Comparing Perceptuo-Motor and Communication Development Across at-Risk Infants Who Later Developed Autism, at-Risk Infants without Delays, and Typically Developing Infants

Background:  Infants who later develop Autism Spectrum Disorders (ASDs) show early gross motor delays (Ozonoff et al., 2008; Bhat, Galloway, & Landa, 2009). The majority of the studies have used retrospective data or general developmental assessments such as the Mullen Scales of Early Learning (Landa & Garrett-Mayer, 2005). Our recent publication reported presence of gross motor delays at 6 months that correlated with language delays at 18 months (Bhat, Galloway, & Landa, 2012).

Objectives: In the current study, we examined the differences in perceptuo-motor and communication development between infants at risk for autism (AU sibs) and typically developing (TD) infants and related them to infants’ future language, social, and motor outcomes at 24 months.  

Methods: 16 TD infants and 16 AU sibs were observed longitudinally at 3, 6, 9, 12, and 15 months of age using the Mullen Scales of Early Learning (MSEL) and the Alberta Infant Motor Scale (AIMS). We have obtained future outcomes on developmental concerns and ASD diagnoses at 18 and 24 months.  

Results: We will particularly report on differences between AU sibs who later developed “developmental delays and ASDs” versus those who did not based on 18- and 24-month outcomes. In terms of AIMS performance, 5 to 7 of the 9 AU sibs who developed delays or ASD diagnoses by 24 months of age, demonstrated motor delays (at or below the 25^th percentile) at the 6- and 12-month visits. Such delays were not observed at other ages. In terms of the MSEL performance, all 9 infants who developed future delays or ASD diagnoses showed delays in at least one domain of the MSEL at 12 or 15 months based on their T-scores values. Specifically, 8 out of 9 AU sibs demonstrated gross or fine motor delays at 12- or 15-months and 5 out of 9 infants demonstrated both receptive and expressive language delays at 12- or 15-months.  

Conclusions: While communication delay is a frequent early marker of ASDs, we also believe that impairments in gross and fine motor control are present in AU sibs who later develop ASDs. This may contribute to the motor challenges the at-risk infant faces during social interactions such as effective use of non-verbal communication with others. Hence, it is important to detect and treat early motor delays and use motor assessments as a window for early diagnosis of future autism-related impairments.