Differences in Object Exploration Skills Between Infants at Risk for Autism and Typically Developing Infants in the First 15 Months of Life

Background: Infants begin to grasp objects at six months of age and continue to explore various object properties based on shape, size, and texture. These fine motor skills lay the foundation for cognitive skills such as object knowledge as well as social communication skills such as hand gestures. Infants at risk for autism present with fine motor delays (Landa et al., 2005), which may affect their object exploration skills and therefore, indirectly influence their social communication and cognitive development. 

Objectives: In the current study, we examined the differences in object exploration skills between infants at risk for autism (AU sibs) and typically developing (TD) infants and related them to infants’ future social and motor outcomes.

Methods: 16 TD infants and 16 AU sibs were observed longitudinally at 6, 9, 12, and 15 months of age within an object exploration paradigm with developmental follow-up and autism screening conducted at 18 and 24 months. At each visit, infants were seated upright in a booster seat and were offered three different objects – a long rattle, a solid ball, and a circular, soft koosh ball. Videotaped data were coded for percent duration of oral, visual, and haptic exploration.

Results: At 6 months, TD infants demonstrated greater mouthing and grasping behaviors compared to AU sibs who showed greater visual fixation towards objects. At 9 months, TD infants began showing active control over objects with an increase in duration of grasping and purposeful object dropping behaviors; in contrast, AU sibs demonstrated a lower duration of grasping behavior and did not increase their dropping behavior until 12 and 15 months of age.  At 15 months, the TD group continued to increase grasping behavior while the AU sibs group continued to show mouthing of objects. We will also report on differences between AU sibs who later developed developmental delays and ASD versus those who did not based on 18- and 24-month outcomes.

Conclusions: We believe that impairments in fine motor control and excessive object exploration may contribute to the poor object exploration skills of AU sibs. Overall, our data suggest that object exploration may be an effective paradigm to assess fine motor and visual attention patterns of infants at risk for autism and could provide a window for early diagnosis of future autism-related motor and social impairments.