In 1790 Alessandro Volta, who developed storage of electricity in what we know as the battery, in his research connected metal rods to a 50-Volts electrical supply and placed the metal ends in his own ears, thereby discovering electrical stimulation to the auditory senses and determined electronic sound "like a thick boiling soup" as what we now know to be electrical static. This lead to hearing mechanisms being devolved in the 20th century.
During the 1950's Andrè Djourno and Charles Eyriès, two French-Algerian surgeons, connected exposed acoustic nerves to electrodes researching direct stimulation and noted sounds experienced by the patient when a current was applied.
Djourno's notes where translated by doctor William House in 1961. He developed devices to stimulate acoustic nerves which he implanted in three patients. Eight years later he, together with Jack Urban, developed a practical single electrode cochlea implant device to help lipreading.
A researcher from Melbourne, Australia, Graeme Clark developed a device with multi-channel stimulace on the cochlea during the 1970's who's device on the 1st of August 1978 was implanted on Rod Saunders, the first recipient in the world with a multi-channel cochlea implantation.
The United States Food and Drug Administration approved the Australian cochlea implants in the United States in December 1984 for use in adults only and then decreased the age for implantation subsequently to 2 years in 1990 and 18 months in 1998 and 12 months in 2002. Special approval from the FDA since have been granted to implantations on baby's as young as 6 months.
New technical and electronically development since the 1990's has decreased the size of the external components to such an extent that one barely can distinguish an implanter in the normal course of action and only younger children wears the bodily strap unit as precaution to damage.
The newest trend is to implement bilateral implants as determining distance and direction as well as sound exclusion in a noisy environment enhances general sound quality hearing ability.