in the control group will be encouraged to spend the same amount of time next to the incubator, observing the infant's behaviour through a standard cluster of indicators. Infants will be assessed at baseline, at the end of the intervention, at term equivalent age, and at 3, 6, 12- and 24-months corrected age, with a battery of physiological, neurobehavioral, and developmental measures.

Discussion: Early interventions in the neonatal intensive care unit have shown important effects on the neurodevelopment of preterm infants, lowering the negative long-term effects of an atypical auditory and interactional environment. This study will provide new insights into the mother-infant early contact as protective intervention against the sequelae of prematurity during the sensitive period of development. An early intervention, such as EVC, is intuitive and easy to implement in the daily care of preterm infants. However, its long-term effects on infant neurodevelopment and on maternal sensitivity and stress still need accurate investigations.

Aims This study aims to test the effects of EVC on infants born prematurely between 25 and 32 weeks and 6 days GA.

The effects on newborns will be assessed at physiological (primary outcome), neurobehavioral, and developmental levels during the intervention, at term equivalent age, and at 12- and 24-months CA. The effect of EVC will also be assessed on maternal stress at hospital discharge and on the mother's presence in the NICU.

Design A four-site randomized controlled trial will be conducted to investigate the short- and long-term physiological and neurobehavioral effects of EVC.

Participants Eighty preterm infants, born at 25 to 32 weeks and 6 days GA, will be recruited from the four centres (20 per centre).

Recruitment will be undertaken in each centre by a trained research assistant (RA), who will review birth records daily. After obtaining permission from the attending physicians of both the mother and the infant, the RA will invite qualifying families to participate in the study and will obtain written informed consent from those enrolling. Infants will be then assigned to the EVC intervention or control group using a randomized design, stratifying infants by gender and GA (see Randomization). Mothers whose infants are assigned to the control group will be asked to spend the same amount of time as that of mothers in the intervention group, observing their infants' spontaneous behaviour, with the subsequent compilation of an observation grid developed ad hoc, according to few indicators drawn from The Neonatal Behavioural Assessment Scale (NBAS).

Eligibility Criteria:
Inclusion Criteria:

* • GA between 25+0 and 32 +6 weeks at birth

  * Apgar score: ≥ 7 at 10 minutes
  * Birth weight: \>3th centile and \<97th centile
  * Birth cranial circumference: \>10th centile
  * Periventricular leukomalacia (PVL) grade 1
  * Intraventricular haemorrhage (IVH) grade 1-2
  * Hypoglycaemia
  * Hyponatremia acceptable, provided they are not persistent and severe
  * Hypocalcaemia

Exclusion Criteria:

* • PVL, grade III and IV

  * IVH, grade III and IV
  * Sepsis (vertical and horizontal)
  * Congenital malformations and/or genetic abnormalities
  * Need of respiratory support with high flow/nCPAP
  * Repeated apnoea associated with bradycardia and fall of saturation
  * Hyaline membrane disease
  * Respiratory Distress Syndrome
  * Hyperbilirubinemia, requiring exchange transfusions during hospitalization
  * Lack of informed consent signed by the parents

The exclusion criteria for the mothers will be:

* Presence of depressive symptoms
* Drug abuse
* Age ˂18 years