Autism is a general term used to describe a complex brain disorder. The disorder is characterized by varying degrees of function in three major areas: verbal and nonverbal communication, social interaction, and repetitive behaviors.
Children with ASD may have difficulty developing language skills and understanding what others say to them. They also may have difficulty communicating nonverbally, through hand gestures, eye contact, and facial expressions.
Not every child with ASD will have a language problem. Some children with ASD may be unable to speak. Others may have rich vocabularies and be able to talk about specific subjects in great detail. Many children with ASD have little or no problem pronouncing words. The majority, however, have difficulty using language effectively, especially when they talk to other people. Many have problems with the meaning and rhythm of words and sentences. They also may be unable to understand body language and the nuances of vocal tones. Other communication differences include stereotyped or repetitive use of language, and a lack of varied, spontaneous, make-believe, or social/imitative play appropriate to their developmental level.
Individuals with autism demonstrate deficits in social skills that range from complete lack of awareness of other people to difficulty forming and maintaining friendships with peers. Difficulties with social interactions can include failure to make eye contact with others as well as lack of ability to regulate or understand facial expressions, body postures, or gestures. Also, these difficulties can be demonstrated by a lack of social or emotional reciprocity (i.e. the "give and take" that comprises most social interactions and conversations held between typically functioning individuals.)
Restrictive, Repetitive and Stereotypic Patterns of Behavior, Interests, or Activities
Individuals with autism may engage in patterns of behavior that are markedly different from those of their typically developing peers. These behavior patterns usually include things like an abnormal preoccupation with one or more item of interest; such as a nonverbal child who only wants to touch fuzzy things, or a child with adequate speech who only talks about trains.
Aside from preoccupations, individuals with autism may follow a specific routine or daily ritual and have difficulty if that routine is different or is changed. Additionally, individuals with autism may engage in a range of stereotyped and repetitive motor patterns, such as hand flapping, toe-walking, body twisting, whole-body movements, etc. Also, an individual with autism is likely to be preoccupied or drawn to parts of objects as opposed to the object as a whole.
It is important to note that autism is considered a "spectrum disorder." This means autism's effects can range from very severe to very mild and anywhere in between.