Autism refers to a continuum or “spectrum” of neurological conditions that impact the person’s ability to communicate, think abstractly and engage in appropriate social interaction and cause repetitive thoughts and behaviors. Autism Spectrum Disorders (ASD) include a range of problems from very severe impairments to those that may not even be detectable to the casual observer.
Because ASD is a very broad range of disorders, it’s hard to point to signs or symptoms that everyone with ASD has. There are, however, certain types of issues that are common to all of ASD, even though they may look very different in different people, depending on the type and severity of the disorder.
People with ASD have difficulty learning and using the many social rules that exist in the world. This includes things like reading other people’s facial expressions, making eye contact and understanding personal space. This may also affect areas such as making friends, using good manners or properly interpreting gestures. As people with ASD get older, they may need to be explicitly taught the “rules” of social interaction that their peers are picking up on their own, such as appropriate dress and hygiene.
People with ASD often have impaired communication skills. In the most extreme cases, they may not develop and use language at all. On the other end of the spectrum, people with autism may have outstanding vocabularies but have difficulty understanding and using figurative language and figures of speech.
Using language in social situations may also be difficult for people with ASD. Social rules such as using an appropriate volume of speech and tone of voice can be difficult. Children with ASD may need explicit instruction on taking turns in conversation and considering the listener’s point of view when speaking. Children with ASD are often noticed to have difficulty using the correct pronouns when they speak.
Some people with ASD engage in echolalia. This is a phenomenon where the person repeats a word, sentence or longer amount of language which they have heard over and over again.
Repetitive behaviors, including echolalia, are also common for people with ASD. Many people with ASD have a particular interest that can be more important than anything else for them. This could be anything from trains or sports statistics to reciting poems or making sure colors are always in rainbow order.
Some people with ASD engage in repetitive movements such as rocking, spinning or flapping their hands. Some enjoy repetitive sensory stimulation, such as running hands under water or feeling a certain type of fabric.
There are five major types of ASD.
Autistic Disorder refers to the classic presentation of delays and disturbances in all three of the areas discussed above (Communication, Social Understanding and Repetition). People with Autistic Disorder usually also have cognitive delays in their development.
Asperger’s Syndrome is a disorder closely related to Autistic Disorder. People with Asperger’s, however, do not have cognitive delays or delays in developing language. They may have other communication problems later in life, however. Asperger’s Syndrome is sometimes called “Little Professor” Syndrome, due to the fact that children who have it often have a single obsessive interest and explain that interest at great length using sophisticated vocabulary.
Childhood Disintigrative Disorder and Rett’s Disorder are disorders where the child develops normally for a period of time and then begins to lose skills they may have already learned or fails to gain new ones, leaving them with severe autistic symptoms.
Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) is a term used to describe people who have symptoms of autism but do not fit neatly into any one of the other categories.
The causes of ASD are not well understood. There appears to be a strong genetic component, and some scientists have suggested that up to 90% of a person’s susceptibility to ASD is genetic. It is not clear, however, which genes are responsible and whether ASD is related to a combination of normally occurring genes or to genetic mutations.
Some studies suggest that autism is also associated with parents who have higher IQ’s. Both mothers and fathers who are older during conception and pregnancy are more likely to have children with ASD.
ASD is also known to be related to some aspects of the prenatal environment. Complications such as diabetes and bleeding during pregnancy may also contribute to developing ASD, as may certain medications taken during pregnancy and exposure to chemicals known to cause other birth defects. The single largest non-genetic cause of autism is viral infection during pregnancy. In particular, exposure to rubella (German measles) in utero increases the chances of ASD.
Children born with low birth weight or who experience loss of oxygen during birth are also at increased risk for ASD.
There is no reliable scientific evidence for any cause of ASD that occurs after birth. There are many theories regarding various toxic substances in the environment, but none have been proven.
Perhaps the most commonly held theory is that vaccines, particularly the measles, mumps and rubella (MMR) vaccine, cause autism. Because ASD symptoms often first become noticeable between 18 months and 3 years, because two types of ASD begin with normal development, and because a large number of vaccines, including MMR, are administered at this age, many people suspected there was a causal link.
In 1998, a British researcher published a study that linked MMR to ASD. Since that time, however, he has admitted that he faked the data, and the study has been retracted.
Because of this episode, the alleged link between vaccines and ASD has been very thoroughly studied. The consensus of all major medical organizations is that vaccines do not cause autism.