Journal of Autism and Developmental Disorders, Vol. 29, No. 3, 1999 Autism During Infancy: A Retrospective Video Analysis of Sensory-Motor and Social Behaviors at 9-12 Months of Age Grace T. Baranek1 This retrospective video study explored the usefulness of sensory-motor measures in addition to social behaviors as early predictors of autism during infancy. Three groups included 11 children with autism, 10 with developmental disabilities, and 11 typically developing chil- dren. Home videos were edited to obtain a 10-minute cross-section of situations at 9-12 months for each subject. Using interval scoring, raters coded several behavioral categories (i.e., Look- ing, Affect, Response to Name, Anticipatory Postures, Motor/Object Stereotypies, Social Touch, Sensory Modulation). Nine items, in combination, were found to discriminate the three groups with a correct classification rate of 93.75%. These findings indicate that subtle symp- toms of autism are present at 9-12 months, and suggest that early assessment procedures need to consider sensory processing/sensory-motor functions in addition to social responses during infancy. Furthermore, prior to a time that they reported autistic symptoms, caregivers used compensatory strategies to increase the saliency of stimuli in order to engage their children more successfully; these strategies may provide a window for earlier diagnosis. INTRODUCTION An accurate diagnosis of autism appears reliable no earlier than 2 to 3 years of age (e.g., Lord, 1995) despite the overwhelming conviction that it is a neuro- developmental disorder of prenatal origin (Bailey, Phillips, & Rutter, 1996; Gillberg & Coleman, 1992; Rutter & Schopler, 1987; Volkmar, Stier, & Cohen, 1985). The early elusiveness of autism leads to specu- lation about whether symptoms actually do exist in infancy and if so, whether they are too subtle to be detected reliably. Earlier diagnosis appears limited by (a) our knowledge of the early development in those infants later diagnosed with autism, and (b) our reliance on conventional classification systems (e.g., DSM-IV; American Psychiatric Association [APA], 1994) based 1 Center for Development and Learning and Division of Occupational Therapy, CB #7255, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7255; e-mail: gbaranek@css. unc.edu on the "triad" of behaviors (i.e., social, language, and behavioral symptoms) manifested in older children with autism. Both the presence of unusual behaviors (e.g., stereotypies) as well as the absence of typically developing behaviors (e.g., verbal language) are con- sidered for diagnosis. Therefore, professionals are re- luctant to diagnose autism prior to the age that a child would typically develop representational capacities and prior to expectations for production of consistent so- cial initiatives such as sharing, offering comfort, and initiating joint attention. Moreover, the course of autistic symptomatology may change considerably with age; thus, symptoms during infancy may not appear at all like later mani- festations of the disorder (Bailey et al, 1996; Gillberg et al, 1990; Watson & Marcus, 1988). Research has also shown that autistic symptoms are easier to recog- nize as they intensify or become more pervasive with age (Adrien et al., 1993; Lord, 1995; Wing, 1969), and parents' awareness of symptoms also varies with their child's stages of development (Stone & Hogan, 1993). 213 0162-3257/99/0600-0213S16.00/0 © 1999 Plenum Publishing Corporation KEY WORDS: Home movies; autistic symptoms; developmental disabilities; early diagnosis; sensory processing; social responsiveness.