This video from NeuroMed is a very good video presentation explaining what it is about this particular clinical pain machine stimulator that describes why it works for certain patients. It takes about 2..5 minutes to get into the explanation in case you want to fast forward to that point. What I like about the video is an attempt to explain the chemical side of how our body works generally, cellular level. Job well done.
What I observed is the effects attributed are not due to frequency, but due to polarity changes - positive/negative charges. As an example one of the "selling techniques" used by some companies is if you put an explanation out on how the body works chemically on a cellular level that adds to the base of knowledge, however to go from one body structure such as a cell and then go to specialized cells creating structures, ie. nerves, you have to be very careful making that leap. The two do not necessarily correlate.
On our new InfrexFRM machine we will incorporate variables to adjust the InfrexFRM to fit prevailing proven methods of successful treatments. As always not all people respond the same way so you always get mixed outcomes. With variability you treat each patient, and are not stuck with protocols specific to general population samples, when your concern is the patient who is in front of you now.