Autism>Diagnosis

Autism: External descriptive diagnostic features

Isolation child seems alone, detached and withdrawn
Sensation may use peripheral vision and/or appear deaf because
  tuned into distant events instead of what is happening nearby
  seem to wrap themselves into their own skin/ body sensations
Movement may be on the move all the time: running, climbing, jumping, ...
 

stereotypical use of body movements: flapping, rocking, twirling, spinning,... or grinding teeth, blinking, grimacing...

Excitements

can get wildly excited in a bodily way, similar to thrills, fits, seizures or orgasms

Language speech is often delayed and may not develop
  difficulties with non-verbal communication
  difficulties with creative and meaningful use of language
  lack of symbol formation, therefore also
Play lack of symbolic and imaginative play
  not purposeful activity but often more a fiddling with objects
  using toys/ objects not as their intended functions
Rituals usually to maintain self-control, which includes
  trying to keep the environment from changing
  may seem bizarre and may be clung to with great tenacity
Sleep sleeping difficulties are common
Eating eating difficulties are also common
Other often don’t seem to care about their possessions
  can get very upset about things being broken or incomplete
  panic after a slight change but be indifferent to big changes
  seem overly independent
  content to be left alone for hours, often already as infants

References: Kanner (1943), Rimland (1964), Rutter (1976, 1979), Frith (1989), Victor (1986), Hocking (1990), Tustin (1990), Alvarez (1992), Hobson (1993), Dzikowski (1993), et al.

'George & Sam' from cover photo from book of same title by Charlotte Moore (www.penguin.com)