Increased parent speech and parent stress is associated with early vocalizations in preterm infants.

Background: Children born preterm are at increased risk of abnormal neurodevelopment, including delays in acquisition of social, behavioral, and language skills. Development of early language skills, including child vocalizations (CVs) and conversational turns (CTs), is impacted by early exposure to parents' speech, which may be affected by parents' mental health.

Objective: To study the association between parental speech, parental measures of stress, anxiety, depression, and preterm infant language.

Methods: Single-center, prospective longitudinal cohort pilot study in preterm infants born at <33 weeks' gestational age (GA). Language ENvironment Analysis (LENA) devices were used to measure language exposure. Parental mental health was measured using the Parental Stressor Scale: Neonatal Intensive Care Unit (PSS-NICU) and the Patient Reported Outcomes Measurement Information System (PROMIS) Anxiety and Depression instruments at three time points. Associations between adult word count (AWC), CVs, and CTs were evaluated using linear regression analysis. Partial correlations and repeated measures analyses were used to study associations between infant language and parental mental health.

Results: 20 infants were enrolled (median GA 30 weeks, 60 % male). CVs and CTs were recorded as early as 30 weeks' postmenstrual age (PMA). There was a positive correlation between weekly AWC and weekly CVs and CTs (R2 0.174, p < 0.0001; R2 0.338, p < 0.0001, respectively). Parental PSS-NICU and PROMIS Anxiety scores decreased over time, while PROMIS Depression scores did not. There was a significant positive correlation between parents' PSS-NICU scores and time spent at bedside (partial correlation 0.49, p = 0.001; 0.46, p = 0.005 for mothers and fathers, respectively). Parent PSS-NICU scores were inversely correlated with CVs and CTs, though this was not statistically significant.

Conclusions: Preterm infants appear to produce vocalizations as early as 30 weeks PMA, even while on non-invasive respiratory support. Higher AWC while parents are at the bedside is strongly correlated with preterm infants' early language skills. Unexpectedly, higher PSS-NICU scores, indicative of increased parent stress, are associated with increased time parents spent with the infant. Further study is required to determine whether increased parent-infant verbal engagement leads to decreased stress in NICU parents.