Tag Archives: Autism Traits

Asperger’s Syndrome – Biological basis

Autistic individuals tend to use different are...

Because of its relative inaccessibility, researchers have only recently been able to study the brain systematically. But with the innovative emergence of new brain imaging tools – computerized tomography (CT), positron emission tomography (PET), single photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI), study of the structure and the functioning of the brain can be done.

With the aid of modern technology and the new availability of both normal and autism tissue samples to do post-mortem studies, researchers will be able to learn much through comparative studies. Post-mortem and MRI studies have shown that many major brain structures are implicated in autism. This includes the cerebellum, cerebral cortex, limbic system, corpus callosum, basal ganglia, and brain stem.

It appears that in autism a disorder is found in the structure of the brain, e.g. the little brain(cerebellum). There is a disorder localized in the frontal lobes. Low blood flow to certain parts of the brain and reduced numbers of certain brain cells also seem to appear along with autism traits.

An exciting development is the Autism Tissue Program Studies of the postmortem brain with imaging methods will help us learn why some brains are large, how the limbic system(interconnected system of brain nuclei associated with basic needs and emotions such as hunger, pain, pleasure, satisfaction, sex, and instinctive motivation) develops, and how the brain changes as it ages. Tissue samples can be stained and will show which neurotransmitters are being made in the cells and how they are transported and released to other cells. By focusing on specific brain regions and neurotransmitters, it will become easier to identify susceptibility genes.

Other research is focusing on the role of neurotransmitters such as serotonin, dopamine, and epinephrine. Problems are found in the general functioning of the brain as a result of a shortage or excess of neurotransmitters (dopamine and serotonin). As a result information entering the brain is not correctly processed.

There is a report by Edwin Cook and his colleagues that the first gene of autism relates to processing serotonin in the brain. In 1990, Dr. Cook said, “the most consistent finding has been over 25% of autistic children and adolescents are hyperserotonemic. After decades of investigation the mechanism of hyperserotonemia has not been determined.” Hyperserotonemia is where you have high-elevated serotonin levels.

Only recently researchers at the School of Medicine have discovered in the placenta what may be the earliest marker for autism, possibly helping physicians diagnose the condition at birth, rather than the standard age of 2 or older. Current studies are searching for characteristics in children at risk for ASD so that the diagnosis can be made prior to age 1. The ideal time for diagnosis would be at birth, according to senior author on the study Dr. Harvey J. Kliman, research scientist in the Department of Obstetrics, Gynecology & Reproductive Sciences at the School of Medicine. They found that the placentas from ASD children were three times more likely to have trophoblast (the embryo’s outer layer) inclusions. Kliman and the team identified trophoblast inclusions by performing microscopic examinations of placental tissues.

“We knew that trophoblast inclusions were increased in cases of chromosome abnormalities and genetic diseases, but we had no idea whether they would be significantly increased in cases of ASD,” says Kliman. “These results are consistent with studies by others who have shown that ASD has a clear genetic basis.” Trophoblast inclusions reflect abnormal folding of microscopic layers in the placenta and appear to result from altered cell growth.

Enhanced by ZemantaTagged as: Asperger syndrome, Autism Causes, Autism spectrum, Magnetic resonance imaging, Neurodevelopmental, Research

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Types Of Autism Revealed

The term “autism” is a generalized term which falls inside a larger medical category oftentimes called “the 5 Pervasive Development Disorders”. Autism is the most common type of development disorder and can appear in a range of  types and severity of condition. This has led to the term “Autism Spectrum Disorder” which can be often used to identify and discuss the differing types of autism. What this implies is that someone diagnosed as having autism will have one of several different types of autism which have features that are comparable in some respects and different in others.

Inside the Autism Spectrum Disorder there exists four subcategories of autism which are Asperger Syndrome, Rett Syndrome, Childhood Disintegrative Disorder and Pervasive Development Disorder Not Otherwise Specified or “PDD-NOS”. Seeing as each of these are types of autism they all share some general autism traits.

It is generally acknowledged that autism is related to the brain or what some are now calling “mindblindness”. At some point between birth and the first two-and-a-half years of age there’s a serious development problem inside the brain that prevents parts of the brain from functioning as one. As the child gets older they find it more and more difficult to communicate and connect to other people around them in what we deem a normal and socially acceptable manner. Dependant upon how bad the brain disorder was early on in life will determine how serious the type of autism is when the child becomes older.

What we have discussed thus far has told us that all types of autism are linked to a condition within the brain. Now we will look at how each of the types of autism are different.

1. Asperger Syndrome (AS)

indicated by impaired speech and communication skills
restrictive patterns in the manner the individual behaves and thinks

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Children with Asperger Syndrome often exhibit very obsessive behavior towards a single subject or topic and refuse to focus on anything else. This makes it very difficult for them to socialize with others, especially their peer group and they find it hard to talk and interact normally. Also very common is delayed learning when it comes to motor skills like riding a bike, being able to catch a ball or even climbing on playground equipment. The child is usually thought of as being clumsy and inept.

2. Rett Syndrome

symptoms tend to be noticed earlier on in a child’s life than other types of autism
generally is encountered only in girls and unexpectedly begins to surface some six to eighteen months after a normal infant development pattern

A baby with Rett Syndrome exhibits a slow down or oftentimes even a loss of customary development skills that were already developed before Rett Syndrome. Added signs of this infant disorder may include problems learning to walk, increased delay in learning basic motor skills and often there is a lessening in skull growth rate.

3. Childhood Disintegrative Disorder (CDD)

less common type of autism
occurs later than other types of autism, not until around age 3 or four
frequently a dramatic loss of social, communication and other kinds of skills

A child afflicted with CDD generally has demonstrated normal development well beyond that phase where other types of autism may become evident. Everything appears fine, until unexpectedly around the ages of 3 or 4 the child in a short time begins to have difficulty speaking normally, doing social activities with others and begins to fall behind in normal skill development for their age group. In very severe cases this may even lead to mental retardation.

4. Pervasive Development Disorder Not Otherwise Specified (PDD-NOS)

generally the mildest type of autism and is usually diagnosed around 4 years old
core features are problems with social interaction and communication

A child with PDD-NOS enjoys the company of other people but has a difficult time reacting appropriately and making genuine connections with their friends. For example they find it difficult to relate to the feelings of others, and as such would not know how to appriopriately react if someone is laughing or crying. Areas of difficulty with respect to communicating with other people include a restricted vocabulary, repetitive language, narrow interests and poor nonverbal communication.

As you can see the definition of autism just isn’t so simple as many people presume it to be. Differing autism features have given rise to a number of different types of autism that will impinge on children and adults in a wide range of ways, often depending upon how severe the condition is for that person.

It is extremely important to understand that the above facts about autism, together with the types of autism discussed, are merely general guidelines and are in no way intended to be a medical diagnosis. If you believe that your son or daughter may have autism, then please seek out medical advice from a physician.

Take action now to find out more about what is autism disorder and learn to help your child and yourself as a concerned parent or an adult dealing with autism. Visit our website now to learn more about the types of autism and much more. Articles on autism, videos and links to other resources including books on autism. Let us help you as we have already helped hundreds of other concerned parents with autistic children as well as adults with autism .
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