Researchers from the HSE Centre for Language and Brain and their Russian and American colleagues have become the first to compare expressive and receptive language abilities of Russian children with Autism at different linguistic levels. Their work helped them refute the hypothesis that children with autism understand spoken language less well than they produce it. The study was published in Research in Developmental Disabilities.
Almost 75% of children with Autism have language impairment, although it is not a diagnostic criterion of ASC. The studies, however, disagree on the difference in the degree of impairment between expressive and receptive language in ASC.
Some researchers have argued that expressive language is more intact in children with ASC than receptive language, and some consider the expressive-better-than-receptive pattern in language to be a unique hallmark of ASC.
Researchers from the HSE Centre for Language and Brain, the Federal Resource Centre for ASD (Moscow State University of Psychology and Education), and Haskins Laboratories (New Haven, United States) decided to check this hypothesis. They tested 82 Russian-speaking children with ASC and compared expressive and receptive language at different linguistic levels within the same group. The scientists used the RuCLAB (Russian Child Language Assessment Battery), which was developed at the HSE Centre for Language and Brain. The comparison was conducted at three levels: vocabulary (word production and comprehension), morphosyntax (sentence production and comprehension), and discourse (text production and comprehension).
The analysis shows that there is no a single expressive-receptive language pattern in children with ASC. For example, it is impossible to say that expressive domain is more intact than receptive. Furthermore, the results show that the difference in expressive and receptive language depends on the linguistic level: single-word production was more affected than single-word recognition in children with ASC, sentence production and comprehension were equally affected, and production of texts was more intact than the comprehension of texts.
‘For us, it was important not only to describe the difference between expressive and receptive language at different linguistic levels in children with ASC, but also to understand whether the level of a child’s non-verbal intelligence affects these patterns,’ said Vardan Arutiunian, author of the paper and a junior research fellow at the HSE Centre for Language and Brain.
In order to understand whether non-verbal intelligence (IQ) affects the difference between receptive and expressive language at different linguistic levels, the children with ASD were divided into two groups. One group included children without intellectual disabilities (non-verbal IQ at normal range), and the other included children with intellectual disabilities (non-verbal IQ lower than the normal range). Word, sentence and text production and comprehension were then compared between the two groups separately.
The results of the study show that non-verbal IQ partially impacted expressive and receptive language patterns. No difference between the two groups was observed at the vocabulary level: in both groups, single-word production was more impaired than single-word comprehension.
The researchers did observe a difference between the two groups at the morphosyntax level: in children without intellectual disabilities, sentence production and comprehension were equally affected, while in children with intellectual disabilities, sentence comprehension was more intact than sentence production.
A difference in expressive and receptive patterns between the two groups was also observed at the discourse level. Children without intellectual disabilities displayed no difference between expressive and receptive domains, while text production in children with intellectual disabilities was more intact than comprehension.
‘The difference between word, sentence and text production and comprehension partially depends on non-verbal intelligence. But it is still too early to talk about any ASC-specific patterns,’ Vardan Arutiunian believes. ‘There are still only a few papers that systematically compare expressive and receptive language at different linguistic levels while taking non-verbal IQ levels into account. Our study is one of the first of its kind, and we will continue our work using neuroimaging methods such as magnetoencephalography, electroencephalography and magnetic resonance imaging.’
The researchers believe that understanding the neurobiological mechanisms of expressive and receptive language in children with ASD will help with the objective diagnosis of language impairments, as well as with speech therapy and rehabilitation.