Visual Stress Cues and Atypical Eye Movements During a Visual Task in Infants with Prenatal Opioid Exposure

Purpose/Hypothesis: The purpose of this study was to investigate atypical eye movements, visual stress cues, and state regulation during a visual task in infants with prenatal opiate exposure (POE). It is hypothesized that infants with POE will have increased nystagmus, strabismus and stress cues and decreased state regulation compared to infants without POE.

Number of Subjects: 41 infants with prenatal opiate exposure, and 23 control infants were included.

Materials/Methods: During a social and non-social visual task, infants looked at faces, bodies, and shapes. Eye gaze was recorded using a video camera which captured the video for offline coding. Researchers created standardized definitions of infant behaviors including infant’s eye movements, visual stress cues, state regulation, and response to handling. A coding checklist was initially developed by the primary researchers, coding five infants. All behaviors were discussed and revisions to the checklist were updated. Researchers then coded an additional four infants separately with inter-rater reliability accepted at .8. Differences in coding were discussed and agreements were reached. Two additional researchers attained reliability and sixty-four infants were coded. Data was placed into SPSS.

Results: Preliminary analysis of maternal and infant characteristics indicated that there were significant group differences between infants without POE and infants with POE for infant birthweight, infant birth length, and maternal tobacco use. These characteristics were included as covariates in the following ANCOVAs. Infant abnormal eye movements (I.e., nystagmus, strabismus), behaviors (fussing, gaze aversion), state regulation (shutting down, remaining calms), and response to handling (rocking, pacifier, auditory stimulation) were used as outcome variables. The ANCOVAs indicated that even after statistically controlling for infant birthweight, birth length, and maternal tobacco use, rates of abnormal eye movements and visual stress signs were significantly different between the two groups of infants.

Conclusions: This study adds to the evidence of the impact of in-utero opioid and polysubstance exposure beyond the development of NOWS. The neonatal visual outcomes described here, including nystagmus, strabismus, gaze aversion, fussiness and growth deficits, suggest the possibility of longer-term health and developmental impacts. Findings reinforce the need for those working with families in the NICU or early intervention to identify infants with early delays to intervene early to mitigate neonatal effects of POE and polysubstance exposure.

Clinical Relevance: Previous literature surrounding POE focuses on health outcomes and some speculate that the scope of adverse infant outcomes is not readily identified or apparent at birth. This research study provides evidence of differences between visual stress cues and abnormal eye movements of infants with POE and NOWS. Identification of early differences may aid in the early identification of developmental delays., justifying PT is an important member of the medical team whose expertise is critical in recognizing infant needs and intervening with infants and families with POE.