Symptoms/behaviors of ASDs can range from mild to severe, and may seem to appear gradually or suddenly. Atypical development may be observed from birth, or more commonly, become noticeable during the 12- to 36-month period. Symptoms may appear in the following areas: Social Skills  - Children with autism have difficulty in social interactions, including but not limited to: - Avoiding Eye Contact and interactions with people and resist or passively accept attention. - Unable to read common social cues, or understand other peoples' behavior. - Difficulty in controlling emotions. Ability to Communicate - Communication skills are affected in children with autism, but difficulties vary. Some children may have good basic language skills, but exhibit difficulty initiating or sustaining conversations, such as not giving others the opportunity to respond. Others may experience delays or regression in language development; still others remain mute or may use language in unusual ways, such as repeating a phrase, or parroting what they hear (echolalia). Body language is also often hard to read in children with autism. Facial expressions, tone of voice and gestures often do not match verbal content and emotions. They have difficulty expressing what they want or need. They may also appear deaf, not responding to their names or attempts at conversation.   Repetitive Behaviors (Stimming) - Patterns of behavior, interests and activities may be restricted, repetitive or stereotyped. For example, a child may spend long periods of time arranging specific toys in a particular manner, rather than playing with the toys. Intense preoccupation with certain topics, such as obsessively studying maps, may also be seen. Odd repetitive motions, either extreme or subtle, such as arm-flapping, freezing, rocking back and forth or walking on their toes may also occur. Often, people with autism demand consistency in their environment. A minor change in routine may be tremendously upsetting. Sensory Difficulties - In children with autism, the brain seems unable to balance the senses appropriately. Many autistic children are highly attuned or even painfully sensitive to certain sounds, textures, tastes or smells. Some seem oblivious to cold or pain, but react hysterically to things that wouldn't bother other children. In some people, the senses are even scrambled. For example, touching a certain texture may induce a gagging response. Unusual Abilities - In rare cases, some children with ASDs display remarkable abilities, such as drawing detailed, realistic pictures at a young age or playing an instrument without training. Some can memorize difficult lists of items, such as statistics or names (this is called islets of intelligence or savant skills).