Lack of muscle development in infants: Could it predict autism?

Kathleen Blanchard's picture
Mother and infant

Researchers say they’ve found evidence that a simple test of head and neck control or head lag in 6-month old infants can help predict genetic predisposition to autism spectrum disorder (ASD). In a series of tests, investigators found muscle control can show if high-risk infants will develop ASD.


What the finding means is that pediatricians can add the simple test at well visits when infants are 6 months of age, which involves a "pull to sit" task.

Motor skill delay test helps diagnose autism for better outcomes

Normally, diagnosis of autism focuses on language and social development. But, “…disruption in early motor development may also provide important clues about developmental disorders such as autism”, according to a statement in a press release from Dr. Rebecca Landa, study author and director of the Center for Autism and Related Disorders at Kennedy Krieger Institute.

In their study, the researchers found that 90% of infants who displayed weak head and neck control and 54% who displayed the sign as infants also had communication and social development delays.

The test is not an indication of autism, but could be useful; combined with other diagnostic tool – 35% of babies who have weak head and neck muscles at 6 months of age had no communication or social developmental delays.

"Our findings show that the evaluation of motor skills should be incorporated with other behavioral assessments to yield insights into the very earliest signs of autism," said Dr. Landa.

The investigation included 40 infants, ages 5.6 to 10 months, who had siblings with autism spectrum disorder and considered high risk.


The test involves pulling infants up from a lying to a sitting position by their hands and looking for alignment of the head with the spine. The test is performed gently but firmly. The head should either be aligned with the spine or slightly in front.

The researchers also examined a second group of 6-month olds for the presence of head lag, which was found to be present in 75% of high-risk infants, compared to just 33% of those at low-risk for the disorder.

To confirm their findings, the team of researchers also performed a longitudinal study that supported the link between delayed muscle development and autism.

They looked at children who were 14-, 24- and 36-months old. Though not all children with autism have delayed muscle development, they did find that “…children with ASD who experience motor delays are more severely impaired by three years of age than children with ASD with no motor delays.

The authors say more research is needed to understand why not all ASD children experience a lag in muscle development. The finding is important because it adds to previous studies showing autism spectrum disorder can be diagnosed early, which means intervening sooner and better outcomes.

Kennedy Krieger Institute
May 16, 2012

Image credit: Morguefile