WASHINGTON (Reuters) - Babies who were later diagnosed with autism played with toys in unusual ways, spinning or rotating them more than other babies, U.S. researchers reported on Thursday.
Their findings, reported in the journal Autism, might help doctors and parents identify children at risk of autism and start to help them earlier, the researchers said.
Babies who went on to develop autism also stared noticeably at objects such as bottles or looked at them out of the corners of their eyes, Sally Ozonoff of the University of California Davis and colleagues found.
"There is an urgent need to develop measures that can pick up early signs of autism, signs present before 24 months," Ozonoff said in a statement.
The American Academy of Pediatrics has recommended that all infants be screened for autism before they turn two, and most pediatricians look for the classic social and communication symptoms.
"The finding that the unusual use of toys is also present early in life means that this behavior could easily be added to a parent check-list or quickly assessed during a visit to a pediatrician's office," Ozonoff said.
"The earlier you treat a child for autism, the more of an impact you can have on that child's future."
Ozonoff and colleagues studied 66 1-year-old babies considered at high risk of autism, mostly because they had siblings with autism.
Nine of them were eventually diagnosed with autism, and seven of these spent significantly more time spinning, rotating and looking sideways at objects than the other children.
No one knows what causes autism, which is marked by impaired social interaction and communication and can range from mild symptoms to profound behavioral difficulties and mental retardation.
Autism and related disorders such as Asperger's syndrome affect an estimated one out of every 150 U.S. children, the Centers for Disease Control and Prevention estimates.
Most evidence suggests it is caused by a combination of genetic and early environmental factors -- perhaps even before birth. It is usually diagnosed by age 3.
"About a third of parents notice signs before a child's first birthday," Ozonoff said.
Reporting by Maggie Fox; Editing by Julie Steenhuysen and Jackie Frank