Effect of stimulation rate on speech perception in adult users of the Med-El CIS speech processing strategy.

The primary aim of the study was to determine the effect of altering channel stimulation rate on the performance of adult cochlear implant users. Six adult users of the Med-El CIS processing strategy underwent tests of categorical identification of synthetic speech, tests of sentence recognition and tests of consonant recognition in three listening conditions: high channel stimulation rate (ranging from 1500 to 2020 pps/ch), a medium rate (800 pps/ch) and a low rate (400 pps/ch). Number of channels was held constant across rate conditions. With the categorical identification task, performance varied by acoustic cue type but did not vary with rate. With the consonant recognition task performance varied by phonological feature, but there was also no significant effect of rate. However, two subjects showed markedly reduced sentence scores at lower rates. Results suggests that higher stimulation rates with the CIS strategy may be beneficial to speech perception in some cases.