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suggest that behaviors of motor functioning in the first months of life (i.e., lower
levels of symmetry) may be used as an early indicator of possible ASD. _
Clifford, Young, and Williamson (2007) analyzed home videos of infants who
were later diagnosed with ASDs, infants who had developmental or language delays,
and typically developing infants between the ages of 12 months and 24 months.
Results indicated that social behaviors such as eye contact quality, positive affect,
nestling, gaze aversion, social peer interest, conventional social games, anticipatory
postures and proto-declarative showing discriminated the infants who were later
diagnosed with ASDs from the other two groups. The researchers suggest that
between the first and second birthdays, infants with a later diagnosis of ASDs can be
better distinguished from infants with developmental delays on a number of basic
dyadic social behaviors rather than triadic behaviors such as joint attention and proto-
declarative showing. Clifford and Dissanayake (2008) indicated that impairments in
gaze and affect emerged in infants later diagnosed with ASDs as early as the first
6 months of life and impairments in joint attention were found throughout the second
year of life. They suggest that abnormalities in dyadic behaviors such as poor quality
of eye contact, impairment in the use of smiling and appropriate affect may be
detected in home videos even before the first birthday and may play a role in later
joint attention impairment.
Ozonoff et al. (2008) compared gross motor development (i.e., supine, prone,
rolling, sitting, crawling and walking) and movement abnormalities of infants later
diagnosed with autism (regression and no regression subgroups), infants with
developmental delays and infants with typical development. Results indicated a
relatively slowed motor development in all clinical groups compared to the typically
developing group. More specifically, the autism (no regression) and the