Autism spectrum disorder (ASD) is a developmental condition that affect a person’s ability to socialize and communicate with others. People with ASD can also present with restricted and/or repetitive patterns of behavior, interests or activities. The term “spectrum” refers to the degree in which the symptoms, behaviors and severity vary within and between individuals. Some people are mildly impaired by their symptoms, while others are severely disabled.
The prevalence rate for ASD within the United States is around 1 in 68. Boys are four times more likely than girls to develop symptoms of ASD. This condition crosses racial, ethnic and social backgrounds equally. Awareness of this disorder and improved screening methods have contributed to the increase in diagnoses in recent years.
Autistic traits are normally distributed within society, and research has demonstrated that such traits also exist within the typically developing population. This phenomenon, known as the Broader Autism Phenotype, describes the degree to which autism persists within typical individuals who fail to meet diagnostic criteria for ASD.
For most, symptoms of ASD often start to appear during the first three years of life (though a small percentage of people might not receive a diagnosis until later in life). Typically, developing infants are social by nature. They gaze at faces, turn toward voices, grasp a finger and even smile by 2-3 months of age. Most children who develop autism have difficulty engaging in everyday human interactions.
Not everyone will experience symptoms with the same severity, but most people with ASD will have symptoms that affect social interactions and relationships. ASD can also causes difficulties with verbal and nonverbal communication and preoccupation with certain activities. Along with different interests, children with ASD generally have different ways of interacting with others. Parents are often the first to notice that their child is showing unusual behaviors. These behaviors can include failing to make eye contact, not responding to his or her name or playing with toys in unusual, repetitive ways.
Symptoms of autism can include impairments to social interaction & communication, and restricted and repetitive patterns of behavior. More specific symptoms are outlined below:
- Delay in language development, such as not responding to their own name or speaking only in single words, if at all.
- Repetitive and routine behaviors, such as walking in a specific pattern or insisting on eating the same meal every day.
- Difficulty making eye contact, such as focusing on a person’s mouth when that person is speaking instead of their eyes, as is usual in most young children.
- Sensory dysregulation forms a strong component of ASD. This often presents as hyper (overly-sensitive) or hyposensitivity (less sensitive) to certain sensory stimuli. Examples include experiencing pain or pleasure from certain sounds, like a ringing telephone or not reacting to intense cold or pain, certain sights, sounds, smells, textures and tastes. The physical and emotional response in these cases can be very overwhelming and result in sensory overload, often leading to meltdowns.
- Difficulty interpreting subtle gestures & facial expressions, such as misreading or not noticing subtle facial cues, like a smile, wink or grimace, that could help understand the nuances of social communication.
- Problems in expressing emotions, such as facial expressions, movements, tone of voice and gestures that are often vague or do not match what is said or felt.
- Fixation on parts of objects, often to the detriment of understanding the “whole” such as focusing on a rotating wheel instead of playing with peers.
- Absence of pretend play, such as taking a long time to line up toys in a certain way, rather than playing with them.
- A lack of social understanding that makes interaction with peers challenging
- Self-injurious behavior. Individuals with ASD will often appear to hurt themselves in response to certain activities or environments.
- Sleep problems, such as falling asleep or staying asleep.
The learning, thinking and problem-solving abilities of people with ASD can range from gifted to severely challenged. Some people with ASD need a lot of help in their daily lives. With a thorough evaluation, doctors can make a diagnosis to help find the best treatment plan.
Scientists have not discovered a single cause of autism. They believe several factors may contribute to this developmental disorder.
- Genetics. If one child in a family has ASD, another sibling is more likely to develop it too. Likewise, identical twins are highly likely to both develop autism if it is present. Relatives of children with autism show minor signs of communication difficulties. Scans reveal that people on the autism spectrum have certain abnormalities of the brain's structure and chemical function.
- Environment. Scientists are currently researching many environmental factors that are thought to play a role in contributing to ASD. Many prenatal factors may contribute to a child’s development, such as a mother’s health. Other postnatal factors may affect development as well. Despite many claims that have been highlighted by the media, strong evidence has been shown that vaccines do not cause autism.
There is no medical test that can determine the possibility of developing autism. Specialists make the diagnosis after screening for social and communication difficulties, and repetitive or restricted behaviors.
Diagnosing autism is often a 2-stage process. The first stage involves general developmental screening during well-child checkups with a pediatrician. Children who show some developmental problems are referred for more evaluation. The second stage involves a thorough evaluation by a team of doctors and other health professionals with a wide range of specialties. At this stage, a child may be diagnosed as having autism or another developmental disorder. Typically, children with ASD can be reliably diagnosed by age two, though some may not be diagnosed until they are older.
Types Of ASD Screening Instruments
Sometimes the doctor will ask parents questions about the child's symptoms to screen for autism. Other screening instruments combine information from parents with the doctor's own observations of the child. Examples of screening instruments for toddlers and preschoolers include:
- Modified Checklist for Autism in Toddlers (M-CHAT) is a list of informative questions about a child where the answers can show whether he or she should be further evaluated by a specialist.
- Screening Tool for Autism in Two-Year-Old’s (STAT) is a set of tasks that children perform under supervision to assess key social and communicative behaviors, including imitation, play and directing attention.
- Social Communication Questionnaire (SCQ) is a series of questions parents answer to help specialists determine if further testing is needed for a child aged 4 years or older.
- Communication and Symbolic Behavior Scales (CSBS) uses parent interviews and direct observations of natural play to collect information on communication development, including gestures, facial expressions and play behaviors.
For more information on these screening tools, please visit the Centers for Disease Control and Prevention
Given that ASD is a developmental condition that begins early in life, having a cascading effect on developmental milestones, there is no known cure. But there is effective treatment available. Treatment options include:
- Education and development, including specialized classes and skills training, time with therapists (such as Speech & Language and Occupational Therapists) and other specialists
- Behavioral treatments, such as applied behavior analysis (ABA)
- Medication for co-occurring symptoms, combined with therapy
- Complementary and alternative medicine (CAM), such as supplements and changes in diet
A child with autism may have co-morbid disorders. Some of those disorders are:
- Intellectual impairment. Many children with ASD have some degree of intellectual impairment. Cognitive and language skills may be weak in a number of domains, often having a profound impact on daily functioning.
- Seizures. 1 in 4 children with autism has seizures, often starting either in early childhood or during the teen years. Seizures, caused by electrical activity in the brain, can result in a short-term loss of consciousness, convulsions and staring spells. An electroencephalogram (EEG), a nonsurgical test that records electrical activity in the brain, can help confirm whether a child is having seizures.
- Fragile X syndrome. Fragile X syndrome is a genetic disorder. It is the most common form of inherited intellectual impairment, and often results in ASD-like symptoms. Around 1 in 3 children who have Fragile X syndrome also meet the diagnostic criteria for ASD. About 1 in 25 children diagnosed with ASD have the gene mutation that causes Fragile X syndrome. Because this disorder is inherited, children with autism should be checked for Fragile X, especially if the parents want to have more children. For more information on Fragile X, see the Eunice Kennedy Shriver National Institute of Child Health and Human Development website.
- Tuberous sclerosis. Tuberous sclerosis is a rare genetic disorder that causes noncancerous tumors to grow in the brain and other vital organs. Tuberous sclerosis occurs in 1-4% of people with ASC. A genetic mutation causes the disorder, which has also been linked to intellectual impairment, epilepsy and many other physical and mental health problems. There is no cure for tuberous sclerosis, but many symptoms can be treated.
- Gastrointestinal problems. Some parents of children with autism report that their child has frequent gastrointestinal (GI) or digestion problems including stomach pain, diarrhea, constipation, acid reflux, vomiting or bloating. If a child has GI problems, a gastroenterologist can help find the cause and suggest appropriate treatment.
- Mental health conditions. Children with autism can also develop mental health conditions such as Anxiety Disorders, Attention Deficit Hyperactivity Disorder (ADHD) or Depression. Research shows that children with ASC are at higher risk for some mental health conditions than children without autism. Managing these co-morbid conditions with medications or behavioral therapy, which teaches children how to control their behavior, can reduce symptoms that appear to worsen a child's symptoms.
- Rett syndrome. Rett syndrome is a developmental disorder that includes a regression in development. Unlike ASD, Rett syndrome mostly affects girls. 1 of every 10,000-22,000 girls has Rett syndrome. Children with Rett syndrome develop normally for 6-18 months before regression and ASD-like symptoms appear. However, after this period, most children with Rett syndrome improve their social communication skills, and autistic features are no longer a major area of concern.