Tuesday, 20 November 2012

Regression and autism continued

Regression.

Definition: "relapse to a less perfect or developed state".

Apologies for the very dramatic and very scientifically 'cold' description of regression. But as has been mentioned in the scientific literature, defining regression where it does occur in cases of autism has been a bit of a sticking point in some quarters.

Indeed, the topic of regression in relation to autism onset has graced this blog before. In that post, the main message was that after a bit of a lack of initial appreciation, regression is now understood to be part and parcel of at least some cases of autism, albeit with some way to go in understanding the precise hows and whys.
"Can you play any other tunes?" @ Wikipedia 

In this post I'm continuing on with regression in light of a few papers which I've recently been able to get hold of full-text.

So the papers by Barger and colleagues* meta-analysing some of the collected works on the prevalence and onset of regression in autism and Ekinci and colleagues** on the phenomenology of regression in autism and finally the paper by Westphal and colleagues*** on Theo Heller's Über Dementia Infantilis.

I've picked these papers to discuss because between them there is about as good and contemporary opinion about regression and autism as one could ask for. Indeed also some interesting ideas which also require a little more follow-up and perhaps a little bit of an autism history re-write too. Without further ado, some points I've picked out:

Barger study:

  • Based on data for a combined nearly 30,000 people with an autism spectrum disorder (ASD), the prevalence of regression - a loss of previously established skills - is approximately 32%. The data used to arrive at this figure was to some degree cobbled together given the different ways of defining regression and sampling data. 
  • They also reported no significant relationship between the child's age and the prevalence of regression, although there was a relationship between sample age and timing of regression similar to that work discussed on a telescoping effect (see here). 
  • Autism as a diagnosis over ASD was more predictive of regression being reported. 
  • Finally, the average age at which regression occurred was reported to be 1.78 years chronological age (21.3 months by my calculation). This average age, with confidence intervals between 20-22 months, was seemingly not dependent on the type of regression.

Ekinic study:
  • A slightly(!) smaller sample of children (N=57, aged 2-17 years) diagnosed with a DSM-IV TR ASD were included for study. 
  • Various measures were used during the study including some very detailed probing of the presence of regression via interviews, hospital files and videos to classify any history of autistic regression (AR). 
  • Based on the quite strict criteria for regression, over 50% of their sample was reported to have a history of AR (56.1%). 
  • Regression was defined one of two ways: Type 1: regression following 'normal' development, or Type 2: regression as a worsening of previous 'autistic features'.
  • Parent-reported gastrointestinal issues/diseases seemed to be more commonly noted in the Type 2 regression over Type 1, bearing in mind the absolute participant numbers were low.

Westphal study:
  • For anyone really interested in Heller's syndrome (Childhood Disintegrative Disorder, CDD), a little bit of important history has been translated. In many respects, it's kinda like reading Kanner's original case studies describing autism in that real lives are charted which share common characteristics. The translation from German is also reminiscent of Uta Frith translating Hans Asperger.
  • The authors suggest that Heller in this 1908 work actually seemed to be describing the core 'triad' of impairments that make up the diagnostic criteria for autism without using the word autism. It makes you think 'what if...'.
  • The prodromal state - early signs and symptoms similar to what prediabetes is to diabetes - of Heller's syndrome is very interesting. Characterised by various 'affective dysregulation', Heller described things like motor restlessness, night terrors and states of extreme agitation as being apparent. Combined with reports of things like tic-like movements, stereotypic behaviours and loss of speech, I'm sure one can see overlap with quite a few behaviourally defined conditions and perhaps even some clues as to the potential connection with things like a pathogenic insult (PANDAS?).  

Cumulatively there is quite a bit of information to take from these papers. First and foremost is the answer to the question, can regression occur in autism... yes. Indeed one wonders whether the recent interest in diagnostic stability and models predicting longer-term outcome might also be affected by instances of regression. 

Next question and a little more of a fuzzy answer: might regression also 'correlate' with other signs and symptoms 'around' the diagnosis of autism? Possibly is the answer based on the Ekinci data bearing in mind we don't actually know what comes first: regression or something like gastrointestinal issues and whether one causes the other or not. That being said, regression might not be totally predictive of other comorbidities like epilepsy as per the paper by Eriksson and colleagues****.

Final question, and an even more fuzzy answer: based on what is known about Heller's syndrome and his original description apparently quite close to what we know as autism, is it possible that somewhere not quite Heller's syndrome but more readily seen in autism, there might be shared clues to the regression that is noted in terms of onset and variables potentially involved? Mmm, I'll leave you to ponder that final question.

To close, a classic Breakfast Club tune about um, forgetting or not...

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* Barger BD. et al. Prevalence and onset of regression within autism spectrum disorders: a meta-analytic review. JADD. August 2012.

** Ekinci O. et al. The phenomenology of autistic regression: subtypes and associated factors. Eur Child Adolesc Psychiatry. 2012; 21: 23-29.

*** Westphal A. et al. Revisiting regression in autism: Heller's Dementia Infantilis. JADD. June 2012.

**** Eriksson MA. et al. Medical conditions affect the outcome of early intervention in preschool children with autism spectrum disorders. Eur Child Adolesc Psychiatry. July 2012.

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ResearchBlogging.org Barger BD, Campbell JM, & McDonough JD (2012). Prevalence and Onset of Regression within Autism Spectrum Disorders: A Meta-analytic Review. Journal of autism and developmental disorders PMID: 22855372