One of the staples of scientific approach is to distinguish the placebo effect of the drug/procedure/etc from a functional effect of the same.
Unfortunately scientific approach is not enough to find correct answers. One needs to filter the information. For example, modern medicine is based on science but the science is bent any way medical establishment wants. The result is pretty clear: millions of people suffering in the name of profit.
Personally I read Adding Neurotherapy to Your Practice by Paul G. Swingle where he provides a huge amount of statistical data that confirms clinical effectiveness of NF. There's no miracle in NF, our brain can learn/adapt if it gets a "feedback", just like when we learn to ride a bike, make mistakes and improve on our skill.