Individuals with ASDs can vary markedly in terms of their developmental functioning in communication, social and behavioural areas, but it is generally recognized that those with a diagnosis of Autism exhibit more severe symptoms, while those with a diagnosis of Asperger Syndrome or High-Functioning Autism and are more able in terms of their overall language and cognitive skills. A diagnosis of Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS) is reserved for individuals who meet some, but not all, diagnostic criteria for autism.
These difficulties emerge in early childhood and generally persist to some degree throughout the lifespan. With therapy, many of the core symptoms can be improved, although there is as of yet no identified "cure" for autism. However, experts agree that early identification and treatment is important for later success.
Autism Spectrum Disorders (ASDs) is a term used to describe a subset of neurological conditions classified as Pervasive Developmental Disorders by diagnostic classification systems. ASDs are characterized by deficits in three primary areas:
Underlying these deficits, individuals with ASDs can have reduced cognitive functioning, to varying degrees. (From Emerging Minds)
Autism is a complex neurological disorder. Today with more awareness and better identification tools, autism can be reliabily diagnosed by 18 months of age.
Autism impacts the typical development of the brain in the areas of social interaction and communication skills. Children and adults with autism typically have difficulties in verbal and non-verbal communication, social interactions, and leisure or play activities. They find it hard to communicate with others and relate to the outside world. In some cases, aggressive and/or self-injurious behaviour may be present. Persons with autism may exhibit repeated body movements (hand flapping, rocking), unusual responses to people or attachments to objects and resistance to changes in routines. Individuals may also experience sensitivities in sight, hearing, touch, smell, and taste.
(From Autism Ontario)