Spectro-temporal discrimination in cochlear implant users

A novel test method was designed to measure the spectro-temporal discrimination ability of cochlear implant (CI) users. The test signals are bandpass filtered, speech weighted noise, with the long term spectrum of speech. The goal of the test is to measure the amplitude difference between spectral bands in two presented signals which is required for the listener just to discriminate between the two sounds. Twenty CI users were tested with the spectro-temporal discrimination test and a conventional speech recognition test. For test stimuli differing in only two spectral bands, CI and normal hearing users show nearly equally good results on the spectro-temporal test. For spectra with four and more bands, the spread in the CI users´ results is great.