Optimization of channel number and stimulation rate for the fast continuous interleaved sampling strategy in the COMBI 40+.

Objective: To investigate the interrelation between number of channels and stimulation rate in the continuous interleaved sampling strategy (CIS). Subjects and Methods: Three of the first recipients of the new COMBI 40+ cochlear implant participated in consonant, vowel, number, and sentence tests. Speech understanding was evaluated for different combinations of number of active channels from two to twelve and stimulation rate per channel between 1,515 and 9,090 pulses per second. Results: The results indicate that the optimum number of active channels is not necessarily the maximum number of usable channels.