Potential Neonatal Neurobehavioral Signs of ASD Risk in Premature Infants
Objectives: To explore the NICU Network Neurobehavioral Scale (NNNS; Lester & Tronick, 2004) as a potential predictor of ASD symptomatology in toddlerhood. The NNNS is a standardized neonatal neurobehavioral assessment that includes specific responses to animate and inanimate stimuli and more general summary scores.
Methods: Participants included 211 families from an 18 month follow-up study of associations between a single family room neonatal intensive care unit (NICU) model of care and infant neurodevelopmental outcome (Lester et al., 2016). Infants were all born <36 weeks gestational age (M = 27.59, SD = 2.27) and <1500 g (M = 967.39, SD = 240.73). Fifteen percent were from very low SES families. The NNNS was administered prior to NICU discharge (M gestational age = 37.75 weeks, SD = 4.60). The NNNS includes procedures in which the infant attends to animate (examiner’s voice and/or face) and inanimate (rattle/ball) stimuli. The NNNS also includes summary scales describing infants’ neurobehavioral status. Participants were seen in our follow-up clinic at 18 months (M = 22.44 months (uncorrected), SD =1 .68). Follow-up measures included the Pervasive Developmental Disorders Screening Test, a parent-report screening measure of ASD symptoms (PDD-ST; Siegel, 2004), and the Response to Name and Response to Joint Attention items adapted from the Autism Diagnostic Observation Schedule (Lord et al., 2000), a method reported on previously (Stephens et al., 2012). Logistic and linear regressions were used to explore relations between scores on the NNNS and ASD outcome measures with gestational age as a covariate.
Results: Logistic regression showed that diminished orientation to voice on the NNNS was related to lack of response to name, χ² = 10.14, p =.04, OR = 1.48, 95%CI 1.12-1.96, p = .006. Analysis of the NNNS summary scores using linear regression showed more non-optimal reflexes were associated with elevated risk scores on the PDD-ST scores, F(3, 177) = 4.74, p =.003, β = 3.39, p = .001.
Conclusions: Results suggest that the NNNS may be related to signs of ASD symptomatology at 18 months in infants born <36 weeks gestational age. The relation between the infant’s response to voice on the NNNS and response to name at 18 months could suggest developmental continuity in response to voice, which is often diminished in ASD. The finding that infants with higher scores on the PDD-ST had less optimal reflexes is consistent with atypical motor behaviors in infants later diagnosed with ASD (Bryson et al., 2007). Although this study was limited by use of ASD symptom counts rather than diagnosis, results suggest potential neurobehavioral signs of risk for ASD in early infancy.