It's Different for Girls
Is diagnosis by brain scan ready for prime time?
Posted Aug 13, 2010
Given the painful process it takes to get a diagnosis, this certainly seems like good news. Especially to some adults on the spectrum, who of have an especially difficult in getting the diagnosis and support they need. Why?
The problem is, the common focus today is on children. Early intervention, and all that. Which is fine, but if you are an adult who has spent the majority of your life undiagnosed, this can be problematic.
Surviving in the world often requires masking the symptoms of AS, or avoiding the situations which trigger symptoms. As I wrote yesterday, there are adults on the spectrum learn to do this very well. Especially women.
In an April 2009 article, Dr. Judith Gould of the UK's National Autistic Society was quoted as saying: "We're failing girls at the moment. We are doing many thousands of them a great disservice. They are either not being picked up in the first place, but if they ask for help they are being turned away. Even if they are referred for diagnosis, they are commonly rejected."
This is quite true of adult females, as well.
In September 2009, Craig Evans of The Autism Hangout interviewed Dr. Tony Attwood about girls on the autism spectrum. In the interview, Mr. Evans asked: "...globally, the statistics are that for every four boys that are born with autism, there is one girl. Now, is this observation still accurate?"
Dr. Attwood responded, "No, I don't think it is. When it comes to Asperger Syndrome, we find that the girls are very good at camouflaging their social confusion, hiding in a group, and making sure they don't get noticed. If you look very carefully, then I think the ratio is actually probably about two to one."
Get a group of women with Asperger's together, online or off, you will find that stories of missed diagnoses are a common thread. In "Perspectives of Autism from My Family," Lori Berkowitz, Board member of the Autism Women's Network wrote:
"I have been different from other people for as long as I can remember. Over the years, I have had many different diagnoses, opinions, and treatments that were not quite right. My parents have tried to get me help since I was a little kid, but no one really knew what to do with me.
I was a smart but strange kid. I didn't understand things, especially people. I didn't fit in. I thought school was dumb. I thought a lot of things were dumb. Turns out a lot of them are, but many were not as black and white as I thought at the time. It wasn't until I was an adult that I began seeing shades of grey.
During my early years of school, I barely talked at all and spent a bunch of time in the principal's office. My teachers and school psychologists thought I could be normal if I tried harder. If I would just be like the other kids, they would like me and wouldn't be so mean to me. I just wasn't ‘applying myself'.
It wasn't until 5 years ago that I finally learned what is ‘wrong' with me. I have Asperger's Syndrome. Autism. I sometimes wonder what would life have been like if we knew that when I was 3 instead of when I was 38? It is hard not to think of all the ‘if's."
I do not believe that Lori's experience is unusual - in fact, I have heard similar stories time and time again. I, too, find myself spending a great deal of time thinking about all of the "if"s. Based on this, and my experiences, I am utterly convinced that current diagnostic processes are failing many, especially girls and women. It's not as if bias has not appeared in autism diagnosis before.
Given all of this, the idea of a non-subjective test for autism spectrum disorders seems like a godsend. But is it?
I'm hesitant to jump on the bandwagon just yet.
First of all, the sample size. The study involved only 20 autistic adults. All of whom happen to be male. All of whom have average, to above average IQ. How, in any way can this be representative of the entire spectrum?
Is truly enough known about variability of autistic brain structure within the sexes to ensure that female differences are captured (if there are any)? If this is not addressed, we may find ourselves repeating the very same errors that have made obtaining a diagnosis for females so difficult, but perhaps even worse.
In an analysis written of the study for the UK's Guardian newspaper, Carl Heneghan, Director of the Centre for Evidence Based Medicine, University of Oxford, describes a good share of concerns about the study. He says, "To obtain a useful result, a diagnostic study needs to include a broad spectrum of the diseased*, from mild to severe. A study also needs to have independent, blind comparison of test results (in this case the brain scan) with a reference standard (the current tests for autism) among a consecutive series of patients suspected (but not known) to have the target disorder and replication of studies in other settings."
Further, despite the vaunted reports of 90% accuracy, the practical results do not even begin to approach that. On his blog, Heneghan writes:
"What has happened is the sensitivity has been taken for the positive predictive value, which is what you want to know: if I have a positive test do I have the disease?
Sensitivity: The proportion of people with disease who have a positive test. Positive predictive value (+PV): The proportion of people with a positive test who have disease.
So, for a prevalence of 1% the actual positive predictive value is 4.5%. That is about 5 in every 100 with a positive test would have autism. Even at a prevalence of 2%, only 8.5% would be correctly identified". (For further on this, reference fellow PT blogger Jonathan Levy's post on the subject)
Even lead researcher on the study, Dr. Christine Ecker, indicates that this technique is not yet ready for prime time. In an e-mail communication to the Guardian she states: "It is currently unknown how these values [which were measured] generalise to the entire population, and across all dimensions of the autistic spectrum, which is why we have clearly stated that we are not yet ready to make our approach available in the NHS just yet."
So far, the brain scan sounds better in concept, than it does in execution. However, it may be a step in the right direction.
*Not my choice of words.