Discrimination of Rippled-Spectrum Signals by Prelingual and Postlingual Cochlear Implant Users
We analyzed the correlation between ripple spectrum resolution and speech recognition in prelingual and postlingual cochlear implant users. The test signal had a band-limited rippled spectrum with a bandwidth of 2 oct. The central frequency of the spectrum was 1, 2 or 4 kHz. The phase reversion test of ripple spectrum was used for estimation of ripple spectrum discrimination. A balanced test set of Russian worlds by Greenberg-Zinder was used for estimating speech recognition. The average ripple discrimination thresholds were approximately 2 ripples/octave in both pre- and postlingual patients. The thresholds did not depend on central frequency. The best correlation between speech recognition and rippled spectrum resolution was found in prelingual patients with perimodiolar electrode array (r = 0.85).