Predictive Factors in Language Development Trajectories Over the First 3 Years of Life: Harnessing an Existing Preterm Cohort

ABSTRACT In utero, organized and predetermined patterns of auditory structural and neural pathway development set the stage for early language acquisition.15 The very low birth weight (VLBW) preterm infant, born at 24-30 weeks gestation is at a critical stage of structural and functional auditory development in a suboptimal environment.3, 15 The Neonatal Intensive Care Unit (NICU),

vastly different from the protected uterine environment, is full of high pitched alarms and harsh mechanical sounds from lifesaving respiratory equipment positioned in close proximity to developing auditory structures,8 putting VLBW infants at significant risk for speech and language delays.2, 3 Compounding the suboptimal ambient auditory environment, NICU hospitalization leads

to sparse exposure to directed speech,210, 211 which has been correlated with poorer neurocognitive outcomes on Bayley III testing at 18-36 months of age.2, 4 Preliminary data from our going longitudinal project with VLBW preterm infants form birth through 18 months suggest that speech input continues to be limited post NICU hospitalization. Further, delays in vocabulary growth are

already observed by their first birthday, although large variability exists. The proposed project harnesses our existing VLBW preterm cohort to examine how gestational age, health and demographic factors, and initial language development trajectories, influenced by parent-child communication patterns, contribute to the rapid emergence of language typically

observed in the second to third year of life. To capture this critical developmental phase, we will follow the current cohort of VLBW preterm infants through 36 months (corrected age), longitudinally collecting measures of quantitative (e.g., adult word count) and qualitative language input (e.g., proportion of infant- vs adult-directed speech, contingent responding) and language proficiency

(i.e., vocabulary size, speech processing efficiency, online novel word learning, Bayley IV developmental scores), and compare their trajectories of language growth with those of age- matched full-term infants. Results from the proposed project will advance our understanding of factors that impact risk and resilience for language growth over time, both in full-term neurotypical

infants and in an at-risk preterm population. Examining factors associated with variability and timing of language emergence within the VLBW preterm population compared to age-matched full-term infants will inform our understanding of why some infants struggle while others flourish. Early identification of infants at increased risk for language delays will provide opportunities for early and

targeted interventions to ameliorate health through improved language outcomes.