Abstract | Summary | Original Article

Social and communication development in toddlers with early and later diagnosis of autism spectrum disorders.

Landa RJ, Holman KC, Garrett-Mayer E.

Archives of General Psychiatry. 2007; 64(7): 853-864.

Question: What is the communication and social development of 14- to 24-month-old children who have older siblings with ASD?

Background: Although there is on-going research looking for an early identification test for ASD in infants, most children are still diagnosed around age 3 or later. What could help improve the early identification of children with ASD is knowing what ASD looks like in infants and young toddlers. As there has been little research looking at the development of children who are eventually diagnosed with ASD, this study assembled a group of children who, because they have older siblings with ASD, are at greater risk of developing the condition. They were tested and observed at 6, 14, 24, and then at 30 or 36 months of age, when a diagnosis of ASD is known to be reliable.

Design: A prospective, longitudinal study.

Setting: A major US medical and research institute.

Participants: 107 siblings of children with a diagnosis of autism and 18 control children in the same age group with no family history of autism or any symptoms of ASD themselves.

Main Outcome Measures: The Communication and Symbolic Behavior Scales Developmental Profile. During the testing, the children were presented with situations that would tempt them to talk to or otherwise to communicate with the tester. For example, a tester opens a jar of bubble mixture, blow bubbles, closes the jar, and then sets it in front of the child. If the child wants more bubbles, s/he has to ask.. The task also tests for joint attention, receptive language, and offers an opportunity to play. The ADOS was used to describe autistic behaviours, the Mullen Scales of Early Learning was used to test for developmental level, and the Preschool Language Scale determined the level of the child’s receptive and expressive language.

Main Results: At 30 or 36 months of age, the children were grouped according to their test results as having an early diagnosis of autism (at 14 months of age), a later diagnosis of autism, being on the broader autism spectrum, or not being on the broader autism spectrum. The children who were diagnosed at 14 months (early diagnosis) differed from all the other groups in having worse impairments in joint attention, use of gestures, sounds, and words to communicate their wants and needs or to share experiences with others. There seemed to be a lack of motivation to interact with others. They also were less likely to engage in shared enjoyment with others or in creative play. At 14 months of age, the later diagnosis group seemed only to have difficulty shifting their attention from one object to another. The social communication skills some of the later diagnosis children seemed to plateau or even decline after a period of apparently normal development.

Conclusions: This study described the early emergence of ASD symptoms in a group of children at risk for developing the condition and a group of children who were not at risk. In children who at 30 or 36 months had a firm ASD diagnosis, there were distinct problems with joint attention, ability to shift attention, and the use of gestures or sounds to communicate with others. At 14 months, children with an early diagnosis tended to have more symptoms than did children with a later diagnosis. Children with a later diagnosis showed variation in the way they developed ASD symptoms. Some had a slowing of their development generally, in others development seemed to stop, and another group lost skills they had already mastered. If screening is contemplated, then two waves should be used: one around the first birthday and another around age two in order to find all of the children who have an ASD.