Friday, March 14, 2014

Understanding Down syndrome – are we doing the right research?

by Sue Buckley from her blog at
I recently had the honour of being invited to be a discussant at a symposium on Language, Reading and School Readiness in Down syndrome at the Gatlinburg conference on Research and Theory in Intellectual and Developmental disabilities (see for program and abstracts). As my remarks were well received I decided to write them up for my blog and perhaps encourage some discussion. There were a number of interesting papers relevant to understanding learning and development in children with Down syndrome during the meeting and as I listened a number of questions emerged for me.
1. How relevant are ‘typical’ models of development?
For example, in trying to understand the challenges that face children with Down syndrome as they learn to read studies frequently compare the way that they learn and use component skills with ‘typically developing’ children matched for word reading ability. One repeated finding is that the children with Down syndrome are ‘behind’ in their understanding and use of phonics – the ability to sound out letters and blend them when faced with an unfamiliar word. However, they are often competent at reading exception words – using visual sight word learning strengths. I think we need to be cautious in the way we interpret these results – as there may be different ways to achieve an endpoint. Given the incidence of hearing impairments in early years and the difficulties of developing clear speech, we should not be surprised that children with Down syndrome are not well set up to hear or manipulate sounds in words in an aural mode as they begin to learn to read and rely more heavily on the visual route to word identification than the phonological recoding one. In my experience, by the time children with Down syndrome have word reading ages of about 8 years, they do begin to be able to sound out words to read them and to spell and they are helped in this by the visual representation of the sounds in letters and by building words with plastic letters i.e. they go from the visual to the phonological as they are exposed to activities with letters and printed words. I am using this example to caution against the view that the only or even the best way for children with a disability to learn to do something is the way most other children do it. It may be more productive to recognise that there are different ways to reach an endpoint and to actually encourage children to use their strengths and build skills in a different order.

The ‘typical’ models we have of development are based on how children without sensory or learning challenges progress – they are not necessarily showing us all the different ways the human brain may be able to achieve an end point. I have used a reading example but I would argue this is just as relevant in other areas of development. If we teach children to sign by pairing spoken words with signs as they start to learn to communicate then we may well be building different pathways in the brain and ones that appear to help them retrieve spoken words as they progress. If delayed motor skills impair children’s ability to explore, manipulate and understand objects can we teach them by demonstration and by physically supporting them to explore toys at the age when other children begin to play with objects?
2. The difficulty of interpreting studies using ‘typically developing’ controls.
Many studies compare children with Down syndrome with ‘typically developing’ children matched on mental age and then identify that the children with Down syndrome are delayed on a measure – for example that they are less likely to use mental state words such as know, think, when telling a story. We usually have no information on how similar the early language learning experiences of the two groups of children have been. Similarly, if we are looking at reading or number outcomes, we have no idea whether the two groups of children have had as much experience of books or counting games at home or how similar their educational experiences have been. Unfortunately, most studies demonstrating differences are interpreted as telling us something about the learning abilities of children with Down syndrome rather than reflecting the more complex picture. Development is dynamic and social – children learn in interaction with others. In this transactional process, child and adult influence each other – if a child is not giving the cues expected of a child of their age it is highly likely the input given to them is not the same. We need to take account of the transactional nature of development if we are to really understand the developmental profile described for children with Down syndrome and how to effectively change it.
3. Are intervention studies a way forward?
In many presentations at the conference the researchers mentioned – as they described a study aimed at perhaps elucidating causal factors behind the children’s delays or difficulties – that once we knew more it would inform interventions. I would argue that this is not the case – we may learn more about causes from intervention studies designed to test causal hypotheses. We may also address the last issue raised – is the delay due to impoverished learning inputs? Training studies may be the most parsimonious way to untangle the effects of changed or impoverished input from an underlying learning difference linked to the extra chromosome.
4. Closer links to practitioners.
I am always very impressed about the quality of researchers working in the USA and the research teams that focus on disability. However, in listening to some of the work that may be relevant to educational progress I was worried about the apparent lack of knowledge of the practical work going on in the field of education. Many educators and those who provide training for educators are well informed about research, the cognitive phenotype associated with Down syndrome and the social and behavioural challenges – and have been suggesting ways to adapt teaching and support to overcome some of these challenges in the classroom for a number of years. While the effectiveness of most such approaches has not been subjected to direct evaluation there is a great deal of practical experience to be shared by educators and closer links between the research and practice communities would benefit both and move things forward faster for children with Down syndrome and their families. I would suggest this applies equally in the field of speech and language research and therapy.
5. Individual differences.
I was pleased that another issue raised by a number of presenters was the need to document individual differences and not just group trends. Group studies are important to show general trends and support policy decisions. However the RCT that shows that an intervention works for a group does not mean every child in the group benefited. The converse may also be true – an intervention which did not show benefits in a whole group analysis may have benefited a subgroup the characteristics of which can be identified but this may never be published (babies and bathwater?). As has been said by others and I have said elsewhere, what a parent, teacher or therapist needs to know is ‘what works for which child in what circumstances’. I think it really is time the research community took this seriously and ensured that group studies also collect in-depth data on the progress of individuals and the factors that specifically affected them in the real world – in both intervention studies and also when describing ‘differences’ in experimental studies as these also vary in extent between individuals with Down syndrome. There is another challenge in here – that when we select measures if at all possible we use measures which mean something in the real world i.e. that can be understood by teachers and parents and have a practical relevance.
6. We need to address the issue of measures.
This was a point I discussed with a number of others at the meeting. If we are to move forward as I think we urgently should and make intervention studies the priority – then we need to accept how poor and often inappropriate most of the standardised measures we use actually are. The three main issues are firstly, inadequate sensitivity – most cognitive and language measures are too crude to capture change which may be having a quality of life benefit for individuals with Down syndrome. Secondly unhelpful norms – most were never designed specifically for those with intellectual and developmental disabilities so usually no standard scores can be obtained. For relevance to the life and education of someone with Down syndrome – we need to know how well they are progressing given they have Down syndrome – not against norms for the non-disabled population. Thirdly, age inappropriate content – how ethically appropriate is it to assess the language of a teenager or an adult with Down syndrome using a preschool language test?

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