1988 Volume 91 Issue 2 Pages 177-184,317
The 22 multi-channel cochlear implant has been implanted in a 40-year-old female patient of complete deaf due to meningitis and in a 45-year-old totally deaf female patient due to sudden deafness. The different speach processing strategies were used; F0, F2 coding with pulse width limiting was administered to the former, whereas F0, F1, F2 coding with current controls was applied to the latter.
The patients were tested with speech tracking, vowel recognition and consonant recognition. The former could recognize 24 “bunsetsu” es per minute for the cochlear implant plus lipreading after 3 months of training, and scores of vowel and consonant tests reached 70% and 54% respectively for the cochlear implant alone, and 100% and 73% for the cochlear implant plus lipreading. The latter could identify 28 “bunsetsu” es per minute and scores of recognition of vowel and consonant were 60% and 54% for the cochlear implant alone, and 100% and 89% for the cochlear implant plus lipreading after 3 months of training.
The strategy for the latter seems to be more effective in understanding speech as that the latter showed more rapid improvement in speech perception than the former, although there were no differences in tests of vowel and consonant recognition.
Modality of the cochlear implant was discussed from the viewpoints of cochlear physiology and psychoacoustics by electrical stimulation.
