Two Autism Studies Find Clues About the "Social Brain" and Early Diagnosis
Marlene Busko Medscape Medical News 2007. © 2007 Medscape July 16, 2007
Explicit instructions to attend to social cues seemed to "normalize" activity in the "social brain" of children with autism, and some toddlers at risk for autism might be diagnosable at 14 months, according to 2 studies published in the June and July issues of the Archives of General Psychiatry, respectively.
Reading Affect in the Face and Voice In 1 study, led by A. Ting Wang, PhD, now at Mount Sinai School of Medicine, in New York, when children with autism spectrum disorders (ASD) '" including autism and Asperger's syndrome '" were given explicit instructions to pay attention to facial expression and tone of voice, this elicited increased activity in the brain's medial prefrontal cortex, the area that is important for understanding the intentions of others.
Dr. Wang commented to Medscape that this is the first study to show that activity in a region that is a key component of the "social brain" can be "normalized" in children with autism, simply by providing them with specific instructions to pay attention to important social cues. She added: "This is important, because it shows that there isn't anything that's inherently wrong with this region. It's not that individuals with autism cannot activate this region. They just require some direction to attend to the salient contextual cues, and this suggests a strategy for future intervention." High-functioning individuals with ASD often have normal or even superior IQs and can have an extensive vocabulary, Dr. Wang explained, but they can still have impairments in understanding the context of conversation, especially when sarcasm or irony is involved. She added that little is known about the neural basis of these communication deficits. Previous neuroimaging studies have shown reduced activity in brain regions that respond to face and voice. In an earlier study, the group found that giving cues about tone seemed to illicit more normal brain responses.
Their goals in the current study were first, to examine the neural circuitry in children with autism who were asked to determine whether a statement in a conversational setting was sincere or ironic, and second, to see whether explicit instructions to pay attention to important cues would elicit more normal patterns of brain activity. A total of 18 boys with ASD (age 7 to 17 years) and 18 typically developing boys (age 9 to 15 years), all with full-scale IQ greater than 70, underwent functional magnetic resonance imaging during the presentation of potentially ironic scenarios. The participants listened to conversations and viewed corresponding cartoon drawings of the scenarios. They were instructed to identify whether the ending comment in the vignettes was sincere or ironic (meant the opposite of what was said).
When given neutral instructions, the typically developing children, but not the children with ASD, showed activity in the medial prefrontal cortex of the brain. However, when they received explicit instructions to pay close attention to facial expression and tone of voice, the children with ASD also showed activity in this region. These findings demonstrate that "by instructing children with autism to attend to faces and voices in various contexts, we may be able to train the brain to use these cues to interpret the intentions of others and negotiate social interactions more successfully," Dr. Wang summarized. Her group will be investigating whether a cognitive behavioral approach could be effective for teaching social perception skills in autism.
Diagnosis of Autism at 14 and 24 Months In a prospective, longitudinal study, Rebecca J. Landa, PhD, from the Kennedy Krieger Institute, in Baltimore, Maryland, and colleagues showed that among toddlers at high risk for autism (who had siblings with autism), of 30 diagnosed with autism at 36 months, 16 had shown atypical social, communication, and play behavior at 14 months (early diagnosis of autism), and 14 showed these differences at 24 months (later diagnosis).
"We need to be screening for autism [early], certainly by 18 months, and if a child passes the screening, we still need to rescreen, because autism can come on board after toddlerhood," Dr. Landa told Medscape.
The average age of diagnosis of autism is between 3 and 6 years of age, she explained. The group aimed to examine patterns of social and communication development from 14 to 24 months in children with early and later diagnosis of ASD.
They evaluated development in 107 infants at high risk for autism and 18 low-risk infants from 14 months to 30 or 36 months, when an outcome diagnosis was made. The outcome diagnoses were autism (30), broader autism phenotype (19), and non-broader autism phenotype (58). "[Fourteen months is] the earliest that autism has ever been reported to be diagnosed, but not all children with autism are going to be diagnosable at this age," Dr. Landa cautioned. She added that in some children, symptoms appear gradually and begin to be present by 24 months. It is also important to note that skills are not completely lacking at 14 months, she observed. "So if you're expecting a child to have a lack of communication or a lack of smiling at people, you're going to miss a lot of the children. Rather, the picture is that there are multiple features, and those behaviors are very inconsistently and infrequently present '" behaviors like social engagement, looking at people and smiling, and initiating communication for social purposes."
Their study highlights the need for early intervention to target social and communication development in toddlers with ASD, the group writes. They add that further studies in larger samples are needed to replicate their preliminary findings and to develop reliable, validated diagnostic tools to allow accurate, earlier diagnoses in children aged 2 years and younger. Arch Gen Psychiatry. 2007;64:698-708 and 853-864.