Infants with obstetric/neonatal complications who typically are admitted to neonatal intensive care units (NICUs) have ~ 2-fold risk for Autism Spectrum Disorders (ASDs). Our longitudinal studies of NICU graduates from birth follow development of regulatory influences on multiple domains including attention, motor skills, social communication, temperament, and cognition. We present behavioral data from the neonatal period through later infancy in NICU graduates later diagnosed with ASDs to help identify patterns in neurodevelopment specific to these infants and/or ASD.
To identify potential behavioral markers and precursors to ASD in early infancy.
To posit potential mechanisms underlying neurodevelopment of behaviors across ASD-specific domains.
NICU infants were evaluated prior to hospital discharge and followed every few months from birth to 5 years. Data included information about medical conditions and demographics at birth, early neurological insult, and a variety of behaviors in multiple domains. This report compares NICU infants later diagnosed with ASD (n = 33) to controls (n = 134) matched on gender (81% male), gestational age at birth (23-41 weeks) and year of birth (1994-2006) from birth to 2 years. Behaviors include neonatal neurobehavior (RNNA), arousal-modulated visual attention (AMA), focused attention and distractibility, exploration in a novel environment, and cognitive and motor performance. Comparisons to early behaviors in term nursery infants later diagnosed with ASDs also will be presented.
In analyses controlling severity of brain pathology and maternal education, ASD infants exhibited behavioral deficits starting in the newborn period. The RNNA showed more visual asymmetry, upper extremity tone problems, and less decrease in number of NB abnormalities between hospital discharge and 1 month. AMA was atypical out to 4 months, with more attention to faster stimuli (like younger infants). Attention deficits and less habituation to distractors during focused attention were noted by 10-13 months, with fewer referencing the examiner or looking at toys, and many spending most of the time looking at distractors. Behavior in a novel environment after 1 year showed repetitive stereotypic movements, lack of toy play, and an atypical positive approach to a 2-ft robot. Scores on BSID-II MDI and PDI declined as early as 7-10 months, which typically only occurs in infants with the most severe brain pathology.
Infants later diagnosed with ASD may form a distinct sub-group of NICU graduates, with atypical visual, motor, and regulatory development. They have a unique behavioral profile, with slower resolution of neonatal problems and development, visual system deficits involving early asymmetry, poor regulation, stimulus-bound attention, and impaired ability to habituate, and motor as well as cognitive impairment starting much earlier than expected. Such deficits may underlie their lack of transition to higher-level visual function that, with deficits in regulation underlying inappropriate reward and motivation systems, produce disinterest in and inadequate processing of social stimuli and events. Whether such behavioral patterns are specific to later diagnosed NICU infants, share common features or are distinct from other ASD cohorts, will be addressed.