Abstract: Methods for non-invasive, in vivo determination of the conductivity of nerves in a region of skin and apparatus for carrying out such methods are described, wherein the methods comprise: (a) providing a skin substrate to be analyzed; (b) applying a first non-invasive electrode to a measuring point of the skin substrate; (c) applying a second non-invasive electrode to a second point of the skin substrate; (d) subjecting the skin substrate to stimulation; and (e) analyzing a change in an electrical signal detected by the first and second non-invasive electrodes; wherein the first and second non-invasive electrodes are associated with an evaluation circuit for analyzing the electrical signal detected by the first and second non-invasive electrodes, the evaluation circuit comprising at least one amplifying element, at least one processing element, at least one recording element, and at least one microprocessor.