The average age of autism diagnosis in the United States is three years of age or older. Interviews with parents, however, have shown that signs of autism often are present long before the diagnosis is made.
"About a third of parents notice signs before a child's first birthday," Ozonoff said. "We felt that our field could do a better job at early diagnosis, so we decided to look at multiple candidates for early screening and early detection," she explained.
Ozonoff and her colleagues decided to look at repetitive behaviors that previous studies indicated developed later than two years of age. These retrospective studies, however, relied on the memory of parents whose children were ultimately diagnosed with autism.
"We wanted to directly test whether or not repetitive behaviors so characteristic of autism might actually be apparent earlier and therefore useful in early diagnosis," Ozonoff said.
In contrast to previous research, the current prospective study began with a group of 12-month olds who had not received any diagnosis. The study group included infants from families who had either an older child diagnosed with autism or an older child developing typically.
To approximate the skewed gender ratio of autism in the real world, 62 percent of the infants enrolled were male. The children in the study were presented with four objects a metal lid, a round plastic ring, a rattle and a plastic baby bottle one at a time for 30 seconds each while being videotaped.
Researchers blind to the outcomes coded the behaviors in the tapes. The children were screened for autism at 36 months. Ozonoff and her colleagues found that children later diagnosed with autism were more likely to repeatedly spin and rotate objects. They were also more likel
|Contact: Phyllis Brown|
University of California - Davis - Health System