What is autism?
Autism is not a disease, but a developmental
disorder of brain function. People with
classical autism show three types of symptoms:
impaired social interaction, problems with
verbal and nonverbal communication and
imagination, and unusual or severely limited
activities and interests. Symptoms of autism
usually appear during the first three years of
childhood and continue throughout life. Although
there is no cure, appropriate management may
foster relatively normal development and reduce
undesirable behaviors. People with autism have a
normal life expectancy.
Autism affects an estimated two to 10 of every
10,000 people, depending on the diagnostic
criteria used. Most estimates that include
people with similar disorders are two to three
times greater. Autism strikes males about four
times as often as females, and has been found
throughout the world in people of all racial and
social backgrounds.
Autism varies a great deal in severity. The most
severe cases are marked by extremely repetitive,
unusual, self-injurious, and aggressive
behavior. This behavior may persist over time
and prove very difficult to change, posing a
tremendous challenge to those who must live
with, treat, and teach these individuals. The
mildest forms of autism resemble a personality
disorder associated with a perceived learning
disability.
What are some common signs of autism?
The hallmark feature of autism is impaired
social interaction. Children with autism may
fail to respond to their names and often avoid
looking at other people. Such children often
have difficulty interpreting tone of voice or
facial expressions and do not respond to others'
emotions or watch other people's faces for cues
about appropriate behavior. They appear unaware
of others' feelings toward them and of the
negative impact of their behavior on other
people.
Many children with autism engage in repetitive
movements such as rocking and hair twirling, or
in self-injurious behavior such as biting or
head-banging. They also tend to start speaking
later than other children and may refer to
themselves by name instead of "I" or "me." Some
speak in a sing-song voice about a narrow range
of favorite topics, with little regard for the
interests of the person to whom they are
speaking.
People with autism often have abnormal responses
to sounds, touch, or other sensory stimulation.
Many show reduced sensitivity to pain. They also
may be extraordinarily sensitive to other
sensations. These unusual sensitivities may
contribute to behavioral symptoms such as
resistance to being cuddled.
How is autism diagnosed?
Autism is classified as one of the pervasive
developmental disorders. Some doctors also use
terms such as "emotionally disturbed" to
describe people with autism. Because it varies
widely in its severity and symptoms, autism may
go unrecognized, especially in mildly affected
individuals or in those with multiple handicaps.
Researchers and therapists have developed
several sets of diagnostic criteria for autism.
Some frequently used criteria include:
- Absence or impairment of imaginative and
social play
- Impaired ability to make friends with
peers
- Impaired ability to initiate or sustain
a conversation with others
- Stereotyped, repetitive, or unusual use
of language
- Restricted patterns of interests that
are abnormal in intensity or focus
- Apparently inflexible adherence to
specific routines or rituals
- Preoccupation with parts of objects
Children with some symptoms of autism, but
not enough to be diagnosed with the classical
form of the disorder, are often diagnosed with
pervasive developmental disorder - not otherwise
specified (PDD - NOS). The term Asperger
syndrome is sometimes used to describe people
with autistic behavior but well-developed
language skills. Children who appear normal in
their first several years, then lose skills and
begin showing autistic behavior, may be
diagnosed with childhood disintegrative disorder
(CDD). Girls with Rett's syndrome, a sex-linked
genetic disorder characterized by inadequate
brain growth, seizures, and other neurological
problems, also may show autistic behavior. PDD -
NOS, Asperger syndrome, CDD, and Rett's syndrome
are sometimes referred to as autism spectrum
disorders.
Since hearing problems can be confused with
autism, children with delayed speech development
should always have their hearing checked.
Children sometimes have impaired hearing in
addition to autism. About half of people with
autism score below 50 on IQ tests, 20 percent
score between 50 and 70, and 30 percent score
higher than 70. However, estimating IQ in young
children with autism is often difficult because
problems with language and behavior can
interfere with testing. A small percentage of
people with autism are savants. These people
have limited but extraordinary skills in areas
like music, mathematics, drawing, or
visualization.
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What causes autism?
Autism has no single cause. Researchers
believe several genes, as well as environmental
factors such as viruses or chemicals, contribute
to the disorder. Studies of people with autism
have found abnormalities in several regions of
the brain, including the cerebellum, amygdala,
hippocampus, septum, and mamillary bodies.
Neurons in these regions appear smaller than
normal and have stunted nerve fibers, which may
interfere with nerve signaling. These
abnormalities suggest that autism results from
disruption of normal brain development early in
fetal development. Other studies suggest that
people with autism have abnormalities of
serotonin or other signaling molecules in the
brain. While these findings are intriguing, they
are preliminary and require further study. The
early belief that parental practices are
responsible for autism has now been disproved.
In a minority of cases, disorders such as
fragile X syndrome, tuberous sclerosis,
untreated phenylketonuria (PKU), and congenital
rubella cause autistic behavior. Other
disorders, including Tourette syndrome, learning
disabilities, and attention deficit disorder,
often occur with autism but do not cause it. For
reasons that are still unclear, about 20 to 30
percent of people with autism also develop
epilepsy by the time they reach adulthood. While
people with schizophrenia may show some
autistic-like behavior, their symptoms usually
do not appear until the late teens or early
adulthood. Most people with schizophrenia also
have hallucinations and delusions, which are not
found in autism.
What role does genetics play?
Recent studies strongly suggest that some
people have a genetic predisposition to autism.
Scientists estimate that, in families with one
autistic child, the risk of having a second
child with the disorder is approximately five
percent, or one in 20, which is greater than the
risk for the general population. Researchers are
looking for clues about which genes contribute
to this increased susceptibility. In some cases,
parents and other relatives of an autistic
person show mild social, communicative, or
repetitive behaviors that allow them to function
normally but appear linked to autism. Evidence
also suggests that some affective, or emotional,
disorders, such as manic depression, occur more
frequently than average in families of people
with autism.
Do symptoms of autism change over time?
Symptoms in many children with autism improve
with intervention or as the children mature.
Some people with autism eventually lead normal
or near-normal lives. However, reports from
parents of children with autism indicate that
some children's language skills regress early in
life, usually before age three. This regression
often seems linked to epilepsy or seizure-like
brain activity. Adolescence also worsens
behavior problems in some children with autism,
who may become depressed or increasingly
unmanageable. Parents should be ready to adjust
treatment for their child's changing needs.
How can autism be treated?
There is no cure for autism at present.
Therapies, or interventions, are designed to
remedy specific symptoms in each individual. The
best-studied therapies include
educational/behavioral and medical
interventions. Although these interventions do
not cure autism, they often bring about
substantial improvement.
Educational/behavioral interventions:
These strategies emphasize highly structured and
often intensive skill-oriented training that is
tailored to the individual child. Therapists
work with children to help them develop social
and language skills. Because children learn most
effectively and rapidly when very young, this
type of therapy should begin as early as
possible. Recent evidence suggests that early
intervention has a good chance of favorably
influencing brain development.
Medication: Doctors may
prescribe a variety of drugs to reduce
self-injurious behavior or other troublesome
symptoms of autism, as well as associated
conditions such as epilepsy and attention
disorders. Most of these drugs affect levels of
serotonin or other signaling chemicals in the
brain.
Many other interventions are available, but few,
if any, scientific studies support their use.
These therapies remain controversial and may or
may not reduce a specific person's symptoms.
Parents should use caution before subscribing to
any particular treatment. Counseling for the
families of people with autism also may assist
them in coping with the disorder.
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