Children with autism have more difficulty filtering and processing sounds, particularly in the brain region typically responsible for language comprehension, a small experimental study of brain activity has found.
The study found two anatomical differences in children with Autism Spectrum Disorder (ASD). The auditory cortex in their left hemisphere – which is typically responsible for auditory perception and comprehension– was thinner. And the gyri – the folds on the surface of the brain’s cerebral cortex – were more curved and deeper.
The more pronounced these differences were, the greater difficulties children had with language comprehension and communication, the scientists said.
The most significant differences were in processing and filtering repetitive sounds.
The international team of researchers combined magnetoencephalography and morphometric analysis in a single experiment for the first time to study children with ASD.
The study in 40 children, 20 with typical development and 20 with a confirmed diagnosis of ASD, was published in Cerebral Cortex on 3 March 2025.
The scientists said people with ASD often had difficulty perceiving and processing sounds such as distinguishing speech in noisy environments, adapting to loud stimuli, or ignoring repetitive noises.
Research indicated that these difficulties were linked to the functioning of the primary auditory cortex, the part of the brain’s temporal lobe responsible for basic sound processing.
But the researchers said the precise ways in which auditory processing impacted language and communication in individuals with ASD remained poorly understood.
To explore the link between sound perception and language difficulties in children with ASD, researchers from the HSE Centre for Language and Brain in Moscow, together with other colleagues from Russia, the US and New Zealand conducted a study.
They combined magnetoencephalography (MEG) which tracks brain activity in response to specific stimuli with millisecond precision, and morphometric analysis based on structural MRI data, which examines the quantitative and qualitative features of the auditory cortex such as its volume, thickness, and the shape of its gyri.
While the children listened to short clicks, the scientists recorded their brain activity. The researchers focused on three components of the brain’s auditory response: M50, M100, and M200, which occur 50, 100, and 200 milliseconds after the sound is presented.
Each component reflects a different stage of processing, ranging from basic perception to filtering and comprehension.
The most significant differences in sound processing were found in the M200 component, involved in processing and filtering repetitive sounds.
“We aimed to determine whether the perception of simple sounds is linked to language difficulties in children with ASD,” said Ms Olga Dragoy, director of the HSE Centre for Language and Brain.
“Our results show that language difficulties in these children begin at a very early stage, when the brain first recognises and processes basic sounds.”
Another co-author, Ms Alina Minnigulova, a research fellow at the HSE Centre for Language and Brain said the auditory cortex in the left, “linguistic” hemisphere helped children not only distinguish sounds but also learn to comprehend language and speak.
“Perhaps it develops differently in children with ASD, which in turn affects their ability to comprehend language,” she said.
“Studying the relationship between auditory processing and language skills can aid in early diagnosis and the development of new educational and therapeutic approaches for children with ASD.”
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