Babies who went on to be diagnosed with autism spent more time looking sideways at toys and other objects.

Infants who play with toys in unusual ways, such as spinning or repetitively rotating a rattle, may be showing early signs of autism, a study suggests.

"The finding that the unusual use of toys is also present early in life means that this behaviour could easily be added to a parent checklist or quickly assessed during a visit to a pediatrician's office," said study author Sally Ozonoff of the University of California Davis.

There is an urgent need to develop measures to pick up early signs of autism before 24 months to start helping children earlier, Ozonoff said, noting about a third of parents become aware of signs before a child turns one, such as failing to respond to their name, less smiling at others and delayed babbling.

"We hope that earlier intervention, when the brain is in a highly plastic state, will result in greater improvements in function and perhaps help prevent some of the major disabilities that can be associated with autism," Ozonoff said in an e-mail.

The American Academy of Pediatrics has recommended that all infants be screened for autism twice before their second birthdays. Pediatricians look for hallmark social and communication symptoms, such as language delays and lack of interest in people.

In the October issue of the journal Autism, Ozonoff and her colleagues reported that babies who went on to be diagnosed with autism or autism spectrum disorder at 36 months spent significantly more time spinning, rotating and looking sideways at objects than other children.

In the study of 66 babies, 35 were considered at high risk for autism mostly because they had an older sibling who was diagnosed with the disorder, and the other 31 babies had a brother or sister without the disorder.

Too early to add to screening tests

Of the infants studied, nine were eventually diagnosed with autism. Of these, seven were more likely to spin, repetitively rotate, stare at and look out of the corners of their eyes at simple objects, including a baby bottle and a rattle, as early as 12 months, the researchers found.

"Our results suggest that these particular behaviours might be useful to include in screening tests," Ozonoff said.

The researchers are conducting a larger five-year study that also includes a high-risk sibling group. They also hope to check the results in a random community sample, to determine how useful the sign is for detecting autism, before pediatricians could add the toy behaviour scores to their early diagnosis checklists.

Current screening tests focus on measures that accurately distinguish children developing autism from children who are developing as expected, such as responding to name, making eye contact and learning words.

Previous studies relied on parents to recall repetitive behaviour in children who were diagnosed with autism, rather than following babies beforehand.

In this study, the children 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 who did not know the purpose of the study scored the babies on their behaviour.

The study was funded by the National Institute of Mental Health.

Autism spectrum disorder is estimated to affect between two and six children in every 1,000 children in Canada.