Tone perception of Mandarin-speaking postlingually deaf implantees using the nucleus 22-channel cochlear mini system

Because Mandarin Chinese is a tonal language, testing the patient's ability to distinguish among four lines is of paramount importance. This paper evaluates the efficacy of the Nucleus 22-Channel Mini System for Mandarin Chinese by comparing the postoperative tone perception test results with the results of the closed-set monosyllable, trochee, and spondee (MTS) test, and the open-set phonetically balanced (PB) word and sentence comprehension tests, which also incorporate tonal features, for eight Mandarin-speaking postlingually deaf patients implanted with this device. Except for one patient, the data clearly indicate that patients who had increased scores on tone perception after implantation also had improvements on other test batteries. Results also substantiate our previous observation that the Nucleus 22-channel cochlear implant enables profoundly and totally deaf patients to distinguish four separate lines in Mandarin Chinese. This would seem to support our earlier speculation that the acoustic cues of fundamental frequency of the four Mandarin tones are extracted by the Multipeak coding strategy of the 22-channel device and transferred to the cochlea, where they are perceived as rate pitch.