A good starting point is to read: What is Neurofeedback?

A very comprehensive bibliography which has links to research about many disorders is available through the International Society for Neurofeedback and Research:

A Meta-Analysis of The Efficacy of Neurofeedback in ADHD in the Journal of Clinical EEG and Neuroscience (July 2009) noted:

“… we conclude that neurofeedback treatment for ADHD can be considered “Efficacious and Specific (level 5) with a high effect size for inattention and impulsivity and a medium effect size for hyperactivity.”

> View the article here

Some of the better websites are:

There are numerous professional texts on traditional neurofeedback and LENS such as:

Dr. Weiner presented at
Psychiatry Grand Rounds
Medical College of Virginia
Virginia Commonwealth University
on December 3rd, 2010

Neurofeedback & QEEG: A non-medication treatment approach for ADHD andsome other disorders
> View the presentation here

Neurofeedback Videos from one of the professional training companies.