How Well Do Hearing Aids Amplify “speech Glimpses” in Multitalker Mixtures?

Reductions in speech audibility are more detrimental in the presence of competing sounds, where there is little redundant speech information, than in quiet. Indeed, our previous work suggests that insufficient audibility of “speech glimpses” may partly explain the poor performance of listeners with hearing loss in multitalker mixtures. An implication of those results is that restoring audibility across the spectrum may be especially critical in such situations. Here we asked whether current hearing-aid amplification strategies adequately restore the audibility of speech glimpses. We used ideal time-frequency separation to isolate target speech glimpses from unaided and aided speech mixtures. We then measured intelligibility for the isolated glimpses and for the original mixtures. Participants were young adults with bilateral sensorineural hearing loss, and individualized non-linear amplification (NAL-NL2) was provided using the Oldenburg open Master Hearing Aid. Results show that amplification generally improved the audibility and intelligibility of the target speech glimpses. For some participants, the intelligibility improvements carried over to the mixtures. For others, the improvements were diminished in the mixtures, suggesting that there were counteracting effects. This approach may provide a useful way to unpack positive and negative effects of hearing-aid processing in multitalker mixtures.