Autism prodrome 27 of 89
specific early marker for autism but rather that gaze to the mouth may play an
important role in language development.
Next, Ozonoff et al. (2008) examined behaviors of atypical object exploration
(with novel play materials) at 12 months as a predictor of subsequent ASD diagnosis
in this sample in which participants were classified into three groups according to
their outcome diagnoses at 24 and 36 months: Autism/ASD group, other delays group
and no concern group. The Autism/ASD group was distinguished from the other two
groups by increased frequency of spinning, rolling and rotating the objects, and by
unusually prolonged visual inspection, often associated with atypical features such as
examining the object from odd angles. Furthermore, repetitive behaviors at 12 months
were significantly associated with cognitive and symptomatic status at the 36 month
outcome, yet some infants who showed these behaviors did not receive an ASD
diagnosis later on. These results suggest that repetitive or stereotyped behaviors are
early risk markers in the development of some but not all children with ASD.
Finally, also using growth curve analyses, Yoder, Stone, Walden and Malesa
(2009) examined the contribution of initial values and growth rates of two early social
skills, i.e., weighted triadic communication and responding to joint attention in
predicting later ASD in a group of SIBS-A followed from 15 to 34 months of age.
Results indicated that both predictors (weighted triadic communication and
responding to joint attention) as well as initial language age were associated with later
ASD diagnosis.
Altogether these studies corroborate findings from the home video and
screening studies in that various behavioral indices of attention, perception,
communication, temperament, social behavior and sensory-motor development
characterize children who later on develop ASDs. Yet no one developmental