Fitting the Nucleus-22 cochlear implant for Spanish speakers.
This work aimed to study the speech comprehension of 13 native Spanish-speaking patients implanted with the Nucleus-22 system. Experiments were performed under two conditions. First, tests of isolated vowel discrimination, bisyllable word recognition in a consonant-vowel-consonant context, and fluency speech comprehension were conducted with the speech processors (SPs) fitted with the frequency boundary distribution as specified by the diagnostic and programming system. This distribution was called default frequency boundary. For the second condition, the SP of each patient was refitted using a procedure based on changes in the frequency-to-electrode mapping, called modified frequency boundaries (MFB), taking into account the formant pattern of the Spanish Rioplatense vowel system. These changes intended to improve the vowel perception and therefore the fluency of speech, as the result of a more adequate placeformant distribution. Patients were retested, and as a consequence of the MFB, improvements in the results of the tests were observed for most of the patients. Counterbalance mode tests were conducted to avoid the influence of training effects in the results. This study suggested that speech comprehension could be improved by adjusting this SP according to the patients' specific language.