Understanding Autism: The Search for Answers

Understanding Autism: The Search for Answers

by Scientific American Editors
     
 

Understanding Autism: The Search for Answers by the Editors of Scientific American

The term "autism" first appeared in the early 1900s and comes from the Greek word "autos," meaning self, used to describe conditions of social withdrawal – or the isolated self. Today, autism is one of three diagnoses that the DSM (Diagnostic and Statistical Manual of

Overview

Understanding Autism: The Search for Answers by the Editors of Scientific American

The term "autism" first appeared in the early 1900s and comes from the Greek word "autos," meaning self, used to describe conditions of social withdrawal – or the isolated self. Today, autism is one of three diagnoses that the DSM (Diagnostic and Statistical Manual of Mental Disorders) includes in autism spectrum disorder (ASD). While our understanding of this condition has grown exponentially, research has been fraught with controversy. Autism appears to be on the rise, depending on how you define it, and its causes more complex than imagined. In this eBook, Understanding Autism: The Search for Answers, Scientific American's editors have gathered the most current information on autism, including how it's diagnosed, risk factors, treatments and therapies. Section 1 begins with the symptoms, or traits, of ASD, which include three main disabilities: lack of social skills, lack of communication skills, and repetitive behaviors. Also in this section, "The Hidden Potential of Autistic Kids" discusses the flip side of the equation – instead of focusing on the condition's limitations, what unique capabilities might people possess – a thread that continues in the remarkable stories of Section 2, "Autistic Savants. Subsequent sections examine the complicated genetic and environmental causes, the nature of the autism "epidemic" as well as the most current therapies. Changes to the diagnostic criteria in the DSM-5 caused understandable concern and are reviewed in two important stories by Ferris Jabr. Finally, in discussing available therapies, two companion pieces by Nancy Shute take us on a journey through the minds of parents, many of whom are desperate to help their autistic kids lead easier, productive and more fulfilling lives. While science rushes to offer better options, this eBook gives a synopsis of the state of the union - what we know and what we don't know about this challenging condition.

Product Details

ISBN-13:
9781466833852
Publisher:
Scientific American
Publication date:
03/18/2013
Sold by:
Macmillan
Format:
NOOK Book
Pages:
172
Sales rank:
1,164,289
File size:
1 MB

Read an Excerpt

Understanding Autism

The Search for Answers


By Scientific American

Scientific American

Copyright © 2013 Scientific American, a division of Nature America, Inc.
All rights reserved.
ISBN: 978-1-4668-3385-2



CHAPTER 1

SECTION 1

Diagnosing Autism


Searching for the Onset of Autism by Mariette DiChristina


Early behavioral intervention has shown some promise as a way to help children with autism. But it's difficult to see the hallmarks of autism before two years of age with today's diagnostic criteria. Could we find other methods?

Seeking to answer that question is Jed Elison at the California Institute of Technology, who is working with Ralph Adolphs at Caltech and Joe Piven at the University of North Carolina among other colleagues around the U.S. and Canada. Elison provided some preliminary findings at the Neuromagic 2012 conference held from May 7 to 10, 2012 on San Simón, the Island of Thought, near Vigo, Spain.

Today's criteria, from the psychiatric bible called the DSM-IV, include attributes of social impairments, communication deficits, and repetitive patterns of behavior and restricted interests (either in intensity or content). "There's a biological reality," said Elison, "that you can't capture perfectly with a classification system like this." Nevertheless, there's "no question that the classification system serves a very important role in identifying kids who require specialized clinical services." Recognizing the condition early can help. "There's some evidence that early intervention alleviates" some of the behavioral challenges for these children, he added.

Elison and collaborative partners of the Infant Brain Imaging Study Network are recruiting families who have a child with autism and an infant sibling under six months of age. Because autism has a genetic component, they employ what they call the "high-risk-sibling" strategy to prospectively characterize the earliest markers of autism. They conduct longitudinal studies with the younger siblings — making an assessment of these infants at six months, 12 months and 24 months. Ideally, they will define the onset of symptoms and its developmental course.

In addition to assessing behavior, the researchers are also examining brain development, specifically the development of white matter microstructure, using diffusion tensor imaging. White matter includes part of the neuron called the axon that is responsible for transmitting electrical signals throughout the brain. "Cognitive and social-cognitive development requires efficient information processing, which consequently requires efficient signal transmission," said Elison. White matter is not developing the same in infants who go to on develop autism, and a recent study suggests that these differences may appear as early as six months.

What about behavioral differences? The researchers are also very interested in subtle attentional and visual-orienting patterns that may be different very early in life. These behaviors are very important for subsequent social-cognitive development and might be amenable to targeted intervention.

Elison highlighted that many of the scientific themes relevant to magic or sleights of hand, including attentional orienting and joint attention, making eye contact, perceiving biological motion, and theory of mind (that is, making inferences about the mental or emotional state of another individual) are especially important themes for autism researchers. "Deficits in any of these areas could make individuals with autism less susceptible to magic," said Elison.

Drawing a connection to the theme of the conference in his conclusion, Elison questioned whether susceptibility to magic or sleights of hand might also vary with development. Several of the attending magicians pointed out that performers must tailor their approach for different audiences and that very young children present unique challenges, because they may still engage in "magical thinking" — believing in unseen causes — and because their cultural knowledge and social-cognitive skills aren't yet fully formed.


--Originally published: Scientific American online, May 15, 2012.


Mixed Signals: Social Intuition Goes Awry by Bruce M. Hood


At the end of Casablanca, when Humphrey Bogart finally tells Ingrid Bergman to get on the plane back to her husband, the young mother watching the afternoon TV movie sheds a tear. Instinctively, her two-year-old tries to comfort her by offering his teddy bear to her. Both the mother and child are displaying intuitive awareness of others' mental states and emotions.

Social intuition comes naturally to most of us, but not all. Autism is a developmental disorder that affects around one in 500 individuals (although this figure appears to be on the rise and depends largely on how you define it). In general, autism can be thought of as a disorder with three major disabilities: a profound lack of social skills, poor communication and repetitive behaviors. It is regarded as a spectrum disorder because it covers a broad range and individuals vary in the extent to which they are affected. All those with the disorder share problems with social intuition, however.

Individuals with autism have a problem with socializing because they lack a repertoire of developmental social skills that enable humans to become expert mind readers. Not mind reading in the way Spock from Star Trek could do, but rather the capacity to infer what others are thinking in different circumstances. Over the course of early childhood typical youngsters increasingly become more sophisticated at understanding that other people have mental states that motivate their behavior. For example, if you leave your bag in the office, then I know that you believe it to be there even though the cleaner has handed it in to lost and found. I can understand you hold a false belief. This ability is called having a "theory of mind," and it is a natural ability in typical children. By the time the average child is around four years old, he or she interprets other people as being goal-directed and purposeful and as having preferences, desires, beliefs and even misconceptions. Without this repertoire of social skills, a human is effectively mind blind — unable to understand what others are thinking and why they do the things they do.

Not only do typical children become intuitive mind readers, but they also become agony aunts as well. They begin to understand others' sadness, joy, disappointment and jealousy as emotional correlates of the behaviors that make humans do the things they do. Again, by four years of age, children have become expert at working the social arena. They will copy, imitate, mimic and generally empathize with others, thereby signaling that they, too, are part of the social circles that we all must join to become members of the tribe. They share the same socially contagious behaviors of crying, yawning, smiling, laughing and pulling disgusted faces that signal they share the same emotional experiences of those around them.


Baffled by Behavior

No wonder individuals with autism find direct social interaction frightening. If you cannot figure out other people, then such interaction must be intensely baffling and stressful. They often do not like direct eye contact, do not prefer to look at faces compared with other things, do not copy, do not mimic, do not yawn when others yawn or retch when others retch, or laugh or join in with the rich tapestry of social signals we share as a species. This inability may be why individuals with autism generally withdraw into activities that do not involve other people.

The incidence of autism is higher in identical twins, who share nearly 100 percent of their genes, compared with fraternal twins, who share only 50 percent, which indicates that there is a genetic component to the disorder. Also, the greater incidence in males compared with females strongly implicates a biological basis. To date, tantalizing evidence exists based on brain-imaging studies that regions in the prefrontal cortex — most notably the frontoinsular and the anterior cingulate cortex, which are activated by social interaction in normal individuals — are relatively inactive in individuals with autism. Autopsy data also indicate that the frontoinsular and the anterior cingulate cortex structures are abnormal in autism disorder.

John Allman of the California Institute of Technology thinks that much of this social deficit may come down to a lack of a special class of spindle neurons, sometimes called Von Economo neurons after their discoverer, who made the observation in 1925. Spindle neurons consist of a very large bipolar neuron that is found only in the frontoinsular and anterior cingulate cortex and thought to provide the interconnection between brain regions that are activated by social learning. This location may explain why spindle neurons have been found solely in species that are particularly social, including all the great apes, elephants, and whales and dolphins.

Humans have the biggest population of spindle neurons located in the frontoinsular and anterior cingulate cortex areas — the same regions that may be disrupted in autism spectrum disorder. Spindle neurons are thought to work by keeping track of social experiences, leading to a rapid appreciation of similar situations in the future. They provide the basis of intuitive social learning when we watch and copy others. It may be no coincidence that the density of spindle neurons in these social regions increases from infancy to reach adult levels somewhere around the fourth birthday in typical children, the watershed when most child development experts agree that there is noticeable change in social intuition skills. This may also explain why individuals with autism, who have disrupted frontoinsular and anterior cingulate cortical areas, have difficulty working out what the rest of us just know without having to think very much.


--Originally published: Scientific American online, March 7, 2011.


Extraordinary Perception by Wray Herbert


When Pulitzer Prize — winning music critic Tim Page was in second grade, he and his classmates went on a field trip to Boston. He later wrote about the experience as a class assignment, and what follows is an excerpt:

"Well, we went to Boston, Massachusetts, through the town of Warrenville, Connecticut, on Route 44A. It was very pretty, and there was a church that reminded me of pictures of Russia from our book that is published by Time-Life. We arrived in Boston at 9:17. At 11 we went on a big tour of Boston on Gray Line 43, made by the Superior Bus Company like School Bus Six, which goes down Hunting Lodge Road where Maria lives and then on to Separatist Road and then to South Eagleville before it comes to our school. We saw lots of good things like the Boston Massacre site. The tour ended at 1:05. Before I knew, it we were going home. We went through Warrenville again, but it was too dark to see much. A few days later it was Easter. We got a cuckoo clock."

Page received an unsatisfactory grade on his essay. What's more, his irate teacher scrawled in red across the top of the essay: "See me!" As he recalls in his memoir Parallel Play (Doubleday, 2009), such incidents were not uncommon in his childhood, and he knew why he was being scolded: "I had noticed the wrong things."


A Question of Focus

The subtitle of Page's memoir is Growing Up with Undiagnosed Asperger's, and indeed Page didn't learn until age 45 that he suffers from what is called autism spectrum disorder, or ASD. ASD is usually defined by impairments in social interaction and communication, but many people with autism and Asperger's syndrome (in which symptoms are milder) also tend to fixate on and remember seemingly irrelevant information in their world. Their attention seems to be awry, or to use Page's words, they notice the wrong things.

But why? What's going on in the autistic mind that makes the details of bus routes infinitely fascinating? Why are people like Page so easily distracted from the main act? Psychologists at University College London think that it might be a mistake to consider such distractibility as simply a deficit. To the contrary, Anna Remington and John Swettenham and their colleagues speculate that people with ASD might have a greater than normal capacity for perception, so that what appears as irrelevant distraction is really a cognitive bonus. They decided to test the idea in the lab.


Selective Attention

Remington and Swettenham studied a group of people with autism spectrum disorder, most of whom had Asperger's, along with normal controls. They asked all the subjects to look at a computer screen, which displayed various combinations of letters and dots forming a ring. The subjects were instructed to very rapidly determine if the letters N or X were present in the ring and then hit the corresponding key on the keyboard. Some of the circles — those with more letters — were more difficult to process than others. There were also other letters floating outside the circle, but the subjects were specifically instructed to ignore those letters. Those floating letters were the laboratory equivalent of an irrelevant distraction in the real world.

The psychologists were measuring perceptual capacity — that is why they varied the complexity of the task. As expected, everyone was slower at the task when the ring contained more letters. The researchers were also measuring distractibility. When a letter outside the ring was one of the target letters (N or X), the subjects often took a longer time finding the N or X in the ring — indicating they were distracted by the presence of a target letter in the location that they were supposed to ignore.

The psychologists reasoned that as long as the subjects' total perceptual capacity was not exhausted, they would also process the irrelevant, distracting letters within their visual field. Once they had surpassed their perceptual capacity — once the ring of letters was sufficiently complex — irrelevant processing would stop. So if ASD subjects in fact have greater processing capacity, then they should process more distracting information even as the main task becomes increasingly complex.


Seeing the Bigger Picture

And that is exactly what they found. As the researchers reported online in the journal Psychological Science, although there was no difference among subjects in either reaction time or accuracy on the main task, those with ASD processed the irrelevant letters while solving much more complex problems. Their reaction times indicated that they were still noticing when the extra letter was an N or X, while also finding the target letter in the ring with the same speed and accuracy as the normal controls. Put another way, they weren't ignoring the main task, nor were they distracted away from it. Instead they were completing their work and moving on, using their untapped capacity.

But here's the rub. Although this increased distractibility may be a talent rather than a deficit, the psychologists point out, it nonetheless can have detrimental consequences in real-life situations. Just ask Tim Page about his uncanny facility for bus routes.


--Originally published: Scientific American Mind 21, 68-69. (March/April 2010)


Early Intervention: Speech Therapy by Marissa Fessenden


Autistic children struggle with many obstacles, including learning to speak. And, experts have noted, if these children learn verbal skills by age five, they tend to become happier and higher-functioning adults than do their nonverbal peers. Thirty years ago, psychiatrists expected only half of all autistic children would gain speaking abilities. Recent studies, however, indicate that as many as 80 percent of children with autism can learn to talk. One such study in 2006 showed that toddlers who received intensive therapy aimed at developing foundational oral language skills made significant gains in their ability to communicate verbally. Now researchers have followed up with a number of those kids and found that most of them continued to reap the benefits of that therapy years after it had ended.


(Continues...)

Excerpted from Understanding Autism by Scientific American. Copyright © 2013 Scientific American, a division of Nature America, Inc.. Excerpted by permission of Scientific American.
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