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Overview of
Autism
Stephen M. Edelson, Ph.D.
Center for the Study of Autism, Salem, Oregon
It has been over 50 years since Dr. Leo Kanner, a psychiatrist
at Johns Hopkins University, wrote the first paper applying
the term 'autism' to a group of children who were self-absorbed
and who had severe social, communication, and behavioral problems.
This paper provides a general overview of the complexity of
this developmental disability by summarizing many of the major
topics in autism.
Prevalence
For many years, the most cited statistic is that autism occurs
in 4.5 out of 10,000 live births. This was based on large-scale
surveys conducted in the United States and England. More recently,
estimates on the prevalence of autism have ranged been as
high as 1/4% to 1/2% of the population. These estimates typically
include those with autism, Asperger syndrome, and PDD.
Autism is three times more likely to affect males than females.
This gender difference is not unique to autism since many
developmental disabilities have a greater male to female ratio.
Major characteristics
Many autistic infants are different from birth. Two common
characteristics they may exhibit include arching their back
away from their caregiver to avoid physical contact and failing
to anticipate being picked up (i.e., becoming limp). As infants,
they are often described as either passive or overly agitated
babies. A passive baby refers to one who is quiet most of
the time making little, if any, demands on his/her parents.
An overly agitated baby refers to an infant who cries a great
deal, sometimes non-stop, during his/her waking hours. During
infancy, many begin to rock and/or bang their head against
the crib; but this is not always the case.
In the first few years of life, some autistic toddlers reach
developmental milestones, such as talking, crawling, and walking,
much earlier than the average child; whereas others are considerably
delayed. Approximately one-half of autistic children develop
normally until somewhere between 1 1/2 to 3 years of age;
then autistic symptoms begin to emerge. These individuals
are often referred to as having 'regressive' autism. Some
people in the field believe that candida albicans, vaccinations,
exposure to a virus, or the onset of seizures may be responsible
for this regression. It is also thought that some children
with 'regressive' autism may have Landau-Kleffner Syndrome
(see next section).
During childhood, autistic children may fall behind their
same-aged peers in the areas of communication, social skills,
and cognition. In addition, dysfunctional behaviors may start
to appear, such as self-stimulatory behaviors (i.e., repetitive,
non-goal directed behavior, such as rocking, hand-flapping),
self-injury (e.g., hand-biting, headbanging), sleeping and
eating problems, poor eye contact, insensitivity to pain,
hyper-/hypo-activity, and attention deficits.
One characteristic which is quite common in autism is the
individual's 'insistence on sameness' or 'perseverative' behavior.
Many children become overly insistent on routines; if one
is changed, even slightly, the child may become upset and
tantrum. Some common examples are: drinking and/or eating
the same food items at every meal, wearing certain clothing
or insisting that others wear the same clothes, and going
to school using the same route. One possible reason for 'insistence
on sameness' may be the person's inability to understand and
cope with novel situations.
Autistic individuals sometimes have difficulty with the transition
to puberty. Approximately 25% have seizures for the first
time during puberty which may be due to hormonal changes.
In addition, many behavior problems can become more frequent
and more severe during this period. However, others experience
puberty with relative ease.
In contrast to 20 years ago when many autistic individuals
were institutionalized, there are now many flexible living
arrangements. Usually, only the most severe individuals live
in institutions. In adulthood, some people with autism live
at home with their parents; some live in residential facilities;
some live semi-independently (such as in a group home); and
others live independently. There are autistic adults who graduate
from college and receive graduate degrees; and some develop
adult relationships and may marry. In the work environment,
many autistic adults can be reliable and conscientious workers.
Unfortunately, these individuals may have difficulty getting
a job. Since many of them are socially awkward and may appear
to be 'eccentric' or 'different,' they often have difficulty
with the job interview.
Subgroups and Related Disorders
There is no adjective which can be used to describe every
type of person with autism because there are many forms of
this disorder. For example, some individuals are anti-social,
some are asocial, and others are social. Some are aggressive
toward themselves and/or aggressive toward others. Approximately
half have little or no language, some repeat (or echo) words
and/or phrases, and others may have normal language skills.
Since there are no physiological tests at this time to determine
whether a person has autism, the diagnosis of autism is given
when an individual displays a number of characteristic behaviors.
In the last five years, research has shown that many people
who engage in autistic behaviors have related but distinct
disorders. These include: Asperger Syndrome, Fragile X Syndrome,
Landau-Kleffner Syndrome, Rett Syndrome, and Williams Syndrome.
Asperger Syndrome is characterized by concrete and literal
thinking, obsession with certain topics, excellent memories,
and being 'eccentric.' These individuals are considered high-functioning
and are capable of holding a job and of living independently.
Fragile X Syndrome is a form of mental retardation in which
the long arm on the X chromosome is constricted. Approximately
15% of people with Fragile X Syndrome exhibit autistic behaviors.
These behaviors include: delay in speech/language, hyperactivity,
poor eye contact, and hand-flapping. The majority of these
individuals function at a mild to moderate level. As they
grow older, their unique physical facial features may become
more prominent (e.g., elongated face and ears), and they may
develop heart problems.
People with Landau-Kleffner Syndrome also exhibit many autistic
behaviors, such as social withdrawal, insistence on sameness,
and language problems. These individuals are often thought
of as having 'regressive' autism because they appear to be
normal until sometime between ages 3 and 7. They often have
good language skills in early childhood but gradually lose
their ability to talk. They also have abnormal brain wave
patterns which can be diagnosed by analyzing their EEG pattern
during an extended sleep period.
Rett Syndrome is a degenerative disorder which affects mostly
females and usually develops between 1/2 to 1 1/2 years of
age. Some of their characteristic behaviors include: loss
of speech, repetitive hand-wringing, body rocking, and social
withdrawal. Those individuals suffering from this disorder
may be severely to profoundly mentally retarded.
Williams Syndrome is characterized by several autistic behaviors
including: developmental and language delays, sound sensitivity,
attention deficits, and social problems. In contrast to many
autistic individuals, those with Williams Syndrome are quite
sociable and have heart problems.
Causes
Although there is no known unique cause of autism, there is
growing evidence that autism can be caused by a variety of
problems. There is some indication of a genetic influence
in autism. For example, there is a greater likelihood that
two monozygotic twins (i.e., identical twins) will have autism
than two dizygotic twins (i.e., fraternal twins). In the case
of monozygotic twins, there is a 100% overlap in genes; whereas
in dizygotic twins, there is a 50% overlap in genes, the same
overlap as in non-twin siblings. Currently, a great deal of
research has focused on locating the 'autism gene;' however,
many researchers speculate that three to five genes will likely
be associated with autism. There is also evidence that the
genetic link to autism may be a weakened or compromised immune
system. Other research has shown that depression and/or dyslexia
are quite common in one or both sides of the family when autism
is present.
There is also evidence that a virus can cause autism. There
is an increased risk in having an autistic child after exposure
to rubella during the first trimester of the pregnancy. Cytolomegalo
virus has also been associated with autism. Additionally,
there is also a growing concern that viruses associated with
vaccinations, such as the measles component of the MMR vaccine
and the pertussis component of the DPT shot, may cause autism.
There is growing concern that toxins and pollution in the
environment can also lead to autism. There is a high prevalence
of autism in the small town of Leomenster, Massachusetts,
where a factory manufacturing sunglasses was once located.
Interestingly, the highest proportion of autism cases were
found in the homes down-wind from the factory smokestacks.
Recently, a large proportion of autistic children were identified
in Brick Township, New Jersey. Several agencies are now attempting
to uncover the reason(s) for the high proportion of autism
in this community.
Physical abnormalities
Researchers have located several brain abnormalities in individuals
with autism; however, the reasons for these abnormalities
is not known nor is the influence they have on behavior. These
abnormalities can be classified into two types--dysfunctions
in the neural structure of the brain and abnormal biochemistry
of the brain. It will be important for future researchers
to examine the relationship between these two types of abnormalities.
With respect to brain structure, Drs. Bauman and Kemper examined
post-mortem brains of several autistic individuals and have
located two areas in the limbic system which are underdeveloped--the
amygdala and the hippocampus. These two areas are responsible
for emotions, aggression, sensory input, and learning. These
researchers also found a deficiency of Purkinje cells in the
cerebellum. Using Magnetic Resonance Imaging, Dr. Courchesne
has found two areas in the cerebellum, vermal lobules VI and
VII, which are significantly smaller than normal in autistic
individuals. Interestingly, there are a some autistic individuals
whose vermal lobules VI and VII are larger than normal. One
or both of these areas of the cerebellum are believed to be
responsible for attention.
With respect to biochemistry, many autistic individuals have
elevated levels of serotonin in their blood and cerebral spinal
fluid, whereas others have relatively low levels of serotonin.
It should be mentioned that other disorders, such as Down
Syndrome, attention deficit/hyperactivity disorder, and unipolar
depression are also associated with abnormal levels of serotonin.
There is also evidence that some autistic individuals have
elevated levels of beta-endorphins, an endogenous opiate-like
substance in the body. It is felt that those individuals who
have an increased pain tolerance may likely be due to elevated
levels of beta-endorphins.
A dysfunctional immune system has also been associated with
autism. It is thought that a viral infection or an environmental
toxin may be responsible for damaging the immune system. As
mentioned above, there is also evidence of a genetic association
to a compromised immune system. Researchers have found that
many autistic individuals have a decreased number of helper
t-cells which help the immune system fight infection.
There is growing evidence that the gut or intestinal tract
of autism children is impaired. Researchers have documented
yeast overgrowths (candida albicans), low levels of phenyl
sulfur transferase, and measles virus in their intestinal
tract.
Sensory impairments
Many autistic individuals seem to have an impairment in one
or more of their senses. This impairment can involve the auditory,
visual, tactile, taste, vestibular, olfactory (smell), and
proprioceptive senses. These senses may be hypersensitive,
hyposensitive, or may result in the person experiencing interference
such as in the case of tinnitus, (a persistent ringing or
buzzing in the ears). As a result, it may be difficult for
individuals with autism to process incoming sensory information
properly.
Sensory impairments may also make it difficult for the individual
to withstand normal stimulation. For example, some autistic
individuals are tactilely defensive and avoid all forms of
body contact. Others, in contrast, have little or no tactile
or pain sensitivity. Furthermore, some people with autism
seem to 'crave' deep pressure. Another example of sensory
abnormalities is hypersensitive hearing. Approximately 40%
of autistic individuals experience discomfort when exposed
to certain sounds or frequencies. These individuals often
cover their ears and/or tantrum after hearing sounds such
as a baby's cry or the sound of a motor. In contrast, some
parents suspect their children of being deaf because they
appear unresponsive to sounds.
Cognition
"Theory of mind" refers to one's inability to realize
that other people have their own unique point of view about
the world. Many autistic individuals do not realize that others
may have different thoughts, plans, and perspectives than
their own. For example, a child may be asked to show a photograph
of an animal to another child. Rather than turning the picture
around to face the other child, the autistic child may, instead,
show the back of the photograph. In this example, the autistic
child can view the picture but does not realize that the other
child has a different perspective or point of view.
About 10% of autistic individuals have savant skills. This
refers to an ability which is considered remarkable by most
standards. These skills are often spatial in nature, such
as special talents in music and art. Another common savant
skill is mathematical ability in which some autistic individuals
can multiply large numbers in their head within a short period
of time; others can determine the day of the week when given
a specific date in history or memorize complete airline schedules.
Many autistic individuals also have a narrow or focused attention
span; this has been termed 'stimulus overselectivity.' Basically,
their attention is focused on only one, often irrelevant,
aspect of an object. For example, they may focus on the color
of a utensil, and ignore other aspects such as the shape.
In this case, it may be difficult for a child to discriminate
between a fork and a spoon if he/she attends only to the color.
Since attention is the first stage in processing information,
failure to attend to the relevant aspects of an object or
person may limit one's ability to learn about objects and
people in one's environment.
Interventions
Over the years, families have tried various types of traditional
and non-traditional treatments to reduce autistic behaviors
and to increase appropriate behaviors. Although some individuals
are given medications to improve general well-being, there
is no primary drug which has been shown to be consistently
effective in treating symptoms of autism. The most widely
prescribed medication for autistic children is Ritalin, (a
stimulant used to treat Attention Deficit/Hyperactivity Disorder).
However, there are no double-blind controlled studies to demonstrate
its effectiveness for those with autism.
The two treatments which have received the most empirical
support are Applied Behavior Analysis (ABA; behavior modification)
and the use of vitamin B6 with magnesium supplements. Behavior
modification involves a variety of strategies, (e.g., positive
reinforcement, time-out), to increase appropriate behaviors,
such as communication and social behavior, and to decrease
inappropriate behaviors, such as self-stimulatory and self-injurious
behavior.
Vitamin B6 taken with magnesium has been shown to increase
general well-being, awareness, and attention in approximately
45% of autistic children. There are also a number of recent
reports about the benefits of another nutritional supplement,
Di-methylglycine (DMG). DMG also seems to help the person's
general well-being, and there are many anecdotal reports of
it enhancing communication skills.
Some people with autism have excessive amounts of a type of
yeast called 'candida albicans' in their intestinal tract.
It is thought that high levels of candida albicans may be
a contributing factor to many of their behavioral problems.
One scenario is that when a child develops a middle ear infection,
the antibiotics that help fight the infection may destroy
microbes that regulate the amount of yeast in the intestinal
tract. As a result, the yeast grows rapidly and releases toxins
in the blood; and these toxins may influence the functioning
of the brain. Excessive candida albicans can be treated with
rather mild medications such as Nystatin.
Food intolerances and food sensitivities are beginning to
receive much attention as possible contributors to autistic
behaviors. Many families have observed rather dramatic changes
after removing certain food items from their children's diet.
Researchers have recently detected the presence of abnormal
peptides in the urine of autistic individuals. It is thought
that these peptides may be due to the body's inability to
breakdown certain proteins into amino acids; these proteins
are gluten (e.g., wheat, barley, oats) and casein (found in
human and cow's milk). Many parents have removed these substances
from their children's diets and have, in many cases, observed
dramatic, positive changes in health and behavior.
As mentioned earlier, many autistic individuals have sensory
impairments. Sensory integration techniques are often used
to treat dysfunctional tactile, vestibular, and proprioceptive
senses. Some of the techniques involve swinging a child on
a swing in various ways to help normalize the vestibular sense
and rubbing different textures on the skin to normalize the
tactile sense. In addition, an autistic woman, Dr. Temple
Grandin, developed a hug machine which provides the individuals
with deep pressure which appears to have a calming effect
on the person.
Many autistic individuals are also sensitive to sounds in
their environment. They may hear sounds beyond the normal
range and/or certain sounds may be perceived as painful. Auditory
integration training, (listening to processed music for ten
hours), is an intervention which is often used to reduce these
sensitivities. Visual training is another sensory intervention
designed to normalize one's vision. There are several different
methods of visual training. One popular program, developed
by Dr. Melvin Kaplan, involves wearing ambient (prism) lenses
and performing movement exercises which appear to reorganize
and normalize the visual system.
Conclusion
Autism is a very complex disorder; and the needs of these
individuals vary greatly. After 50 years of research, traditional
and contemporary approaches are enabling us to understand
and treat these individuals. It is also important to mention
that parents and professionals are beginning to realize that
the symptoms of autism are treatable--there are many interventions
that can make a significant difference.
The logo for the national parent support group, the Autism
Society of America, is a picture of a child embedded in a
puzzle. Most of the pieces of the puzzle are on the table,
but we are still trying to figure out how they fit together.
We must also keep in mind that these pieces may fit several
different puzzles.
©1999, Copyright
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