Below average intelligence
At least average intelligence
An exceptionally high intelligence
Prepare them for transitions.
Try to stop their fixations because they can be a distraction.
Use visual clues and materials.
Minimize environmental stimuli that might overload their sensory input.
Is at least average.
Ranges, but can be so low that the person is not even testable.
Unusual attachment to physical objects
Desire for sameness
Oversensitive to stimuli
Difficulty with social interactions
Speaking in nonsense syllables
Here's an interesting quiz for you.