There are vast differences between Autism and High Functioning Asperger Syndrome. These fall under a category called PDD-NOS which stands for Pervasive Development Disorder - Not Otherwise Specificed.
A Pervasive Development Disorder or any type of disorder cannot be cured, it is a lifelong disability. However, the far-reaching range - all the way from autism at one of the spectrum, to a person who is high functioning and can hold down a job shows just how varied this disorder is.
I think the term "milder" is entirely inappropriate.
At one end, (let's use a child as an example) a mother may be trying to cope with a 4 year-old boy who doesn't speak, has temper tantrums, use a rocking motion when distressed. The child may find 2 or 3 games, puzzles etc and play with them over and over and over again.
A child with High Functioning Autism may be misdiagnosed as having ADHD. Because children with AS feels his/her senses are overloaded by noise, view recess out in the playground as chaos with too much stimuli coming in. The cihild may act out due to the high level of stress he/she feels when things aren't quiet and ordered. There is said to be an overlap beween High Functioning Aspeger Syndrome and OCD "Obsessive-Compulsive Disorder."
Teachers are catching on. They now know that children with Autism or AS need a closed off separate space, with a partition high enough not to see the other students. In this case, a Teacher's Assistant is a great benefit for such a child, to help them to focus and keep on task.