Abnormal Head Growth Could Signal Autism

Could head size be an indicator of potential autism in your baby? The answer is "maybe" according to a study conducted at the University of Washington's Autism Center.

A team of researchers led by Sara Webb, a UW research assistant professor of psychiatry and behavioral sciences, found that 60% of autism cases were associated with an abnormally fast growth of the head between six and nine months of age, well before the behavioral symptoms typically surface, which usually occur at around age 12 months.

"This abnormal or accelerated rate of head circumference growth is a biological marker for autism," Webb said in a press release. ""By itself, head growth is not an indicator of autism," Webb said, "because kids are going to be getting bigger and development is so variable."

According to Webb, typical symptoms of autism in infants include such behaviors as a child's failure to respond to their name, a preoccupation with certain objects, not pointing to things, a lack of interest in other people and the absence of babbling.

Abnormal head size alone is not always an indicator of autism. But, when combined with a disproportionate head-to-body size ratio, red flags should go up and the child evaluated. Twenty percent of children with autism have a condition called macrocephaly, or abnormally large head size. "Some of the children in our study started with a very small head size and later their growth accelerated," Webb said. "What we are looking for is disproportionate growth in children compared to the rest of their body."

Pediatricians typically measure a child's head circumference for the first 18 months after birth as a normal part of monitoring a child's early physical development. Webb is hopeful that the study will lead to pediatricians identifying possible autism cases earlier for intervention as a result of the study.

Webb's data relied on data from boys aged 3 to 4 years old who were being studied at the Center. They have expanded their study, and are now looking at the records of nearly ten times the number of children diagnoses with autism, to check their early results.

Co-authors of the paper are Theresa Nalty, Jeff Munson and Catherine Brock, who are all affiliated with the Autism Center, and Robert Abbott, a professor of educational psychology at the University of Washington. The National Institute of Child Health and Human Development and the National Institute of Mental Health funded the research.