Professor Courtenay Norbury of University College London, shares some background to the new DLD terminology and some implications for planning services
Developmental Language Disorder: background and implications
Language is a uniquely human skill that underpins our social interactions, learning, and access to many leisure activities. It is therefore no surprise that talking and listening skills predict children’s school success and social and emotional well-being. Self-talk is also an important tool for being able to control our own behaviour and to regulate our emotions.
For most children, language learning is effortless with new words and grammatical structures learned implicitly from interactions with others or from stories or even some children’s television programmes (Octonauts being a personal favourite). However, for some children learning language is not so easy. Sometimes difficulties learning language are part of a broader developmental condition, such as autism or Down syndrome. For others, language deficits are unexplained, and other aspects of development may not be so affected. As a community, we have agreed to identify these children as having Development Language Disorder, or DLD.
Labels are important
When children aren’t developing as expected, a diagnosis can be extremely important to parents as it gives a label that allows them to talk to other professionals and family members, to find out more about the condition, and is often necessary to access services. Until recently, we have been very inconsistent in how we label DLD, leading to much confusion and a lack of public awareness of language disorder and how it affects children’s lives. It also has far reaching consequences for research funding, research publications, and thus prioritisation of services. Most people in society have heard of autism or dyslexia, and agree that services for children affected by these conditions are a necessity. But if we don’t have a name, how can we convince the public that language disorders are a priority?
Recently, Dorothy Bishop led the CATALISE consortium of researchers, clinical and education practitioners, policy makers and representative from parent organisations to achieve consensus on a diagnostic label and core diagnostic criteria. You can read these reports in detail here and here. Although there was much debate amongst the consortium members, we agreed on DLD as the most appropriate label.
Why DLD and not specific language impairment?
There is growing recognition that language problems often co-occur with other developmental concerns such as attention deficits (ADHD); behaviour problems; intellectual disabilities; problems with reading, writing, and maths; executive function deficits and motor difficulties (Developmental Coordination Disorder; Dyspraxia). Thus, the term ‘specific’ language impairment caused confusion and led to some services excluding children that had other difficulties. The CATALISE team strongly recommended that co-occurring deficits should not preclude diagnosis or access to services.
There was considerable discussion about the connotations of ‘disorder’ versus ‘impairment’ versus ‘need’. Disorder is a word that most members of the public would associate with a condition that is serious, has functional impact, and is worthy of support and intervention. It is also in line with other recognised developmental conditions such as autism spectrum disorder and attention deficit hyperactivity disorder. Finally, it emphasizes the fact that language disorders stem from biological factors that affect the child’s ability to learn. Changing aspects of the environment can be helpful, but we need to recognise that, as with most other developmental disorders, DLD is a lifelong condition that is not readily cured, and thus requires on-going support.
How many children have DLD?
Recent research from my lab indicates that two children in every primary school classroom start school with DLD. Children with DLD also experience early functional impacts, in that they are more likely to show evidence of social, emotional and behavioural difficulties, and very unlikely to meet early curriculum targets (for example, on the Early Years Foundation Stage Profile). Importantly, our work also demonstrated that lower scores on a non-verbal IQ test did not yield a fundamentally different profile of language, learning aptitude, or behaviour. For these reasons, CATALISE recommended that diagnosis of DLD should not require a discrepancy between verbal and non-verbal abilities, nor should services be restricted to those with non-verbal IQs within the typical range.
What causes DLD?
Like autism and ADHD, there is no simple answer to this question. We know that DLD is associated with a number of risk factors such as family history, male sex, socio-economic disadvantage, lower levels of parental education, and problems around or before time of birth. Some of these risk factors are often considered ‘social’ or ‘environmental’ risk factors and there is a common misperception in the media that language disorders stem from poor parenting practices. This is absolutely not the case! Research has demonstrated that small differences in genes (some of which may be inherited) can influence brain development in a way that makes language learning harder. That doesn’t mean that we are powerless to intervene – we can adapt environments to facilitate language learning. However, we should recognise that differences in what parents of children with DLD say and do is not ‘causing’ their children’s language disorder, but reflects a complicated interplay of genetics, response to the child’s language difficulties, and parent confidence in speaking, listening and reading.
What can be done to help?
Many research groups around the world are now demonstrating that language abilities are incredibly stable, particularly once children are of school age. Children continue to learn new words and grammar, and in fact, the rate of learning is the same for children with DLD as it is for children without language disorder. However, high stability means that ‘narrowing the gap’ between children with DLD and their peers or in effect ‘curing’ language disorder is rare. So should we focus all of our therapy efforts on very young children? For language disorders associated with other developmental conditions, early intervention is crucial. But when no other risk factors are present, I’m not so sure, in part because there is good evidence that many of these children will resolve early difficulties without any extra help.
To my mind, a focus on developing children’s oral language skills in the early school years is a huge priority, particularly as language is the best predictor of academic success. The goal for therapy services should be to ensure that children have the language they need to access the curriculum, interact with peers, and use language as a tool to manage their behaviour and solve problems. Supporting adolescents and young adults with DLD in the transition to secondary school, higher education, and independent living is also a priority, especially given the strong links between language, employment, and good mental health. This group of young people is currently under-served and under-represented in clinical services and research. I hope that by raising awareness of DLD and being consistent in our terminology, we can achieve better outcomes for all of our children.
Find out more about DLD: www.youtube.com/RALLIcampaign