What Is Autism Spectrum Disorder? Autism spectrum disorder (ASD) is characterized by: Persistent deficits in social communication and social interaction across multiple contexts; Restricted, repetitive patterns of behavior, interests, or activities; Symptoms must be present in the early developmental period (typically recognized in the first two years of life); and, Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning. The term “spectrum” refers to the wide range of symptoms, skills, and levels of impairment or disability that children with ASD can have. Some children are mildly impaired by their symptoms, while others are severely disabled. The latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) no longer includes Asperger’s syndrome; the characteristics of Asperger’s syndrome are included within the broader category of ASD. Information on ASD can also be found on the Eunice Kennedy Shriver National Institute of Child Health and Human Development website and the Centers for Disease Control and Prevention website . Causes Scientists dont know the exact causes of autism spectrum disorder (ASD), but research suggests that both genes and environment play important roles. Genetic factors In identical twins who share the exact same genetic code, if one has ASD, the other twin also has ASD in nearly 9 out of 10 cases. If one sibling has ASD, the other siblings have 35 times the normal risk of also developing the disorder. Researchers are starting to identify particular genes that may increase the risk for ASD. Still, scientists have only had some success in finding exactly which genes are involved. For more information about such cases, see the information below about Fragile X syndrome and tuberous sclerosis. Most people who develop ASD have no reported family history of autism, suggesting that random, rare, and possibly many gene mutations are likely to affect a persons risk. Any change to normal genetic information is called a mutation. Mutations can be inherited, but some arise for no reason. Mutations can be helpful, harmful, or have no effect. Having increased genetic risk does not mean a child will definitely develop ASD. Many researchers are focusing on how various genes interact with each other and environmental factors to better understand how they increase the risk of this disorder. Environmental factors In medicine, environment refers to anything outside of the body that can affect health. This includes the air we breathe, the water we drink and bathe in, the food we eat, the medicines we take, and many other things that our bodies may come in contact with. Environment also includes our surroundings in the womb, when our mothers health directly affects our growth and earliest development. Researchers are studying many environmental factors such as family medical conditions, parental age and other demographic factors, exposure to toxins, and complications during birth or pregnancy. As with genes, its likely that more than one environmental factor is involved in increasing risk for ASD. And, like genes, any one of these risk factors raises the risk by only a small amount. Most people who have been exposed to environmental risk factors do not develop ASD. The National Institute of Environmental Health Sciences is also conducting research in this area. More information is available on their website . Scientists are studying how certain environmental factors may affect certain genes—turning them on or off, or increasing or decreasing their normal activity. This process is called epigenetics and is providing researchers with many new ways to study how disorders like ASD develop and possibly change over time. ASD and vaccines Health experts recommend that children receive a number of vaccines early in life to protect against dangerous, infectious diseases, such as measles. Since pediatricians in the United States started giving these vaccines during regular checkups, the number of children getting sick, becoming disabled, or dying from these diseases has dropped to almost zero. Children in the United States receive several vaccines during their first 2 years of life, around the same age that ASD symptoms often appear or become noticeable. A minority of parents suspect that vaccines are somehow related to their childs disorder. Some may be concerned about these vaccines due to the unproven theory that ASD may be caused by thimerosal. Thimerosal is a mercury-based chemical once added to some, but not all, vaccines to help extend their shelf life. However, except for some flu vaccines, no vaccine routinely given to preschool aged children in the United States has contained thimerosal since 2001. Despite this change, the rate of children diagnosed with ASD has continued to rise. Other parents believe their childs illness might be linked to vaccines designed to protect against more than one disease, such as the measles-mumps-rubella (MMR) vaccine, which never contained thimerosal. Many studies have been conducted to try to determine if vaccines are a possible cause of autism. As of 2010, none of the studies has linked autism and vaccines. Following extensive hearings, a special court of Federal judges ruled against several test cases that tried to prove that vaccines containing thimerosal, either by themselves or combined with the MMR vaccine, caused autism. More information about these hearings is available on the U.S. Court of Federal Claims website . The latest information about research on autism and vaccines is available from the Centers for Disease Control and Prevention . This website provides information from the Federal Government and independent organizations. Early Signs & Symptoms Symptoms of autism spectrum disorder (ASD) vary from one child to the next, but in general, they fall into two areas: Social impairment, including difficulties with social communication Repetitive and stereotyped behaviors. Children with ASD do not follow typical patterns when developing social and communication skills. Parents are usually the first to notice unusual behaviors in their child. Often, certain behaviors become more noticeable when comparing children of the same age. In some cases, babies with ASD may seem different very early in their development. Even before their first birthday, some babies become overly focused on certain objects, rarely make eye contact, and fail to engage in typical back-and-forth play and babbling with their parents. Other children may develop normally until the second or even third year of life, but then start to lose interest in others and become silent, withdrawn, or indifferent to social signals. Loss or reversal of normal development is called regression and occurs in some children with ASD. Social impairment Most children with ASD have trouble engaging in everyday social interactions. For example, some children with ASD may: Make little eye contact Tend to look and listen less to people in their environment or fail to respond to other people Rarely seek to share their enjoyment of toys or activities by pointing or showing things to others Respond unusually when others show anger, distress, or affection. Recent research suggests that children with ASD do not respond to emotional cues in human social interactions because they may not pay attention to the social cues that others typically notice. For example, one study found that children with ASD focus on the mouth of the person speaking to them instead of on the eyes, which is where children with typical development tend to focus. A related study showed that children with ASD appear to be drawn to repetitive movements linked to a sound, such as hand-clapping during a game of pat-a-cake. More research is needed to confirm these findings, but such studies suggest that children with ASD may misread or not notice subtle social cues-a smile, a wink, or a grimace-that could help them understand social relationships and interactions. For these children, a question such as, Can you wait a minute? always means the same thing, whether the speaker is joking, asking a real question, or issuing a firm request. Without the ability to interpret another persons tone of voice as well as gestures, facial expressions, and other nonverbal communications, children with ASD may not properly respond. Likewise, it can be hard for others to understand the body language of children with ASD. Their facial expressions, movements, and gestures are often vague or do not match what they are saying. Their tone of voice may not reflect their actual feelings either. Many older children with ASD speak with an unusual tone of voice and may sound sing-song or flat and robotlike. Children with ASD also may have trouble understanding another persons point of view. For example, by school age, most children understand that other people have different information, feelings, and goals than they have. Children with ASD may lack this understanding, leaving them unable to predict or understand other peoples actions. Communication issues According to the American Academy of Pediatrics developmental milestones, by the first birthday, typical toddlers can say one or two words, turn when they hear their name, and point when they want a toy. When offered something they do not want, toddlers make it clear with words, gestures, or facial expressions that the answer is no. For children with ASD, reaching such milestones may not be so straightforward. For example, some children with autism may: Fail or be slow to respond to their name or other verbal attempts to gain their attention Fail or be slow to develop gestures, such as pointing and showing things to others Coo and babble in the first year of life, but then stop doing so Develop language at a delayed pace Learn to communicate using pictures or their own sign language Speak only in single words or repeat certain phrases over and over, seeming unable to combine words into meaningful sentences Repeat words or phrases that they hear, a condition called echolalia Use words that seem odd, out of place, or have a special meaning known only to those familiar with the childs way of communicating. Even children with ASD who have relatively good language skills often have difficulties with the back and forth of conversations. For example, because they find it difficult to understand and react to social cues, some highly verbal children with ASD often talk at length about a favorite subject, but they wont allow anyone else a chance to respond or notice when others react indifferently. Children with ASD who have not yet developed meaningful gestures or language may simply scream or grab or otherwise act out until they are taught better ways to express their needs. As these children grow up, they can become aware of their difficulty in understanding others and in being understood. This awareness may cause them to become anxious or depressed. Repetitive and stereotyped behaviors Children with ASD often have repetitive motions or unusual behaviors. These behaviors may be extreme and very noticeable, or they can be mild and discreet. For example, some children may repeatedly flap their arms or walk in specific patterns, while others may subtly move their fingers by their eyes in what looks to be a gesture. These repetitive actions are sometimes called stereotypy or stereotyped behaviors. Children with ASD also tend to have overly focused interests. Children with ASD may become fascinated with moving objects or parts of objects, like the wheels on a moving car. They might spend a long time lining up toys in a certain way, rather than playing with them. They may also become very upset if someone accidentally moves one of the toys. Repetitive behavior can also take the form of a persistent, intense preoccupation. For example, they might be obsessed with learning all about vacuum cleaners, train schedules, or lighthouses. Children with ASD often have great interest in numbers, symbols, or science topics. While children with ASD often do best with routine in their daily activities and surroundings, inflexibility may often be extreme and cause serious difficulties. They may insist on eating the same exact meals every day or taking the same exact route to school. A slight change in a specific routine can be extremely upsetting. Some children may even have emotional outbursts, especially when feeling angry or frustrated or when placed in a new or stimulating environment. No two children express exactly the same types and severity of symptoms. In fact, many typically developing children occasionally display some of the behaviors common to children with ASD. However, if you notice your child has several ASD-related symptoms, have your child screened and evaluated by a health professional experienced with ASD.
Posted on: Thu, 10 Jul 2014 10:27:06 +0000
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