Published on September 22nd, 20170
Developmental Language Disorder: Cutting a Path Through the Terminological Jungle
September 22 is Developmental Language Disorder Awareness Day. To help bring attention to the issue, we are happy to share the article below, reprinted with permissions from the Royal College of Speech Language Therapists.
By Dorothy Bishop
The year 2017 will be an important one for SLTs. The [Royal College of Speech Language Therapists] (RCSLT) is endorsing a change in terminology on the basis of a consensus exercise carried out last year. The term ‘language disorder’ will be recommended for children with severe and persistent language problems, with ‘developmental language disorder’ (DLD) replacing specific language impairment (SLI) in cases where there is no associated biomedical condition. Here, I aim to summarise the process that led to this change and describe the implications for those working with children with language disorders.
As a psychologist who has done research in this area since the 1970s, I had become increasingly frustrated at the lack of public awareness of SLI. The typical intelligent layperson is well aware of the existence of developmental dyslexia, autism spectrum disorder and attention deficit hyperactivity disorder, so why don’t they know about SLI? With colleagues Courtenay Norbury, Maggie Snowling, Becky Clark and Gina Conti-Ramsden I set up a campaign to Raise Awareness of Language Learning Impairments (RALLI) in 2012, with the idea of providing short, evidence-based video clips on YouTube to redress the balance.
We immediately hit a problem: we needed to explain what SLI was, but there was not good agreement about this. Furthermore, there was growing unease with the term SLI among many experts, as evidence mounted that the textbook descriptions of children with specific problems affecting only language development corresponded to a tiny minority of children presenting with language difficulties.
This discomfort was complemented by concerns among practitioners that children were being denied services because they did not fi t a specific definition of SLI that required them to have a substantial mismatch between verbal and nonverbal abilities and no other types of developmental problem. In some places, children could also be regarded as not having SLI if they came from a socially deprived background – on the logic that there was an environmental explanation for the language problems. Was this reasonable?
It was clear that there was little agreement on these issues, but they had important implications for both researchers and clinicians.
This confused situation provided the impetus for the RALLI group to turn its focus on issues of definitions and terminology for children’s language disorders. The approach we took to tackle this problem was the Delphi method. I had never heard of this until I had a serendipitous conversation with Professor Trisha Greenhalgh, who is a general practitioner with expertise in the use of qualitative research methods. I described the problem of SLI to her – that I was working on a condition that was common but which nobody had heard of – and my desire to improve the situation, and she suggested the Delphi method as a way of doing this.
I immediately saw the potential of the approach: it involves moving towards consensus by providing a panel of experts with a set of statements, which they can both rate and comment on. Panel members get to see one another’s ratings and comments, but the whole process is anonymised. This means they can know if their view is out of line with that of others, and then decide whether to stand their ground and make a better case, or change their views. An advantage of this approach is that the exercise can be conducted online, which means that you can include people from all over the world, and they can make their responses at a time they find convenient. The anonymity is also key: people are more willing to give an honest opinion and are less able to pressurise others if everyone can see the whole set of opinions without being aware of who said what.
We realised early on that the task ahead of us was mammoth, because we could only tackle the question of terminology if we knew which children we were talking about. So we needed two Delphi projects: one to reach some agreement about criteria for identifying children with language problems and another to tackle terminology.
Another complicating factor was that children’s language disorders are the concern of a wide range of professionals. We had to decide how far these should all be represented on our panel: it seemed appropriate to have SLTs predominate, as they are the profession with a core role in intervention, but we also aimed to include teachers, psychiatrists, paediatricians, general practitioners and psychologists. We also thought long and hard about how best to incorporate the views of families affected by language disorder, given that the intricate discussions of a Delphi panel required a sophisticated level of literacy and abstract comprehension as well as good knowledge of the academic literature.
On our panel we also included representatives of charities and support groups who had a close connection with families aff ected by language disorders and could judge the likely impact of diff erent criteria and terminology on them, as well as some panellists with affected relatives. We included panellists only from Englishspeaking countries, not because other countries don’t have terminological issues, but because if it’s hard to reach agreement about definitions and labels for language disorders in one language, it would be even harder to do so across languages.
I was impressed and humbled by the seriousness with which the panel approached their task. Not only did people make cogent arguments for or against specific positions, they also showed willingness to amend their views in the light of evidence. The job of pulling together all the viewpoints between rounds of ratings fell to me and Maggie Snowling; it was challenging but also fascinating, because reading people’s comments gave real insights into why there was disagreement on some issues – insights that made it easier to then reformulate statements for the next round, so that we ultimately obtained good agreement on both the Delphi projects. Nevertheless, some panel members had to concede that their views would not prevail and they did so with good grace, recognising the importance of obtaining agreement to improve recognition of children’s language disorders.
New criteria and terminology
The detailed results of both Delphi projects are now published as Open Access papers, so anyone can read them. The changes from previous practice are not huge, but there are nevertheless some points that will be controversial and will affect SLTs in clinical practice.
First, as noted above, we now recommend that we should talk of ‘developmental language disorder’ where previously ‘specific language impairment’ was used. Some panel members thought that ‘disorder’ was potentially stigmatising, but the counter argument was that milder terms such as ‘diffi culties’ or ‘needs’ suggested mild or transient difficulties. We wanted a term that would specifically apply to children whose difficulties were severe enough to interfere with everyday functioning in communicative and academic contexts. We also proposed that we should use what we knew about outcomes from longitudinal studies to restrict the term ‘disorder’ to children whose language problems were unlikely to resolve with good teaching alone.
We explicitly rejected two widely-used criteria for language disorder: first, the idea that ‘disorder’ requires a mismatch between verbal and nonverbal ability, and second, the notion that an uneven profile of language skills is diagnostic of disorder. Although these criteria have been influential for many years, they have no basis in evidence, and have arguably led to many children who would benefit being denied services.
In 2017, we plan a number of initiatives to raise awareness of the new criteria and terminology. My hope is that by reaching clearer agreement about how to recognize and talk about DLD we will make it easier to achieve recognition for these common problems and ensure that support is available for all children who need it.
References and Resources
Bishop DVM, Snowling MJ, Thompson PA, Greenhalgh T and CATALISE Consortium. (2016). CATALISE: a multinational and multidisciplinary Delphi consensus study of problems with language development. Phase 2: Terminology (preprint – not peer reviewed). PeerJ. doi: 10.7287/peerj.preprints.2484v1
Bishop DVM, Snowling MJ, Thompson PA, Greenhalgh T and CATALISE Consortium. (2016). CATALISE: a multinational and multidisciplinary Delphi consensus study. 1. Identifying language impairments in children. PLOS One.
Professor Bishop’s International Journal of Language and Communication Disorders Winter Lecture is available to view online: tinyurl.com/o5glrlv
Bishop, Dorothy. (2017). Developmental Language Disorder: Cutting a Path Through the Terminological Jungle. RCSLT Bulletin, February, 12-14. Retrieved from https://www.rcslt.org/clinical_resources/docs/bulletin_feb2016_pg12_13
About the Author
Dorothy Bishop is a professor of developmental neuropsychology in the Department of Experimental Psychology at the University of Oxford.