Project combines investigation of early autism markers with outcome measures

Dawson's project, which is part of the autism longitudinal study, will explore how various developmental factors influence outcome and how possible subtypes of autism may be involved in the wide range of outcomes that are observed. Another aspect of the project involves further development of reliable methods for detecting autism as early as possible. It will also extend behavioral information for the longitudinal study back to infancy.

Several years ago Dawson, professor of psychology, and Julie Osterling, UW graduate student in clinical child psychology, pioneered a new way of looking at development in infants with autism. Their groundbreaking study using home videos taken at first birthday parties provided insight into the development of social, affective, joint attention and communicative behaviors in infants with autism.

The study compared first birthday videos of children who were later diagnosed with autism with those of children with typical development. Coders who were blind to the diagnosis counted the number of times the birthday boy or girl displayed a range of social and communicative behaviors. Four specific behaviors­making eye contact, pointing to objects, showing objects to others and responding to someone calling their name­proved to be significant. They enabled Dawson and Osterling to correctly identify 10 of the 11 children with autism at the age of one year­two to three years earlier than autism is typically diagnosed. In the current project, Dawson and Osterling will again use videotapes of first birthday parties, but of a larger group of children and with an additional comparison group­children with mental retardation who do not have autism.

This is a key issue, according to Dawson, because many children have both autism and mental retardation. "It is important to know what behaviors would allow the clinician to recognize developmental delay only, versus delay with autism, or autism only," she notes. Second birthday party video tapes will also be part of the project. Along with the first birthday party home videos, they will shed light on variations in developmental patterns that are likely the result of different subtypes of autism. There seem to be two different patterns of early development, explains Dawson. In most children with autism, symptoms are probably present from birth and they become evident to parents even before their child is a year old. However, in about 25 percent of children with autism, the pattern of development seems to follow a normal course until about age 2 or 3 before it regresses and the child develops autistic symptoms.

"We used to think that this reported discrepancy in age of onset was just due to some parents not being as aware of their child's symptoms, but now that we have home videos we have been able to go back and take a look," says Dawson. "Although the information is only anecdotal so far, it really does look like there are children with autism who experience regression.

"We want to scientifically document differences in age of onset using the home-video methodology we have developed and, more importantly, look at whether these variations are related to different outcomes and different brain measures. It's reasonable to expect that something very different must be going on for a child who has normal development and then regresses. It may be that these are different forms of autism." In addition to the home video portion of the project, Dawson will also investigate the relationship between markers of early development in autism, both behavioral and neurobiological, and later outcome. "We want to figure just out how intervention affects outcomes by taking a careful look at the natural course of intervention in the group of children with autism and the group of children with mental retardation in the longitudinal study."

For each of the children in the study, Dawson will document the age at which intervention began or begins, the type of intervention and the intensity of intervention, including such aspects as the number of hours per week, the therapist- or teacher-to-child ratio and the degree to which the child's family is involved in the intervention.

"The combination of information we are collecting in the longitudinal study will allow us to statistically examine the interaction between early markers and intervention in predicting outcomes at ages 6 and 7," explains Dawson. She and her colleagues will plot intervention throughout the three-year course of the study, between ages 3 to 4 and ages 6 to 7, gathering information with monthly phone calls and, in some cases, retrospectively for those children who began intervention before the start of the study. In addition to the standardized measures of intellectual and language ability, outcome measures taken between ages 6 and 7 will include severity of autistic symptoms, whether the child has behavioral problems and type of school placement.

A child with autism focuses his attention on a toy during his first birthday party. The photo is from Dawson and Osterling's study of home videos.

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