Autism is an umbrella term to describe people with a neurological disorder that affects their psychological and sometimes physical development. There are varying degrees of autism, ranging from total mental retardation to a mild developmental delay in an otherwise normally functioning child.
Different types are:
Early Infantile Autism, or Classic Autism
This classic type of autism first noted by Leo Kanner in 1943 was often present at birth, with parents reporting that their babies seemed different, did not maintain eye contact, didn’t learn how to smile and didn’t cry when they left the room, which is a normal response to being separated from the mother. Sometimes this type of autism can develop as late as three years old but there are often signs earlier than that. This type of autism was noted to affect one in 10,000 babies or small children.
Regressive Autism, or Acquired Autism
This is when a child is born developmentally normal and meets his milestones and then has a sudden or gradual loss of skills, usually starting at 15 to 30 months in age. The Neuropsychology Review wrote:
"A significant proportion of children diagnosed with Autistic Spectrum Disorder experience a developmental regression characterized by a loss of previously-acquired skills. This may involve a loss of speech or social responsitivity, but often entails both ... the setback is both puzzling and disturbing since it may transform a typically developing toddler into a non-verbal child with a severe form of AD."
Asperger’s Syndrome, or High-Functioning Autism
This is a mild form of autism, described by Dr. Hans Asperger in 1943. With asperger’s syndrome, the person is of normal intelligence and has no difficulties with speech, although they may struggle to find the right words to describe what they want to discuss and may find conversations awkward.
They may not know the right moment to begin or end a conversation and may not understand jokes or sarcasm. They can have difficulty understanding tones of voice and facial expression, as well as social cues.