May 16, 2012 -- Infants who show developmental delays in head and neck muscle control may be at increased risk for autism, a new study suggests.
Though preliminary, the findings are among the first to suggest that delays in motor development during infancy may be an early warning sign of autism.
However, the findings are preliminary and aren't ready for use in diagnosing autism spectrum disorders.
The research will be presented at the International Meeting for Autism Research in Toronto.
Head Lag: Early Sign of Autism?
A baby typically should be able to control her neck muscles by around 4 months of age, so that when she is pulled from a lying to sitting position her head should remain in line with her torso and not flop back.
Delays in reaching this developmental milestone have been observed in premature babies and in those with cerebral palsy, but the new research now links the trait to autism.
The researchers studied infants at high risk for autism because they had an older sibling diagnosed with an autism spectrum disorder.
In one study group, about 40 children were tested for head lag at 6, 14, and 24 months, followed by testing for autism spectrum disorder between the ages of 30-36 months.
According to the findings:
- Ninety percent of the infants later diagnosed with an autism spectrum disorder exhibited head lag when they were 6 months old.
- About half (54%) of children with any social or communication delay showed evidence of head lag as infants.
- Thirty-five percent of children who appeared to be developing normally between 30 and 36 months exhibited head lag at 6 months of age.
In a second study group that compared high-risk babies to those with a low risk for autism, 15 (75%) high-risk infants and seven (33%) low-risk infants showed evidence of head lag at 6 months of age.
Not all high-risk children in the study with a diagnosis of autism spectrum disorder (ASD) experienced head lag as infants, and not all infants with head lag developed autism.
Roughly a third of 2 1/2- to 3-year-olds who did not have ASD showed evidence of head lag at 6 months of age.
"Head lag at 6 months does not mean a child is going to have autism," says researcher Rebecca Landa, PhD, who directs the Center for Autism and Related Disorders at Baltimore's Kennedy Krieger Institute. "But this motor delay appears to be a window into neurodevelopment, particularly when coupled with other developmental delays, and it should be brought to the attention of a pediatrician or other specialist."
Kennedy Krieger has posted videos on YouTube that show normal head/neck control in infants (youtu.be/HzJdR_gvnZ0) and head lag (youtu.be/kk40gQx01uk).
1 in 54 Boys in U.S. Has ASD
In the U.S., around 1 in 88 children -- including 1 in 54 boys -- has autism spectrum disorder.
While most children are not diagnosed until after their third or fourth birthdays, it is now possible to confirm a diagnosis in children as young as 12 months, says autism expert Alycia Halladay, PhD.
Halladay is director of environmental research for the advocacy and research group Autism Speaks.
She calls the new research "intriguing" but cautions that it's preliminary and must be confirmed.
"The first step is to replicate these outcomes in larger studies in multiple sites," she tells WebMD.
Since head lag does not appear to be specific to autism, its diagnostic value remains uncertain, Halladay says.
"We don't want parents to get the message that head lag means their child has autism," she says. "But this could prove to be a red flag to identify children that might benefit from very early interventions for a number of outcomes."
These findings will be presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.