A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Spring, 2019 | Number 2, Volume 33

Highly accurate diagnosis of ASD possible at 14 months

Most children with autism spectrum disorders (ASD) receive a diagnosis after their third birthday, but a new study indicates that trained professionals can make an ASD diagnosis with a high degree of accuracy when children are as young as 14 months of age.

Karen Pierce and colleagues analyzed data on 441 toddlers with ASD and 828 controls without ASD. All of the children had received their first diagnostic evaluation between 12 and 36 months of age and had undergone at least one subsequent evaluation, with all evaluations performed by licensed psychologists. Diagnoses included ASD, features of ASD, language and developmental delay, and other developmental issues.

The researchers report that the overall diagnostic stability for ASD was 0.84, which was higher than for any other diagnostic group. Only 2 percent of children initially diagnosed with ASD were later found to be developing typically. Among children initially diagnosed with ASD, the most common transition was from ASD to ASD features (9 percent). 

The diagnostic stability of ASD at 12 to 13 months was only 0.50, but increased to 0.79 by 14 months and 0.83 by 16 months. Twenty-four percent of toddlers did not receive an ASD diagnosis at their initial evaluations but were identified later. The most common transition in this group was an initial designation of developmental delay (25 percent) or language delay (16 percent), transitioning to later-onset ASD.

Study coauthor Karen Pierce notes that early diagnosis is important, saying, “The sooner you can address issues of ASD, the better the outcome for the child.” She adds, “Synaptic density, or connections between neurons in the prefrontal and temporal cortex, brain regions centrally involved in higher order social behavior, doubles between birth and one to two years in age. It’s conceivable that outcomes for children with autism could be improved if treatment occurred during this period of rapid brain growth, rather than after, which is more commonly the case.”


“Evaluation of the diagnostic stability of the early autism spectrum disorder phenotype in the general population starting at 12 months,” Karen Pierce, Vahid H. Gazestani, Elizabeth Bacon, Cynthia Carter Barnes, Debra Cha, Srinivasa Nalabolu, Linda Lopez, Adrienne Moore, Sunny Pence-Stophaeros, and Eric Courchesne, JAMA Pediatrics, April 29, 2019 (free online). Address: Karen Pierce, Department of Neurosciences, University of California, San Diego, 8110 La Jolla Shores Dr., La Jolla, CA 92037, [email protected]


“Autism diagnoses prove highly stable as early as 14 months,” Scott LaFee, UC San Diego News Center, April 29, 2019.