There are about 188,000 people around the world who have received cochlear implants. In the United States alone, there are about 30,000 adults and over 30,000 children who are recipients of cochlear implants. This number continues to grow as cochlear implantation is becoming more and more accepted. In 1961, Dr. William House began work on the predecessor for today's cochlear implant. William House is an Otologist and is the founder of House ear institute in Los Angeles, California. This groundbreaking device, which was manufactured by 3M company was approved by the FDA in 1984. Although this was a single channel device, it paved the way for future multi channel cochlear implants. Currently, as of 2007, the three cochlear implant devices approved for use in the U.S. are manufactured by Cochlear, Med El, and Advanced Bionics. The way a cochlear implant works is sound is received by the cochlear implant's microphone, which picks up input that needs to be processed to determine how the electrodes will receive the signal. This is done on the external component of the cochlear implant called the sound processor. The transmitting coil, also an external component transmits the information from the speech processor through the skin using frequency modulated radio waves. The signal is never turned back into an acoustic stimulus, unlike a hearing aid. This information is then received by the cochlear implant's internal components. The receiver stimulator delivers the correct amount of electrical stimulation to the appropriate electrodes on the array to represent the sound signal that was detected. The electrode array stimulates the remaining auditory nerve fibers in the cochlea, which carry the signal on to the brain, where it is processed.