Exploring the Autism Spectrum:

Understanding the autism spectrum

Autism is not a single disorder, but a spectrum of closely-related disorders with a shared core of symptoms. Every individual on the autistic spectrum has problems to some degree with social skills, empathy, communication, and flexible behavior. But the level of disability and the combination of symptoms varies tremendously from person to person. In fact, two kids with the same diagnosis may look very different when it comes to their behaviors and abilities.

If you’re a parent dealing with a child on the autism spectrum, you may hear many different terms including high-functioning autism, atypical autism, autism spectrum disorder, and pervasive developmental disorder. These terms can be confusing, not only because there are so many, but because doctors, therapists, and other parents may use them in dissimilar ways.

But no matter what doctors, teachers, and other specialists call the disorder, it’s your child’s unique needs that are truly important. No diagnostic label can tell you exactly what problems your child will have. Finding treatment that addresses your child’s needs, rather than focusing on what to call the problem, is the most helpful thing you can do.

The autism spectrum disorders (ASDs)

The autism spectrum disorders belong to an “umbrella” category of five childhood-onset conditions known as pervasive developmental disorders (PDD). Some autism specialists use the terms pervasive developmental disorder and autism spectrum disorder interchangeably. However, when most people talk about the autism spectrum disorders (ASDs), they are referring to the three most common PDDs:

• Autism
• Asperger's Syndrome
• Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS)

Childhood disintegrative disorder and Rett Syndrome are the other pervasive developmental disorders. Because both are extremely rare genetic diseases, they are usually considered to be separate medical conditions that don't truly belong on the autism spectrum.

The three autism spectrum disorders differ in their impact. Classic autism, or autistic disorder, is the most severe of the autism spectrum disorders. Asperger’s Syndrome, sometimes called high-functioning autism, is the mildest. PDD-NOS, or atypical autism, falls somewhere in between. According to the Autism Spectrum Resource Center, only 20% of people on the autism spectrum have classic autism. The overwhelming majority fall somewhere on the milder range of the spectrum.
In both children and adults, the signs and symptoms of the autism spectrum disorders revolve around problems with social interaction, language, and restricted activities and interests. However, there are enormous differences when it comes to the severity of the symptoms, their combinations, and the patterns of behavior.

Since the autism spectrum disorders share many similar symptoms, it can be difficult to distinguish one from the other, particularly in the early stages. If your child is developmentally delayed or exhibits other autism-like behaviors, you will need to visit a medical professional for a thorough evaluation. Your doctor can help you figure out where, or even if, your child fits on the autistic spectrum. Keep in mind that just because a child has a few autism-like symptoms does not mean he or she has an autism spectrum disorder. These disorders are diagnosed based on a distinct pattern of multiple symptoms that disrupt the child’s level of functioning.

Social interaction in autism spectrum disorders

Basic social interaction can be difficult for children with autism spectrum disorders (ASDs). Many kids on the autism spectrum seem to prefer to live in their own little world, aloof and detached from others. This detachment from others can sometimes be seen even in babies. Some autistic infants don't respond to cuddling, reach out to be picked up, or look at their mothers when being fed. When they're older, autistic children may not hear when others are speaking to them or respond to affection in typical ways (standing stiffly when hugged, for example).

• Common social interaction impairments seen in autism spectrum disorders include:
• Poor eye contact.
• Unusual or inappropriate body language and facial expressions.
• Lack of interest in other people.
• Prefers to be alone.
• Lack of empathy.
• Doesn't share interests or achievements with others (drawings, toys).
• Resistance to being touched.
• Difficulty or failure to make friends.

Communication in autism spectrum disorders

Children with autism spectrum disorders have difficulty with both verbal and non-verbal communication.

Speech problems

Problems with verbal communication are a telltale sign of the autism spectrum disorders. According to the Yale Developmental Disabilities Clinic, speech is absent in about 50 percent of classical autism cases. In other cases, kids may not start to talk until very late. Those with classical autism who do speak, often do so in odd or unusual ways. For example, children on the autism spectrum may:

• Speak in an abnormal tone of voice, or with an odd rhythm or pitch.
• End every sentence as if asking a question.
• Use echolalia (the parrot-like repetition of the same words or phrases).
• Respond to a question by repeating it, rather than answering it.
• Refer to themselves in the third person.

Language comprehension

Language comprehension is also commonly impaired in children with autism spectrum disorders. Kids with autism may not understand simple directions or questions. Those who do have a firm grasp of spoken language often take what is said too literally. Metaphors and other figures of speech (such as "it's raining cats and dogs") can be confusing, and they are typically oblivious to attempts at humor, irony, and sarcasm. Kids with autism spectrum disorders often:

• Have trouble starting a conversation or keeping it going.
• Use language incorrectly (grammatical errors, wrong words).
• Have difficulty communicating needs or desires.
• Don’t understand simple statements or questions.
• Confuse pronouns.

Nonverbal Communication

When kids with autism spectrum disorders do choose to interact with others, they sometimes come across as cold or "robot-like." But while they may appear emotionally flat, the reality is that autistic individuals are far from unfeeling. What can look like indifference or insensitivity is actually due to "mind blindness," or an inability to see things as other people do.

This makes the "give-and-take" of social interaction very difficult for children with autism spectrum disorders. Subtle social cues such as facial expressions, tone of voice, and gestures are often lost on them. They may also have trouble communicating through their own nonverbal behaviors. For example, your child may avoid eye contact, make very few gestures, or use facial expressions that don't match what he or she is saying.

Restricted behaviors in autism spectrum disorders

Children with autism spectrum disorders are often restricted, rigid, and even obsessive in their behaviors, activities, and interests. This can show up as:

• Repetitive body movements
• Following an inflexible schedule
• Attachment to unusual objects
• Preoccuption with a narrow topic of interest

Repetitive movements

Children with autism spectrum disorders commonly engage in repetitive movements such as hand flapping, rocking, or twirling. Such self-stimulatory behavior, also known as "stimming", may preoccupy your child to the exclusion of all other activities and interests. Alternately, he or she may spend hours arranging toys in specific ways, watching moving objects such as a ceiling fan, or focusing on one specific part of an object.

Often, kids on the autism spectrum also exhibit clumsiness, abnormal posture, or eccentric ways of moving. For example, a child with autism may walk exclusively on tiptoe.

Inflexible or obsessive activities and interests

Some children with autism spectrum disorders follow rigid routines and are resistant to any changes in their schedule or environment. For example, they may insist on taking a certain route to school and become extremely upset if they have to go another way. They may have a temper tantrum if the furniture in their house is rearranged or they have to eat lunch at a different time than they're used to. Many children with ASDs also form obsessive attachments to unusual objects such as keys or rubber bands, or become preoccupied with a very specific topic. This topic often involves numbers or symbols (maps, train schedules, sports statistics), and the child may spend hours memorizing and reciting facts about it.

Common problems on the autism spectrum

While not part of autism’s official diagnostic criteria, kids on the autism spectrum often suffer from one or more of the following problems:

• Sensory Problems - Many children with ASDs either underreact or overreact to sensory stimuli. At times they may ignore people speaking to them, even to the point of appearing deaf. However, at other times they may be disturbed by even the softest sounds. Sudden noises such as a ringing telephone can be upsetting, and they may respond by covering their ears and making repetitive noises to drown out the offending sound. Children on the autism spectrum also tend to be highly sensitive to touch and to texture. They may cringe at a pat on the back or the feel of certain fabric against their skin.
• Emotional Difficulties – Kids with autism spectrum disorders may have difficulty regulating their emotions or expressing them appropriately. For instance, your child may start to yell, cry, or laugh hysterically for no apparent reason. When stressed, he or she may exhibit disruptive or even aggressive behavior (breaking things, hitting others, or harming him or herself). The National Dissemination Center for Children with Disabilities also notes that autistic kids may be unfazed by real dangers like moving vehicles or heights, yet be terrified of harmless objects such as a stuffed animal.
• Uneven Cognitive Abilities - The autism spectrum disorders occur at all intelligence levels. However, even kids with normal to high intelligence often have unevenly developed cognitive skills. Not surprisingly, verbal skills tend to be weaker than nonverbal skills. In addition, children with ASDs typically do well on tasks involving immediate memory or visual skills, while tasks involving symbolic or abstract thinking are more difficult.

Asperger's Syndrome and PDD-NOS

Symptoms of Asperger’s syndrome

Asperger’s syndrome is the mildest of the autism spectrum disorders. Unlike autism, speech is not delayed or impaired in Asperger’s. Children with this disorder have good language and verbal skills. They have normal to high intelligence. However, they have problems socializing and communicating effectively with others.  Children with Asperger’s syndrome often come across to others as socially “clueless” or eccentric.

• The signs and symptoms of Asperger’s syndrome include:
• Obsession with a specific topic.
• Long, one-sided conversations.
• Inability to read other people’s reactions or nonverbal cues.
• Unusual or inappropriate eye contact, gestures, and facial expressions.
• Insensitivity to the feelings of others.
• An overly-formal, high-pitched, or robotic speaking voice.
• Failure to grasp humor, irony, and figures of speech.
• Repetitive routines and rituals.
• Clumsy or odd movements.
• Sensitivity to light, sound, and pain.

Of all the signs and symptoms, an excessive, all-encompassing preoccupation with a narrow subject or interest (such as airplanes, spiders, or weather) is often the most prominent. A person with Asperger’s may spend a great deal of time memorizing facts or collecting and organizing things related to his or her obsession.

Symptoms of PDD-NOS

For children who meet some, but not all, of the criteria for autism or Asperger’s syndrome, a diagnosis of PDD-NOS (Pervasive Developmental Disorder - Not Otherwise Specified)is given. PDD-NOS is also sometimes called atypical autism).

The PDD-NOS diagnosis is reserved for kids who have many autistic-like symptoms, but don’t quite fit into the “box” for the other autism spectrum disorders. For example, their symptoms might have started after the age of three, or they may demonstrate repetitive behaviors and abnormal speech, but have better social skills than other autistic kids. In some cases, a diagnosis of PDD-NOS is eventually changed to something else as the child gets older and the symptoms become clearer.

Related links for autism spectrum disorders

General information about autism spectrum disorders

All About Autistic Spectrum Disorders (PDF) – Booklet for the parents of autistic children. Covers symptoms, causes, and treatment options. (Foundation for People with Learning Disabilities)

Autism Information Center: Symptoms – Describes the symptoms of autism and the autism spectrum disorders, including deficits in social skills, communication, and repetitive behaviors and routines. (Centers for Disease Control and Prevention)

Pervasive Developmental Disorders – Guide to the symptoms, causes, diagnosis, and treatment of the pervasive developmental disorders, including autism. (National Dissemination Center for Children with Disabilities)

Autism Characterized by Extraordinary Variability – Article on the wide degree of variability among people with autism spectrum disorders. (Autism Speaks)

Social skills, communication, and repetitive behavior

Autism and Communication – Covers the normal development of speech and language, and how this developmental process differs in autistic kids. Features a detailed description of autistic communication problems. (National Institute on Deafness and Other Communication Disorders)

Core Features of Autism: Social Skills – Fact sheet on the impairment in social skills shown by infants and children with autism. (Autism Consultation and Training Now)

Core Features of Autism: Communication – Fact sheet from the Australian government on the language, verbal comprehension, and nonverbal communication problems demonstrated by children with autism. (Autism Consultation and Training Now)

Core Features of Autism: Play and Behavior – Fact sheet from the Australian Child to Adult Development Study covers the symptoms of autism involving play and repetitive or stereotyped behavior. (Autism Consultation and Training Now)

Stereotypic (Self-Stimulatory) Behavior – Covers the common self-stimulatory behaviors, also known as stimming, seen in autistic kids. (Center for the Study of Autism)

Asperger’s syndrome

Asperger’s Disorder – Guide to the characteristics of Asperger’s syndrome, diagnosis, educational issues, and what the disorder looks like in adults. (Autism Society of America)

How Might Asperger's Appear to a Parent? – Excerpt from the book “School Success for Kids With Asperger’s Syndrome” describes what Asperger’s disorder looks like. (Prufrock Press Inc.)

Asperger's Syndrome – Guide to the signs, symptoms, causes, and treatment of Asperger’s syndrome. (Kid’s Health)

Asperger's Syndrome – Comprehensive overview of Asperger’s syndrome, including symptoms, diagnosis, and treatment. (Yale Developmental Disabilities Clinic)

Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS)

Connections to PDD-NOS – Jumping off point to a wealth of resources on Pervasive Developmental Disorder – Not Otherwise Specified. (National Dissemination Center for Children with Disabilities)

Pervasive Developmental Disorder - Not Otherwise Specified - Provides a definition of PDD-NOS and a case study of a child with the diagnosis. (Yale Developmental Disabilities Clinic)

Melinda Smith, M.A. and Jeanne Segal, Ph.D. contributed to this article. Last modified on December 5, 2007.