Led by Professor Maggie Snowling, Professor Charles Hulme and Dr Emma Hayiou-Thomas this six-year longitudinal study from 2007, funded by the Wellcome Trust, investigated the nature of the developmental relationships between dyslexia and specific language impairment (SLI).
It is widely accepted that children who have pre-school speech or language difficulties often develop reading difficulties and that children who go on to develop dyslexia have early language weaknesses. This study traced the development of three groups of children from the age of ~3 to 8–9 years old:
- children from a family where there was a history of dyslexia;
- children who had pre-school speech and/or language difficulties;
- children who had neither a family risk of dyslexia nor a pre-school language difficulty.
The Wellcome Language and Reading project had the following aims:
- Trace the language and literacy development of children at family-risk (FR) of dyslexia, children with SLI and controls, and to find out how common reading difficulties are in these groups of children at 8 years old
- Investigate the co-occurrence of dyslexia and SLI
- Investigate the contribution of home environment to the development of literacy skills in ‘at-risk’ and typically developing children
- Investigate whether intervention could improve the reading skills of children whose reading development was delayed at 6 years old
- Consider how a child’s response to intervention relates to the severity of their underlying cognitive and language deficits
- Contribute to genetic studies of dyslexia and SLI
Plan of investigation
The project was divided into six phases. Each phase involved assessing children on a battery of tests specifically designed to look at language, literacy and phonological skills. There were 260 children in the initial sample and the children were seen at annual intervals at approximately 3.5, 4.5, 5.5, 6.5, 7–8 and 9 years old.
To confirm whether or not a child was at risk of dyslexia, the team aimed to assess both parents of each child in the study. Parents also completed a self-report questionnaire. More than 350 parents were formally assessed on tests of literacy and phonological skills (see M. J. Snowling, P. Dawes, H. Nash & C. Hulme (2012) Validity of a Protocol for Adults Self-Report of Dyslexia and Related Difficulties). Aside from using these data to validate self-report of dyslexia, we noticed that a worrying number of parents who have poor literacy are not aware that they themselves could be ‘dyslexic’ (see R. Leavett, H. Nash & M. J. Snowling (2014) Am I Dyslexic? Parental Self-Report of Literacy Difficulties). Many parents also report attentional difficulties. They may be in need of advice on how best to support their child’s learning. In addition it is important to help them with ways of ensuring that their child’s progress in reading and writing is ‘on track’.