How and when autism symptoms appear dictate illness severity

Among the most baffling observations about autism is that some children appear to have symptoms early in life while others develop normally and then regress prior to age 3. Still others have mild developmental delays and then experience a plateau in development.

Evidence suggests these are different types of autism, and new research supports that idea. Researchers at Kennedy Krieger Institute in Baltimore found in a new study that children with early symptoms may actually be at lower risk for poorer outcomes than children who develop normally and then experience a loss of skills.

In data collected from 2,720 parents, researchers found children with regression had a distinct increase in the severity of symptoms, such as not attaining conversational speech. The outlook was even worse for children whose parents also said the regression phase was severe.

"Children with developmental plateau are an especially under-researched group, and these findings have important implications for those designing and prioritizing clinical evaluations," a co-author of the study, Dr. Paul Law, said in a news release.

More than one-third of the parents surveyed said they had concerns about their child's general development before they noticed the more obvious signs of regression.

The study is published online in the Journal of Autism and Developmental Disorders.

-- Shari Roan