Autism is a lifelong, non progressive neurological disorder typically appearing before the age of three years. The word “autism” means a developmental disability significantly affecting verbal and non-verbal communication and social interaction. The classic form of autism involves a triad of impairments – in social interaction, in communication and the use of language, and in limited imagination as reflected in restricted, repetitive and stereotyped patterns of behaviour and activities. It was in 1943 that Leo Kanner, a psychiatrist at Johns Hopkins University, created the diagnosis of autism.

Autism is a spectrum disorder. The symptoms and characteristics of autism can present themselves in a wide variety of combinations, from mild to severe. Although autism is defined by a certain set of behaviors, children and adults can exhibit any combination of the behaviors in any degree of severity. Two children, both with the same diagnosis, can act very differently from one another and have varying skills.

Traits

Persons with autism may also exhibit some of the following traits.

• Insistence on sameness; resistance to change
• Difficulty in expressing needs; uses gestures or pointing instead of words
• Repeating words or phrases in place of normal, responsive language
• Laughing, crying, showing distress for reasons not apparent to others
• Prefers to be alone; aloof manner
• Tantrums
• Difficulty in mixing with others
• May not want to cuddle or be cuddled
• Little or no eye contact
• Unresponsive to normal teaching methods
• Sustained odd play
• Spins objects
• Inappropriate attachments to objects
• Apparent over-sensitivity or under-sensitivity to pain
• No real fears of danger
• Noticeable physical over-activity or extreme under-activity
• Uneven gross/fine motor skills
• Not responsive to verbal cues; acts as if deaf although hearing tests in normal range.

Autism is one of five disorders coming under the umbrella of Pervasive Developmental Disorders (PDD), a category of neurological disorders characterized by "severe and pervasive impairment in several areas of development," including social interaction and communications skills (DSM-IV-TR). The five disorders under PDD are Autistic Disorder, Asperger's Disorder, Childhood Disintegrative Disorder (CDD), Rett's Disorder, and PDD-Not Otherwise Specified (PDD-NOS). Each of these disorders has specific diagnostic criteria as outlined by the American Psychiatric Association (APA) in its Diagnostic & Statistical Manual of Mental Disorders (DSM-IV-TR).

For a diagnosis of autism, the main symptoms must be clear before the age of 3 years. The disabilities are lifelong and there is no known cure, though careful training and sensitive support can bring improvements. The autistic impairments may be associated with cognitive disabilities. Two-thirds of those with classic autism (or Kanner syndrome) are severely to mildly handicapped in cognition and intellect. Most people with Asperger’s have average to higher IQ. Across the autistic spectrum, perhaps 10 per cent have distinctive abilities—in such fields as art, music, mathematics or memory—and are called autistic savants. (The proportion of people with such special abilities in the whole population is only one per cent).

According to the Canadian Autism Research and Strategy Agendas released in White Paper from the Autism Society of Canada, autism now effects at least one in every 200 Canadian children. The reported number of cases has risen by 150% in the past 6 years. To view this paper in its entirety, please go to www.autismsocietycanada.ca and follow the links.

Causes of Autism

There is no known single cause for autism, but it is generally accepted that it is caused by abnormalities in brain structure or function. Brain scans show differences in the shape and structure of the brain in autistic versus non-autistic children. Researchers are investigating a number of theories, including the link between heredity, genetics and medical problems. In many families, there appears to be a pattern of autism or related disabilities, further supporting a genetic basis to the disorder. While no one gene has been identified as causing autism, researchers are searching for irregular segments of genetic code that autistic children may have inherited. It also appears that some children are born with a susceptibility to autism, but researchers have not yet identified a single "trigger" that causes autism to develop.

Other researchers are investigating the possibility that under certain conditions, a cluster of unstable genes may interfere with brain development resulting in autism. Still other researchers are investigating problems during pregnancy or delivery as well as environmental factors such as viral infections, metabolic imbalances, and exposure to environmental chemicals.

Autism tends to occur more frequently than expected among individuals who have certain medical conditions, including Fragile X syndrome, tuberous sclerosis, congenital rubella syndrome, and untreated phenylketonuria (PKU).

Development

Children with ASDs develop differently from other children. Children without ASDs develop at about the same rate in areas of development such as motor, language, cognitive, and social skills. Children with ASDs develop at different rates in different areas of growth. They might have large delays in language, social, and cognitive skills, while their motor skills might be about the same as other children their age. They might be very good at things like putting puzzles together or solving computer problems, but not very good at some things most people think are easy, like talking or making friends.

Children with ASDs might also learn a hard skill before they learn an easy one. For example, a child might be able to read long words, but not be able to tell you what sound a "b" makes. A child might also learn a skill and then lose it. For example, a child may be able to say many words, but later stop talking altogether.

Source: https://autismawarenesscentre.com/definition-autism/