HKU Bulletin April 2006 (Vol. 7 No. 2)

11 Learning to Understand Autism S cientists have discovered that the brains of Chinese children with autism have grey matter differences compared to children without the disorder. Drs Grainne McAlonan and Chua Siew Eng, Assistant Professors of the Department of Psychiatry, have become the first to use Magnetic Resonance Imaging (MRI) to map grey and white matter differences across the whole brain in Chinese children with autism. What they discovered, in examining the brain anatomy of high-functioning Chinese children with classical autism, was abnormalities in connectivity in the parts of the brain governing social interaction. Autism is a neurodevelopmental disorder which affects an individual’s ability to interact socially and communicate properly with others. It is often marked by repetitive behaviour and restricted interests. Although highly genetic it remains one of the least understood disorders of brain development and, as Dr McAlonan explained, “We do not know exactly what causes it, nor do we know exactly how the brain changes in autism. “Hence research into all aspects of autism is vital to better understand this condition and assist those who suffer from it.” Working alongside scientists from Cambridge University’s Brain Mapping Unit the team was able to use MRI to look in detail at changes in brain structure in Chinese children with autism. “There have been other studies done in western populations using MRI. However no-one has looked at the relationship between brain structures affected by autism as we have done. “When brain regions are connected together they grow together – therefore you expect their volumes to be positively correlated. In autism we found that the volumes of brain regions involved in 'social' behaviour were not correlated to the same extent as in control children without the disorder.” The researchers interpreted this as evidence for ‘disconnectivity’ across brain regions control l ing social behaviour in autism. “We believe this starts very early in life and may explain why people with autism have such difficulty in a range of social interactions,” said Dr McAlonan. She explained that although people with autism experience difficulties in social spheres they may also have very striking strengths or talents. “How the brain develops to cause this uneven pattern of ability is a great puzzle and therefore very challenging from a scientific perspective. As a parent I can only imagine how difficult it must be to have a child who struggles to interact socially, who may not smile or greet one and whose potential may not be recognised because our world demands that we interact socially in almost every walk of life.” The research should increase understanding of the condi t ion, and help in developing new management approaches for children with the disorder. 10 RESEARCH Language Study Is a Family Affair W hen Stephen Matthews and Virginia Yip started a family, they produced more than a child. A baby in the house provided the perfect starting point for these linguists to research the development of bilingualism in children. Timmy, now aged 12, was followed by sisters Sophie, 9, and Alicia, 5. Together with four offspring of other academics, they have been extensively videotaped interacting with Chinese- and English-speaking researchers and had their utterances transcribed and analysed for insights into how children become bilingual. The result is the world’s largest video-linked database on the subject, which has been posted on the website of the Language Data Exchange System of Carnegie Mellon University in the United States. Matthews and Yip are also writing a book, The Bilingual Child: Early Development and Language Contact , to be published by Cambridge University Press. Their study is the first to pair English and Chinese, as most other research has paired two European languages. The children all had a native English-speaking parent and a native Cantonese- speaking parent. Matthews, Associate Professor and Head of the Department of Linguistics, and Yip, a professor of linguistics at The Chinese University of Hong Kong, found children learned the languages at different paces and there was a lot of interaction between each language. The children tended to master Cantonese first, reflecting the extended family structures in Hong Kong where they have frequent contact with their Cantonese-speaking relatives. But just because one language was dominant did not rule out the development of bilingualism. “One subject, Janet, was very fluent in Cantonese from age two and a half, but only produced odd words in English. Suddenly at age three, her English exploded into full sentences,” Matthews said. “It’s all latent, it’s all there,” said Yip. “I’m sure she already understood a lot of English before she started speaking it. We call this a long silent period. It happens in second-language acquisition by adults, too.” Matthews and Yip also found the grammar of one language influenced the other. Some subjects in the study would use Cantonese grammar in English, for example, asking a question with the form ‘this is what’ not ‘what is this’. Or the other way around, using English grammar in Cantonese and saying ‘give her chocolate’ rather than the correct form, ‘give chocolate her’. “You don’t see these structures in monolingual children at that age,” Matthews said. Changes at home had an influence on language usage. When English-speaking relatives were visiting, children tended to speak more English. Some children also had a natural preference for speaking one language, or would object when their parents switched to their non-native language. Yip said they hoped their findings could provide guidance for parents who want to raise bilingual children. Their main advice was to have a lot of family support, accept that it may take a little longer to master two languages so there will be some delays in speaking, and provide a good balance of input from both languages. Even monolingual parents could encourage bilingualism by providing their children with a social network that connects them to children who speak other languages, she said. The more typical Hong Kong family, where both parents are native Cantonese speakers but also speak English, is next in their sights. Matthews and Yip plan to study families where one parent chooses to speak English to the child, to track how bilingualism develops in such circumstances.