Science Fair: Small Samples and Diagnosis Difficulties
An occasional column about science news pertaining to autism
Compiled by Robert B. Waltz
A study from UCLA claims that the "social" part of the brain is not as well connected in people with autism, resulting in the characteristics of the condition.
Commentary: I have a few concerns about this one. One is the small sample size -- just 17 in the autism group. That's only half the size needed to be statistically meaningful, plus it doesn't cover the whole spectrum. (The very fact that they refer to "high-functioning autism" shows a real lack of understanding of the variety of traits shown by people with autism.) The control group is also too small -- and if they already know what they're looking for, what is the control group for anyway? But I'm even more concerned by the fact that study after study has shown that people with autism have unusual brains -- but not identical unusual brains. All those people out there who think in pictures, e.g., surely have very different brains from someone like me; I think in codes and have no visual thinking ability at all. I strongly suspect that whatever the researchers found is correct for some people with autism, but not all.
A study from Washington State University says that a good gauge of autism in young children can be how quickly their irises dilate or contract in response to changes in lighting conditions.
Commentary: Instinctively I have some sympathy for this idea. My eyes never seem to get used to really bright lights. But... here we go again with the small sample sizes. 24 people tested. Only half had autism. All "high-functioning." So: twelve autistic children, who do not cover the whole spectrum, and 70% of the time, the kids with autism had a less robust response than the normal kids.
Call me back when you've done the same test on a hundred times as many children, with the autistic ones being of all degrees of functioning; I'll be interested.
This next one isn't about autism as such, but many people with autism have depressive symptoms, so I thought I would include it. Many people with depression feel weak and listless, as if they have no energy. It turns out that they may be right. Mouse studies show that mice with defective mitochondria (the portions of the cell which makes energy available to the rest of the cell) show symptoms typical of depression.
And here is a speculation that depression might actually be caused by an infectious agent in some cases.
Commentary: The one caution here (apart from the fact that the first article concerns an animal model that may not translate well to humans and the second involves an infection no one has seen) is that not all human depression is marked by lethargy. I for one have shown no lack of energy when I get "depressed;" I suffer melancholia but not fatigue symptoms. I suspect (for a long list of reasons I won't bore you with) that many other people who suffer autism and depression also suffer this atypical type of depression, so this may not apply to us.
You probably know that the rate of autism diagnoses has skyrocketed in recent years. The main reason is that the definition of autism has become broader (and more precise), plus we're more aware of the condition and so more likely to diagnose it. But there is a certain tendency in psychiatry to over-diagnose "popular" conditions -- there is some evidence that this has happened with biopolar illness, for instance, and perhaps for some of the personality disorders. Now there is evidence that this is happening with autism as well -- an estimated 9% of diagnoses are wrong.
Commentary: I would hate to take away anyone's autism diagnosis, but the hypothesis here -- that some people who are diagnosing autism are not prepared to diagnose it accurately -- rings very true. I was diagnosed at age fifty by someone who was supposedly trained to do so -- but who clearly did not know how to do it. He did not use any standard checklist. Instead, he gave me a personality test (which does not diagnose autism) and an IQ test (which doesn't diagnose much of anything except the ability to take an IQ test), and asked my family a few questions. I could do the diagnosis better than that! Happily, the AuSM staff agrees that I'm autistic, but it's worth noting that there are occasional bad diagnoses out there.
Author bio: AuSM member Robert B. Waltz was diagnosed with autism in 2012. He earned his B.A. in physics and mathematics from Hamline University in 1985. He is the author of three books on folklore, the editor of the online folk music database The Traditional Ballad Index, and recently has been informally studying the biology of autism.