While it has been known that weak head and neck control in babies may signal developmental delays, new research revealed that it could also signal autism.
A simple pull-to-sit test for babies may help in early detection of autism spectrum disorders, according to the findings from the Kennedy Krieger Institute in Baltimore.
"If there is a family member with autism, the presence of motor disruption in infancy is a red flag, indicating that social and communication development could also be delayed," Dr. Rebecca Landa, lead author of the study and director of the Center of Autism and Related Disorders at Kennedy Krieger Institute, told ABCNews.com. "We recommend that if an infant sibling of a child with an autism spectrum disorder displays head lag in a pull-to-sit task, parents should mention this to a specialist, who will determine whether there are other signs of delay or qualitative indicators of disrupted development."
Researchers studied two groups of infants who were considered to be at high genetic risk of autism spectrum disorder. The first group included 40 babies, ages 5 to 10 months old.
Tune in to World News tonight to learn more about head lag and autism.
The scientists performed a task in which they pulled the babies, who were lying on their backs, by the arms up to a seated position. The infants were tested at 6, 14 and 24 months old. They found that 90 percent of babies who were diagnosed with ASD showed head lag as infants. Fifty-four percent of children who had other developmental delays also showed weak head and neck muscles as infants.
In the second group, Landa and her team examined the presence of a head lag in babies who were at high genetic risk, versus those at low genetic risk. They found that 75 percent of high-risk infants exhibited the head lag, whereas 33 percent of low-risk infants did.
About 1 percent of American children ages 3 to 17 have an autism spectrum disorder, and it is the fastest-growing developmental disorder, according to the Autism Society. The condition characterizes a complex set of brain development disorders characterized by repetitive behaviors and difficulty with social interactions and verbal and nonverbal communications.
Motor disruption tends to be present in children with ASD early in life, and early disruption in motor development can indicate that something could be awry in neurodevelopment, said Landa.
Early intervention in autism is crucial, and identifying a head lag within the first year of life may help families get babies the developmental interventions they need. Otherwise, the disorder may not be properly addressed until the child is 1 to 4 years old, when social and communication impairments tend to emerge in children with autism.
The simple head lag test is a good sign of the functioning of the motor system, overall muscle tone and central nervous system, said Dr. Stefani Hines, director of the Center for Human Development at Beaumont Children's Hospital in Detroit.
But head lag can stem from a number of different conditions, and Hines cautioned against parents assuming the head lag indicates ASD, as it can also reveal neuromuscular disorders, developmental delay and cerebral palsy.
Hines said the new study is another tool in the arsenal in helping to assess high-risk children for autism. The findings will help pediatricians be more cognizant of the importance of assessing head lag in ASD and other developmental disability diagnoses.
"The head lag test can be done at an early age, even before first words are heard," said Hines. "That's what makes this finding of particular importance. A positive head lag sign may prompt us to be on high alert for a possible emerging ASD diagnosis in high-risk children. "