Although symptoms of autism have been observed in children as young as eight to 12 months, some parents report that their child had normal or near-normal development and then experienced a regression, as their communication and/or social skills worsened, according to background information in the article. Estimates of the prevalence of this "regressive pattern" vary widely and depend for the most part on parental memories that may be biased by later events, the authors suggest.
Emily Werner, Ph.D., and Geraldine Dawson, Ph.D., of the University of Washington, Seattle, analyzed home videotapes of first and second year birthday parties for children without autism and for children who have been diagnosed with autism spectrum disorder (ASD). Of the 56 children included in the study, 15 were children diagnosed with ASD whose parents reported a worsening in social and/or communication skills during the second year of life, 21 were children with ASD whose parents reported that they had had impairments before age one year (early onset) and 20 were typically developing children. All the children in the study were younger than seven and all but three were younger than four years old.
The researchers coded the frequency and duration of a number of behaviors seen on the videotape, including language, gaze, repetitive behavior, emotion and playing with toys. In addition, they conducted an interview with the child's primary caregiver designed to help the caregiver recall the child's early development, including questions about social responsiveness, language skills and temperamental differences.
Infants with ASD with regression showed more frequent use of words and babble at 12 months compared to normal infants. Early onset ASD infants showed the least frequent use of words and babble. The level of joint attention (frequency of pointing) was the same for normal infants and infants with ASD with regression at 12 months. "In contrast, infants with ASD with early onset of symptoms and no regression displayed fewer joint attention and communicative behaviors at 12 months of age," the authors report. "By 24 months of age, both groups of toddlers with ASD displayed fewer instances of word use, vocalizations, declarative pointing, social gaze, and orienting to name [responding to the use of their name] as compared with typically developing 24-month-olds."
"While we cannot be certain from these data that children with autistic regression were developing entirely normally before the regression occurred, the results of the present study suggest that at least some children with autism do not display prototypical impairments in joint attention, such as a lack of declarative pointing, nor do they display obvious delays in their use of language at the end of the first year of life," the authors write. "Future research should focus on examining whether autistic regression in the first two years of life is distinct from later regression seen in cases of childhood disintegrative disorder and determining whether regressive forms of autism represent genetic subtypes and/or distinct etiologies [causes]."
(Arch Gen Psychiatry. 2005; 62: 889-895. Available pre-embargo to the media at www.jamamedia.org.)
Editor's Note: This study was supported by grants from the National Institutes of Child Health and Human Development (NICHD), Rockville, Md., which is part of the NICHD Collaborative Program of Excellence in Autism, and was facilitated by a NICHD grant to the Center on Human Development and Disability, Seattle.
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