Monita Chatterjee

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Auditory stream segregation was measured in cochlear implant (CI) listeners using a subjective "Yes-No" task in which listeners indicated whether a sequence of stimuli was perceived as two separate streams or not. Stimuli were brief, 50-ms pulse trains A and B, presented in an A_B_A_A_B_A... sequence, with 50 ms in between consecutive stimuli. All stimuli(More)
Fundamental frequency (F0) processing by cochlear implant (CI) listeners was measured using a psychophysical task and a speech intonation recognition task. Listeners' Weber fractions for modulation frequency discrimination were measured using an adaptive, 3-interval, forced-choice paradigm: stimuli were presented through a custom research interface. In the(More)
Speech recognition is robust to background noise. One underlying neural mechanism is that the auditory system segregates speech from the listening background and encodes it reliably. Such robust internal representation has been demonstrated in auditory cortex by neural activity entrained to the temporal envelope of speech. A paradox, however, then arises,(More)
Three experiments were designed to examine temporal envelope processing by cochlear implant (CI) listeners. In experiment 1, the hypothesis that listeners' modulation sensitivity would in part determine their ability to discriminate between temporal modulation rates was examined. Temporal modulation transfer functions (TMTFs) obtained in an amplitude(More)
Although some cochlear implant (CI) listeners can show good word recognition accuracy, it is not clear how they perceive and use the various acoustic cues that contribute to phonetic perceptions. In this study, the use of acoustic cues was assessed for normal-hearing (NH) listeners in optimal and spectrally degraded conditions, and also for CI listeners.(More)
Two experiments investigated the ability of 17 school-aged children to process purely temporal and spectro-temporal cues that signal changes in pitch. Percentage correct was measured for the discrimination of sinusoidal amplitude modulation rate (AMR) of broadband noise in experiment 1 and for the discrimination of fundamental frequency (F0) of broadband(More)
Cochlear implant (CI) and normally hearing (NH) listeners' recognition of periodically interrupted sentences was investigated. CI listeners' scores declined drastically when the sentences were interrupted. The NH listeners showed a significant decline in performance with increasing spectral degradation using CI-simulated, noise-band-vocoded speech. It is(More)
It is hypothesized that channel-interaction in cochlear implant listeners as measured in a modulation-masking experiment would be influenced by both the tonotopic overlap between masker and signal as well as an interaction between their envelopes. Two experiments were conducted to measure the effects of maskers with noisy and steady-state envelopes on(More)
In multi-channel cochlear implants, electrical current is delivered to appropriate electrodes in the cochlea to approximate the spatial representation of speech. Theoretically, electrode configurations that restrict the current spread within the cochlea (e.g., bi- or tri-polar stimulation) may provide better spatial selectivity, and in turn, better speech(More)
Envelope detection and processing are very important for cochlear implant (CI) listeners, who must rely on obtaining significant amounts of acoustic information from the time-varying envelopes of stimuli. In previous work, Chatterjee and Robert [JARO 2(2), 159-171 (2001)] reported on a stochastic-resonance-type effect in modulation detection by CI(More)