Wednesday, March 2, 2011

Theories of autism: lessons from Dr House

Source
I've just been watching House. I say watching. To be honest, the details of this week's plot passed me by as I was trying to follow it whilst simultaneously eating my dinner and having a conversation-slash-argument about, of all things, carbon taxing.

Anyway, the plot is pretty much the same each week: Patient shows up in the hospital with a weird combination of symptoms; House and team conduct various ethically dubious tests; initial diagnosis is  disconfirmed, usually by some new symptom; House finally ends up with the correct diagnosis and a single cause that neatly explains all of the symptoms. The patient this week had some extremely rare syndrome that gave her photographic memory and kidney failure.

So here's the question I found myself asking: What lessons does House's anarchic approach to medicine have for autism research? I'm not talking of course about his dodgy ethics, the lack of informed consent or the disregard for proper procedures. We've had enough of that recently thank you very much.

The crucial point is that for House the cause he ultimately identifies has to explain everything.

In case you missed Autism 101, autism is defined in terms of impaired social and communication skills, co-occurring with repetitive behaviours and/or restricted interests. But it's oh so much more than that. Associated features include intellectual disability, epilepsy, sensory hypersensitivity, motor coordination problems, memory difficulties, face processing impairment. And so on. Autism is also associated with certain strengths, particularly in perceptual processing, and a disproportionate (but still rare) incidence of savant skills including amazing feats of artistry, musicianship, and calculation.

If House could explain autism, it would be the best episode ever.

The genius behind House (and yes I do realise he's a fictional character) is the premise that, although there are many potential explanations for a given individual symptom, start looking at combinations of symptoms and suddenly the plausible underlying causes are reduced drastically.

I do wonder whether autism researchers may be missing a trick here. Social difficulties on their own could have multiple causes. But social difficulties combined with motor discoordination and epilepsy? Suddenly the possibilities are no longer endless.

But here comes the big "however". House is dealing with a single patient. He knows that all of the symptoms he's trying to account for affect that one patient. With autism, on the other hand, we're dealing with a group of people who, in a very general sense, have some things in common but, as individuals, are all different from one another.  We know, for example, that people with an autism diagnosis tend to have issues of social anxiety and also that many are hypersensitive to sound. But we don't know if it's the same individuals in both cases. So should we be thinking in terms of a common mechanism that could neatly account for both features, or would that be trying to explain the co-occurrence of two things that never actually co-occur?

Over the years, a number of grand unifying theories of autism have been proposed that try and link together different symptoms. But they are all theories of autism, assuming that autism is a single homogeneous entity.

I'm not suggesting that we need a completely new theory for every individual. But I do genuinely believe that if we're ever going to make sense of autism, we need to recognise the fact that the 'core' symptoms that define autism can come about by a number of different means. Any given theory probably won't apply to everyone.

The lesson from House is that looking at all the symptoms might help identify these different causal pathways.

As ever, I'd love to hear your thoughts.


Update (28/03/11):

This post has been reposted at the Shift Journal website and has garnered some more really insightful comments there too. I hadn't come across the Shift site before I was contacted by the editor but there's some really nice stuff there on Neurodiversity. Well worth checking out.

13 comments:

  1. I've always thought that looking for *the* cause of autism was like looking for *the* cause of intellectual disability - a doomed enterprise, given the multiple causal routes to a final common path.

    ReplyDelete
  2. another issue is that we are grouping lots of people together under the banner of autism who almost certainly have completely different conditions. we talk about a symptom core, but often the differences between people with 'autism' are as striking as the similarities. If you think of 'autism' as a description rather than a single disorder, the need for a one unifying cause goes.

    ReplyDelete
  3. I agree 100%. With both of you! But now ever so slightly worried that didn't come across in the post...

    ReplyDelete
  4. Did you see the episode where "Asperger's" was whispered about House because he didn't want the rug changed in his office? That, and his attention to detail and social uhm...differences. The "Lines in the Sand" was exquisite. The child kept making pictures of lines to mimic the ones floating in his visual field. It was a clue. He was trying to communicate.

    I love the explanation Dr. Temple Grandin ("Thinking in Pictures") gives of autism: it is a recessive genetic trait. You get one gene, you get genius, two...full blown autism. It really does seem like so many mental "afflictions" (autism/manic depression/schizophrenia/bipolar/ADHD--even dyslexia and other learning problems) give the bearer unique perspectives that often label them creative thinkers at the same time. My son used to belong to a gifted Math group. The teacher professed that half of the kids had labels. One man's disease is another man's difference. Maybe it does have something to do with the genetic "degree of expression". But obviously it leads to a genetic advantage or we would have been weeded out by now. It is in this vein that many see autism as a "variation on a theme" of humanity.

    You are correct in the preponderance of co-occuring conditions. In our case, our son was tested for Fragile-x (negative): Neurofibromatosis and Tuberous Sclerosis were also considered because of a portwine birth-mark and café au lait spots on his skin...indicating a possible brain/spinal cord malformation early in his development that is indicated through his skin(my understanding). They are three identified genetic etiologies of autism that you can add to the mix.

    ReplyDelete
  5. Thanks RB. Will look out for the Lines in the Sand episode. I've only recently got into House (not much worth watching on TV in Australia).

    I'm not sure what to make of Temple Grandin's genetic theory. I agree that people with various "afflictions" have unique perspectives on the world but can't really see how any of that confers a reproductive advantage.

    The issue of co-occurring conditions brings me back to a fascinating presentation by Catalina Betancur at the Autism Brain Research meeting last year. She was arguing that around 20% of cases of autism can be traced back to a known genetic syndrome. I guess we can think of these as classic House cases, where a wide range of cognitive and physical differences can be traced back to a common underlying cause.

    The big question is how to make sense of the remaining "idiopathic" cases. As Courtenay mentioned, we're probably lumping together a whole bunch of different "conditions". I'd like to think that we'll eventually be able to divide these individuals up into meaningful subgroups based on the patterns of co-occurrence of different symptoms or maybe biomarkers. That's still a way off though.

    That Betancur presentation:
    http://crackingtheenigma.blogspot.com/2010/11/autism-brain-research-meeting-day-1.html

    ReplyDelete
  6. I understand what you're saying about the reproductive advantage. People who are seriously handicapped by "behaviors" may not reproduce at the level of us dumb bunnies. But---a person whose genetic expression of those same behaviors is less pronounced, say, like a rocket scientist or artist, definitely confers a quality of life to the "tribe" as a whole.

    ReplyDelete
  7. I love this post!

    And yes, I do get very impatient with theories that only address one or two things about autism, and either fail to explain or actually conflict with other aspects of it.

    *cough*extrememalebraintheory*cough*

    I also agree with those other commenters (and you), though, in that because autism is so heterogeneous, and is currently such a loosely defined umbrella category, that there's probably never going to be a theory that accounts for all of it, because it's not actually a seamless whole.

    So maybe the answer is to try and find meaningful "subtypes" of autism, and then look for Unifying Theories of those.

    (I find autism fascinating because I *am* autistic, and I think it is human to try to understand oneself. I think you guys find autism fascinating because we are unlike you in lots of fundamental ways, and it is human to try to understand the Other. I find you guys fascinating, too. :) )

    ReplyDelete
  8. "But obviously it leads to a genetic advantage or we would have been weeded out by now. It is in this vein that many see autism as a "variation on a theme" of humanity."

    No, do not look to genetic advantage, for most mental illnesses (bi-polar (especially in females), schiz too, etc. lead to reduced fitness.

    Thus, look elsewhere than genes for the trigger--look to pathogens.

    ReplyDelete
  9. I just found your site and am intrigued by the dialogue! As speech-language pathologist who concentrates much of my work and life with individuals on the spectrum and their families, I give thoughtful consideration to all posits about "why" we have such explosive numbers on the spectrum. The evidence I have gathered in both research articles and life experience clearly suggests a genetic link. This bears out with the "advantage camp."

    The core characteristics that, until our technological rise, compelled individuals with spectrum qualities to be more 'loaners' and less likely to find mates have now proven to be substantially positive qualities in many respects. Individuals with strong analytical, technologically oriented brains find exceptional employment opportunities that provide excellent incomes. This also allows these individuals to be in social proximity and to meet others with similar interests where, prior to technology, there were significantly less opportunities to meet 'like minds', fall in love and create families. In the families I have worked with for over 10 years, it is amazing the common threads that exist when taking family histories. Typically one parent or the other eventually shares experiences of loneliness and not belonging either as a child and/or continuing into adulthood. Usually there is at least one or more 'quirky' family members who are experts in one or more areas but socially awkward, have sensory issues and digestive concerns.

    Does this also lead to the question of environmental influence? Of course. We know that genetic predisposition in other disorders can cause an individual to be more sensitive to allergens, toxins, and stimuli. It is plausible, if autism is genetically based, there is a genetic difference indigenous in their make up that, when an exposure to a toxin others are resilient to, have a more remarkable response thus expressing the autism gene more fully.

    Will autism eventually flesh out as a singular, more concretely diagnosible disorder through a more convincing criteria than we currently use with the DSM-IV? I cannot say. My hope is that we come to understand autism as a group of possible expressions that need to be considered with each individual, addressed individually, and supported appropriately.

    ReplyDelete
  10. Toe-walking http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2933674/table/T1/

    woke up in the middle of night mentally comparing cerebral palsy and autism. Your recent tweet about hypoxia at high altitudes led here. Also, I continue to think it is a sort of brain damage. I would never say that in front of the person, but if it is an avoidable form of hypoxia...

    Also, seems to be distal damage, ie, peripheral. Perhaps brain, as dysgraphic hands and toe-walking feet has minimal damage peripherally.(ala a neuropathy) caused by some sort of hypoxia.

    Sorry...had to tell somebody

    ReplyDelete
  11. 'Sorry had to tell somebody'
    just as a blink of eye contact or gentle tap on the shoulder of 'another'. Is this a silhouette of our holy grail. Is this the defining edge of the global unifying definition we seek. Understanding these communication processes, their motivations at every level, here in a macro dimension of the 'globally distributed creature' humanity is, or also at the micro interconnect of the lonely neuron's interface. Genetic architecture has selected a male - female format, with powerful capabilities for preserving the recessive in transient environmental adversity. Vaccination produces a predictable economic benefit along with a predictable response from the gene pool. As Albert might once have said 'I never intended the bomb'. Faith is all we have, but it is only chemistry.

    ReplyDelete
  12. Autism is the direct experience of Jung's Collective Unconscious - every symptom and disability correlates to an eternal form or archetype

    How do I know this - I had autism - I learned to see my behaviors and how they correlated to dreams revealing eternal forms - when I did it long enough and reconciled a syndrome to an eternal form all sensory, social and otherworldly impairments dissolved - took 25 years of 24/7 processing to undo genetic, birth delivery and environmental pre-conditions

    So much for Dr. House

    ReplyDelete
  13. Learn more about birthmark treatment in delhi, please visithttp://www.skindelhi.com/birthmark.html

    ReplyDelete