European Counterpoint to Chapter 16

Abstract

Stimulation of tissues with electricity for medical purposes is not a new idea. Two thousand years ago, Roman physicians recommended the electrical discharge of the torpedo fish for the treatment of headache and gout. Interest in electrical methods of stimulating hearing began when Volta discovered the electrolytic cell in 1790. He inserted metal rods into his own ears and connected them to a circuit that produced approximately 50 volts. When the circuit was completed, he experienced a sensation which he described as a blow to the head; it was followed a few moments later by a noise that sounded like the boiling of a viscous liquid. Volta’s unpleasant experience probably discouraged others. Few attempts to investigate the phenomenon were carried out over the next 50 years, but the sensation was always momentary and lacked tonal quality. Nevertheless, it was apparent that a sense of hearing occurred with an electrical stimulation of the inner ear. A great deal of experimentation was needed to determine how this could be used to restore hearing. Many questions are still unanswered. What is the best way to “code” the complexities of sound into electrical pulse? Does it matter where the electrodes are placed inside the inner ear? What are the effects of long-term electrical inner ear stimulation on the hearing nerves and brain?