Autism, Autism Spectrum Disorder, Asperger’s Syndrome… What are they, and what’s the difference?

What’s in a name?

Autism Spectrum Disorder has several labels, and these labels have shifted over the years as scientists’ understanding of the disease has improved. Psychologists keep a giant book called the Diagnostic and Statistical Manual that describes in great detail every single recognized psychological disorder. About once every 15 years, a new version of this book is put out to update doctors and scientists about what has been learned. This can result in some confusion. Everyone gets comfortable with the titles that have been given for each disorder and then suddenly a new Diagnostic and Statistical Manual gets published that says everyone needs to start calling it something else.

This is exactly what has happened with Autism. In the previous version of the Diagnostic and Statistical Manual, there were 5 disorders: Autistic Disorder, Rett Syndrome, Childhood Disintegrative Disorder, Asperger’s Disorder, and Pervasive Developmental Disorder Not Otherwise Specified. Each of these disorders was considered to be a part of a family of disorders called Autism Spectrum Disorders. But then came 2013, and a new version of the Diagnostic and Statistical Manual was released. It was decided that having five different disorders with overlapping symptoms that were all frequently called autism was all just a little bit too confusing. So now all of these disorders have been combined into just one Autism Spectrum Disorder.

Ok, so we get that psychologists like to make talking about disorders super confusing by changing their names every decade or so, but what is Autism Spectrum Disorder? The main three symptoms are problems with social interaction, problems with communication especially about emotional topics, and a tendency to perform repetitive behaviors. People with an Autism Spectrum Disorder basically process emotional and social information very differently than everyone else, making it very hard to interact with the outside world. So things that come naturally to most people like empathy and predicting how someone will react to something are really difficult for people suffering from this disorder.

Wait, wait, wait. How do psychologists know that someone else’s mind is processing emotional and social information differently? That’s like saying Autistic people don’t see the color blue the same way as everyone else. How can you possibly know that?

Scientists have come up with some really clever tests to measure how people process social or emotional information. Covering every single test used to measure differences between autism and “normal” patients would take so long that by the end I’d probably qualify for a master’s degree in the subject. But let’s look at a few examples.

Memory for emotional words or sentences

One way to measure how a person processes emotional or social information is to look at your memory. For example, one study from a group working at Ohio State University gathered a group of Autism patients and a group of non-Autism patients that were the same age and had the same IQ and verbal skills. Each person was read 10 “high-emotion” sentences such as “he hits his teacher” and 10 “neutral” sentences like “he is drinking tea”, and was then asked to remember as many of the sentences as possible. The idea here is that your brain pays more attention to the emotional sentences than the neutral ones, so most people should have an easier time remembering the emotional sentences. Indeed, the non-Autism patients did a better job recalling the emotional sentences than they did the neutral ones. The Autism patients, on the other hand, remembered the emotional and neutral sentences equally well; they didn’t show any memory enhancement for sentences that were emotional.

The Moral Dilemmas Film Task

Another interesting example of scientists trying to measure differences in emotional processing is a study that used the Moral Dilemmas Film Task. Autism and non-Autism patients that were the same age, gender and IQ, were shown short clips that were emotional in nature and had some form of moral dilemma in them from the popular tv show House. Afterwards, patients were asked to simply write about what they had seen. Here is an example of what an Autism patient and non-Autism patient wrote to describe the same scene. First the non-Autism patient:

“A young woman is receiving the results of organ donor compatability [sic] test from her male doctor. She is relieved to know that she is compatible and therefore potentially able to save someone close to her through the level of emotion she shows. She also finds out she is pregnant. She is happy; however, the doctor reveals to her that as such she is not eligible to be a donor; her feelings immediately change from joy to shock and sadness. She remains strong and states that she needs to speak to her husband of the dilemma that she now faces.”

Notice how the description uses lots of words like “relieved”, “happy”, “joy”, “shock”, and “sadness” to explain how the woman feels. Now compare that to a description from one of the patients in the Autism group:

“The man received the woman’s results back from the lab. The woman matches ‘‘You do match’’ The man also tells the woman that she’s pregnant: The woman holds her hands together. She inhales deeply. The man tells her she cannot be a donor. The woman stays holding her hands and breathing strongly. The man does not say anything else. The woman says ‘‘I have to tell my husband.’’ The man is shadowed by something he has stubble on his face. The woman has brown hair and she is younger than the man. They are sitting down in armchairs. The woman is sitting forward and the man is sitting back in his chair. There is music in the background.”

The Autism patient spends much more time describing details about what the people looked like and a lot more time describing items in the environment like the chairs. When it comes to describing the woman, there are lots of words about what she is doing such as “inhales”, “holding her hands”, and “breathing strongly” but not about how the woman feels. The study found this was a pattern. The Autism group had no problem remembering and describing the scene with accurate details, but was far less likely to describe emotions to the characters in each scene.

Automatic Blink Paradigm

I want to talk about one more test called the Automatic Blink Paradigm that scientists use to measure how Autism and non-Autism brains process emotional information differently. The test is really simple but very clever. People are asked to look at a screen, and a series of words are flashed in front of them really fast; about eight words per second. Their instructions are to ignore words of every color until they see a black word. Every time they see a black word they need to read it out loud. The scientists set up the words so that there will be a series of words in random colors, then there will be a black word, then one or two more colored words, and then another black word. One study published by Ben Corden and his colleagues showed a graph to help visualize how this test works.

Corden fig 1

When the subjects see the first black word, their brain starts to read it. If the second black word appears while their brain is still processing the first one, then subjects will have a hard time reading the second black word. They miss it. But, and here is where things get interesting, if the second black word is a highly emotional word like “rape” or “bastard” then the brain gets really aroused by the word and they are likely to get it right even though they were busy processing the first black word. The idea is that emotional words are considered more important and when they appear the brain works a lot harder to process them. But when an emotionally neutral word like “sparrow” is shown and the brain is busy processing something else, it just lets it go as unimportant information. So, when Corden and his fellow scientists ran this study with non-Autism patients they found exactly what we would expect. If the second black word was neutral, their brains struggled to process it because they were still thinking about the first black word. When the second word was emotional, they were able to say it even though their brains were still thinking about the first black word. Autism patients on the other hand showed no differences in processing neutral or emotional words. This suggests that the brains of the Autism patients were not flagging the emotion words as arousing or important the same way the brains of the non-Autism patients were.

One thing you might be wondering is what is the point of all this research? Why go to such trouble just to prove that people with Autism are in fact different. There are two broad reasons why research like this is done. First, to better understand the disorder. For example, some have wondered if Autism patients just have trouble describing abstract or complex things in general. Studies like the ones highlighted above allow us to see that Autism patients can describe things in great detail, they just don’t use as many emotions in their descriptions. Second, once you find good ways to measure differences between Autism and non-Autism brains, you can start trying different treatments or drugs and measure if they help or hurt the condition.

The scientists studying this disease have done an amazing job coming up with ways to measure how a person processes emotional information in the world. But these tests and definitions can leave you with a rather cold, clinical feeling about this disorder. What does it feel like to experience autism? There are quite a few essays and blog posts online in which people with an Autism Spectrum Disorder describe the difficulties of the disorder (for examples see here, here, or here). From reading through these descriptions one point that jumps out at me is that people with Autism are not emotionless. They feel love, hate, sadness, or joy. This is not a condition in which those emotions are gone, it is one where the way the brain handles those emotions is different.

But what causes the brain to process emotional information differently? For my next post in this series, I will look into what is known about the causes of Autism Spectrum Disorder.

Politicus Cerebri

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