A new research at University of Washington's Autism Center, has cited that accelerated growth in children may be the first evidence preceding the onset of many behaviours that enable physicians to diagnose Autism.
The reserarchers said that children with autism have normal-size heads at birth but develop accelerated head growth between 6 and 9 months of age. Almost 20 pct of children with autism have abnormally large head sizes, or what is called macrocephaly.
The study, led by Sara Webb, a UW research assistant professor of psychiatry and behavioral sciences, also pointed out that this aberrant growth is present in children having the early onset form of autism as well as those later diagnosed with the regression type of the disorder.
"We know there are a number of risk factors for autism, and if we can pinpoint them we have better ways of identifying children at risk so we can get them into prevention or monitoring. This abnormal or accelerated rate of head circumference growth is a biological marker for autism. It occurs before the onset of behavioral symptoms at 12 months of age such 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," said Webb.
She added: "By itself, head growth is not an indicator of autism," she said, "because kids are going to be getting bigger and development is so variable. However, if you notice it and some of these other symptoms, it is a red flag to seek evaluation."
She said that it is important to understand that the data used in the study were not taken from single point in time, but were based on three measurements made during the first three years of life,
For the study, the researchers obtained the medical records of 28 boys who were diagnosed with autism spectrum disorder between the ages of 3 and 4 at the UW Autism Center and eight boys with developmental delay. All these boys were participating in a larger longitudinal study.
Typically paediatricians do infant head measurements on a regular basis through the first 18 months of life, but not later. To chart the growth of each child and compare it with the range of normal development, three measurements, including at birth, were needed.
Webb indicated that usually parents would have a difficult time detecting abnormal growth, as there is a range of normal head sizes.
"Some of the children in our study started with a very small head size and later their growth accelerated. What we are looking for is disproportionate growth in children compared to the rest of their body. In this study nearly 60 percent of the autistic children had accelerated growth but only six of the children met the criteria for macrocephaly," she said.
Webb said that she hopes to see this information being used by paediatricians to screen children and refer them earlier rather than later for evaluation and intervention before other symptoms develop.