Attentional Modulation of Event-Related Potentials as a Measure of Voluntary Stream Segregation for Cochlear Implant Listeners

The present study combined a behavioral task with recordings of event-related potentials (ERPs) to determine whether selective attention modulates ERPs in CI listeners and whether this can be used as an objective measure of stream segregation. Eleven CI listeners were instructed to attend to a series of target sounds in the presence of interleaved distractor sounds. The target and the distractor sounds were spatially separated in the electrode array. A deviant was randomly introduced in the target stream and the listeners were asked to detect it. A reference passive condition was recorded with the same stimuli, where the listeners were encouraged to watch a muted movie. The analysis of the ERP waveforms revealed that selective attention modulates the ERP responses in CI listeners. Specifically, the responses to the target stream were, overall, larger in the active relative to the passive listening condition. Selective attention did not affect the ERP responses to the distractor stream. The results suggest that CI listeners can use electrode separation to perceptually group sequential sounds and deploy selective attention on the basis of the resulting auditory objects.