Taken from EEGInfo,

Neurofeedback is direct training of brain function, by which the brain learns to function more efficiently. We observe the brain in action from moment to moment. We show that information back to the person. And we reward the brain for changing its own activity to more appropriate patterns. This is a gradual learning process. It applies to any aspect of brain function that we can measure. Neurofeedback is also called EEG Biofeedback, because it is based on electrical brain activity, the electroencephalogram, or EEG. Neurofeedback is training in self-regulation. It is simply biofeedback applied to the brain directly. Self-regulation is a necessary part of good brain function. Self-regulation training allows the system (the central nervous system) to function better.

A quote from Siegfried Othmer, Ph.D. :

Our intellectual abilities and emotional resources can be considerably enhanced with neurofeedback training.

Can it help people with Autism?

The short answer is yes.

I can tell you that Neurofeedback helps because I have Autism and had a lot of symptoms like anxiety and depression because my brain wasn’t working right. I went through the program and noticed a significant amount of improvement. I have been able to process ideas and thoughts at a regular pace instead of being bombarded by them constantly. My brain does not get overloaded like it used to and I feel like I woke up from a dream where I couldn’t do anything completely but now I actually have a shot at living a productive life. More on that here