Function of Autism Diagnosis and History

diagnosed as having autism spectrum disorder differed from nonrisk infants in terms of their eye contact, failure to orient to name, impoverished social interest and affect, atypical visual attention, temperament, and delayed language devel-opment. By preschool age, behavioral symptoms of autism spectrum disorder include impairments in social orienting, eye contact, joint attention, imitation, responses to the emo-tional displays of others, and face recognition.4-8 Although the social behavior of individuals with autism spectrum disorder has been well characterized, the basic neurobiological mech-anisms underlying these impairments are poorly understood. Neuroimaging studies9,10 of children with autism spec-trum disorder revealed abnormalities in the cerebral cortex, medial temporal lobe, and cerebellum. These abnormalities may have their origins in early prenatal life.11 In a study of children with autism spectrum disorder who were 3 to 4 years of age vs children with developmental delay and typical development, Sparks et al12 found increased total cerebral volume and proportionally large amygdala volume in the children with autism spectrum disorder. Findings suggest increased volume early in development but slowed growth of the frontal (white and gray matter), temporal (white and gray Autism spectrum disorder is a category of neurodevel-opmental disorders characterized by impairments insocial relationships and communication and by the presence of repetitive interests and stereotyped behaviors. Basic impairments, such as lack of attention to others and failure to orient to name, often appear within the first year of life.1 Using retrospective investigations, other subtle impairments in the domains of motor and sensory percep-tion, attention, and social behaviors are present in the first year.1,2 In a study of high-risk infants, Zwaigenbaum et al3 found that by 12 months of age, infants who later wer