Though my knowledge on these devices is limited, I will say that electrical vibrations coming from the body are being picked up by the machine and then interpreted by the software program. I was not a believer till I tried it for myself.

I wish the machine was cheaper, because I would buy one for my own use!!!

Purhaps, someone with better understanding will explain it better.

Quantum Biofeedback, working through sixteen different electrical factors of the body, calculates combinations of impedance, amperage, voltage, capacitance, inductance, and resistance for Electro-Physiological Reactivity (The Xrroid Process). The body is indeed electric; therefore reactivity in the body can be measured electrically. E-P Reactivity results are based upon the ability to establish a "Tri-Vector" connection for an energetic "3-Dimensional" view of the client's current reactions to over 10,000 different items. All accomplished completely independent of user influence to help avoid bias or error. The picture painted by the reactions may help to create a better understanding of the individual factors pertinent to lifestyle and wellness. Once established, the Quantum Biofeedback auto-focus program, designed to monitor a client's reactions, helps optimize the quality and quantity of the stress reduction results.


http://www.thequantumalliance.ca/english/biofeedback.html

The Scio is a Random number generator....I would recommend a machine that uses white noise diodes.
Hope this helps
DrJames
http://www.QauntumEHealing.com