Electrical Excitation of Nerves in the Skin at Audiofrequencies

This is a report of results obtained in preliminary tests of perception of signals applied directly to the skin in the form of electrical potentials. The lowest signal level that could be felt and the highest level that could be applied without extreme discomfort to the observers were determined for sine wave potentials ranging from 100 to 10,000 cps. The difference between the lowest and highest levels was about 25 db over this frequency range. Difference limen measurements for intensity and frequency showed that intensity discrimination is not greatly different from what it is for hearing, but the ear is vastly superior in the matter of frequency discrimination.