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In this study, the Cochlear Implant Programme of the ENT Department of Ospedale Civile di Venezia, is presented. Between 1989 and 1994, after a rigorous selection process, 36 patients were selected to be implanted with a cochlear prostheses: 28 with the multichannel Nucleus 22 device, 5 with the Clarion implant and 3 with the single channel Med-E1 BTE device. The distribution of the patients according to age, etiology, duration of auditory deprivation, age at onset of deafness, is presented. The different speech-coding strategies of the Nucleus system (Wearable Speech Processing, Multipeak speech processing and Spectral Maximum Sound processor) and the stimulation mode (common ground, bipolar, bipolar + 1) as well as the Clarion speech coding strategy (Continuous Interleaved Samples and Compressed Analog) are briefly discussed. The rehabilitation programme, the specific speech recognition assessment test batteries-Consonant Confusion Test, Vocal Confusion Test, Speech Tracking, MAC battery-as they are employed in our department, are presented. As we have analyzed our results, certain factors appear as predicting a favourable outcome: - age of onset of deafness; postlingual patients, who have developed communication skills compare favourably to the perilingual group. - durations of auditory deprivation, as it is related to surviving cells in the cochlea: the shorter the period of deafness, the better the results. - length of electrode insertion, as it is determined by ossification of the cochlea. - high dynamic range of the MAP. - percent of activated electrodes: a number of 10 active electrodes or less predicts a poor outcome. - for simplification reasons, a new variable is introduced-Auditory Deprivation Index- and its positive correlation to the performance presented. - the time period of experience with the device, length and quality of rehabilitation and family support have to be mentioned.

Cochlear Implantation is a recognized procedure for acoustical rehabilitation of the profoundly or totally deaf unable to effectively use a traditional hearing aid. Since 1989, 30 patients (27 postlingual and 3 perilingual) have been operated on by the senior Author with the implantation of a multichannel device: Med-El (3 cases), Clarion (3 case) and Nucleus Mini-22 (24 cases). The first 24 Nucleus cases, with a multipeak speechcoding strategy, are the object of this retrospective report. Selection of patients was performed according to an international protocol which includes PTA and Speech Audiometry, CT and/or MRI imaging of the ear, the Promontorial Test, an evaluation of lip reading ability, a psychological evaluation, a trial with two recent and currently available aids. The operation was carried out under general anesthesia. An extended endaural approach was adopted. The internal package of the device was firmly seated onto the temporalis squama and the electrode array was introduced into the tympanic cleft via a posterior tympanotomy. The electrode system was inserted into the scala tympani through a cochleotomy drilled out at the anteroinferior border of the round window. The whole system was fixed to the bony walls of the mastoid and squama using an ionomeric bone bonding agent. Starting at the second postoperative month and up to the 24th month of utilization of the device, each patient was evaluated with regard to his or her ability to recognize environmental sounds, to detect prosody transitions and to understand speech with and without visual cues. Selected tests, either close or open set, were used from the MAC and the Iowa Cochlear Implant Battery, as well as the Helen test. Telephone conversation was also evaluated. Results were very encouraging in all cases, showing that the multichannel cochlear device provides the properly selected patient a substantial auditory rehabilitation allowing him or her to understand speech in most instances without any visual cue.