ASD (Autistic Spectrum Disorders) is a disorder of development that affects language, social skills and behaviour. Children with ASD are unable to interpret the world and what is happening around them in the same way that other children do. There is a range of severity and intellectual ability, from the severely impaired child with classical autism, to a child with Asperger syndrome. High-functioning autistic children with Asperger syndrome may have a high level of intelligence but have difficulty with social interaction.