Children within the pervasive developmental disorder spectrum often appear relatively normal in their development until the age of 24-30 months, when parents may notice delays in language, play or social interaction. Any of the following delays, by themselves, would not result in a diagnosis of a pervasive developmental disorder.
 
Autism is a combination of several developmental challenges. The following areas are among those that may be affected by autism:
 
Communication:
Language develops slowly or not at all; uses words without attaching the usual meaning to them; communicates with gestures instead of words; short attention span;
 
Social Interaction:
Spends time alone rather than with others; shows little interest in making friends; less responsive to social cues such as eye contact or smiles;
 
Sensory Impairment:
May have sensitivities in the areas of sight, hearing, touch, smell, and taste to a greater or lesser degree

Play:
Lack of spontaneous or imaginative play; does not imitate others' actions; does not initiate pretend games;

Behaviors:
May be overactive or very passive; throws tantrums for no apparent reason; perseverant (shows an obsessive interest in a single item, idea, activity or over. The child may even "withdraw into himself", engaging in repetitive self-stimulation such as rocking or rhythmic moving of the hands. These children often seek out the security of routines, and can become very dependent on them. They may avoid new experiences or situations.
 
Perceptions
It appears both from the observations of others and by first person accounts that these children often experience perceptions differently. Sights, sounds, textures that we easily accept can cause anxiety and even rage in a child. One child, for example, said that red hurt his eyes. Another flew into a rage when she felt the "prickle" of wool. Yet other experiences that may seem important to us may be completely ignored. While at times they may seem hypersensitive, at other times seeming to be extremely distractible, yet at other times being overly focused on an activity or on self-stimulation. They may find human contact stressful at times, or show an unusual focus in their sensory experiences, such as an exaggerated interest in smell, or in rhythmic motion.
 
Emotion
All of the confusion experienced by the child can make the world a frightful place. Difficulties in understanding and articulating their own emotions, or those of others, may cause your child's response in some situations to appear to be inappropriate. Emotional outbursts are common and it may be difficult for them to regain control. Our response to these outbursts may increase their confusion, frustration and anger. These outbursts may result in a child trying to hurt themselves or others.