Developmental Patterns to Watch if You Suspect That Your Child May Be Autistic


One of the goals of making a diagnosis of Autism Spectrum Disorder (ASD) is making the diagnosis as early as possible so that early learning intervention can be introduced to lessen the effects of autism. Typically, a diagnosis is not reached until a child is between 2-3 years old; however, within the past year, researchers at the Kennedy Krieger Institute have listed 10 signs of autism in 6-12 month old infants that parents can watch for in their infant to help pediatricians with a potential diagnosis.

More recently, researchers report that these signs of autism occur in patterns. In a collaborative effort from the Kennedy Krieger Institute, the Johns Hopkins University School of Medicine, the Johns Hopkins Bloomberg School of Public Health, and the Aging Brain Center at the Institute for Aging Research and Hebrew Senior Life at Harvard Medical School, researchers have just published in the journal Child Development the results of a longitudinal study testing 235 children with and without an older sibling with autism, over a period of ages 6 to 36 months.

The purpose of the study was determine if there were any patterns of development during the first three years of life between children with and without ASD. The goal was to discover the earliest period possible that ASD can be diagnosed in children. The study used the distinctions of early-onset ASD (by 14 months) and later-onset ASD (after 14 months) to differentiate between children diagnosed with ASD and to help identify where development begins to differ between the two and between children with and without ASD during their first 3 years.

According to a news release from the Kennedy Krieger Institute the study consisted of:

"204 infant siblings of children with ASD, who are at a higher genetic risk for developing ASD, and 31 infants with no family history of ASD. The infants were examined at 6, 14, 18, 24, 30 and 36 months of age. Confirmation of ASD classification was made at the 30 or 36 month visit for all participants because diagnosis at this age is considered definitive. At each visit, researchers evaluated the infants for motor, language, communication, social-affective and symbolic abilities, as well as typical symptoms of ASD."

After the data was collected, the infants were categorized into three groups consisting of Early-ASD, Later-ASD and Non-ASD. What the researchers determined is as follows:

Developmental Patterns
Early-ASD versus Later-ASD

• By 14 months, the Early-ASD group exhibited significantly lower expressive language and shared social smiling scores than the Later-ASD group.

• By 18 months, the Early-ASD group exhibited greater delays in receptive and expressive language development compared to the Later-ASD group.

• At 24 months, this gap between the Early- and Later-ASD groups had closed due to increasing impairment in the later-ASD group.

• At 30 and 36 months, there were no detectable differences between the Early- and Later-ASD groups.

Early-ASD versus Non-ASD groups

• At 6 months, the Early-ASD and Non-ASD groups exhibited comparable development.


• At 14 months, the Early-ASD group diverged from Non-ASD development in all measured aspects of development, except for fine motor functioning.

• These differences were sustained through 36 months.

Later-ASD versus Non-ASD groups

• At 6 months, the Later-ASD and Non-ASD groups exhibited comparable development.

• At 14 months, the Later-ASD group’s scores were significantly lower than the Non-ASD group’s for fine motor and some language skills.

• At 24 and 36 months, the Later-ASD group performed below the Non-ASD group on all abilities examined except fine motor functioning at 24 months.

According to Dr. Rebecca Landa, the study’s lead author and director of Kennedy Krieger’s Center for Autism and Related Disorders, she notes that the study's determined patterns of development closely matches reports of early observations made by parents whose children were later diagnosed with ASD. The significance of this is that it shows the importance of parental observations in developmental changes that may be missed by health professionals during a routine visit.

“If parents aren’t seeing their children steadily develop new skills, they should talk to their pediatrician or contact their local early intervention program,” says Dr. Landa. “Results from this study show that communication delays are often present in the second year of life in children with autism, especially involving language comprehension.”

For now, the limit as to the earliest possible age to begin to detect signs of possible autism is at six months in infants. However, if an older sibling is diagnosed with autism, then the likelihood of the younger sibling developing autism is increased and bears careful observation by parents and communication with the infant’s pediatrician and health professionals skilled at diagnosing autism for providing early intervention as soon as possible.

For an informative article about detecting autism at home, follow this link to an article about the top ten signs of autism in infants.

Image Source: Courtesy of MorgueFile


Kennedy Krieger Institute news release “Distinct developmental patterns identified in children with autism during their first three years”

“Developmental Trajectories in Children With and Without Autism Spectrum Disorders: The First 3 Years”
Child Development--article first published online: 30 OCT 2012; Rebecca J. Landa et al.