Abstract
We implanted single channel cochlear electrodes to the round-window niche of guinea pigs to examine whether or not the second formant (F2) information could be transmitted to the auditory system. The response of the auditory nerve was examined by recording the compound action potentials (CAP) which were evoked by electrical pulses applied to the cochlea through the round-window membrane.
The results showed that it is difficult to transmit F2 information by using the dif-ference of stimulus intensity because the dynamic range of CAP induced by stimulus current is too small. On the transmission of the second formant information for single channel cochlear implants, we proposed that the second pulse corresponding to the F2 was inserted between pitch pulses with the time difference which was inversely proportional to the F2 frequencies.
It seems that further investigations must be carried out of the ability to discriminate speech sound.
