Electroacupuncture according to Voll (EAV) is named after Dr Reinhold Voll (1909–1989), a German physician who combined acupuncture theory with electrical measurement. Starting in the 1950s, Voll built devices that measure electrical resistance at acupuncture points on the hands and feet, proposing that the reading at each point reflects the health of a corresponding organ.
The practitioner touches a probe to specific points while the patient holds a separate electrode, and the device gives a numeric reading. A "balanced" reading is taken as a sign of health at the corresponding organ; a high or low reading is read as a sign of stress or dysfunction. Some later devices extended this into testing remedies — placing a vial of a homeopathic remedy or a food into the circuit and watching whether the reading changes — a use generally called electrodermal or "bioresonance" testing.
The measurement itself — skin electrical resistance — is real and does vary with things like moisture, pressure, and anxiety. What is not established is that the reading at a specific acupuncture point diagnoses the state of a specific internal organ, or that it can identify which remedy will help a specific patient. In several controlled tests, EAV devices have not been able to distinguish real substances from placebo vials at better than chance, and no version of this technology has approval as a diagnostic device for internal disease. It should not be used in place of standard diagnostic tests such as blood work or imaging.