Autism is a developmental disorder caused by congenital brain function impairment, which will have a great impact on a person's vision, hearing, feeling and understanding. Autism mainly affects people's communication. Patients can't understand others' oral and non-verbal communication well, and they can't learn the appropriate ways to deal with people, things or events. The main features of autism are: 1. Serious language development problems. Language develops slowly, usually with some special speech patterns or word patterns, which artificially endow some words with inappropriate special meanings. 2. Serious deviation from normal social relations. Autistic children seldom use their eyes to communicate, are unwilling to be hugged by others, and don't know how to play with others or make friends with others. 3. The perceptual response is abnormal. Sometimes it may appear to be deaf and unresponsive to speech or voice, but sometimes it may overreact to some ordinary voices. Sometimes there is no response to cold, heat and pain, but sometimes it will overreact. 4. Intellectual problems. Most autistic people are mentally retarded, and only about a quarter of them are normal. But some of them will have some outstanding talents, such as painting, arithmetic, music and so on. 5. Fixed patterns in activities and interests. You may be used to repeating a certain action on your body, or you may act according to a fixed habit every day, such as walking the same route and wearing clothes in the same order, and once the inherent habit changes, you will feel upset.