Changes in vowel quality after cochlear implantation

Since auditory feedback is partially restored after cochlear implantation, the aim of the present study was to investigate features of vowels, which reflect improvements in speech production. Ten postlingually deafened subjects (5 male/5 female) were recorded reading a German text before and 3 and 12 months after implantation, respectively. Selected vowels were analysed regarding the fundamental frequency (F(0)), the formant frequencies (F(1), F(2), F(3)) and the vowel space (difference between F(1) and F(2) in hertz). The F(0) decreased only descriptively after 3 and 12 months, respectively. F(1) of the vowel /e/ was significantly lower after 12 months (411 +/- 20 compared to 349 +/- 25 Hz, p < or = 0.05) and for /o/ after 3 months (446 +/- 29 compared to 408 +/- 31 Hz, p < or = 0.05) for the male patients: their vowel space also expanded significantly for the vowel /o/ (372 +/- 37 compared to 467 +/- 32 Hz, p < or = 0.05) after 12 months. Regained auditory feedback after cochlear implantation had an effect on the improvement of the production of vowels.