Autism spectrum is an umbrella
term used to describe a range of conditions characterized by difficulties
in social interactions and communication, unusual sensitivity to sensory inputs,
and restricted or repetitive behaviors. The word “spectrum” means there is a great array
of symptoms with various degrees of severity. Among people diagnosed with autism, there can be a
wide range of intellectual and learning abilities, from highly capable to severely challenged.
A number of other conditions tend to occur more often in autistic people, including
gastrointestinal disorders, epilepsy, feeding problems, anxiety and depression.
People with autism are often stigmatized, bullied, and have troubles developing
a relationship or landing a job. Autism has a remarkably high heritability
but there is a role for environmental factors including parental age, maternal infection
or exposure to certain medications or toxins before or during pregnancy, low birth
weight, and extreme premature birth. Multiple genes have been involved, many of them
having a function in synaptic formation or pruning – the processes in which connections between
brain cells and brain areas are established. Neuroimaging studies show widespread
differences in an autistic brain. Notably, there are alterations in neuronal connectivity -
some connections are enhanced, while others are reduced. Overall, though, an autistic brain
seems to have more connections than usual. There is also evidence that areas of
the brain containing the so called “mirror neurons” are different in most people
with autism. “Mirror neurons” are thought to be responsible for “mimicking” behaviors
that form the basis of our ability to learn new expressions or skills by imitating other
people. For example, by seeing an adult smile, a baby learns to smile back. Altered function
of these neurons may underlie the inability to express emotions or understand other
people’s emotions in someone with autism. Our brain has a certain limit on the amount
of information it can process at one time. A typical brain selectively focuses on some
aspects of the surroundings and ignores others, keeping sensory input at a manageable level. An
autistic brain, on the other hand, seems to absorb all information more or less equally, or in some
cases, fixates on a different object or subject. As a result, autistic people may notice details
that others do not, but have difficulty following the topic of a conversation or seeing other
people’s point of view. They may take in more information than their brain can handle and become
overwhelmed. This causes stress and may affect the ability of the brain to process the information
properly, resulting in a delayed response or no response at all. In trying to reduce sensory
input, people with autism typically withdraw from others and follow a strict daily routine.
Depending on the affected sensory modalities, some people avoid eye contact, others cover their
ears to reduce noise level, wear loose clothing to reduce touch, or eat the exact same foods
day after day. Changes to a daily routine can cause stress and upset because they bring about
new and potentially overwhelming information. Performing repetitive movements, known as
stimming, is a common way to relieve stress. A person with severe autism may be at risk of
overloading their brain with too much sensory input, causing distress, which may lead
to disruptive or self-harming behaviors. On the other hand, changes in brain wiring
may also result in intellectual strengths such as keen observation, great attention to
details and excellent memory. People with autism often have intense interest in certain specific
subjects and, if receiving proper guidance and support, may excel in a particular career.
Signs of autism usually manifest early in life and diagnosis can often be made by age
2 or 3. Early diagnosis is important as it can help children get the support they need to
overcome difficulties and develop their strength.
