A new study has confirmed that language delay leaves a “signature” in the brain, primarily measured by differences in brain volume. It’s the primary signifier for Autism Spectrum Disorder (ASD), a developmental disability characterized by social, communication, and behavioral challenges.
Researchers from the University of Cambridge in the UK have just published new findings in the journal Cerebral Cortex, as reported by Medical News Today.
It’s a serious disorder, affecting millions. The Centers for Disease Control and Prevention (CDC) estimates that ASD occurs in about 1 in 68 children in the US, and that it is five times more common in boys than girls.
“Appearing during early childhood, ASD does not typically carry with it identifying physical characteristics,” notes Medical News Today. “However, those with the condition may communicate, behave, and learn in ways that are different from the majority of other people.”
No medical tests exist for the diagnosis of ASD; as a result, doctors make clinical decisions after assessing a child’s behavior and development.
What are the signifiers?
For one, delayed language onset. That is said to occur when a child’s first meaningful words come out after 24 months of age, or when their first phrase occurs after 33 months.
The lead author of the study, Dr. Meng-Chuan Lai of the Cambridge Autism Research Centre, believes the current research will help medical scientists better understand the varieties of ASD that present in doctors’ offices worldwide.
“Although people with autism share many features, they also have a number of key differences,” explains Lai. “Language development and ability is one major source of variation within autism. This new study will help us understand the substantial variety within the umbrella category of ‘autism spectrum.”
To conduct their study, the research team studied 80 adult men with autism – 38 of whom had delayed language onset – who were part of the Medical Research Council Autism Imaging Multicentre Study (AIMS).
In the men who had delayed language onset, the researchers found that certain key regions of the brain had smaller volumes, including the temporal lobe, insula, and ventral basal ganglia. Additionally, these men also had larger brainstem structures, compared with those who did not have delayed language onset.
The research team also noted a link between language function and a specific pattern of grey and white matter volume changes in key brain regions, including the temporal, frontal, and cerebellar structures.
Dr. Lai says their study shows how the brains of autistic men differ, based on early language development and current language function.
“This suggests there are potentially long-lasting effects of delayed language onset on the brain in autism,” Lai explains.
But since the American Psychiatric Association removed Asperger Syndrome as a distinct diagnosis from its diagnostic manual in 2013, it has become important for researchers to distinguish the entire spectrum of disorders.
“We need to move beyond investigating average differences in individuals with and without autism, and move towards identifying key dimensions of individual differences within the spectrum,” Lai says.
The social and economic costs are daunting. Diagnosis and treatment of ASD costs at least $17,000 per year per child. Additionally, many children do not receive a final diagnosis until they are older than age 2, which means children with ASD may not get the early help they require.