Broadband auditory stream segregation by hearing-impaired and normal-hearing listeners.

PURPOSE To investigate the effects of hearing loss on auditory stream segregation of broadband inharmonic sounds. METHOD Auditory stream segregation by listeners with normal and impaired hearing was measured for 6-component inharmonic sounds ("A" and "B") using objective and subjective methods. Components in the A stimuli ranged between 1000 and 4000 Hz, whereas B stimuli were generated at the same frequency ratio but scaled upward in frequency relative to the A stimuli. In Experiment 1, streaming was measured by having listeners detect a delay inserted into a sequence of A and B stimuli (A_B_A_B_...) for B stimuli with different frequencies. In Experiment 2, streaming was measured using an ABA_ABA_... sequence, and the frequency of the B stimulus decreased until listeners reported that they could "no longer hear two separate streams." RESULTS Experiment 1 indicated no significant differences between groups in the size of the just detectable delay and no significant interactions between group and the scaling factor between the B and A stimuli. Experiment 2 revealed no significant differences in streaming abilities between normal-hearing and hearing-impaired groups. CONCLUSIONS Overall, results indicate that listeners with normal and impaired hearing have similar auditory streaming abilities for broadband inharmonic complex stimuli.