UCSF offers three cochlear implant systems: The HiResolution Bionic Ear manufactured by Advanced Bionics, Corp., the Nucleus Freedom device manufactured by Cochlear Corp. and the Pulsar manufactured by the Med-El Corporation.

The Implant System has three parts:

1. Implantable stimulator.
The implantable stimulator consists of an electrode array and other electronic components. The electrode array is inserted into the cochlea to provide direct electrical stimulation to the auditory nerve. The electronic components are housed in a bio-compatible case which is surgically implanted under the skin and behind the ear selected for implantation. A magnet inside the case couples to the magnet in the headpiece.

2. Headpiece & Transmitter.
The headpiece and transmitter are worn externally on the head, and sit over the internal portion. The transmitter magnetically couples to the implanted stimulator. The microphone picks up sound in the environment and the transmission system sends the custom-coded signal across the skin to the implantable stimulator and electrode array. Electrical current is then sent to the auditory nerve which in turn sends signals to the brain where they are interpreted as sound.

3. Speech processor.
The speech processor is worn externally on the body. One model is similar in size to a pager or cell phone. Another model is similar in size to a behind-the-ear hearing aid. The speech processor converts sound into a distinctive code. It is this code which is transmitted across the skin via radio waves to the implantable stimulator. The signal is carried from the speech processor to the transmitter by a special cable worn underneath the clothing.