Description of the French 12 channel cochlear implant

The sound information is sequentially transmitted to 12 electrodes implanted in the cochlea. An electrode bearer introduced through the round window is now commonly used. Frequencies between 100-4 000 Hz and intensities between 40-100 db are only transmitted in a 3 msec time sampling. The output signal is a positive square wave followed by an equal negative wave. Its voltage varies from 2.5 to 6.5 volts. Its duration varies from 0 to 200 microsec. Its frequency is equal or inferior to 300 Hz. The outside emitter weighs 600 g. This system has been implanted in 58 patients and allows partial speech discrimination without lipreading for more than 6 years.