Effects of stimulation rate on frequency discrimination in cochlear implants

The stimulation rate may possible improve the frequency discrimination of cochlear implants. The frequency discrimination was measured at stimulation rates of 250, 720, 900, 1200 and 2400 pps/ch (pulses per second per channel) to the four apical and basal electrodes. Eleven post-lingually deafened adults having the Nucleus cochlear implant with the ESPrit 3G speech processor using the ACE (advanced combined encoder) participated in the study. For each stimulation rate, the frequency discrimination below 1 kHz was significantly higher than that above 1 kHz. The stimulation rate had no significant difference on the frequency discrimination. In addition, the high-frequency discrimination with the basal electrodes was lower unlike a normal cochlea response to auditory signals. This further validates the findings of no significant effect of stimulation rate on atonal speech recognition.