Well Stage 1 of SCALES has now closed. With the help of 194 schools and 243 fabulous teachers, we have screening data for 7,674 children or ~70% of all of the children that started school in Surrey last September!
We have a very short period of time to select from this dataset the 500 children we want to assess in detail – school starts on 5th September! Of the 500 children selected for Stage 2 of the study, 200 will be in a ‘low-risk’ group, meaning that on the screening questionnaire, teacher ratings suggest these children are developing as expected and no one is concerned about the child’s language or communication skills. The other 300 will constitute a ‘higher-risk’ group. Some of these children will already have statements of special educational need, and many will be monitored by the school because of language or communication concerns. The rest will have scores on the screening measure that are significantly below the average range – we are interested to know how many of these children actually do have language impairments. To do this, we need to assess all of the children and determine which ones do or do not meet criteria for language impairment.
Now, you might think that as a speech-language therapist and someone who has been researching developmental language disorders for about 15 years, selecting the test battery and making a provisional diagnosis should be the least challenging aspect of this project. On the contrary – this bit is proving to be hugely difficult and thought provoking. Whatever measures we choose now we are stuck with for the next three years. And how we make a research ‘diagnosis’ influences all other findings; prevalence rates, rates of co-morbidity, stability of deficit, etc.
As the current debacle that is DSM-5 clearly illustrates, deciding what is and what is not a ‘disorder’ is not as straightforward as we would like it to be. To give you an idea of why this may be so, I thought I’d talk you through my own disorder – I have a significant running impairment. You may not have heard of Running Impairment (RI) before, but we can think about diagnosing RI in much the same way we need to think about diagnosing language impairment (see for example, the Great SLI Debate).
Deviation from the statistical norm
Measurement of many human skills and attributes is ‘normally distributed’ and can be plotted on a bell shaped curve like this one:
I’m guessing that running speed is a trait that is also normally distributed, so imagine that the X-axis represents running speed in standard units, with 3 representing super fast, and -3 representing super slow. Now, if you asked 100 people to run 100 metres, about 68 would run it within the range indicated by the dark blue area. As the majority of people run within this speed range, this marks the statistical ‘average’. About 27 people would come under the lighter blue areas – half of them would be a little bit faster than average and the other half a little bit slower. That leaves about 5 people who have running speeds at the extremes – Usain Bolt at one end, and me at the other.
Of course, running speed is heavily influenced by age and gender, so I want to compare my running speed to other women of a particular age. But I’m afraid that even using middle-aged women as my comparison group, I’m fairly sure I’d be in the bottom 3%, which is generally regarded as significantly slower than average. So if we define disorder solely on the basis of distance from a statistical average, I am definitely running impaired.
The nice thing about running speed is that it is pretty straightforward to measure and is culturally invariant in that we can measure it exactly the same way in the UK as we would in any other country in the world (as the Olympics is about to demonstrate). Language and communication, on the other hand, are extremely complex and expectations of what is ‘typical’ vary enormously from one cultural to the next. Not all aspects of language are normally distributed either: vocabulary is, but aspects of grammar are not. Some aspects of language and communication are extremely difficult to measure in a standard way. For example, conversational skills involve two people, so how we converse may depend as much on our conversational partner as it does on our own intrinsic abilities. And while we have good normative data on a range of linguistic markers, we are seriously lacking appropriate normative data for many aspects of communication. Can anyone tell me what the average amount of eye-contact is for a 5-year-old girl or boy?
You may also wonder how we decide which point on the bell-shaped curve is suggestive of a problem. Should everyone outside of the dark blue area be considered ‘impaired’? As that would include just under 1/3 of the population, this probably isn’t sensible. But if we only include those at the extremes, we may miss a number of individuals who are really struggling. When it comes to language and communication, these decisions can often be driven by resource implications.
Finally, you may think my running disorder has little to do with intrinsic ‘impairment’ and more to do with slothfulness or lack of appropriate training. Which brings us to…
Biological and environmental influences
These days there is considerable research focus on identifying ‘biological markers’ of developmental disorders. There is a sense in which if some deficit or difference has a biological origin, it is more ‘real’ and that a biological marker will make diagnosis easier and earlier, paving the way for early interventions. However, for many complex disorders, identifying these markers has been rather complicated and their predictive value rather disappointing. One reason for this is that development is influenced by environmental factors as well as biology.
I’m quite certain that my RI has a biological component – if you were to look at me, long distance runner would not be the first thing that came to mind. In fact, a colleague once described me as a ‘giant athletic teddy bear’ which may give you a better idea. I’ve never seen my parents so much as run for a bus, never mind run for fitness or leisure, which may also suggest a biological basis. However, the fact that no one in my family runs also meant that I was never really encouraged to do much running at home. And it was pretty easy to avoid serious fitness challenges at school too in favour of music or academic activities. So like many developmental disorders involving language, my RI has been influenced both by a biological disposition and unfavourable environmental influences.
But could I have overcome this biological vulnerability with sustained environmental input (otherwise known as intervention)?
Response to treatment
It has been suggested that perhaps the best way to diagnosis disorder is to see how the child responds to intervention (sadly something we can’t do this time in SCALES). I’m not really sure how – if the child improves significantly, does that mean the child did or did not actually have a disorder? And what should we provide for children who aren’t going to be ‘cured’ by our interventions?
Anyway, I’m pretty sure that 6 sessions of running intervention as a pre-schooler with the England coach would have done nothing to improve my running speed in the longer term (6 sessions being the average amount of speech-language therapy provided to pre-schoolers reported in Glogowska et al. 2000). Running 3x per week during term times for a whole school year may have gone some way to establishing good running habits, but in my experience, once I stop having regular running support, I just stop running. (3x a week seems to be the typical model for RCTs of language intervention in primary schools).
I have in fact tried to tackle my RI at various points in my life, even to the extent that I managed to run the London Marathon the year I finished my PhD (in a rather respectable 5 hours and 15 minutes). The outcome is usually the same – I greatly improve my stamina and can run longer and longer distances without feeling like my chest will explode, but my speed never increases very much. I’ve come to accept that I am destined to remain a slow runner. I now run every week with Psychology Women’s Running Club. I have no expectation of getting faster, but they just make me feel better about my RI.
So, like many children with language and communication impairments, my disorder is life-long. Although I can make substantial improvements in some aspects of running with sustained intervention, I can’t be ‘cured’ of slow running (though I have learned to be happier with my running speed). When I’m running, I often ponder how we could develop intervention research paradigms for communication disorders that would focus on these outcomes, rather than a continued focus on outcomes solely measured by a move into the ‘normal range’ on some arbitrary assessment…
I suspect there may be some readers who are still unconvinced by my self-diagnosis of RI. Some might say that this isn’t a disorder, only a difference, just a bit of variation in the rich tapestry of human life. After all, we can’t all be wonderful at everything. I do have a lot of sympathy with this view and would not usually identify myself as ‘disordered’, largely because my running impairment has rarely prevented me from doing the things that I want to do. Which brings me to…
Impact of disorder/difference on daily living
I can assure you that being the slowest runner in the school did nothing for my street cred as a child, as evidenced by the audible groans that reverberated around the gym whenever I was assigned to a particular team. (Though this level of social ostracism was probably compounded by ginger hair and a penchant for white knee socks and patent leather shoes). Fortunately I had a few other things going for me and so managed to survive school with some self-esteem intact.
I also grew up in America, which has created a society in which no one needs to run or walk anywhere. In fact, if you want to walk to the shops or a park or a library, it can be pretty difficult to do in many American towns and will almost certainly raise a few eyebrows. England is more at home to walkers, but with buses, tubes, cars and even shop mobility scooters, my lack of running finesse really doesn’t disadvantage me at all. Might have done though if I’d lived in rural Africa…
There is considerable debate about whether impact should be part of any diagnostic criteria for disorder. If a child scores below some arbitrary cut-off on some measure of language or communication, but the child is succeeding in his or her own environment, or even performing exceptionally well on some other aspect of development, should we label this child as ‘disordered’? Do we want to expend precious resources on children who may be just fine?
No one will invest resources in my RI and that is ok. I’m not suffering now. But it is worth considering whether my RI is a marker for other disorders that really might cause me grief, and be costly to address in future years. For example, being a rubbish runner may put me at greater risk of obesity and heart disease and these things are not good. Similarly, a low score on a particular language test at school entry may not be too disruptive now, but may be a precursor to difficulties with literacy or social understanding in later years. In that case we need to determine whether addressing the earlier vulnerability improves later outcomes in different areas of development. Tricky to show the causal links though…
Back to SCALES
So my immediate concern is selecting an appropriate test battery for the SCALES project. In the first instance, we need to concentrate on standardised measures of language and decide a score that is significantly below the scores of other children of the same age. I hope I’ve convinced you of two things: (1) that this is a tough decision and no doubt other clinicians or researchers would use different tests, different cut-offs and that these may well yield different results. We will be looking at different diagnostic algorithms and how this relates to outcome and impact in the longer term. (2) Even if a child scores in our ‘impaired’ range, this does not necessarily mean the child has a ‘disorder’. There are clearly many other things to take into account and how children change over time will be most informative.
As for my running – you can catch me at Virginia Water Lake on Thursday afternoons at 4.30…
If you are interested in reading more about this, try these papers:
Tomblin, J.B. (2006). A normativist account of language-based learning disability. Learning Disabilities Research and Practice, 21, 8-18.
Norbury, C.F. & Sparks, A. (2012). Difference or disorder? Cultural issues in understanding neurodevelopmental disorders. Developmental Psychology, on-line first.