Sensitivity to interaural level and envelope time differences of two bilateral cochlear implant listeners using clinical sound processors.

Objectives: To assess the sensitivity of two bilateral cochlear implant users to interaural level and time differences (ILDs and ITDs) for various signals presented through the auxiliary inputs of clinical sound processors that discard fine timing information and only preserve envelope cues.

Design: In a lateralization discrimination experiment, the just noticeable difference (JND) for ILDs and envelope ITDs was measured by means of an adaptive 2-AFC method. Different stimuli were used, including click trains at varying repetition rates, a speech fragment, and noise bursts.

Coding of vowellike signals in cochlear implant listeners.

Neural-population interactions resulting from excitation overlap in multi-channel cochlear implants (CI) may cause blurring of the "internal" auditory representation of complex sounds such as vowels. In experiment I, confusion matrices for eight German steady-state vowellike signals were obtained from seven CI listeners. Identification performance ranged between 42% and 74% correct.

Characteristics of fricatives and sentence duration after cochlear implantation.

Ten postlingually deafened patients (5 male, 5 female) were examined after cochlear implantation to measure improvements in their quality of speech. Parameters such as the spectral maximum of fricatives and the duration of utterances were analysed in speech recordings taken at regular intervals after implantation. The speech samples were recorded in an audiological chamber.