The validity of the Language Environment Analysis system in two neonatal intensive care units

Exposure to the parents' speech is positively associated with preterm infant's face preference

BACKGROUND

The parents' presence and involvement in neonatal care is a promising approach to improve preterm infants' neurodevelopmental outcomes. We examined whether exposure to the parents' speech is associated with the preterm infant's social-cognitive development.

METHODS

The study included infants born before 32 gestational weeks in two neonatal units. Each infant's language environment was assessed from 16-hour recordings using Language Environment Analysis (LENA®). Parental presence was assessed with Closeness Diary for 14 days during the hospital stay. Attention to faces and non-face patterns was measured at the corrected age of seven months using an eye-tracking disengagement test.

RESULTS

A total of 63 preterm infants were included. Infants were less likely to disengage their attention from faces (M = 0.55, SD = 0.26) than non-face patterns (M = 0.24, SD = 0.22), p < 0.001, d = 0.84. Exposure to the parents' speech during the neonatal period was positively correlated with the preference for faces over non-face patterns (rs = 0.34, p = 0.009) and with the preference for parents over unfamiliar faces (rs = 0.28, p = 0.034).

CONCLUSION

The exposure to the parents' speech during neonatal hospital care is a potential early marker for later social development in preterm infants.

IMPACT

The exposure to the parents' speech during neonatal intensive care is a potential early marker for optimal social-cognitive development in preterm infants. This is the first study to show an association between parental vocal contact during neonatal intensive care and early social development (i.e., face preference), measured at seven months of corrected age. Our findings suggest that we should pay attention to the parents' vocal contact with their child in the neonatal intensive care unit and identify need for tailored support for face-to-face and vocal contact.

Language environment and parent-infant close contact in neonatal care and emerging lexical abilities of very preterm children-a longitudinal study

AIM

This longitudinal study investigated associations between language environment and parent-infant close contact in the neonatal intensive care unit (NICU) and preterm children's lexical abilities.

METHODS

NICU language environment of 43 very preterm infants (born<32 gestational weeks) was measured with the Language Environment Analysis System (LENA; variables: number of adult words, conversational turns, and child vocalisations). Parent-infant close contact (holding and skin-to-skin contact) in the NICU was reported using parental closeness diaries. At 15 and 18 months' corrected age, lexical development was measured with screening methods, and eye tracking-based lexical processing was assessed at 18 months. N varied between 29 and 38 in different outcome measures.

RESULTS

LENA measured conversational turns and child vocalisations, and parent-infant close contact associated positively with lexical development (r = 0.35-0.57). High numbers of NICU adult words associated negatively with lexical processing (r = -0.38- -0.40). In regression models, conversational turns and parent-infant close contact explained 34%-35% of receptive development.

CONCLUSION

Findings suggest that adult-infant turn taking and parent-infant close contact in the NICU are positively associated with lexical development. High numbers of overheard words in the NICU may not favour later lexical processing. Further research is warranted on the significance of NICU language environment on later lexical abilities.

Randomised controlled trial of maternal infant-directed reading among hospitalised preterm infants

AIM

A randomised trial to study the impact of a maternal-driven, infant-directed reading intervention on preterm infant language compared with matched controls.

METHODS

Infants born at 22-32 weeks in Women & Infants Neonatal Intensive Care were gestationally stratified to a reading intervention (n = 33) or standard care (n = 34). At 32-, 34- and 36-weeks postmenstrual age, 16-h language recordings were obtained in the hospital. Bivariate group comparisons and regressions adjusting for gestational age and multiples were run to predict word counts and conversational turns. Longitudinal analyses were conducted by negative binomial models containing intervention, randomised gestation group, recording number (1-3), an intervention × recording number interaction term and multiple birth adjustment by generalised estimating equations.

RESULTS

In adjusted analyses, by 36-weeks postmenstrual age, infants in the reading group had twice the number of conversational turns as infants receiving standard care (Rate ratio 1.98, 95% CI 1.33-2.93, p < 0.05). In longitudinal analyses, only infants in the reading group had a significant increase in the conversational turns between 32- and 36-weeks postmenstrual age (Rate ratio 2.45, 95% CI 1.45-4.14, p < 0.05).

CONCLUSIONS

A maternal infant-directed reading curriculum in the hospital demonstrated a positive impact on interactive conversations by 36-weeks postmenstrual age.