19449
Imitation Abilities in 12-Month-Old Infants at High Risk for Autism Spectrum Disorder (ASD): Parents Provide a Vital Perspective
Imitation is an early-emerging and fundamental behavior associated with the development of communication and social cognition. Deficits in imitation in very young children with ASD are thought to play a primary role in the abnormal development of social communication. Younger siblings of children with ASD (high-risk siblings, HR) are at higher risk of developing ASD and other developmental problems than those in the general population. Experimental studies of HR infants with ASD suggest group differences across domains by the first birthday, particularly in the areas of communication and social interaction (Ozonoff et al., 2010; Rozga et al., 2011; Zwaigenbaum et al., 2005). A recent study suggested that imitation is compromised in all HR infants and not specifically HR siblings who develop ASD (Young et al., 2011), but little is known about early imitation skills according to parents.
Objectives:
We examined imitation based on parental report (First Year Inventory; FYI; Baranek et al., 2003) in 12-month-old HR and low-risk (LR) infants.
Methods:
Participants included 96 families of 12-month-old infants: 71 at HR and 25 at LR for ASD. Questions on the FYI comprise two domains (Social Communication (SC) and Sensory-Regulatory), each domain consisting of four constructs. The current study focused on the SC domain and its Imitation construct which taps into early-emerging motor, vocal, and social imitation skills. At 36 months, the infants were assessed by a team of expert clinicians and classified as having ASD (n=16); other delays, subclinical autism symptoms, or a history of either (HR-ATYP; n=36); or typical development (HR-TYP, n=19; LR-TYP, n=25). Analysis consisted of between-group ANOVAs followed by post-hoc tests.
Results:
The groups differed on the Social Communication domain (F(3,92)=5.2, p=.002) and two of its constructs: Social Orienting and Receptive Communication (F(3,92)=3.0, p=.021) and Imitation (F(3,92)=6.0, p=.001). Post-hoc analyses showed that infants with ASD had significantly higher (worse) scores on SC compared to HR-ATYP (p=.025, d=.75) and LR-TYP (p=.001, d=1.18) but not HR-TYP infants. The ASD group had higher scores on the Imitation construct than the HR-ATYP (p=.004, d=.94), HR-TYP (p=.002, d=1.17), and LR-TYP (p=.002, d=1.10) groups, with large effect sizes for each comparison.
Conclusions:
These results suggest that, although other skills at this age may also be impaired, parent-reported imitation discriminated the ASD group from all other groups of HR and LR infants with large effect sizes. Parents have the advantage of observing their children across highly familiar contexts, including during well-practiced routines. Motor and vocal imitation games constitute integral components of these playful routines, which often take on a trial-like structure. Thus, missed opportunities for imitation are readily noticeable and reportable. These findings suggest that parent-reported information about imitation skills at 12 months may help identify infants at highest risk for an ASD among HR siblings. Our study has implications for early screening instruments, as imitation can be easily operationalized, typically occurs frequently across modalities (motor, vocal), and is readily observable and reportable by parents.