Sensory-Motor and Language Behaviors in Infants with High and Low ASD Risk in the First Year of Life

Background: Early motor, sensory, and language signs of ASD are a priority for the field as they could provide: 1) earlier diagnosis criteria and 2) the development of targeted interventions. Currently, early signs of ASD including reliable language, social, cognitive, and motor differences have been identified from 12 to 24 months of age. More recent work has begun to identify differences between typical development and infants at high risk for ASD in the first year of life. These high-risk infants are identified in infancy as having an older sibling who has ASD. There are reports of upper extremity and language developmental variation in the first year of life in infants at-risk for ASD. For example poor midline behaviors and poor coordination of upper extremity movements with early babbling have been identified.

Objectives: We conducted a multi-disciplinary, behavioral study of infants with and without risk factors for autism to characterize gross motor, upper extremity movement and sensory response trajectories in the first year of life and their relationship to early signs of autism including language and gesture.

Methods: Thirty-nine infants participated in a longitudinal study at 2, 4, 6 and 12 months of age. Twenty-five infants were at high risk for ASD with a sibling or first cousin with ASD, and the remaining 14 infants were classified as typically developing with no ASD risk factors. Five infants went on to receive an ASD diagnosis at age 3–4 yr. Infants were part of larger study to develop earlier diagnostic tools for ASD.

Results: Infants’ gross motor skills, spontaneous and upper extremity movements, sensory response (visual, auditory, tactile) and language behaviors were evaluated from standardized video recordings during a naturalistic play session at 2, 4, 6 and 12 months of age. Repeated measures statistical approaches (parametric or non-parametric) were used to analyze main effects of risk group and changes in trajectory. Differences in trajectory were observed in gross motor skills (p < .05), midline performance with the hands (p < .05), and response to sensory stimulation (p <.1). All groups of infants produced vocalizations and arm movements (rhythmic arm movements and gestures) at 6 & 12 months. At 12 months a higher proportion of children with ASD did not produce coordinated overlapping gestures with the upper extremities and vocalizations.

Conclusions: Identification of specific behaviors that are discriminative of ASD in the first year of life is of high impact because interventions that begin early in life can reduce the severity of cognitive and behavioral impairments ultimately lessening the expression of disability.