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.