MA DPhil FBA FMedSci FRS
Professor of Developmental Neuropsychology
- Wellcome Trust Principal Research Fellow
Genetics, neurobiology and psychology of children's communication impairments
My research is concerned with trying to understand the nature and causes of language impairments in children. In some cases, language difficulties have an obvious cause, such as hearing loss or a syndrome such as Down syndrome. In other cases, children have particular difficulty learning to talk or understand language for no obvious reason.
My recent work has been particularly focused on these children with 'specific language impairment' or SLI, who are quite common (around 3% of the population) but tend to be neglected by researchers. Using twin studies, I have shown that there is a strong genetic component to these disorders, and I have worked with molecular geneticists to try and find out more about particular genes that are implicated. Currently, we are also conducting a study of children who have an extra X or Y chromosome, who are at particular risk of speech and language dififculties, despite having broadly normal intelligence. These children are very variable in their language skills – although many have difficulties, others have no obvious problems. We hope that by relating their genetic makeup to their language abilities, we will be able to throw light on the causes of their language difficulties, and also gain more understanding of how genes affect language learning in children who have the normal complement of chromosomes.
My work also extends into the study of related conditions, such as autistic spectrum disorder and developmental dyslexia, which share many overlaps with SLI. I am particularly interested in whether genetic variants that cause a risk for language impairment are also implicated in these other conditions.
In another line of research I have used measurements of brain activity to study how children with SLI respond to different sounds. By averaging the small electrical signals in the brain that are elicited by sounds, we can gain insights into which sounds children can distinguish, and which brain regions are involved in sound perception. In this work we have found evidence that children with SLI engage larger and less focal brain regions than other children of the same age, especially when listening to speech sounds. The challenge is to work out if this is an underlying cause of their language problems, or rather a consequence of weak language skills.
Ultimately, by unravelling the genetic and neurological causes of language problems, we hope to be able to find ways of helping overcome these problems with early intervention. However, such translational studies are a long way off, and meanwhile, we are also doing studies of children's learning which may lead to more immediate application. We have found that children with SLI have no basic impairment in learning to associate sounds and pictures, but they do have particular problems in learning to recognise sequential patterns. This difficulty is evident even when no language is involved, and could explain why children have such difficulties with learning grammatical constructions, such as appropriate use of past tense endings. This work could help us identify the best conditions for teaching language skills.