An Examination of Non-nutritive Suck in Relation to Prenatal Environmental Exposures and Subsequent Neurodevelopment

• In Event: 3-064 - The Effects of Environmental Toxicity on Neurodevelopmental Outcomes Across Infancy and Early Childhood

Integrative Statement

Sensitive tests of early neurofunction are essential in infancy as this is a critical period of brain growth that lays the foundation for many areas in neurodevelopment including communication, motor, socio-emotional, cognitive, and behavioral domains. However, there are limited quantitative neurodevelopmental measures that can be administered in the first year of life; therefore, researchers are restricted to standardized tests that frequently underestimate delays. Emerging retrospective data show that infant non-nutritive suck (NNS - sucking on a pacifier with no nutrient being delivered) physiology is linked to childhood language, motor, IQ and overall neurodevelopment (Adams-Chapman et al., 2013; Malas et al., 2015; Wolthuis-Stigter et al., 2017). In addition, given that delayed sucking can be an indicator of brain injury (Slattery, 2012), NNS is often used as an index of early brain development. Quantitative neuro-assessment tools, like infant NNS, could potentially provide automated data collection critical for early detection of delays. Our center for research on early childhood exposure and development (CRECE—part of the Environmental influences on Child Health Outcomes Program) examines how mixtures of environmental exposures impact the health and development of infants and children living on the heavily-contaminated island of Puerto Rico has provided an opportunity to test this hypothesis. In CRECE, we are examining the extent to which NNS relates to neurodevelopment in infants and whether the NNS response itself is a sensitive indicator of neurotoxicity induced by prenatal phthalate exposure (a group of chemicals found in personal care products, etc.). We expect that suck patterns with higher amplitudes, more cycles per burst, and higher frequencies will be associated with reduced prenatal phthalate exposures and improved neurodevelopment scores. Maternal prenatal exposure to a range of environmental chemicals is measured throughout pregnancy. Then, a subsample of infants has their NNS sampled using our custom research pacifier between 4-6 weeks, which yields the NNS duration, amplitude (CmH20), frequency, suck burst, such cycles, and cycles per burst. At the same visit infants are given the ASQ-3. Thus far, 36 participants have completed this ongoing study and bivariate correlations were completed to examine these preliminary data. NNS frequency significantly correlated with prenatal, urinary levels of monoethyl phthalate (MEP; r=-.341, p=.027) and monobutyl phthalate (MBP; r=.314, p=.043). NNS amplitude significantly correlated with the phthalate MBP (r=-.389, p=.023). Lastly, the NNS amplitude was significantly correlated with ASQ Fine Motor Score (r=-.407, p=.014). Overall, these very preliminary data suggest that certain features of infant suck are associated with specific prenatal phthalate exposures and neurodevelopment scores, the remaining correlations were not significant. Data collection is ongoing with a projected sample size of the NNS subset n=100. The larger N will allow us to explore these early trends in more detail using linear regression models controlling for infant birthweight and birth gestational age. Results from this study will be the first to prospectively determine the sensitivity of NNS as a quantitative index of prenatal environmental toxicant exposures linked to specific neurodevelopmental delays. Findings could have important clinical implications on the type of assessments utilized in young infants.

Authors

• Emily Zimmerman, Northeastern University
  Presenting Author

• Deborah Watkins, University of Michigan
  Non-Presenting Author

• Morgan Hines, Northeastern University
  Non-Presenting Author

• Gredia Huerta Alvarado, University of Puerto Rico, San Juan
  Non-Presenting Author

• Zaira Rosario Pabon, University of Puerto Rico
  Non-Presenting Author

• Justin Manjourides, Northeastern University
  Non-Presenting Author

• Carmen M Velez Vega, University of Puerto Rico
  Non-Presenting Author

• Jose Cordero, University of Georgia
  Non-Presenting Author

• John Meeker, University of Michigan
  Non-Presenting Author

• Akram Alshwabekah, Northeastern University
  Non-Presenting Author