Monday 24 February 2014

The [universal] early identification of autism or not?

As I might have already intimated, whilst I'm all in favour of the very early identification of autism and the potential effects this might bring to a child in terms of something like benefiting from early intervention, I'm not overly enthused by the collected evidence which has been amassed so far in this area despite some promising data.
Under my umbrellas @ Wikipedia 

Most people with some knowledge of autism will know that it is an extremely heterogeneous condition, with presentation also seemingly tied up with the risk of various other comorbidity appearing alongside. That autism also seems to include an element of regression for quite few on the spectrum, means that the holy grail that is very early red flags hinting at the earliest manifestation(s) of autism is going to be a difficult universal concept to find. Also complicated by various other factors including ethnicity, issues around the possible stability of symptoms in the early years and the possibility of plural autisms. Oh and healthcare providers can, on occasion, be barriers themselves too (see here).

Two papers recently caught my eye on this topic, coming to quite different conclusions.

The first paper by Samango-Sprouse and colleagues* based on an impressive participant number (N=1024) reported that their "study demonstrates an efficient means to identify infants at risk for autism spectrum disorder by 9 months of age and serves to alert primary care providers of infants who are vulnerable for autism spectrum disorder before symptoms are discernible by clinical judgment of primary care providers, parental concerns, or by screening questionnaires". They arrived at this conclusion on the basis of "abrupt head circumference acceleration and the absence of head tilt reflex by 9 months were used to identify infants at risk for autism spectrum disorder". So, with some more work to do, looking at head size and the head tilt reflex might be something to watch for in subsequent publications.

The second paper by Stenberg and colleagues** including an authorship list of the great and good of autism research (including Drs Hornig and Lipkin) came to a rather different conclusion based on the behavioural identification of children aged 18 months as likely having autism: "results imply that it might not be possible to detect all children with ASD at this age". Their participant size was even more impressive.

Of course I am kinda looking at apples and pears in comparing these two findings. The Samango-Sprouse study looking at something rather more physiological than behavioural, as compared to the Stenberg findings which was putting the M-CHAT (Modified Checklist for Autism in Toddlers) screening tool through it's paces based to a large part on the MoBa cohort. Again, with ear to the autism research ground, some people might remember that M-CHAT (itself a revision of the CHAT) has gone through even more adaptation fairly recently with the Diana Robins paper*** talking about M-CHAT-R/F (see here for more details). One therefore wonders if the Stenberg findings are already out-of-date even before they were published?

Insofar as the issue of rapid head circumference acceleration being potentially linked to the development of autism, well, we know the topic of head size and autism is a complicated one (see this previous post). I'm also thinking back to the work that came out the MIND Institute a couple of years back, which suggested that brain enlargement in relation to autism might show some link to the issue of regression (see here) at least for some types of autism. Quite how this data (if reproduced) would impact on the Samango-Sprouse findings is still unclear.

Don't get me wrong, the issue of early red flags potentially pointing to autism is a very, very important area of autism research. Every once in a while one hears about some ground-breaking research that a new marker for autism is on the horizon - see Jon Brock's post one example of this a few months back - but more often than not, nothing further comes of such research. What perhaps I would like to see more of in this area are a few things:

  • some better appreciation for 'the autisms' over the singular concept of autism (and different developmental profiles / red flags potentially being present across different sub-groups?),
  • greater amalgamation of various sources of information, behavioural and physiological, to see if looking at overt signs and symptoms together with something like head growth charts, might actually yield more real-world effects in combination. Although seemingly forgotten, the issue of airway anatomy and autism (no, really) might also be something to include here alongside other early markers that have been previously suggested.

Oh, and remember that at least one of the diagnostic schedules to denote autism or not has recently gone through a bit of a change, so one waits to see how this might affect all this early identification talk too.

Music to close. Having seen the Lego Movie not-so-long ago with some of my brood, I can very much recommend it for all ages. And just remember: everything is awesome...


* Samango-Sprouse CA. et al. Identification of infants at risk for autism spectrum disorder and developmental language delay prior to 12 months. Autism. 2014 Feb 18.

** Stenberg N. et al. Identifying Children with Autism Spectrum Disorder at 18 Months in a General Population Sample. Paediatr Perinat Epidemiol. 2014 Feb 18.

*** Robins DL. et al. Validation of the modified checklist for Autism in toddlers, revised with follow-up (M-CHAT-R/F). Pediatrics. 2014 Jan;133(1):37-45.

---------- Samango-Sprouse CA, Stapleton EJ, Aliabadi F, Graw R, Vickers R, Haskell K, Sadeghin T, Jameson R, Parmele CL, & Gropman AL (2014). Identification of infants at risk for autism spectrum disorder and developmental language delay prior to 12 months. Autism : the international journal of research and practice PMID: 24550549 Stenberg N, Bresnahan M, Gunnes N, Hirtz D, Hornig M, Lie KK, Lipkin WI, Lord C, Magnus P, Reichborn-Kjennerud T, Schjølberg S, Surén P, Susser E, Svendsen BK, von Tetzchner S, Oyen AS, & Stoltenberg C. (2014). Identifying Children with Autism Spectrum Disorder at 18 Months in a General Population Sample Paediatr Perinat Epidemiol. DOI: 10.1111/ppe.12114

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