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.
