Temperament in Infants at Heightened Risk for Autism Spectrum Disorder

An observational measure of temperament (MN-PARS) was compared to a parent-report measure of temperament (IBQ-R) at the 6- and 12-month time points for 31 infants at heightened risk for ASD (HR-D = 8) and 15 age-matched LR infants. The Child Behavior Checklist/1½ to 5 was collected at 24 months. Autism diagnostic status was determined at 24 months by trained clinicians. As measured by the MN-PARS, LR infants displayed more negative affect at 6 months and less negative affect at 12 months than HR-D infants, who showed the opposite pattern. On IBQ Negative Affectivity, HRD infants displayed significantly more negative affect at 12 but not 6 months than LR infants. Although many significant correlations were found within each temperament measure, there were virtually no significant correlations between IBQ-R temperament dimensions and conceptually similar MN-PARS ratings at 6 or 12 months. Qualitative inspection of MN-PARS temperament profiles suggested that HR-D infants appeared more passive and dull at 6 months than LR infants, but that by 12 months they showed more irritability and less adaptability. The measure that best differentiated the HR-D and LR infants was the Pervasive Developmental Problems Scale on the CBCL/1½ to 5, which was administered at 24 months