Formant frequency discrimination in a subject implanted with an intracochlear stimulating electrode

Abstract

In a four‐choice, vowel identification test, the implanted subject identified the spoken word in 50 to 60 percent of the trials. Experiments were conducted to determine which acoustic features were being utilized by the implanted subject. Pairs of steady‐state synthesized vowels were presented to the subject. Both a discrimination test and a difference scaling procedure indicated that the subject could easily discriminate between synthetic vowels with different first formant frequencies. However, the subject had great difficulty in discriminating between synthetic vowels with different second formant frequencies when the first formant frequencies were identical. This result was found to be consistent with an identification task using natural vowels in a single word context. The errors made by the subject in a four‐choice vowel identification task were analysed (error rate = 45%). When the subject made an error, he generally chose the word containing the vowel with a first formant frequency closest to the ...