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The evidence that cochlear implant listeners routinely experience stream segregation is limited and equivocal. Streaming in these listeners was explored using tone sequences matched to the center frequencies of the implant’s 22 electrodes. Experiment 1 measured temporal discrimination for short (ABA triplet) and longer (12 AB cycles) sequences (tone/silence durations = 60/40 ms). Tone A stimulated electrode 11; tone B stimulated one of 14 electrodes. On each trial, one sequence remained isochronous, and tone B was delayed in the other; listeners had to identify the anisochronous interval. The delay was introduced in the second half of the longer sequences. Prior build-up of streaming should cause thresholds to rise more steeply with increasing electrode separation, but no interaction with sequence length was found. Experiment 2 required listeners to identify which of two target sequences was present when interleaved with distractors (tone/silence durations = 120/80 ms). Accuracy was high for isolated targets, but most listeners performed near chance when loudness-matched distractors were added, even when remote from the target. Only a substantial reduction in distractor level improved performance, and this effect did not interact with target-distractor separation. These results indicate that implantees often do not achieve stream segregation, even in relatively unchallenging tasks. [ABSTRACT FROM AUTHOR]

This work assessed relationships among intraoral pressure (IOP), electropalatographic (EPG) measures, and consonant sequence duration, in the following obstruents, clusters, and affricates of German: /t/, /[sh]/, /[sh]t/, and /&teshlig;&ligtieb;/. The data showed significant correlations between IOP and percentage of articulatory contact (PC) for all speakers, whereas duration and place of articulation (measured by the EPG center of gravity) contributed less to IOP changes. Speakers differed in the strength of this relationship, possibly reflecting differences in vocal tract morphology or degree of laryngeal abduction. Single-point EPG and IOP measures in fricatives showed consistent correspondences across consonantal contexts, but the relationships for the stops were more complex and reflected positional effects. Temporal compression was observed for both members of the cluster, but only the fricative portion of the affricate. Conversely, coarticulation was observed for both the stop and fricative portion of the affricate, but only for the stop portion of the cluster, possibly reflecting biomechanical constraints. No clear differences were observed in coarticulatory resistance for stops and fricatives. These data contribute to a limited literature on articulatory-aerodynamic relationships in voiceless consonants and consonant sequences, and will provide a baseline for considering longer combinations of obstruents. [ABSTRACT FROM AUTHOR]