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Clinical assessment and results are described in 66 patients (among them 20 were less than 20 years old). Voice changes may be objectively observed on sonograms. Phonetic discrimination depends on the electrical and nervous status of the implanted deaf cochlea. Discrimination of words and sentences with reference list, but without lipreading, is commonly obtained. Discrimination of unknown words is more difficult and varies from one patient to the other. Discrimination with lipreading progress elicited by the device depends on the pre-operative status and the own possibilities of each patient. Psychoaffective improvement is evident in every case, especially in 3 cases of autistic deaf-mute children. We shall try to summarize the efficacity of the French 12-channel cochlear implant regarding the clinical results we obtained in 66 patients who have been implanted between October 1976 and September 1983. Among them, 39 suffered from pre-lingual deafness and 27 from post-lingual deafness.

In the CHORIMAC-12, the French device, the whole speech information despite its redundancy is transmitted to the few cochlear nerve fibers that are still present. Only loud speech intensities between 40 db and 100 db are introduced in a filter battery which gives out the frequency information in 12 channels including the 100–6000 Hz. This 60 db intensity scale is transmitted in a compression rate of about 6 db. The time sampling is 3 msec. A 12 electrode bearer or 12 separate electrodes (in case of ossified cochlea) transmit the electrical information. The electrical stimulus is a square wave: its frequency is equal or inferior to 300 Hz; its voltage may vary between 2.5 and 6.5 volts; its duration may vary between 0 and 200 μsec. The performances of the system is demonstrated by means of a system of computerized psychophysic tests and speech intelligibility tests.