Autism Health Article

Definition

Autism is a chronic and often severe disorder of brain functioning that begins during childhood. It is marked by problems with social contact, intelligence, and language, coupled with ritualistic or compulsive behavior, sensory integration and processing problems, and strange environmental responses.

Description

Autism is a lifelong disorder that interferes with the ability to understand what is seen, heard, and touched. This can cause profound problems in personal behavior

and in the ability to relate to others. A person with autism must learn how to communicate normally and how to relate to people, objects, and events. However, not all patients suffer the same degree of impairment. The severity of the condition varies between individuals, ranging from the person with extremely unusual and aggressive behavior to one with something resembling a mild personality disorder or a learning disability.

Autism occurs in as many as one in 1,000 children, and incidence is rapidly increasing. It is found three to four times more often in boys than in girls. The condition occurs around the world in all races and all social backgrounds. Autism usually is evident in the first three years of life, although in some children it is difficult to pinpoint when the problem actually takes hold. Often, the condition may not be diagnosed until the child enters school. A person with autism can have symptoms ranging from mild to severe.

Two subgroups of autism have recently been explained by clinicians. Those with essential autism, as defined by diagnostic tests, appear to have higher IQ scores and fewer seizures than those with complex autism, which offers a poorer outcome.

Causes & symptoms

Although the exact causes of autism are unknown, many possibilities have been proposed. Most experts believe that several independent factors contribute to development of autism. The number and combinations of these factors probably differ from person to person. Research points to such precipitating conditions as fetal alcohol syndrome, genetic connections (as with identical twins), brain stem defects, lead poisoning, a nervous system defect, infections, food and inhalant allergies, infant vaccination reactions, and digestive system deficiencies.

Further studies point to major disturbances in the body chemistry of children with autism. Disruption is most often found in fatty acid metabolism, electrolyte balances, problems with digestive functioning, production of red and white blood cells, and the body's balance of minerals. Diseases that may trigger autistic behavior include rubella in the pregnant mother, tuberous sclerosis, candiasis infection, fragile X syndrome, encephalitis, cytomegalovirus (CMV), a severe form of a herpes simplex infection, and untreated phenylketonuria.

There also appears to be a strong genetic basis for autism. In October 2001, the National Institutes of Health (NIH) reported that two regions of chromosomes contain genes involved with autism, and that two other chromosomes had a weaker relation to autism-related genes. Genetically identical twins are much more likely than fraternal twins to both have autism if one is affected. In a family with one autistic child, the chance of having another child with autism is about one in 20, much higher than in the normal population. Sometimes, relatives of an autistic child have mild behaviors that look very much like autism, such as repetitive behaviors and social or communication problems. Research also has found that some emotional disorders, such as manic depression, occur more often in families of a child with autism. At least one group of researchers has also found a link between an abnormal gene and autism. The gene may be just one of at least three to five genes that inter-act in some way to cause the condition. Scientists suspect that a faulty gene or genes might make a person vulnerable to develop autism in the presence of other factors, such as chemical imbalance, infection, or a lack of oxygen at birth.

Autism affects the way in which the brain uses or transmits information. Studies have found abnormalities in several parts of the brains of those with autism that almost certainly occurred during fetal development. The problem may be centered in the parts of the brain responsible for processing language and information from the senses. Profound problems with social interactions are the most common symptoms of autism. Infants with the disorder will not cuddle, avoid eye contact, and in general do not seem to like or require physical contact or affection. Often, the child will not form attachments to parents or the rest of the family. The child may not speak at all, or speak very little and may show bizarre patterns of speech, such as endlessly repeating words or phrases. About 10% of those with autism have an exceptional ability in particular areas, such as mathematics, memory, art, or music.

Most autistic children appear to be mentally retarded to at least some degree. Bizarre behavior patterns are very common and may include repeated mimicking of the actions of others, complex rituals, screaming fits, rhythmic rocking, arm flapping, finger twiddling, and crying without tears. Many of these children may react to sounds by banging their head or flapping fingers. Some less affected autistic adults who have written books about their childhood experiences report that sounds were often excruciatingly painful to them, forcing them to withdraw from the environment or to try to cope by withdrawing into their own invented world. A common characteristic of individuals with autism is an insistence on sameness. There may be strong reactions to changes in food, clothing, and routines.